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Ownboard W2 help WANTED :)

Hi all,

I bought an Onboard W2 in August, and for the most part, I love the board. However, the board has been turning off when braking. After this happens, the board will not turn on for several minutes. The battery is around 60% or 70% when it happens. I had to bail going down a hill because of this, and luckily, only suffered minor injuries. Any advice?

Alternatively, I am in Missouri and will part ways with it for the right price.

Thanks everyone!

It sounds like the controller is getting an over voltage spike maybe? Does it happen at low battery or if you are breaking really gently?

Thanks for your help!

I usually keep my battery at around 50%. It has happened once when I was gently braking downhill, and another time braking on flat ground. I am so confused by this. I contacted ownboard and they told me to buy a new battery, but I cannot fathom why it would be a battery issue?

It might be a bad connection in the pack, or the BMS is reading some fault and shutting the pack down

You can open the pack and replace the BMS or at least check for signs of damage if they won’t replace it

Alternatively you can try a different ESC, my old board started to cut out and it was my ESC going bad

Can I buy a different battery/bms? I’d like to avoid this problem from reoccurring in the future. Or do I have to use their battery and BMS?

Also, do I even need a BMS? sorry I am a noob to this.

You can buy a new battery from many other sources, including forum members. I suggest going to the new forum at forum. (you have to copy/paste the URL, the hyperlink is blocked here) to find a new battery

You done necessarily need a BMS since you can use a balance charger, but a 10s balance charger is much more expensive so you’ll want a BMS. You can bypass the BMS and rely on the ESC to not pull too much power and you’ll have less points of failure

If it’s not the battery, I’ve got some speed controllers I need to sell off

Again, I really appreciate you taking the time to teach me these things. Can you tell me the exact battery I’ll need? Is it a 10s lipo or 10s lion?

You can get any 10s battery, but the standard is using the samsung 30Q cell, you can go to the other forum and ask for someone to sell you one

Either will work, li-ion is a little lower voltage on average but has the same full charge voltage

Usually li-ion will have better capacity (in terms of weight and volume) and lipo will have better discharge. Li-ion will have more cycles but lipo is cheaper

Ok, so if I buy a 10s LiPo without a bms, as long as I charge them properly, it should work seamlessly with the other components on the board?

Sure, but you will need a 10s balance charger

Alternatively you can buy 2 5s lipos and put them in series, just make sure to charge them at different times (if you charge both at the same time with different chargers, it will short out across the ground of your wall socket power unless they are independent circuits)

Have you charged to 100% recently? Could be your pack is way out of balance and when you brake, one cell group goes to 4.2v (cell over voltage protection) and the bms cuts power. After a few minutes the voltage settles and bms resets.

If you charge to 100% the bms will balance the pack. If what I described is happening with the pack at 60%, it may take the bms days to balance the pack. If it’s that far out of balance I’d be very concerned about pack health.

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Wow, that is very interesting! I always stop charging the pack at 90%, so this could be it… So I will charge it to 100%, and then do I need to leave the board on in order to balance the cells?

Another thing I notice when it happens is that even my battery percentage LCD display goes from 60% to not even lighting up-no power to the lcd display…

That confirms my suspicious further.

Typically you need to keep the charger plugged in for many hours, maybe as much as 48 hours. The principle of operation (short version) is, the bms allows slight overcharge, then cuts off charging current while draining down the high cells. This repeats until the cells are more or less balanced. The pack voltage will creep up very slowly during this process. This can be seen on the board’s meter. You should see it hit 90% then slowly ever so slowly climb up toward 100%. It may never reach 99%.

You’re doing a good thing charging to 90%, but occasionally, say every 15-30 rides, you should charge it all the way up to keep things balanced and check out the health.

You should keep the board turned off during charging.

So, to reiterate, I need to charge my board for 48 hours, and my BMS may actually not be broken?

Possibly, if one of the cells is at a low voltage while the pack is still charged it will trip the safety and cut power

Ok, are there any precautions I should take while charging the pack since the pack may be unhealthy?

Since electric skateboards are kind of like lipo RC stuff with respect to battery, the normal precautions are

  • be in the same room while charging. Stop charging if you leave the room.
  • consider charging outdoors
  • have a path planned to outdoors
  • have a fireproof blanket to grab the thing with and toss it outside
  • fire extinguisher, bucket of sand

Extra precautions you could take, and this is totally up to you:

  • take enclosure off
  • check temperature of cells, wires, connections, bms during charge (it’s normal for the balance resistors of the bms to get quite hot, but not melting stuff hot)
  • if anything besides the balance resistors get more than warm, disconnect, worry a lot, read a lot, keep monitoring, store pack outside until you figure out what’s up
  • check individual p-group voltages often. If any go above 4.3v unplug and be worried. Be careful when measuring – it’s easy to short out multimeter leads
  • put a watt meter between charger and pack so you can see how many watt-hours and amp-hours have gone into the pack, and see pack voltage at a glance.

It’s worth noting, your pack may have a weak/damaged p-group that drains down faster than the rest of the pack, and triggers bms cutoff. Ownboard’s advice might have been correct. It’s worth doing some diagnostics/maintenance to confirm though.

And I agree with just about everything @ZachTetra has said too.

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Follow deucesdown’s instructions, he’s way more careful then I would ever be, after the pack is charged you’ll want to give it a while to balance then charge it again to make sure it’s correctly balanced

If after a couple rounds of that the battery voltage is 42.xx (depends on the exact charger) you’re probably good to ride again. If not you’re gonna have to open the battery and check the voltage of each group, be very careful when opening it to not touch anything with metal (I.e. scissors or knives)

If the charge port is a 5.5x2.5 jack I suggest connecting a short length of wire to the probe ends and only stripping the last 1mm so you don’t short the port out, normally I use alligator clips to connect everything

Probably much safer and easier to take the battery out and charge it on a kitchen table with the windows open so you can chuck it outside if it starts venting smoke

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@ZachTetra and @deucesdown So I charged my board for a long time and its at 41.8v do I keep charging until 42v+?