12s4p Samsung 30q battery range problem (attached vesc riding data)

Ok so I have a 12s4p Tb battery and for some reason the range has drastically decreased. It continually cuts off and I can’t figure out what to do.

Yesterday I went for a long ride and it cut off at 7-8 miles and wouldn’t turn back on till I charged it a little. I was watching the vesc app on my iPhone and the cells were around 3.6-3.5 volts coasting while the entire voltage was 44v when the board dropped. I’ll post my ride settings and have my battery cut off start at 33.00 and the cut off end at 30.00. I normally do 36-33 but lowered it to do a long ride.

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At 5.8 miles the voltage sagged to 21 volts quickly. Does anyone know what could be causing this? Should I lower my cut off settings.

I did update my vesc’s from 2.18 to 3.35 last night but haven’t riden yet. I’m nervous about the cut offs

Dead cell? Where did you get the battery and can you individually check each cell. Also make sure everything is plugged all the way in and not hanging half out

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If you go down to 30V on 12s the cells are down to 2.5V. I would say that is too low for 30Q. At least you reduce the life time (number of charge cycles) a lot. I think you should stop between 36V and 39,6V - check the discharge curves of 30Q. Edit: typo

I got it from torqueboards and I have no battery experience so I didn’t want to open it up unless I absolutely had to.

Every time I read up on cut offs, people were advising around 36 and 33.6 for cut off end for 30q cells. I could be mistaken.

Is this what happens when you have a dead cell

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33.6v IMO is the lowest you want to go with li-ion, 36v is also good as you will get lots more charge cycles.

33.6V is down to 2.8V per cell on 12S (33.6v/12s). It should be Ok, but generally speaking going lower on minimum voltage and higher on maximum voltage reduces the number of charge cycles a battery can handle. Going down to 30V equals 2.5V per cell on a 12s - that is way too low if you care about battery lifespan. I have not had dead or weak batteries (yet!) so I do not know how they perform.

@torqueboards got any ideas on what you think could be happening?

@Mattmccrary8 Not sure, but you can send us an email and send it out to us and we’ll check on it for you.

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Sounds good, just sent you a email with the ride data attached.

3.35per cell… which is 40.2v… cutoff for a 12s…

But yes if you have a series pack out of balance/dropped, when you ask for the juice, the whole pack sags…

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Ya I think the pack has to unbalanced or something. Was super tough to stay on when it hit those deep cut offs

If you have a hobby charger… I normally unplug the balance lead from the bms… And measure the individual cells… Find the low one. Then use a 2 pin header to charge the low cells as 1s to bring it back into viable range.

This method only works if the cell hasn’t been abused… If you’ve done several charge cycles like this then likely the IR of that series pack is hgher and will likely no longer maintain balance due to the IR difference…

Ya I think I’m going to just send it in to Torqueboards once they send me a RMA. I’m just hoping it can be salvaged like you’re saying. Not trying to continually spend, just want to ride :sob:


bad welds/poor connections within the P groups can do this. Its not the only cause of course. I’ve seen bad BMSs (the charge/discharge type. not charge only) do this as well when components start to go bad.


Looks like there was a fault code. Mid ride it dropped to 21.3 volts. @Namasaki I saw you in a couple different forums discussing similar problems? @Ackmaniac

Use the BMS only for charging. Kick it out of the Battery-VESC cycle. If you don’t have a BMS check your wires.

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Is that I have to physically do to the bms or is that a setting I can change in my vesc’s. I’m running FW 3.35

Battery and VESC should have a direct connection. BMS should not be included in that cycle. And then you can have a additional cycle between the BMS and the Battery. this way the BMS is only there for charging.