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Originally Posted by vskid3
The way I understand it is that the BMS+ spoofs the SoC causing the car to use more electricity and the two battery packs are directly connected to each other, correct? Do you just have to have the appropriate number of series cells and let lithium's flat discharge curve keep the stock pack in a healthy range? It's too bad there's no way to replace that NiMH brick altogether.
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Yes, that is my general understanding of it.
Planetaire is running 70 series A123 20Ah LiFePo4 cells which should give him a nominal voltage of ~224V, and maximum voltage (while charging) of around 250V. The OE pack at 100% charge should be at 227V (1.35V/cell x 168 cells). So, I just took that and divided by 3.6V and that gives you about 60. I chose 56 just because running the OE pack at max charge voltage sounds a bit harder on it than it could be if I just lowered the pack voltage a little. The BMS plus 2 is faking the SOC anyways, so I might as well run it at a voltage that is a bit more battery friendly.
The BMS plus 2 has several different modes that allow you to do different things. I believe you can completely replace the OE pack with your own, but I am not too interested in that at this point as mine is still good, so I haven't looked into it. I know it has a mode specifically setup to work with the Enginer kit that I used to have. I have no idea what it does though. I still have lots of reading to do on it.
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Those cells look like a pretty good deal. They would be great for an e-bike or e-motorcycle. Maybe I'll have to get my e-bike put together again...
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I completely agree. Finding a nice easy way to assemble them has been my only issue. It seems a lot of people rivet them or bolt them together. I'm not a big fan of passing 100A through two rivet connections.