Many standard bike racks will fit. I got this one on Amazon.

Sent from my LM-K500 using Tapatalk

The location on the Rover is terrible in my opinion.

Sent from my LM-K500 using Tapatalk

What exactly happens when you say the battery "claims to charge up"? Does the Charge light come on red? For how long?  What does the meter on the battery read?

Quote from: JTK77 on May 27, 2021, 06:16:06 AM
Rad controller limits only amps.

Good to know.

I only have 400 miles on my Rad. I just got it a few weeks ago. Previous miles on a mountain bike.

If the Rad controller does not raise its 750W limit with a higher-voltage battery, there would be no increase in amperage to the motor.

Quote from: ejonesss on May 25, 2021, 07:42:13 AM
the shipping rules for batteries makes it that consumers can not ship batteries and it would be too costly for manufacturers to provide pre generated shipping label and battery shipping kit (an ebike company tried that and it failed).

From the USPS:

"Customers can take to their local Post Office packages containing lithium batteries installed in electronic devices that are bound for many international destinations, and Army (APO), Fleet (FPO) and Diplomatic Post Office (DPO) locations. For information on specific country restrictions, please see the Postal Explorer or the Individual Country Listings of the International Mail Manual.

"Lithium batteries can be shipped domestically, including Alaska and Hawaii. Different requirements apply to domestically-shipped rechargeable lithium batteries than on international commercial air transportation. See Section 349.22 at https://pe.usps.gov/text/pub52/pub52c3_027.htm for USPS' requirements regarding domestic transportation of lithium batteries."

I am not affiliated with Rad. I am an engineer and mostly just like to know how things work, so yes, I am a nerd.  I do have an interest in maximizing battery life, as I ride every day and put on well over 4000 miles a year. And understanding more precisely what the State of Charge (SoC) is at any time. So knowing more about the BMS is helpful. I have also seen a lot of speculation on how the Rad BMS works, some of which is not correct, so I wanted to find out for myself more about it.

Curious why you would want a higher-voltage battery.

I have seen comments about how the Rad charger is of lesser quality than some aftermarket chargers.  Based on what I see in the Rad battery, I have to question that.

Here is a competitor's battery pack.  The silver rectangle is the BMS. It is taped to the cells, and there are over a dozen wires connecting the BMS to the cells. Compare that to Rad's construction. You can't tell from my photos, but the Rad plastic battery holder is securely screwed to the base. Dense foam pieces are used to isolate and protect the circuit board from the top of the case. Electrical connectors, such as from circuit board to the LED meter, use locking connectors, but are also secured with tape (second photo is Rad).

Which would you say is of higher quality?

The battery pack can be opened up by removing the screws at the bottom of the base. On my battery there are two small stickers across the base-to-case seam that indicate that the warranty will be void. I am surprised Rad suggested opening on your own.

https://www.radowners.com/index.php?topic=1025.0

The silver squares on the circuit board are direct connections to the cells. Just be careful not to accidentally short them out.

I'm not 100% sure exactly when balancing takes place; more guessing based on observations and Rad instructions. I may intentionally unbalance a cell and take some measurements to learn more, but that will have to wait as I am a bit busy for a couple of weeks.

Here is a good reference on various Li-Ion balancing methods:
https://onlinelibrary.wiley.com/doi/full/10.1002/est2.203

Quote from: vudude on May 21, 2021, 09:45:33 PM
Thanks for the peak inside the Rad battery pack. Are the cells 18650? What is the branding on the cells? Thanks

The cells are 18650, which denotes only the size of the Li-Ion cell (18mm x 16 mm), much like the designation AA. None of the visible cells were oriented so as to show the manufacturer, but Rad says that they use Samsung 35E cells:
https://bit.ly/3iAetTr

The Rad battery charge port is connected to the battery through a semiconductor switch turned on by the Rad BMS. If the BMS is not seeing charge voltage at the charge port, it won't turn on the charge switch. The low voltage that you're seeing is due to leakage current. ("Leakage" in this context is an electrical term and not a description of a defect.) If you put just a bit of resistance across the charge port terminals, you'll see the voltage drop dramatically, because there is insufficient current to support it.

When the key switch is turned on, the BMS turns on the discharge semiconductor switch, which supplies power to the battery connector and the LED battery pack meter.

The key switch does not directly make or break a connection to the battery; the semiconductor switches do that. The key switch signals the BMS.

More information on the Rad BMS:
https://www.radowners.com/index.php?topic=1025.0

The Rad battery pack is made up of batteries, Battery Management System (BMS) circuit board, key switch, charging port, power connector, and battery meter.

The Rad BMS uses a Sino Wealth SH367008 Li-Ion Battery Management chip. Sino Wealth is a Chinese integrated circuit manufacturer. The spec sheet for the chip is in Chinese, but Google Translate does a good job.

"SH36700X has built-in high-precision voltage detection circuit and delay circuit to monitor voltage, current and temperature to ensure the safety of the pack. At the same time, the series of chips also have Balance function to extend battery life."

The Rad battery pack has 13 groups of 4 cells each, with the 4 cells connected in parallel and the 13 groups connected in series. Because of the parallel connection, each group of 4 cells is essentially one cell with 4 times the capacity of an individual cell. Unless otherwise noted, further use of the term "cell" refers to a group of 4 parallel-connected cells. To the BMS, each group is in essence one cell.

The Rad chip uses a passive switching shunt resistor method for balancing. It does not use active balancing. Balancing is done during charging only.

Shunt resistors are switched in to equalize the voltage of each cell by dissipating the energy from higher-voltage cells down to the lowest cell voltage. Resistors are connected in parallel with each series-connected cell through semiconductor switches. The switches are controlled by the Sino Wealth chip.

The shunt resistors draw only a small amount of current and would be ineffective at high charge current. Balancing must take place at the end of the charge cycle. This is almost certainly after the Rad Charge light has turned green. To balance cells, Rad instructs that the charger be left on for 12 hours, long after the green Charge light. I have observed the charger continue to supply current to the battery pack after the green light illuminates. If an aftermarket charger cuts off current at charge complete, the pack may not be balanced.

The circuit board has semiconductor switches to disconnect the battery under both charge and discharge conditions as a whole pack. There is no provision to connect or disconnect individual cells or groups of cells. The pack is disconnected under charge overvoltage, discharge overvoltage, charge under voltage, discharge under voltage, short circuit, and high or low temperature.

With the key switch in the Off position, the semiconductor switches are off. Turning the key switch on "wakes up" the chip and the discharge switches are turned on presenting voltage to the battery power connector. As long as the key switch is on, the BMS is active and drawing current, albeit small, from the battery. The key switch does not disconnect power directly, but basically tells the chip to do so.

Construction of the battery pack is high quality. The mechanical construction is very good, with a plastic holder for the cells that is very well secured, as is the circuit board. Battery connections are direct to the circuit board with welded straps. Components and connections to the circuit board are all environmentally protected (think humidity) with conformal coating - the blue stuff that you see in the photo.