V8 "Please repair" and full tilt back at 50-65% battery.

[Heymelon]

So as title says, I can ride the wheel fine until I get down to those percentages. Then the wheel tilts me back and says please repair. It is at this point unrideable. It usually lets me keep riding if I restart it and go really slow, like 10km/h. But eventually it will repeat this process until I'm not able to start it at all before I give it charge.  When I charge it up it works fine again.

So it seems like my BMS is bugged or a cell or two is not getting fully charged? At least that is what has been explained to me by a friend who has a similar Issue with his V10 that does the same thing at 50%. However his doesn't take full charge while mine does, and euc world typically reads 85V or a little above and 100% at charger green light.

Anyone have any ideas or possible fixes for this that isn't send the wheel to a battery expert for manual balancing? I have no warranty on it, bought it used last year. Checked all the cables once or twice on control board and to the battery. 

 

Also I get this error indicator: 

[Heymelon]

No? No one knows of this problem or have any proposed solutions? 

[enaon]

On 7/25/2022 at 5:41 PM, Heymelon said:

V8 "Please repair" 

Anyone have any ideas or possible fixes for this that isn't send the wheel to a battery expert for manual balancing?

I think it speaks for it self. 

Edited July 27, 2022 by enaon

[Begodecrashtestdummy]

On 7/25/2022 at 10:41 AM, Heymelon said:

So as title says, I can ride the wheel fine until I get down to those percentages. Then the wheel tilts me back and says please repair. It is at this point unrideable. It usually lets me keep riding if I restart it and go really slow, like 10km/h. But eventually it will repeat this process until I'm not able to start it at all before I give it charge.  When I charge it up it works fine again.

So it seems like my BMS is bugged or a cell or two is not getting fully charged? At least that is what has been explained to me by a friend who has a similar Issue with his V10 that does the same thing at 50%. However his doesn't take full charge while mine does, and euc world typically reads 85V or a little above and 100% at charger green light.

Anyone have any ideas or possible fixes for this that isn't send the wheel to a battery expert for manual balancing? I have no warranty on it, bought it used last year. Checked all the cables once or twice on control board and to the battery. 

 

Also I get this error indicator: 

My wheel kept doing that .wheel was fine for about an hour of riding then it would tilt back I thought for no reason but here I blew the dc converter on my rs19 high speed and it caused the fan that cools the motherboard to constantly run at a low speed instead of just kicking on to high voltage to cool the wheel .so my wheel wasn’t properly cooling .if it his 80c it will automatically tilt back .have you monitored your temperature when it tilts back.if not check the begode app or euc world when it does it to see if it’s at 80c .also do you hear your fan kicking on?

[alcatraz]

It's probably unwise to charge it after you've hit that warning. 

The battery needs servicing.

Have you noticed that you can deplete it further after you've left it full on the charger for longer, like day(s)?

[alcatraz]

If you're up for a little DIY failsearching, you could try to balance the pack yourself. It's not a long term solution though because you won't solve the cause of he imbalance.

[alcatraz]

On second thought, maybe your problem is different. You mentioned that you've always been able to turn on the wheel which is unlike the problem I'm thinking of. Either you've got a different version bms or a different problem.

There's a fire hazard by charging cells that have gone below 2.5v. To confirm that they aren't you need to open the depleted pack up and measure it with a multimeter. After that you can try and balance it if needed. (probably not a good long term solution, could work ok for 6-12months)

[Heymelon]

On 7/28/2022 at 4:09 AM, Dosingpsychedelics said:

have you monitored your temperature when it tilts back.if not check the begode app or euc world when it does it to see if it’s at 80c .also do you hear your fan kicking on?

Yeah, I don't think it is a temperature thing or that it has a fan. It behaves the same way at the battery mark regardless of speeds or temps. 

[Heymelon]

On 7/29/2022 at 4:05 AM, alcatraz said:

On second thought, maybe your problem is different. You mentioned that you've always been able to turn on the wheel which is unlike the problem I'm thinking of. Either you've got a different version bms or a different problem.

There's a fire hazard by charging cells that have gone below 2.5v. To confirm that they aren't you need to open the depleted pack up and measure it with a multimeter. After that you can try and balance it if needed. (probably not a good long term solution, could work ok for 6-12months)

Ty for all your replies. Yeah I can always turn it on, but I can not deplete it further after the warning has triggered unless I charge. It just tilts me off. Though I haven't tried to leave it like that for a longer time. Yeah cell balancing manually seems hard or expensive and as you say not a permanent solution. So is it the case that the BMS just is bad or why does it happen? My friend says that older inmotion wheels have pretty crap non "smart"BMS and these things can happen with them. 

Do you have any source I can read about the fire hazard by charging lower volt cells? I have only seen people on forum mentioning that but from what I've heard elsewhere fires are mostly caused by short circuits due to bad wiring or design, physically damaged cells or maybe overvolt from a wacky or too strong charger and failing overvolt protection. 

[alcatraz]

Google "18650 potential fire hazards" perhaps.

Vibrations and aging combined with how the cells are designed/arranged can cause certain kinds of short circuits.

I've have a V8 with busted balancing for 4-5 years. I can ride it fine but the more I ride, the more frequent I need to balance. If I don't ride it, I balance it once every 1-2 years. If I ride it every day maybe I need to balance once every 3 months. 

The advantage of doing manual balancing is that you automatically monitor your pack = low risk of spontaneous bursting into flames. Without monitoring, you don't know if the bms is working or not. Some might call it a guarantee against fires.

The disadvantage is that you can't sell your wheel because it depends on the owner knowing a bit of diy. And you shouldn't deplete the pack completely.

It's not expensive. It's just a bit time consuming. It's easy to live with after you've done it. 

[alcatraz]

What the pack needs is balancing wires attached. With those you can monitor and balance the pack without disassembling anything except for the wheel side cover. Balancing leads cost nearly nothing. It takes a little while to route them and solder them, but that's it. 

[Heymelon]

11 hours ago, alcatraz said:

What the pack needs is balancing wires attached. With those you can monitor and balance the pack without disassembling anything except for the wheel side cover. Balancing leads cost nearly nothing. It takes a little while to route them and solder them, but that's it. 

Oh really. Well om not adverse to some diy. I was just under the impression that I also would need some pretty advanced tools and stuff that could get pretty pricy. Maybe it is a bit simpler then I thought, I had assumed it was something reserved for battery experts or some such. 

[alcatraz]

Yeah if you're not inclined to diy or wish to go a bit deeper into the world of lithium, then it might not be for you.

The stuff I'm talking about is hobby stuff used in the RC world for decades. It's available on aliexpress if you're lazy to look for it.

What you'd need is:

5x 5p jst xh female leads ~30cm 3usd? (balance leads)

1x soldering iron + solder 10usd?

1x 8s battery voltage tester 2usd?

1x single cell charger usb board 2usd? (manual balancing)

1x 2p jst-xh male lead 50cm 1usd?

assorted heatshrink

Then a hairdryer/lighter, knife I assume you have at home.

[alcatraz]

Before you decide to go down this route, you should open the pack and measure it to confirm that you have cells that need some help to balance (low voltage). For that you require a multimeter. Buy/borrow?

[Heymelon]

3 hours ago, alcatraz said:

Before you decide to go down this route, you should open the pack and measure it to confirm that you have cells that need some help to balance (low voltage). For that you require a multimeter. Buy/borrow?

Aight, ty for all the help! I'll start out with the multimeter and go from there. I think this sounds doable but I just need the time to do it right. And I will need to do some research to be comfortable diving in,I don't want to risk doing damage to it as it's my main commuter atm and works as that. 

[Bogdanele]

Did you do it?

I have the same issue pretty much with my v8. At 40% it tilts back, the LEDs light up red, and it shuts off. Can't turn it back on. Given the battery sag, it can happen at 50% if you ride hard. It's super annoying. It started happening in the last month or so. The wheel believes it's ridden over 7000km.

[mrelwood]

13 hours ago, Bogdanele said:

I have the same issue pretty much with my v8. At 40% it tilts back, the LEDs light up red, and it shuts off. Can't turn it back on. Given the battery sag, it can happen at 50% if you ride hard. It's super annoying. It started happening in the last month or so. The wheel believes it's ridden over 7000km.

This exact issue was also discussed in another thread. The owner opened up the wheel and the battery pack, and as expected, he found a bad cell group in the pack. Given how far the issue had gone, the only way to fix it is to take the battery to a battery repair shop, or to replace the battery altogether. Installing a manual balancing system is an advanced electrical work, and generally shouldn’t be done by anybody who needs to ask guidance on how to do it.

7000km is a good amount of distance for the V8F’s battery pack, and unless it has been especially well treated, it is not at all strange for it to start dying at that point.

 Do note that like @alcatraz said above, besides being dangerous for the rider, if the issue escalates and the bad battery cell gets below 2-2.5V, the pack should no longer be charged as the fire risk gets elevated substantially.

[Bogdanele]

Opening up the battery has been much more involved than anticipated, it's like an onion, so many layers. Had to hammer out the side cover of the wheel, then took forever to slide the battery box out (after not moving for 5 years, it wasn't willing to slide out willingly), then opening the box in 2, then some transparent shrink wrap, then thick sticky battery tape. Kudos to inmotion for making a battery so well protected, it really feels solid. The problem i now have is that the circuit board is soldered on one side of the pack, so i can't measure individual cells' voltage. I also have a tiny capacity controller i thought could work, but it's not turning on when i plug the cable harness with the 7 wires.

I'm also surprised how small the pack is. I have USB powerbanks to charge phones with 16 cells, the v8 has 40. Much better cells, but still, it feels like a tiny pack for the workhorse it's been to date.

[mrelwood]

If a cell is bad, it drags the parallel cell(s) down with it. So any issues should be well measurable either at full or at as low as it currently gets.