Battery wont charge and weird noise coming from BMS

I’ve been riding my board for about 2 weeks. Yesterday I left my board on for a couple days by accident and now my board wont charge, plugging in the charger the light indicator on the charger doesnt even light up. I have 2 lipos through a supower bms and whenever i plug in my loop key I get a weird, very soft, siren/alarm like sound coming from the BMS.

Any ideas whats going on?

you drained your cells to low…

check the voltage of the pack and report back

Voltage is probably too low to initiate charging. you will need to “jump the pack” by charging with low current at the battery terminals. Once you bring the voltage of the cells above 2.8v the bms should allow charging again. You will need a controllable power source to do this since you don’t want to dump to much current into the pack when the cells are too low.

Of course, check voltages with a multimeter to be sure this is the problem.

… and try not to have to do that too often, cells don’t like that too much, it seems to shorten the lifespan a bit. Obviously shit happens… but you know.

maybe he could do some sort of regen braking charging…

get pulled by a car with light brakes on for a bit to revive the cells… only if you have vesc though

Not very good for the BMS either. That whine is the BMS screaming for help. :joy:


I just saw that you are running li-po… It isn’t to a great idea to run lipo with a bms. Most BMS units, if not all, have a low voltage cut-off far to low for prismatics. Chances are you have puffed your packs and they are now toast.


I just checked the voltages of my batteries the voltages of the first lipo every cell is at 3.4v which is my cutoff in vesc. My second lipo which is plugged into 6-10 on the BMS is at 2.3v 1.9v 2.9 1.4 3 For a grand total of 11.5v It originally is a 5s zippy compact 5000mAh 18.5v pack

Do i just buy a new one? Is it safe to try and rescue this pack?

also the lipos arent puffed at all no changes in appearance

what in the hell.

your cells are down to 1.4v? your bms shouldn’t have let them drop below 3.2. those are dead batteries.

not to mention crazily unbalanced

hahahaha that’s how jake puffed his evolve-leftovers pack he made.

unless you want to tap into and charge each cell individually i would toss that shit into a bag and call waste management.

I left my loop key in so my board was just on for like 4 days. Nothing the BMS could do at that point.

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damn :frowning:

Is there something wrong with my build? Seems kinda shitty that I destroy my batteries just by leaving my board turned on.

You have a balance board not a BMS. At least that is what it seems by your description.

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time to call waste management. for the love of god, DO NOT throw those in the trash lol

I have this exact model

Did you bypass the bms for discharging? Even if you didnt, lipos can self discharge when they get too low, that’s why you see most of us use cylindrical li-ion. They are more stable at low voltages.

No everything is going through the bms, both charge and discharge