Li-Ion battery life can be extended significantly by not charging the batteries to their full capacity. For example, charging the battery to 100% capacity, one can expect 300-500 discharge cycles. Charging to 80-85% capacity , one can expect 850-1500 discharge cycles. (Source: batteryuniveristy.com.)
If you are not using the full capacity of your Rad battery when riding, you can take advantage of this characteristic and extend the life of your Rad battery. I typically ride 10-12 miles per day, with minimum level (1-2) assist, and my battery capacity drops only about 20% on the battery meter. On trips into town, I ride about 15 miles at higher assist (3-4), and then use about 40% capacity. Clearly, I could charge to only 80% capacity and have ample reserve capacity at the end of my rides.
The Rad battery charger will on its own charge to 100% capacity. You can charge to a lesser capacity with it by simply disconnecting the charger before it has completed a normal charge cycle - that is, before the CHARGE LED turns from red to green. But how do you know when to do this to achieve an 80% charge?
I have developed a simple smart switch to do this. It plugs in between the Rad charger and Rad battery, and monitors the charge. When the battery has been charged to 80%, the smart switch disconnects the charger from the battery. (The CHARGE LED will turn green, just as it does if you unplugged the charger from the battery.)
I have been testing my smart switch for several days now, and so far it is working as expected. I will continue testing to fully validate the design.
I would like to emphasize that this smart switch does not alter the Rad charger or charge characteristics at all. It simply disconnects the charger as if you had unplugged it. Rad even recommends charging to only 75% when storing the battery for more that two weeks (although they offer no way to determine when this level of charge has been achieved!), so it is a perfectly legitimate thing to do.
I am an electrical engineer. I have developed and marketed several add-on electronic devices for automotive and other uses. I use a professional circuit board fabrication company and quality components from a major electronics distributor. If there is interest, I will market my smart switch for Rad users. The cost of the smart switch will be about $50. Considering the cost of a replacement Rad battery, I think it is a wise investment.
I would appreciate any feedback on interest in such a smart switch. I welcome questions.
Quote from: DickB on May 12, 2021, 04:40:55 PM
I would appreciate any feedback on interest in such a smart switch. I welcome questions.
Not questioning the value of your switch, but rather the pricing. For $95-$100, one could get a brand new charger (of higher quality than the stock RAD charger) that does what your smart switch can do, plus:
1) Allow the user to choose the charge rate to a perfectly safe, but still faster, 3 amps (stock charger is 2 amps) if they need the battery charged faster or an even slower 1 amp rate for even longer battery longevity, and
2) Allow the user to have 2 chargers, using one as a backup.
https://lunacycle.com/luna-charger-48v-advanced-300w-ebike-charger/ (https://lunacycle.com/luna-charger-48v-advanced-300w-ebike-charger/)
https://www.bafangusadirect.com/Standard-48V-Bottle-Shark-Battery-Charger-p/42.htm?gclid=EAIaIQobChMIzNGnrpHG8AIVB__jBx18DAPMEAQYByABEgKI__D_BwE (https://www.bafangusadirect.com/Standard-48V-Bottle-Shark-Battery-Charger-p/42.htm?gclid=EAIaIQobChMIzNGnrpHG8AIVB__jBx18DAPMEAQYByABEgKI__D_BwE)
As a side note, I've only seen my battery charge to 53.8V when the light turns green on the RAD stock charger, thus suggesting it only charges to 95%. Has that been your experience?
I'd buy your SmartSwitch2 just so I could use my Rad charger efficiently. I have the Luna charger, so I would use your switch + Rad charger at a remote location.
Thanks for your comments.
I'm working on an alternate design that would be about half the cost.
Yes, Rad is using a float voltage of about 54 volts. It suggests that Rad has made a trade-off between longevity and duration by intentionally not charging to maximum cell capacity. Even so, there is still significant battery life extension by charging to only 80% of what Rad charges. (Setting the Luna charger to 80% is actually going to charge to about 90% of what Rad does.) BTW charging to less than maximum cell capacity as a battery life tradeoff is not an uncommon practice by manufacturers.
There are several reasons why a Rad owner might not want to use an aftermarket charger. For one, Rad recommends against it. Many owners will take that to heart. Why would Rad make this recommendation, beyond wanting you to buy only their charger? A non-knowledgeable user might use an aftermarket charger in ways that are detrimental to the Rad battery, such as charging at a 5 amp rate (which is likely higher than the cell manufacturer's recommendation). If you use an aftermarket charger to charge to 100% of cell capacity, you will be reducing battery life versus using the Rad charger. Some users might not know this. And while a small thing for many, others may be unable to change connectors on an aftermarket charger. Many users prefer plug and play.
Although my smart switch works, I have a much simpler solution to partial charging with the Rad charger.
Standard silicone diodes have a forward voltage drop of about 0.8 – 1.0 volts at 1-5 amps. Simply placing two diodes in series in the circuit between the Rad charger and the Rad battery will drop the float voltage to provide less than a full charge. I've tested one cycle with two diodes and achieved an 80% charge level. Other than the reduced float voltage, the charger behaves just like before, charging at a constant 2.03 amps, then tapering off. The Charge Indicator starts red and then turns green at charge completion as usual.
I've verified the charge level both by measuring rest voltage of the battery after charging and using the Rad Battery Charge Indicator.
The float voltage after the diodes was 52.7 volts, and the rest voltage after my dual diode charge was 52.0 volts. This correlates to the following table from Benzo Energy, a Li-Ion battery manufacturer (I added the Rad battery column):
Voltage
Rad Cell Charge
54.6 4.20 100.00%
52.8 4.06 90.00%
51.7 3.98 80.00%
51.0 3.92 70.00%
50.3 3.87 60.00%
49.7 3.82 50.00%
49.3 3.79 40.00%
49.0 3.77 30.00%
48.6 3.74 20.00%
47.8 3.68 10.00%
44.9 3.45 5.00%
39.0 3.00 0.00%
On the bike and using the Rad Battery Charge Indicator, when first turned on the battery at rest indicated 100% charge. However, after a minute or two of use, the Charge Indicator dropped to 80%, indicating true capacity. This is typical operation of the Rad Battery Charge Indicator, as Rad users have probably noticed.
I've been using bare parts and clip leads for this test, but I'm waiting on parts to build a simple cable with male and female barrel power connectors and two diodes to plug in between battery and charger to charge to 80%. Since I'm a geek, I'll add a volt-amp meter, because I like to monitor what's going on.
If you go this route, pick standard (not Shottky) diodes of sufficient current and voltage rating. I'm using 1N5402 diodes rated at 3 amps and 200 V (available of course at Amazon). You can use a 2.1mm x 5.5mm DC Plug Power Adapter Extension Cable of sufficient current rating (18 or 20 gauge) to build. Just cut the cable in half (shortening it is OK), solder the two diodes into the positive lead with the diode bands facing the battery, and insulate with shrink wrap. Less than $15 in parts.
That sounds like a good plug and play solution. Maybe use higher amp diodes in case someone chooses a faster 3-amp charger (but can still use the plug-and-play device assuming barrel connectors). I haven't tried yet, but I'm thinking of opening up the charger and seeing if there's a potentiometer to reduce the float voltage. Of course, this would eliminate the possibility of charging the battery to "full" (95% in RAD's case).
If you find a potentiometer inside and replace it with one mounted on the case, you could still dial up full charge.
BTW this morning I measured a float voltage of 54.3 V on a full charge (no diodes), so that's darn close to 100%.
Interesting. My charger floats at 54.0V.
Probably just meter accuracy. My meter is specified as +_1.2% accuracy, so that's +- 0.5V. Probably just a variation in meters. I have two DVMs that do read within 0.1V on the Rad battery, but I have one that I got for free at Harbor Freight and it's different by almost 1 V.
Next time I order parts I'm going to get a Maxxim MAX6350 voltage reference IC and check it out against my DVMs.
I finished my geek version. The charger has just come off constant current and entering constant voltage mode, with the current just dropping.
The lower jack on the meter box has the two diodes in series. The upper jack is a direct connection for 100% charge.
I've also attached a paper showing how to build a simple adapter and more detail on the theory behind it.
Great write up showing the step by step. The one you made with the voltmeter/ammeter is especially pretty.
The literature that I had studied described a delta between float charge and charged battery voltage, but I'm not seeing that much. I just completed a charge with 4 diodes and ended up with a open-circuit voltage (OCV) of 51.7 V. That's exactly 80% per my recent test:
https://www.radowners.com/index.php?topic=1016.msg5122#msg5122
I made this box and it works as expected. I will add a port to measure the voltage so I can properly label the switch positions based on the voltage.
I found that 4 diodes gets closer to 80%. Also, the diodes got hotter than expected, so I upgraded to 6A diodes with heatsinks.
NTE5852 and NTE5253.
Quote from: DickB on July 19, 2021, 02:37:34 PM
I found that 4 diodes gets closer to 80%. Also, the diodes got hotter than expected, so I upgraded to 6A diodes with heatsinks.
NTE5852 and NTE5253.
Any chance you have an updated parts list? I recently bought a Radwagon 4 and extending the battery life sounds ideal considering the cost of these batteries. I wouldn't mind putting together a unit with the display and I probably have a good portion of the parts already.
TIA!
Depending on your mark-up, I would definitely be interested in this. I just got a RR1 a few weeks ago. I bought an extra battery when I ordered the bike after reading about the life of the battery. Something like this would be great. Especially since it would stop charging itself and not have to be monitored.
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This is my latest version. The box has two power connectors for the charger; one for full and one for partial charge. The project box that I used is a but small and required modifying the meter case a bit to fit. The meter measures power in, so you can estimate how much power was consumed by the battery.
Quote from: MurderNote on July 20, 2021, 11:45:55 AM
Depending on your mark-up, I would definitely be interested in this. I just got a RR1 a few weeks ago. I bought an extra battery when I ordered the bike after reading about the life of the battery. Something like this would be great. Especially since it would stop charging itself and not have to be monitored.
Sent from my iPhone using Tapatalk
The Rad charger doesn't need to be monitored. There is no harm in leaving it plugged in indefinitely. Rad recommends disconnecting after 12 hours to avoid wear in the charger. As there are no moving parts in the charger, this advice is unnecessary in my view. You have lots of electronics, like your television and appliances with touch buttons, that are powered all the time.
Quote from: DickB on July 20, 2021, 02:23:03 PM
This is my latest version. The box has two power connectors for the charger; one for full and one for partial charge. The project box that I used is a but small and required modifying the meter case a bit to fit. The meter measures power in, so you can estimate how much power was consumed by the battery.
Thanks so much! I really appreciate you sharing your project. Adding those Digi-Key p/n's was great! I will design a 3d printable enclosure for my unit and share the deign here when completed.
Stay RAD!
Oh, yeah. I understand that. I mean if there was a charger that said what % the charge is on the battery if I only wanted to go to 80%. That your design automatically turns off at 80% full, I could just plug it in and go about my business rather than hanging around until it hit 80 so I could unplug it and extend my battery life.
Sent from my iPhone using Tapatalk
Quote from: DickB on July 20, 2021, 02:23:03 PM
This is my latest version. The box has two power connectors for the charger; one for full and one for partial charge. The project box that I used is a but small and required modifying the meter case a bit to fit. The meter measures power in, so you can estimate how much power was consumed by the battery.
So I was thinking that a switch could be added to the schematic in place of the 2nd female jack...that way you would use the switch to change it from 80% charge to 100% charge thus saving on hardware and the need to swap the cable.
I modified your schematic to what I think it would look like with the switch added..I am no electrical engineer but I think I got it right. Lemme know what you think..
As long as you operate the switch with power off, and the switch is rated for 2A or more, fine. If not, you would need a switch rated at 2A AND 60V DC - not common.
Quote from: DickB on July 30, 2021, 06:22:00 AM
As long as you operate the switch with power off, and the switch is rated for 2A or more, fine. If not, you would need a switch rated at 2A AND 60V DC - not common.
Gotcha! Lemme see what I can figure out. Thanks for that info, learning stuff every day! ;)
Actually, you can use a single-throw switch to just short the diodes for 100% charge.
Quote from: DickB on July 31, 2021, 10:00:13 PM
Actually, you can use a single-throw switch to just short the diodes for 100% charge.
That switch would still need to meet the proper spec though as you mentioned prior?
I have not been able to find any affordable 60VDC 2A switches but I had another idea I just need to research that a bit more
Quote from: peanutbutterpope on August 03, 2021, 10:01:26 AM
I have not been able to find any affordable 60VDC 2A switches but I had another idea I just need to research that a bit more
Right, which is why I used a second jack instead of a switch.
If you don't throw the switch with power applied, a 2A or greater switch of lesser DC voltage rating will work.
Quote from: DickB on August 03, 2021, 11:41:58 AM
If you don't throw the switch with power applied, a 2A or greater switch of lesser DC voltage rating will work.
Gotcha! Thanks for taking the time to school me here. I should be able to figure this out...I was looking at some other possible alternative to accomplish my single jack charger goal. I will post back in another day or so, just need to catch up on some other projects
How would one know when a battery charge is about 80% by watching the charging current?
I charge my rad city battery through a WATTs up meter. I notice towards the end of a charge the current drops. Can you suggest a current value that might indicate an 80% charge? Thanks
Quote from: ipsailor on August 09, 2021, 08:22:05 AM
How would one know when a battery charge is about 80% by watching the charging current?
I charge my rad city battery through a WATTs up meter. I notice towards the end of a charge the current drops. Can you suggest a current value that might indicate an 80% charge? Thanks
You can't by monitoring charge current, but you can by monitoring charge voltage.
The Rad charger operates in Constant Current mode when charging starts. It will maintain 2A charge rate until the battery is nearly fully charged. Then it will enter Constant Voltage mode, but by then the battery is more than 80% charged. If you monitor voltage, the battery will be about 80% charged when it reaches 52V.
Can you monitor voltage if all you've got is a multimeter? If yes, how would I do that?
Take the battery off the bike, turn it on, probe the terminals while it is charging.
Thank you, DickB! I will try this on my next charge. I always remove the battery and charge it on my workbench in my basement.
If you knew your battery's starting voltage, could you calculate how long it would take to reach 80%? You could set a timer on your phone to go test it then.
I would be interested in buying your smart switch if you start selling them.
While the smart switch works, I am using my much simpler diode device. It lowers the float voltage to the 80% charge level and requires no monitoring - you just use the charger as usual, and the charger can be left on indefinitely. You could estimate charge time to 80% knowing the starting voltage, but why bother?
Quote from: DickB on August 11, 2021, 04:29:15 AM
You could estimate charge time to 80% knowing the starting voltage, but why bother?
Anyone with electronics fabrication tech skills care to sell me a diode device?
The parts are relatively inexpensive, but I got parts from multiple sources, so shipping costs can add up. I'd consider making a small batch if there is sufficient interest.
DickB, in a prior post you mentioned having to upgrade the diodes due to heat issues. Was that for your smart switch or diode device, or both? Are you recommending 4 diodes instead of 2 in the diode device for closer to 80% charge?
Diode device. 4 diodes. I posted parts list.
Quote from: DickB on August 11, 2021, 04:50:06 AM
The parts are relatively inexpensive, but I got parts from multiple sources, so shipping costs can add up. I'd consider making a small batch if there is sufficient interest.
I can solder, but it ain't pretty. If you're keeping a tally, I'd buy two (one for both myself and my wife).
Mike
Don't you have to be mindful of how the battery BMS balances the cells in the pack? From what I've seen, different BMS's will start their balancing stage after different charge voltage thresholds. This is one of the reasons why Rad Power recommends leaving the battery charging for up to 12 hours on the first initial few cycles. If you consistently charge up to a specific lower voltage and that voltage isn't high enough to trip the balancing mode of the BMS in the pack, you run the risk of throwing the cells out of balance and causing big fiery problems down the road. Have you looked into how the BMS on the Rad batteries balance the cells?
-Dan
The Rad BMS enables balancing based on voltage difference between cells, not a specific cell voltage or charge voltage. Balancing is enabled when cell voltage is between 3.3V and 4.45V (42.9 - 57.8V float voltage).
Rad uses a Sino Wealth SH367008 chip in the battery BMS. The numbers are from the chip spec sheet.
The chip uses passive balancing during the charge cycle only. Shunt resistors bypass charge current past the higher-voltage cells to the lower-voltage ones. The Rad charger Charge light turns green when current to the battery drops below about 200 mA, but small current continues to flow. That is why the charger is left on for 12 hours, to permit the balancing current.
To clarify, the smart switch will cut off current before balancing, and if used would require charging to 100% without the switch for 12 hours every month or so. That is one of the reasons that I switched to the diode circuit. The diode circuit limits float voltage to the 80% charge level, but does not shut off charge current and does enable balancing.
That's a perfect clarification! Thanks! 👍👍
Quote from: DickB on August 11, 2021, 04:50:06 AM
The parts are relatively inexpensive, but I got parts from multiple sources, so shipping costs can add up. I'd consider making a small batch if there is sufficient interest.
What's your idea of a small batch? Including one for me, I think you're up to 3.
Any other takers out there for one of these diode device units? Please speak up!
Maybe it needs its own thread?
I will put together a parts cost spreadsheet and see what quantity makes sense.
Parts cost to me is $25.18 plus shipping. I'd build 5 and sell for $40 each plus shipping ($8 for Priority mail in the US).
Quote from: DickB on September 01, 2021, 11:39:45 AM
Parts cost to me is $25.18 plus shipping. I'd build 5 and sell for $40 each plus shipping ($8 for Priority mail in the US).
Count me in for 1. Message me how you want paid and when to pay. Thank you!
I'll jump in for one as well if you are still looking for people.
I will be making up a batch. It will be a couple of weeks for me to order parts and build. When I work out how to take orders and payment, I will post here.
Quote from: DickB on September 04, 2021, 05:03:56 AM
I will be making up a batch. It will be a couple of weeks for me to order parts and build. When I work out how to take orders and payment, I will post here.
Just a thought. Chase bank, so I assume others too, use a service called Zelle/sp. If you set it up in your bank's app, people can send you money by sending it to your cellphone number, which you include when you setup your account. Maybe you can PM with interested buyers to provide your cellphone number rather than post it here in the public forum.
By the way, I'll take one.
Thanks for the tip. I will likely use PayPal, either via email invoice or Buy Now button on my website. It costs me a bit, but makes order taking and shipping very easy for me.
I'm a newb but count me in for one too! Thanks!
Sent from my iPhone using Tapatalk
If you want a diode device, send a message with your email address. I will send you a PayPal invoice. You can pay with a PayPal account or credit card.
Quote from: DickB on September 09, 2021, 09:12:13 AM
If you want a diode device, send a message with your email address. I will send you a PayPal invoice. You can pay with a PayPal account or credit card.
Hi Dick, PM has been sent.
Mike
Ditto
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I'm in for one too.
Any more takers? He can't start until he gets a few more takers.
Thanks
Mike
Quote from: MikeC on September 12, 2021, 11:46:19 AM
Any more takers? He can't start until he gets a few more takers.
I just messaged DickB about acquiring at least the DigiKey parts from him and possibly doing a deal for the enclosures where I would design and print all the boxes for this project, offering custom color options and maybe adding the product name to the enclosure.
A 3d printed box would allow for faster assembly since all the holes/tabs etc. would be baked into the design.
Sounds great! Thanks for reaching out to Dick. Hope this can be pulled off!
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Quote from: DickB on May 15, 2021, 08:47:04 PM
Probably just meter accuracy. My meter is specified as +_1.2% accuracy, so that's +- 0.5V. Probably just a variation in meters. I have two DVMs that do read within 0.1V on the Rad battery, but I have one that I got for free at Harbor Freight and it's different by almost 1 V.
Next time I order parts I'm going to get a Maxxim MAX6350 voltage reference IC and check it out against my DVMs.
Yes, Dick, I was thinking the same 4 diode setup would fix this issue. I have used Ohm's Law, since 7th grade, a while ago.
I'm an IT guy, not a circuit builder, but have done some simulations for RaspPi's.
For we geeks, the wiki on Ohm's Law is just the ticket! Enjoy. Great exchange of ideas!
https://en.wikipedia.org/wiki/Ohm%27s_law
Dick B.. I would like one. prattclan@aol.com contact me when I can order one thanks
Quote from: dennis pratt on September 23, 2021, 10:31:31 AM
Dick B.. I would like one. prattclan@aol.com contact me when I can order one thanks
Heya Dennis, I will be making at least one for myself and would be more than happy to hook you up if you have not got in on any batches already. Sending you an email shortly. Cheers!
Nice job DickB, I like it. A welcome addition to Rad's Charger.
I've had a few people contact me about making a diode device. I did build one batch, but don't foresee building another batch anytime soon. Contact peanutbutterpope about a possible build.
Quote from: DickB on October 29, 2021, 06:47:26 AM
I've had a few people contact me about making a diode device. I did build one batch, but don't foresee building another batch anytime soon. Contact peanutbutterpope about a possible build.
Heyo! Anyone wanting a "battery extender" post up here and shoot me a PM. I have been planning to order parts and build my unit plus offer some units to the community. I will offer the kits a completed unit or a DIY kit which requires soldering (for a discount).
I will post up here before I order all the parts to give others a chance to get in on this batch of kits.
Thanks for your interest.
I'm in. Ray St.Denis styan.ray@gmail.com
I would like to purchase one.
Quote from: RayStDenis on October 31, 2021, 11:09:59 PM
I'm in. Ray St.Denis styan.ray@gmail.com
Quote from: Papa Fixit on November 05, 2021, 06:22:47 PM
I would like to purchase one.
Hey all, apologies for my delayed response here..it's been a funky, rough week or so. I will get you guys taken care of in this upcoming batch of battery extenders. I am planning to order parts in another week or so and will be purchasing and building the units prior to taking any payments and I expect approx. 2 weeks for assembly and testing once parts deliveries arrive. I am planning to have a couple extra units available after the group buy and will gauge further interest.
Thanks for posting up and I will update here again in a couple/few days.
Cheers
~Morgan
Is it still possible to get in on the next batch? If so I'm in.
Quote from: geekxx on November 06, 2021, 08:47:51 AM
Is it still possible to get in on the next batch? If so I'm in.
Not too late at all...that is part of the reason why I am not finalizing this batch order for another week..to give time for more people to get in on this batch. I will update here again prior to ordering parts for this batch and I will post up the list of all group buy participants (for transparency).
Thanks again for your interest~
Updates coming soon...still plenty time for more people to get in on this batch.
Cheers!
Quote from: peanutbutterpope on November 06, 2021, 10:44:27 AM
Updates coming soon...still plenty time for more people to get in on this batch.
Cheers!
Good to hear; please add me to your list - thanks!
Quote from: JimInPT on November 06, 2021, 10:45:17 AM
Quote from: peanutbutterpope on November 06, 2021, 10:44:27 AM
Updates coming soon...still plenty time for more people to get in on this batch.
Cheers!
Good to hear; please add me to your list - thanks!
I got you bro!
Add me too please. Thanks.
Heya all, I just wanted to post an update on the battery extenders.
I will be placing my order for the parts on Monday (Nov. 22) so there are just a couple more days to get in on this batch. I will double check this thread prior to placing the order. I will also make a couple videos and post them on my YouTube to share so that others can make their own or maybe I will offer a DIY kit of the battery extenders if there is any interest there.
Anyways, looking forward to building these very soon
Cheers!
I would like to be included on the list for a battery extender please.
Quote from: notmarkmiranda on November 20, 2021, 12:50:24 PM
I would like to be included on the list for a battery extender please.
Got you on the list!
Heya all, just wanted to post a quick update.
I have been getting my shopping carts ready to place my orders and wanted to offer a price breakdown as I will not be charging for my time on these (but will gladly accept tips on top of parts/shipping costs). I do plan on making content for my Youtube when I am designing (the 3d printed cases) and assembling these units. I will be offering a range of colors for these to be printed but I think I will keep the standard color orange to match the RPB logo/theme.
Anyways, here is my group buy cost breakdown..
RPB-BattEx1 Parts Cost
LCD Display- $12.99
Power jack socket- $1.60
Heat-sink for diode- $4.96
Cable assembly- $2.94
R-100PRV 6A- $5.48
R-100PRV 6A anode- $5.48
3DP case- $5.00
Shipping- $12.00
GB Special Price $50.45
So far there are 6 people signed up for this group buy and I will be ordering enough parts to make 10 units in all this batch and future units I will make available through either an Etsy store or a direct purchase using Paypal invoicing. There is STILL a tad bit of time left to get in on this batch if you are not signed up already...I will double check here prior to placing my orders tomorrow morning.
Cheers!
Can you show a list of initials of those on your list? Want to make sure I'm on it.
PS Price is very reasonable.
Cheers,
Ray St.Denis
Quote from: RayStDenis on November 21, 2021, 10:43:19 PM
Can you show a list of initials of those on your list? Want to make sure I'm on it.
PS Price is very reasonable.
Good idea; just confirming I'm still intending to buy.
Quote from: RayStDenis on November 21, 2021, 10:43:19 PM
Can you show a list of initials of those on your list? Want to make sure I'm on it.
PS Price is very reasonable.
Cheers,
Ray St.Denis
Doh! My bad guys...I coulda swore I posted this message the other day but that might have been when my browser crashed.
Anyways, here is the list of people in the group buy..
JimInPT
geekxx
Papa Fixit
RayStDenis
Bobr
notmarkmiranda
Quote from: JimInPT on November 06, 2021, 10:45:17 AM
Good to hear; please add me to your list - thanks!
Quote from: geekxx on November 06, 2021, 08:47:51 AM
Is it still possible to get in on the next batch? If so I'm in.
Quote from: Papa Fixit on November 05, 2021, 06:22:47 PM
I would like to purchase one.
Quote from: RayStDenis on October 31, 2021, 11:09:59 PM
I'm in. Ray St.Denis styan.ray@gmail.com
Quote from: Bobr on November 07, 2021, 01:13:40 PM
Add me too please. Thanks.
Quote from: notmarkmiranda on November 20, 2021, 12:50:24 PM
I would like to be included on the list for a battery extender please.
If I missed anybody, lemme know and I will get you added. I've got enough for 10 full kits w/ displays mostly ordered and will be placing the order for the rest of the parts when I get paid in a few days.
Thanks again and I will post back here after I order the rest of the parts.
Is it too late to get on this?
I v have two batteries and keeping them both at the right charge state it's hard.
Thanks!
Quote from: Omidia Ramin on November 29, 2021, 01:07:35 PM
Is it too late to get on this?
I v have two batteries and keeping them both at the right charge state it's hard.
Thanks!
I will have 3 extra units on this batch! I got you marked down for one unless you want two?
One is awesome!! Thank you!
I live in Canada and shipping will be more. I'm happy to pay the more.
What's the next step?
Why not send everyone a Paypal invoice? That way you would have your working capital early.
Quote from: RayStDenis on November 29, 2021, 06:40:39 PM
Why not send everyone a Paypal invoice? That way you would have your working capital early.
I agree and was thinking the same thing - even if it's an estimated amount for now, I'm happy to cough up. Let us help lighten the load, PBP! Use your money for Christmas presents, as it should be.
Can I be added to the list?
I'll take 2 kits instead of 1 if you have an extra. Thanks
Quote from: JimInPT on November 29, 2021, 09:13:55 PM
Quote from: RayStDenis on November 29, 2021, 06:40:39 PM
Why not send everyone a Paypal invoice? That way you would have your working capital early.
I agree and was thinking the same thing - even if it's an estimated amount for now, I'm happy to cough up. Let us help lighten the load, PBP! Use your money for Christmas presents, as it should be.
Quote from: RayStDenis on November 29, 2021, 06:40:39 PM
Why not send everyone a Paypal invoice? That way you would have your working capital early.
First off, thanks for the consideration..you chaps are good peeps. Secondly, I don't have much of a life and no holiday obligations 8)
Most importantly, it can keep more motivated if I don't collect any money until the battery extender units are ready to ship and won't feel stressed or rushed if I get a couple days behind as I am a disabled veteran and some days the struggle is tougher than the rest.
Just wanted to include an update..I am placing my DigiKey order shortly and will be placing my Amazon order tomorrow. My order from NTE has shipped and will be delivered soon and I will update shortly after that arrives.
Quote from: Omidia Ramin on November 29, 2021, 04:05:31 PM
One is awesome!! Thank you!
I live in Canada and shipping will be more. I'm happy to pay the more.
What's the next step?
I missed this message but Canada should not be any problem..maybe a little bit more on shipping.
Stay tuned here for updates etc and I will be invoicing the group buy members once I have the units assembled/tested and ready to ship.
Thanks again mate!
Quote from: peanutbutterpope on December 01, 2021, 09:51:36 PM
Quote from: jshape46 on December 01, 2021, 10:18:21 AM
Can I be added to the list?
Added!
Quote from: Bobr on December 01, 2021, 08:36:50 PM
I'll take 2 kits instead of 1 if you have an extra. Thanks
Adjusted!
Alright, and with that..this group buy is full BUT stay tuned if you missed this round, I will be taking what I earn from these units and will be making at least 1 more batch so please post up below and I will get another group buy list going.
Thanks again and I will continue to update weekly (or more).
Cheers!
No hurry as far as I'm concerned, Peanutbutter, so take your time and enjoy the process. Thanks again for all your efforts!
I just came across this thread. It looks like I'm a bit late to the party but if you decide to make more I would be interested in buying one. I thought about getting a timer but this would be easier.
Quote from: Slowrider on December 02, 2021, 07:44:53 PM
I just came across this thread. It looks like I'm a bit late to the party but if you decide to make more I would be interested in buying one. I thought about getting a timer but this would be easier.
I will notify you when I work on the next batch..I am hoping to make these on a regular basis.
Parts haul update..
I received my Digikey and NTE orders just the other day and am waiting on the jacks and LCD screens to arrive. I already have 1 LCD screen and some jacks from when I ordered parts to build my own unit so I will be using those to get a jump start on the 3d modeling for the enclosure in the next couple days.
More updates soon
Cheers!
I also would be interested in your solution. Let me know when you make more.
Thanks
Quote from: PatcoRad on December 16, 2021, 07:01:37 PM
I also would be interested in your solution. Let me know when you make more.
Thanks
I got you mate!
I will be working on the enclosure 3d model design later today and will post some screenshots from that here later as well. I was reviewing the build and parts list yesterday when I realized I forgot to order something. Nothing big but a small setback either way. The metal bars used to connect the pairs of diodes is what I forgot to order. After doing some thinking I decided I can accomplish the connection between the diodes using a copper strap(made from copper sheet/plate), which I will be ordering in the next few days. I might also need to order some nuts to secure the diodes in the enclosure but I will check my supplies first.
*edit-Also, I forgot to mention that after checking the parts list etc, I realized I only ordered half the jacks required to complete all 10 units so I must order 10x more of those in the coming days.
More here soon!
Quote from: peanutbutterpope on December 19, 2021, 07:22:09 AM
I will be working on the enclosure 3d model design later today and will post some screenshots from that here later as well.
Thanks for the update, PB, but I hope you'll take time to enjoy the Christmas/New Year's holidays and relax a bit. I think I speak for most in saying your efforts, as always, are appreciated and it's not a rush for me. If you change your mind about accepting prepayments to help carry the costs, please be sure to let me know.
Cheers,
Jim
Quote from: JimInPT on December 19, 2021, 08:36:57 AM
Thanks for the update, PB, but I hope you'll take time to enjoy the Christmas/New Year's holidays and relax a bit. I think I speak for most in saying your efforts, as always, are appreciated and it's not a rush for me. If you change your mind about accepting prepayments to help carry the costs, please be sure to let me know.
Cheers,
Jim
Thanks for the kind words Jim. I most definitely did something nice for myself this holiday..been acquiring parts for my new PC build which I am just about ready to mod/assemble and I have been spending some time with my mates playing some games etc.
I was able to order the rest of the jacks needed to complete this first batch of battery charge extender units as well as the copper bar I will use for the grounding straps. Now its time to get busy on the 3d model again and am hoping to get a test print going a bit later.
More updates soon..thanks again all and have a most wonderful holiday season!
Thanks PB
Quote from: peanutbutterpope on December 21, 2021, 06:07:22 AMI most definitely did something nice for myself this holiday..been acquiring parts for my new PC build which I am just about ready to mod/assemble and I have been spending some time with my mates playing some games etc.
That's cool. I'm sorta geeky that way too, as an old engineer with engineer OCD. Used to build CP/M boxes in the '80s and a few early PC clones in the late-80s and '90s but then got hand-me-down Dells every couple of years from my Dad for about 20 years since he liked to buy near the top of the line every couple of years. Sweet deal for me!
Two years ago, I built my first PC in about 25 years and had to learn all the specs and jargon all over again. i7-8700K-based with 64Gb DDR4 3600, built to drive a big 4k display for stock trading, not gaming. Since then the OCD said I had to poke and prod and hot-rod stuff, so I upgraded the power supply, case fans, CPU cooler (Noctua D15 rocks!), CPU to i9-9900K so I could keep the mobo and after waiting 13 months, trying and getting mad I finally found a brand-new 3080 for "only" a little over $1,400 in October. Just in time; they're about $700 more now. Just got tired of waiting; getting older and had VR and pretty-decent flight-sim gear gathering dust since they caused my original 1660 (great for 2-D charts, not so much for 3-D games) to barf. The 3080 was definitely a "hold my beer and watch this" upgrade.
Now I'm OCD'ing the Rad MiniST2 with accessories, tweaks and a new 35A Bolton upgrade waiting for the garage to stop freezing so much. Your charger mod should really pay off with extended battery life.
Anyway, have fun with your new rig, too! Winter's the time for indoor recreation.
Hi PBP, I just joined today! I also would like to be on your list for your next batch.
Thanks and Merry Christmas!
Just joined today as would love to get on the list for the next batch as well!
Sent from my iPad using Tapatalk
This is a great idea and thread. If / when the next batch happens please add me to the list for 2....
Hi DickB,
I wont get my Radrunner 2 for a few more days, but, I also would like to be on your list for your next batch.
A switch like this with the option to disable it should already included as part of the battery. License it, get it done.
Please add me for two as well. Second RadMini due to arrive Tuesday!
Thanks,
SMunsey
Quote from: DickB on May 15, 2021, 08:47:04 PM
Probably just meter accuracy. My meter is specified as +_1.2% accuracy, so that's +- 0.5V. Probably just a variation in meters. I have two DVMs that do read within 0.1V on the Rad battery, but I have one that I got for free at Harbor Freight and it's different by almost 1 V.
Next time I order parts I'm going to get a Maxxim MAX6350 voltage reference IC and check it out against my DVMs.
In 2015, I paid $11 for this item:
https://amzn.to/3GQ6p9e
All I had to do was solder on leads for two 9 volt battery connectors. Since then, I have once sprayed the selector switch with contact cleaner. It was calibrated and came with a paper showing each of the four voltages to the nearest 0.01 millivolt.
It's advertised as an AD548. In fact, it's an AD584. The item I bought is out of stock, but searching for AD584 brought up quite an assortment.
I'm amazed at how accurate some cheap meters are these days.
Quote from: DickB on May 14, 2021, 08:00:36 AM
Although my smart switch works, I have a much simpler solution to partial charging with the Rad charger.
Standard silicone diodes have a forward voltage drop of about 0.8 – 1.0 volts at 1-5 amps. Simply placing two diodes in series in the circuit between the Rad charger and the Rad battery will drop the float voltage to provide less than a full charge. I've tested one cycle with two diodes and achieved an 80% charge level. Other than the reduced float voltage, the charger behaves just like before, charging at a constant 2.03 amps, then tapering off. The Charge Indicator starts red and then turns green at charge completion as usual.
I've verified the charge level both by measuring rest voltage of the battery after charging and using the Rad Battery Charge Indicator.
The float voltage after the diodes was 52.7 volts, and the rest voltage after my dual diode charge was 52.0 volts. This correlates to the following table from Benzo Energy, a Li-Ion battery manufacturer (I added the Rad battery column):
Voltage
Rad Cell Charge
54.6 4.20 100.00%
52.8 4.06 90.00%
51.7 3.98 80.00%
51.0 3.92 70.00%
50.3 3.87 60.00%
49.7 3.82 50.00%
49.3 3.79 40.00%
49.0 3.77 30.00%
48.6 3.74 20.00%
47.8 3.68 10.00%
44.9 3.45 5.00%
39.0 3.00 0.00%
I made a similar chart last April, based on data from someone who had used a computer to record voltage each second as he discharged a Samsung 18650 at a constant current. I don't remember if it was a 35E. As I recall, each reading listed time, voltage, and culombs drained so far. There were thousands of entries. I took the culombs at the bottom and multiplied by .1, .2, .3... etc, to find the points on the list showing voltage at 90%, 80%, etc. Like you, I then multiplied by 13.
My chart varies from yours.
54.7 100%
51.7 90%
51.0 80%
50.2 70%
49.3 60%
47.9 50%
46.3 40%
44.5 30%
41.7 20%
39.0 10%
At the time, I thought I'd validate this empirically, but that would entail routinely running the battery down until the controller kept shutting off the motor. Besides, my energy use per mile seems to vary from day to day, depending on things like hills on my route, pedal assist gear, throttle use, and speed. (I think a hub motor may use more energy per mile at lower speeds than at higher speeds.)
I've ordered a mechanical countdown timer switch, up to 12 hours in 15-minute increments. With the data I've logged in the past year, I should have a good idea how long to set the timer if I want to charge the battery from one voltage to another.
Oh yes... the display on my Bolton aftermarket controller reads 0.5 volt low, like yours.
I did run an empirical test on my Standard Rad battery and Rover 5. I ran full throttle on level roads, stopping every two miles to measure battery voltage after 30 seconds. I went 20 miles before the battery was basically exhausted, so for the most part every mile is 5% of capacity. I based my meter chart on these results.
I have 2300 miles on the battery after about 6 months. I plan to repeat the test at 1 year.
Quote from: DickB on January 20, 2022, 06:01:45 AM
I did run an empirical test on my Standard Rad battery and Rover 5. I ran full throttle on level roads, stopping every two miles to measure battery voltage after 30 seconds. I went 20 miles before the battery was basically exhausted, so for the most part every mile is 5% of capacity. I based my meter chart on these results.
I like your chart. Your knee at 44 volts(20%) agrees with other curves I've seen. For several months, I amassed empirical data by logging voltage and mileage readings each morning before riding. I've noticed that knee, so now I recharge at that point. From my data, I've noticed another knee: above 50 volts or so, I tend to get a lot more "miles per volt."
Internal resistance may be the problem. You were apparently able to maintain an efficient speed. Around here, I often have to slow to a walk. Perhaps below 50 volts (65% on your curve), battery resistance limits the current the controller can deliver. Acceleration would be slower and I'd spend more time climbing at inefficient speeds.
In particular, a 300-yard grade at 6% leads to my house. The whole block is 600 yards. Historically, the limit was 35, and that was quite safe. There are four small houses on that block, and apparently at least one household with political pull wanted it treated as a private road. About 1990, the town posted it at 16 mph and ordered the town cop to issue tickets. It was expensive for a town of 200 households to have its own cop, but how else could they enforce a law like that? There was a rapid turnover because it was as abusive to cops as to those ticketed.
I used to observe the hill with a stopwatch. In spite of all the tickets, about half the vehicles continued to drive at 35. That meant the cops were profiling. My mother was on the council. I told her the limit was a ridiculous burden to anyone who obeyed it. She ignored me until the day she got a warning. I think the cop was politely making her aware that he'd been told to enforce a ridiculous limit. When she brought it up at the next meeting, councilmen scoffed at her and fired the cop.
A mayor was elected who loved to do favors and inconvenience people. He got only 12% of the vote, but nobody else wanted the job. He had a speed bump put in at the bottom of the grade and another 200 yards from the bottom. Vehicles including his would come to a complete stop for each bump. He didn't mind the inconvenience as long as he was inconveniencing others.
After I installed a layback seat post, my Radrunner was the only vehicle in town that crossed those bumps without slowing. Hitting them at 25 wasn't uncomfortable because my riding position put most of my weight on the pedals. I changed my mind when I got home from the grocery store with cracked eggs. That wasn't so bad, but I was afraid I might arrive with broken spokes the next time. Now I slow to a virtual stop, like everyone else, and climbing that hill is a drag. I should have gotten a mid-drive bike with gears.
Where can one order a smart switch?
Where does one buy a SMART SWITCH?
Quote from: Webfor65 on January 24, 2022, 02:21:06 PM
Where does one buy a SMART SWITCH?
What exactly are you referring to as a "smart switch"? I have a bunch of those both as wall switches and plug-in adapters for my Alexa network to control things, including running my Rad charger for either 7 or 12 hours with a voice command.
If you're referring to a variable-charge-percentage charger controller, just post your interest in this thread; "peanutbutterpope" is working on the first batch and considering doing more later on (see Reply #63), so he's keeping a list of interested people. The first batch has not shipped yet, so you'll need a bit of patience.
Quote from: Webfor65 on January 24, 2022, 02:21:06 PM
Where does one buy a SMART SWITCH?
I bought a 12-hour mechanical timer instead. (Simply to count down, the digital timers I saw looked like a hassle to use.)
As a rule of thumb, the battery charges at 2 volts per hour. Suppose I'm at 47.6 volts and I want to charge to 80%. According to DickB's chart, that's 51.6 volts, so I set the timer for 2 hours.
It's possible that not topping off could be harmful. I've been keeping track of voltages and watt-hour inputs for several months. Generally, partial recharging requires about 1.16 x average voltage x voltage change. (in the paragraph above, it would be 1.16 x 49.6 x 4.0, or 230 watt-hours.
However, charging all the way usually takes a lot extra, and that extra amount varies so much that charging from 42 volts could take more energy than charging from 40. I think that extra energy goes into equalizing, and the need may be different every time. I think letting the cells get way out of balance could ruin a battery pack much faster than charging all the way.
Rad Power recommends disconnecting the charger as soon as the green light comes on. I may not be awake to do that. I may use the timer to avoid leaving the charger on for hours extra. To start, my estimate would be an hour for every two volts I need, plus at least an hour for topping off. I'll probably change that according to observations.
An hour after seeing a green light, I have reconnected the charger and had it continue charging with two red lights. That could mean that after the battery settled down, the controller found that some cells still needed equalizing. If the timer shuts off after a reasonable charge time while I'm sleeping, the battery can settle down before I turn the charger back on in the morning to check. Allowing that rest may help the controller equalize cells.
PB, Are you still producing the Battery charger controllers? If so put me on the list. Bill Asbell
Looks like this device can be used as battery charger controller: https://www.aliexpress.com/item/32886201775.html
The charger needs to reach float voltage and the current drop for battery balancing to take place. This device would shut charging down before balancing could take place. You would need to not use it periodically to keep cells in balance. The diode device allows cell balancing to take place at a lower float voltage.
It would be a convenient way to charge to a lower voltage and State Of Charge for long-term storage.
PBP, Please count me in . I need one, russeljp@charter.net
Has anyone heard from the Peanutbutterpope, or received a battery extender from him. I have tried to message him and haven't herd back from him and it seems this post has died out for some reason. Does anyone know what's going on. Some news would be helpful. Thanks in advance. I hope all is well. Thanks Russ
Heya everybody, apologies for my lack of updates. It's been pretty hectic over here but I am filming a small video to post an update and explain the challenges and show my progress. I will link the video here once ready.
I will reply to messages and posts later tonight as well.
Thanks again for your patience and again, please forgive my lateness.
Cheers!
Quote from: peanutbutterpope on April 07, 2022, 06:51:23 PMI am filming a small video to post an update and explain the challenges and show my progress. I will link the video here once ready.
Thanks, PBP, good to hear from you and looking forward to watching your video.
Hey PBP glad to see your post. I was worried about you, with the pandemic and the world, the way it is today you just never know.
Quote from: rjp on April 09, 2022, 06:20:27 PM
Hey PBP glad to see your post. I was worried about you, with the pandemic and the world, the way it is today you just never know.
Thanks mate! I had some issues the other night and lost all my footage I had uploaded to my PC when we lost power, also had to reinstall windows. Fun stuff!
Anyways, a quick update here..I had some problems getting the enclosure I designed to print properly. After numerous attempts to no avail..I finally decided that I should just order some enclosures, modify and print custom lids for the display. I have a pair on order and will be modding my design to fit the new enclosure and should have something better to show very soon (I will be filming the assembly again to share to Youtube for those wanting a DIY kit). I will get some pics of the test unit I have mostly built. Needing to repair my multimeter so I can figure out the polarity of the barrel plug cable..sadly the manufacturer spec sheet does not show which is ground/primary.
Other than that, my biggest concern was whether to add ventilation holes or not??
I will 100% be posting replies to comments/messages I have not replied to yet this evening.
Apologies for my delays and thanks for your continued patience...ALMOST out of this tunnel ;D
Thanks for the update!