You can't add just one battery in parallel, you basically have to have 2x, 3x, etc of the total number of cells in series. For me I have 96 cells in series and 3 in parallel, so if I wanted to add another in parallel I would have to add 96 additional cells.
Originally Posted by CyberBill
your BMS needs to support the number of cells in your battery pack. My BMS supports 96... so I really can't add another module unless I replace the BMS, which is kind of integral to the car. I would have to reverse engineer the CAN protocol and create a replacement interface that allows the rest of the Bolt to talk to the new BMS.
Thank you for the explanation! The two details above are the exact two things I was wondering about. The parallel requirement to multiply evenly makes sense, and I am sure there are massive advantages to keeping the stock BMS and not trying to code up something custom.
And yes, totally agreed on the cost piece. Trial and error is a bit of the process, especially when you're doing something totally new like this!
Thanks to having some time off around the holidays, I've been able to get some good work done on the car.
First up - steering works!! It works really quite well, without any binding after my initial adjustments. The entire setup is far more straight forward than my original version, and I'm very happy with it now. The final setup is that I've got a vibration reduction U-joint attached to the steering rack - it connects via a 3/4" DD shaft up through a coupler (for easy assembly/disassembly) and into another U-joint. That U-Joint connects through the firewall support joint and into the steering column's U-joint. It's a lot better than the 4 or 5 U-joints I thought I was going to use, and I also don't have to use any support joints other than the one on the firewall. Initially I had a TINY bit of binding, but found that it was caused by one of the joints being installed too far onto a shaft, and cutting it down by just a hair resolved it.
Secondly - the brakes work!! After a ordering brake fittings over and over again, I finally got a solution that works. It was incredibly annoying when I would order something through Amazon or eBay and the wrong part would show up - which happened 3 times!! The final solution is that I use an adapter to go from the Bolt master cylinder's M12x1.5mm threads into a standard AN-4 fitting. Then I downsize it to AN-3 - and use a stainless steel braided PTFE brake hose to another AN-3 fitting. Then I have one final AN-3 to the standard brake line (M10x1.0mm bubble) so I can attach it to the car's existing lines. I'm getting a teeny bit of leaking on one joint, but I've got some thread sealant on the way to fix that up. Otherwise the brakes are bled, and they work, and it's ready for the first drive.
Thirdly - the rear battery pack is complete and reassembled. I've done a bunch of upgrades to it to make it safer and easier to work with, which I will cover in depth in a video on my YouTube channel in probably 2 months (I'm very slow with editing!)
Lastly - I'm just finalizing some work on the low voltage system in the car, and prepping everything to be reinstalled so I can FINALLY drive the car around the block for the first time. It's SO CLOSE!!
Purchases
M8 bolts of various sizes, M4 screws in various sizes, and some spacers for M6, M8, and M10 - BoltDepot - $80
12-pin Flange mount Deutsch connectors (5x) - eBay - $61
Very nice! I?m surprised the rear tabs on that box didn?t pull out when you finished welding. I guess you could pound them back in some if they did. Nice job?
Very nice! I?m surprised the rear tabs on that box didn?t pull out when you finished welding. I guess you could pound them back in some if they did. Nice job?
You mean warp out due to heating from the welding?
I don't tend to get a lot of warping when I weld unless I really go crazy with the heat and stick on one area for too long. Typically I will do tack welds all around the piece, and then do short stitch welds around it multiple times until it fills in completely. I also use an air compressor and a small battery powered fan to cool off the parts.