[philsev]

I have been looking for a project car (roller) to convert to an EV for a few months. I came across this car that had already been converted and was priced reasonably. I was told that the previous owner had let it sit and batteries were dead. It was powered by 40 CALB batteries and has a Warp11 motor. The photos below should give an idea of the rest of the system.

IMG_20200710_110514266_HDR.jpg

drive.google.com

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drive.google.com

I am looking at purchasing these for power:

3948.56US $ 23% OFF|40pcs/lot Lifepo4 3.2v 200ah Battery With Busbars For Battery Pack - Rechargeable Batteries - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

My question is if this looks reasonable. I should end up taking less space with the newer batteries as well I think so will need to rebuild the cages for the batteries.

Also, I would like to "clean up" the cabling mess where the controller and charger are as well as put in a charger that would allow for fast charging. What would your recommendations be for this?

Thank you in advance for your time and consideration.

Arthur

Hi Arthur
My answer will differ from others. I have been using CALBS for nine years. I have built six cars of my own. I will only use LIFE batteries. Very stable not one problem in all that time with the batteries. Actually I lost a cell once. I tried a BMS, and it fried the battery and left my wife stranded. Yes they are less dense. But far more safe. I can tell you a couple of stories with them, that if I had used OEM batteries I would have burned my house down. You have a great old controller and a good motor. Have fun. If I chose a new project I will still use LIFE chemistry.

 

[philsev]

Which BMS did you use? I know that some of them can be very problematic.
This is due to a fundamental problem with many BMS systems - they try to actively manage the cells at all states of charge.
In my opinion the M should stand for 'monitoring' - my 96s2p OEM batteries are constantly monitored, NOT BALANCED, and the cell difference has not changed a millivolt in 3 weeks and 400 miles.

Bottom balancing causes issues when charging, and top balancing causes issues when discharging. With a proper monitoring system it is possible to intelligently cut off power or alert the driver whenever a cell gets too low, and shut off or pull back charging when too high. This provides the ultimate in safety without materially affecting the charge levels of the cells.

-Isaac

Not sure the name of the BMS. It tried to balance at the top of charge. That was the only time I used a BMS with the LIFE batteries. I very carefully bottom balance. This saved my pack this spring. Long story, one of my cars sat for 18 months. I was not worried because I have had batteries sit for 5-8 years and they were fine. Same voltage as when I left them and had full capacity. So I did not monitor my pack for 18 months. Yeah! I forgot I had a drain.....instruments.
When I looked at the pack I had less than 0ne volt on each battery and one that had reversed. I will not go into detail, but I carefully charged the batteries to full pack voltage over a week. All of the batteries looked OK. I did have some concerns about capacity. The reversed battery had about 15% capacity. I was surprised it worked at all. I had two cells that were .5 volts, they ended up with about seventy percent capacity. The rest of the pack was about 87 to 90 percent capacity. I wired around the really low cell and so my pack now has about 90 % capacity based on the two low capacity cells.
I have been told that this is not possible with batteries drained so much. I would have agreed before. But since this happened to me, I know it is possible. I believe the only reason my pack survived was , bottom balance. The batteries were so close to each other in voltage when they were way discharged, I think this is why I only lost one cell. I have been using this car as my daily driver for the last few months....all is good.