Parallel Batteries with Ludi BBSHD

[Wamedrano]

I hav been testing parallel battery setups with my hub motor. Everything good and safe and stable. I get consistent more power for longer and a bit more torque.

my question is this 2 40A BMS 52 V 19.2 AH BATTERIES

would this mean I can setup controller to draw 80A without overwhelming the bms in each battery since it will draw 40 and 40 or will I still be limited to the per battery max bmsbut it’s still splits for example set controller for 40A max and it will use 20 and 20.

also is this the same for wattage as both batteries ideal output ration is 200-2000watts. Would that mean that combined the draw can be up to 4000w.

asking this questions I don’t want my ludi to ruin my batteries would like to setup settings on ludi well.

thanks in advance

[stts]

waste of time

[paxtana]

We have tested and found running parallel with significant imbalances does not cause a huge rush of current from one pack to the other even with voltage difference of a volt or two. Though to be fair we did not take things further extreme than that; likely the equalization would scale with the level of imbalance, but to what extent we do not know.

[Retrorockit]

I'm not an expert at his so check what I say . But it seems that you have created a 52V (which would be 14s battery) that is twice as large (so maybe 8- 10p). The individual cells have an Amp limit.
18650 is usually 35A. But 21700 can go to 45A. So you have the same Voltage and Amps, but twice the Watt hours. It actually might make as much sense to just have a switch to go from one battery to the other to avoid the issues mentioned above. 2x36V batteries in series would get you 72V. But there are 72V 21700 batteries available. Higher Voltage at the same amps is easier on everything. But thermal limits can be exceeded that way also. The Ludi controller can probably handle that but the stock one won't.
You said BBSHD, but then mentioned hub motor???
If you put them in series then 104V x 40A= 4160W. That's getting into electric oven territory. So if you're trying to cook something.........
But 60-72 Volts 21700 batteries makes more sense.
A fully charged 52V=58Vx40A=2300W so that's where I think you're at. Up from 30Ax48V (54V)x30A=1620. And with almost 40Ah you can actually use it when needed.
750W=1HP. So you've gone from 2HP to 3HP. A pretty good bump.

[Diggs Ut]

Have you read through the discussion on parallel packs?

https://electricbike.com/forum/forum/knowledge-base/batteries-aa/20725-paralleling-bms-protected-li-ion-packs

[Wamedrano]

Guys my setup has worked wonders. The performance increase by joining packs 2x 20ah is significant I use to be 1 pack at a time guy.
stts Ebiker—- you are right I monitor every run for this reason and suspect this will be an issue in some time but both parkas are brand new and together.

my biggest dilemma is this the Ludi setting have a battery Amp limit. It goes up to 105A. The confusing part is the the wolf pack has a 50A bms yet the Luna press for the app and 52 wolf pack and fire wolf pack are much higher than that so it has me going in circles.

im not sure what to put there because the mate does not have 50a for a wolf pack.

[stts]

waste of time

[Retrorockit]

One thing about the Volts vs. Amps question is wire sizes go up considerably with Amperage. In automotive systems 6 Volt requires larger cables than 12V, and buses with their rear engines, complex lighting, with climate control and safety interlocks for various devices go to 24V to reduce the weight and cost of their more complex electrical system. Even though this makes every single electrical part specialized and more expensive. So 72V @30A. would probably be a better solution than 52V. @ 40A. for the same power. You may have a controller rated for higher power but the windings in the motor are the same.
At the power you have now how are your brakes, tires, driveline, and suspension working for you?

[Wamedrano]

Guys we are getting technical and I appreciate it but it does not answer my question. The Ludi app has 3 preconfigured profiles for the Luna batteries. My concern is that wolf pack has a 50 amp bms but in the app the wolf pack profile has it at 70 amps. Am I missing something ? if you do not know how to use Ludi settings app probably not the question for you. I would never run 105 amps that would be ludicrous. And I have been running the 20ah ones for a while on my juiced bike always at the same voltage .

[stts]

waste of time

[Wamedrano]

Okay SSTS thanks for your input but the app has three settings max is 105A but; when you select Wolfpack it marks it as 70A yet the battery tech spec is 50A bms. When doing parallel the batteries share the load so when pulling 40 amps they are pulling 20 and 20 amps each hence why voltage slag is very low when batteries in parallel. Example one battery in R mode will sag 6-7 volts While in parallel it only sags 1-2 volts max. So that’s why I assumed it would do but I mentioned 40a because I also have 20ah 40 a packa

[stts]

waste of time

[paxtana]

Wamedrano you do not have to select one of the presets, you can adjust the max current to whatever you want. The presets are just a handy thing to use if you want to do so but selecting them is not inherently better than manually selecting what would work best for your situation.

With two in parallel you could probably set max in the app anywhere from 80-100A without tripping the bms. At that much current I would be more concerned about the chain snapping than a battery issue; I recommend a beefy 8s groupset from box components