First post: 10s3p build charge problem

Hi all, hope this is the right place for this question:
Had a person build me a pack and BMS (Bluetooth). I received it, and I’ve had problems with it. The builder was initially helpful troubleshooting but has now ghosted me. I’m hoping they show up but I thought I’d ask here for opinions. I’m a sparky but unfamiliar with esk8, building this with 12yo son and having a blast.
Here are some screen shots of the charge and discharge. The 4 cell groups seem to be the only ones moving. Balancing is poor (I think).

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Damn. That’s a mess


2 things:

Who built this?

Can you post photos of the battery?


Yea I gotta see this battery


It’s packaged up to return but here is the setup

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Rather not say “who” yet to avoid blame. I just want to get it working and learn.

Is that exposed wire on the left side?

Fair enough :man_shrugging:t2: maybe once it’s cleared up you can share.

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That was the fuse holder doing a fit check. Not soldered in yet

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Doesn’t look like Thisguyhere, M.Hboards, Dexter or any one else’s work I would recognize :thinking:

If the builder was @hyperion1 or @dirtbag they’re not coming back. Just letting you know :man_shrugging:t2:

If you can’t work anything out with the builder or fix it yourself, and you need to get a new battery, @Skyart is a builder in the USA who seems to be popping off right now

And just so I’m clear, I’m not name hunting because I want to know who built a battery that broke, that shit happens. I’m looking for names because ghosting shouldn’t be considered acceptable :frowning:


If I don’t hear in the next couple of days, I’ll put the battery on the bench and start disassembly. Just wondering if anyone can interpret the BMS screen caps for an easy culprit?

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Here is where it sits, in its packaging. I have the balance voltage set low - should I move it higher for storage?

Sorry to not be the exact help you need, but I think I can generally advise you on what to do next to fix this.

(This could be solvable through the software of the BMS, but I’m going to give advice as though your BMS is the standard ‘dumb’ ones most people have in their builds.)

  • Take pack out of board and disconnect everything from it

  • Measure p groups to find the problematic ones, as they probably weren’t labeled by the builder

  • Use a 4.2v charger (if you vape, or know a buddy who does, I figure you have one) to bring the lower charged p groups up to the highest charged p group (looks to be 3.767 from the photo)

  • Wait at least a day before assembling everything back together as some groups might drift again (this can be a sign of either old or dead cells, dragging the surrounding cells / p groups down with it)

  • If everything looks gucci, make it all pretty again

  • Connect and ride :ok_hand:

@thisguyhere can you please link that write up you did on this? I looked at your profile and website but can’t find it :thinking:


What cells did you use? Looks like classic behaviour of new and old cells, or different types of cells probably. There is no way to make that work, it will only work as well as the weakest P-pack in the chain.

Is this salvaged laptop cells?

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The note on it says Samsung 30Q. I doubt thats true though. @Lazairtyler how much did you pay for this ?

It certainly looks like bad cells, no doubt about it.

If you aren’t going to name anyone, what is the seller’s reputation?

This one?


Yeppers, thanks


Wow! Appreciate all the help everyone! I was able to get comms established with the builder thankfully. He is honouring the return for rework. I half believe I’ll never see the pack again, and half super optimistic - younger fella who is trying so hoping hope prevails.
I will dig into the shared write up and educate myself.
I will give updates as the rework starts.

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Paid legit price - $350 Canadian

Well, I feel like a sucker. Mailed the pack back and totally ghosted now. I’m a bit bitter.