Noob question thread! 😀 ask your questions here!

legend27 · January 3, 2019, 4:33pm

Thanks! I’ll let it go and hopefully this won’t be my last post.

edit: It’s bestech D140

Andy87 · January 3, 2019, 4:37pm

The d140 specs

legend27 · January 3, 2019, 4:40pm

all packs are at 4.21V and sometime goes up to 4.22V while B1 is still at 4.17

Andy87 · January 3, 2019, 4:43pm

If you can monitor it than have a look that they don’t charge over 4.25v. If I charge my lipos the first cell usually higher in voltage too till reached 4.25v than goes down to 4.2v till all cells are 4.2v

legend27 · January 3, 2019, 4:43pm

whole pack now at 42.0V volts and B1 is on the edge of 4.17V and 4.18V. The other groups rise to 4.22V sometimes.

This is the first charge with my new 4amp charger

legend27 · January 3, 2019, 4:48pm

Charger just turned green and I took it out. Most of the packs are at 4.21V or even 4.22V while B1 is still at 4.17V. Does the BMS still balance while the charger is not connected?

Andy87 · January 3, 2019, 4:50pm

Not sure how it is with the d140. Why not let the charger attached for a while?

PS: as long as the cells not more than 0.1v our of each other I wouldn’t worry so much. They will probably anyhow discharge slightly different.

legend27 · January 3, 2019, 4:54pm

So the charger dosen’t charge the battery anymore. All packs are now at 4.21V unless B1 that is still at 4.17V.

Do you think it’s save to plug the charger in again and let it go?

J0ker3366 · January 3, 2019, 4:56pm

Lipos or li ion? If its li ion, I’m willing to bet a single cell in b1 is dying.

legend27 · January 3, 2019, 4:58pm

It’s li-ion 10s6p samsung 30q. This is the second charge so hopefully it’s not already dying.

J0ker3366 · January 3, 2019, 4:58pm

Are you able to check each individual cell?

legend27 · January 3, 2019, 4:59pm

Not really. That would mean I have to tear all the heatshrink and welds off. I can only check the parallel groups…

J0ker3366 · January 3, 2019, 5:02pm

Leave it @ what its @ right now. Maybe set your cutoffs a volt higher for saftey, but go riding. Running the pack down a little. A few volts worth. Charge it again and see what happens.

I’m almost positive though you have a dying cell. Did you buy (who from) or build the pack?

legend27 · January 3, 2019, 5:03pm

All parallel packs are now at 4.21V unless one that is 4.2V. B1 is still at 4.17V.

I bought the cells from nkon and made the pack myself. I had no problems with the first charge but that was also with another charger

edit: But do you think it would be safe to plug the charger in again?

J0ker3366 · January 3, 2019, 5:04pm

Have you tried that charger again?

legend27 · January 3, 2019, 5:05pm

No, but I can do it.

J0ker3366 · January 3, 2019, 5:05pm

Go ride it if anything. If you’re going to plug the charger in, might as well make it useful lol. Sitting there plugging and unplugging isn’t doing major harm but you are taking away from the life of components. Go ride it.

legend27 · January 3, 2019, 5:08pm

Plugged in my old charger and it also shows green. Will let it sit for a few minutes and monitor each group

legend27 · January 3, 2019, 5:21pm

While charging the pack all groups charged completely fine. They were all at the same volts. Could it still mean a dead cell?

J0ker3366 · January 3, 2019, 5:30pm

So all packs are balanced the same? Go ride it! Run em down. Come back and check your groups. If they’re balanced, cool. If not, you have internal problems.

So for this instance we’re going to say that your pack is still balanced after riding. Plug in the charger that wouldn’t balance completely. If it throws that pack lower, plug the other charger in. If that charger balances them out, then you know its that charger that’s messed up.