[dain254]

I've been charging my Volt Modules in parallel for several months now with no issues on my Tomberlin Vanish UTV - my top balance cheap BMS simply has a parallel harness that plugs into the two balance ports. I've seen this done with as many as 6 modules. The only thing to watch out for is before plugging it in make sure they start at the same voltage so there isn't a huge surge of current to balance them upon plugging in!

 

[dain254]

One other important aspect to consider if paralleling through the BMS taps is to have modules that came from the same batch (so the same original pack). As Brian mentioned, when you load the cell the voltage sags and if you have slightly different cells there will be some amperage between the BMS leads depending on how the different cell groups handle the current draw.

 

[dain254]

Molten - I saw how Yabert tied his in parallel a while back which led me to thinking there has to be an easier way! There is a company that makes a clip that grabs onto the tabs on the cell groups easily but I still don't trust it. I never run the vehicle below 3.2V/cell which is another reason I think I'm fairly safe. The small wires used could also somewhat act as a fuse themselves - but I agree the absolute safest way would be to use a fuse and a proper BMS that is using that harness to measure individual cell voltages.

As for the BMS itself, it is one of the eBay "SUPER HAPPY FUN TIME BMS 60A" that can be bought for about $30 I'm seeing. Since I only have it tied into my charge circuit which is somewhere around 15A, I can easily get away with the low current BMS. I randomly check my cells from time to time and they have never been off even slightly - again likely due to the fact they came from the same complete Volt pack.

 

[dain254]

It would have to be wired differently - and I'm not even sure how it could work! Someone smarter than me might be able to figure it out. If the fuse blowing meant the voltage would show zero, the BMS I have would stop it from charging so you would know there is an issue somewhere - other BMS could just show a 0V.