Re: Battery Hookup source, details
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Not using a BMS is a recipe for firey disaster if anything ever goes wrong. You can probably get away with it since the cells are healthy and aging pretty equally, but the purpose of a BMS is to make sure each cell in series doesn't overcharge or over discharge. If either condition occurs for too long, it can result in damage that can cause thermal runaway, and lithium fires are not fun.
(Seen the videos of the Chevy Bolts on fire? That kind of fire.)
The biggest danger is that your charger could be charging your string of series cells to the right overall voltage, but one might not charge to the right level, leaving the rest at a higher than normal state of charge, accelerating wear, and getting closer to a thermal runaway event - and you can't tell unless you're checking individual cell levels, because the charger only knows the voltage of the entire string, not each cell.?
Simple BMSs aren't very expensive, nor are they difficult to install. I'd highly recommend using them with any lithium battery pack.
That being said - you definitely can get away with not using one, but you should know the risks, and I personally feel like the safety justifies the little bit of extra cost and work of adding a BMS.
- Jacob
On Sat, Jun 18, 2022, 9:38 AM jerry freedomev via <freedomev= [email protected]> wrote:
Hi Jacob and All, ? BatteryHookup has some great deals in Bolt like modules, not sure which model they came from.? ?But other than size they are Bolt/LG cells in different size packages. I use new Bolt modules in my S-10EV I bought from them at great prices. I've never used a BMS on my Volt modules for 3 yrs without any problem, still perfectly balanced and the Bolt are working out the same. The Bolt module type is much better for a BMS as? 240amphr cells vs Volt has to be modules in parallel would need 5x more BMS. I picked them because Volt modules were known to not need a BMS, a costly PITA and took a gamble that Bolt modules would too for overall low cost/kwh. What you do need is a charger that won't go over 4.12vdc/cell x # of cells.? Jerry
If you wanted to use lithium batteries, my recommendation would be to use Chevy Volt modules and upgrade to a more modern speed controller. If you care more about driveability than originality, this is the best option. Lead acid and the original speed controller are less comfortable and the batteries won't last as long.
The biggest issue is you'd need to get a BMS and a new charger, and redo some wiring. This is a bit of a learning curve, but not that bad.
Something like the above would be perfect.?
Total cost would probably be around $1-3k depending on how fancy you want your speed controller and how much range you wanted.
- Jacob Hello,
I have a working 1975 citi car that hasn't been used for a few years because I didn't want to buy the wrong batteries and I thought they wouldn't last long due to limited use.? Now that gas it so high I am thinking maybe now is the time.? I have read multiple posts over the last few years about battery options different than the normal golf cart 6v batteries and the required chargers and battery managers.
IF you have current estimates for either tires or a battery set please reply so I can consider putting this car into service again.
thanks,
John
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