I have a brand new battery in my skateboard and everything worked well for 2-3months.
Nowadays, my skateboard started to suddenly cut off/switch off irrespective of the load (sometimes up to the hill, sometimes just on the flat road, etc). The remote therefore also loses connection, and I cannot switch back on the board with the switch on/off button anymore.
The battery is not drain or whatever, it happens even if the battery is fully charged. The only way to revive the board is to plug in the charger for a second, then it reacts again to the switch on/off button, and everything works.
Sounds like somehow the board suffers from a quick shortcircuit, and it won’t react to anything to protect the electronics. But after the charger is connected, it just resets everything.
Has anybody encountered such a problem before? What could be the issue?
but why does it start to work again after pluggin in the charger? Because I don’t touch the wires at all after that.
So is it really a temporary short-circuit-kinda protection?
If there was a short you’d hear a bang and something would be permanently damaged. Esk8 batteries will just melt or blast clear whatever shorts them out, unless it’s an enormous block of solid copper or something. In that case the cells will very likely just go into thermal runaway
Can you give more details on the board? Who made the battery, what specs does the board have
I have no idea how your board is wired, realistically the loose connection is intermittent and when you plug in charger, the board draws power from it instead of the battery.
The board was originally built by a Chinese no-name company 4 years ago.
I bought it on Alibaba (not Aliexpress) around that time because it was 4WD, 500W each hub motor and could bear 120kg and go around 40+ km/h.
Therefore it had 2 ESCs synced to drive both trucks at the same time and a quite big battery (10s4p with LG m26 cells in an interesting 5 x 8 (row x cell) layout). The wheels were normal 90mm PU wheels and since the company disappeared and the PU wheels were not standardized, I couldn’t get new wheels, after they became worn.
After this, I bought Meepo donut wheels/trucks (2 sets), and even since the ride is so smooth the wheels do not even wear fast. The battery died 2-3 months ago, so I contacted a battery producer company on Alibaba (again, not Aliexpress), I gave them the features I needed and chose LG MH1 cells - the "successor of the old/original LG M26). Both the old and the new pack have cells with the max discharge of 10A.
So bought a proper BMS for the pack as it is not part of the battery (due to space limitations). I told the Alibaba producer to not install BMS, just provide the cabling - they were amazing though. I sent pictures and they reproduced the battery pack i needed for like 180 USD with shipping).
There are definitely a whole lotta cables and connectors I used when installing the new pack and now everything just nicely fits into this big black cover (it has a fireproof black 1mm adhesive sheet as well (not shown on the image) to insulate the whole stuff.
I have no idea what tools you have avaible but heres what I would do:
Unplug the battery from w/e load is present in the board.
Check voltages with a multimeter(both pack and individual series voltages)
If all seems fine, do a load test of 1C on the pack and see if voltages holds (both pack and individual cells).
If above is all good, the fault isn’t your pack but located somewhere else. I’d start checking all the connections to see if something is loose or has bad soldering.
Seeing the XT/MR connectors(the yellow ones), this was my first thought. Over time, with vibration, the pins on the male connector can bend inward, causing a loose connection. Hit a hard bump, and it can disconnect for a few milliseconds, enough to cause a fault.
Try unplugging and replugging them, it should be very firm.
Congrats on the deal! Suspiciously cheap though… I wonder if there’s some bad welds in the pack that have come loose. This would cause all kinds of issues, including random cutouts.
Shipping to Singapore though, so the shipping was cheap, <20 dollars.
The labor was super cheap, each cell still cost around 3.5 USD (which is a good price compared 6-7 on Aliexpress), and I needed 40 pieces → 140 USD.
The battery is fine according to some quick multimeter measurements.
I checked all the plugs that I installed (the big red ones) and some were a bit loose. I wouldn’t say it was the problem, but at least I squeezed the female once a bit with pliers, plugged in the male pins, and pliers again to make them very hard to disconnect.
The battery’s XT60 connector is good, very nicely fit together, no looseness recognized there.
I might have found the real problem, which is the cabling of the lights. It is not that visible in the picture, but there are thinner cables besides the motor cables that go out from the cover. Those are for 12V LED lights and one of the negative cables was so broken that when I wanted to check it actually torn.
But my problem happened during daylight too, when I didn’t switch on the lights; and when they were not switched on, I couldn’t measure the 12V on the light cables, so they were not under load.
Anyway, I hope that unplugging that LED cable and taping it (until I get new connectors and do the soldering) + the cable check will do its job. Now, I am in the testing phase again and (not) looking for a quick shut-off again
Thanks all the inputs guy, will come back to you soon
I contacted others too, but they provided the best price with assembly and shipping. And they really do everything, so in case anybody needs a new pack, you should try them.
Your issue is what my board (also was built by a Chinese company) did when the battery was close to dead. Not dead as in it needed to be charged but dead as in the battery was almost at the end of its life. It lasted a few days after it started doing that before it was just fully dead and would no longer work unless plugged in.
I know you say the battery is new but figured I’d mention it just in case they sent you a bad or older battery. I still think it is worth checking everything else to be sure since worst case scenario you’ll know all the connections are good to go if you do need a new battery.
