At what voltage your pack reaches 100%

[PXSS]

@Eboosted

unlike the Reaper this one has some sag even testing on the bench, just for a split second, it goes from 42v to 40.5v on full bench throttle, maybe it’s because I have a faster (higher sample rate) battery tester, but I don’t remember this sag when I first build it, hopefully this sag it’s perfectly normal or maybe the bullet connectors connecting each pack are not a very good idea, I’m not sure though, what do you guys think?

You were running 35A through it, so yeah, that is normal.

@Eboosted

Another test I did was to check at what voltage the brick charger stopped charging. As soon as it got 41.4v charger stopped

Are you 100% it stopped? do you have a wattmeter to measure the power/current flow?

[Eboosted]

Thanks man, if you see the bench braking it seem I’m pushing too much current back to the battery, I’m affraid this could be causing cell damage.

Even on the bench under no-load braking I’m getting an high increase of input voltage until 43.3v

Should I lower battery min?, I still need more braking force at high speeds and less at low speeds (belt slippage before dead stop)

[PXSS]

You’re still bypassing the BMS? If so then yeah. You are damaging the cells

[Eboosted]

I’m begining to charge at 40V from now on, cant wait for my power supply.

[PXSS]

That’s not going to help if your cells go out of balance… Why don’t you just dicharge through the BMS and avoid all of this???

[Eboosted]

On that builld I don’t have BMS, just a small 10A BMS I’m currently using for charging.

I’m going to buy a couple of Bestech BMS next month though

I’m keeping close monitor on the cells to check if they go out of balance, so I could rely on VESC battery cut off sart and cutoff end.

On the other hand, as you might know, I had very bad experience with Battery Supports BMS when it cutted out regenerative current back to a full charged battery causing a sudden increase in current flowing through the VESC causing a reboot, hence loosing brakes on unexpected situations, I rather have less charge cycles than loosing brakes on a crossing after a downhill.

I have three options to fix thi:

1. A lab power supply adjusted to charge only until 40v, should increase battery life cycles, should avoid the BMS issue and will help me balance empty cells on every charge cycle.

2. A brick charger with adjustable cut off end voltage and continuous cell balance monitoring

3. A Bestech BMS which hopefuly won’t have the Battery Supports issue in conjuction with the current brick chargers I’m using at the moment. On this matter I’m relying on forum members experience only