Tesla V2 showing less battery lights than before

[Yffisch]

Usually my Tesla V2 (1500wh - some extra battery was added when I bought it to replace the speaker) has had 8 lights shining on the wheel when it's fully charged. I've had the wheel now for 2 years and probably 6300km so battery capacity should of course be reduced. However, now when I charge it to fully charged, it only displays 6 lights maximum.
It's almost like 25% of the batteries just got disconnected and everything works as normal with the rest 75% cells.
What I'm thinking is that some batteries have "melted", but it's just a guess. Or if those "extra batteries" that were added by the salesman instead of the speaker, somehow got disconnected? I have not opened it up. It's working perfectly fine as it is though, it just feels a bit weaker and less battery capacity. But maybe it's just natural after 2 years to never get back to 8 lights, and it will be even more less every year that pass?

Edited April 29, 2023 by Yffisch

[alcatraz]

The lights represent the pack voltage, not capacity.

Is this a factory v2 with 1500Wh? If so then I'm familiar with it.

It's got two packs connected in series, and an external balancer.

First of all, try another charger or measure the output charger voltage with a multimeter. If that checks out then open the right side, disconnect the pack from the board and measure the pack voltage. This is probably where there's a problem.

[alcatraz]

The factory v2 1500 shouldn't replace the speaker though.

How about taking off the side panels and taking a picture of both sides.

[Chriull]

1 hour ago, Yffisch said:

However, now when I charge it to fully charged, it only displays 6 lights maximum.

Capacity ("number of lights") is measured by battery voltage.

You have some very roughly 2/8=25% less of the usable voltage range.

Very likely some cell groups are dead and no longer fully charge, hold no charge at all or are already reverse charged.

Li ion cells can take astonishingly much "beating", but in the end they are a fire hazard. You should look for some professional repair or replacement.

Another reason for this could be a misadjusted charger - it can happen that they provide less voltage over time. This would be easier to replace/readjust and no potential fire hazard!

[Yffisch]

6 hours ago, alcatraz said:

The factory v2 1500 shouldn't replace the speaker though.

How about taking off the side panels and taking a picture of both sides.

Well, I think it was supposed to be 1020wh initially, or maybe it was 1200wh. Then seller asked me if I wanted to make it a T3/V3 with 1500wh by removing the speaker and add more batteries. I'll see if I can take of the panels today and check.

5 hours ago, Chriull said:

Capacity ("number of lights") is measured by battery voltage.

You have some very roughly 2/8=25% less of the usable voltage range.

Very likely some cell groups are dead and no longer fully charge, hold no charge at all or are already reverse charged.

Li ion cells can take astonishingly much "beating", but in the end they are a fire hazard. You should look for some professional repair or replacement.

Another reason for this could be a misadjusted charger - it can happen that they provide less voltage over time. This would be easier to replace/readjust and no potential fire hazard!

It's the original charger that has always worked the same so I'm not sure. Maybe I should send the wheel back to the seller for checking it out. Although, it's time for a new one pretty soon anyways since I basically use the same wheel 2-3 years before I switch to a new one.
I actually noticed I went up to 7 lights, but some minutes later it was down to 6 again. Like it tried to come up to 7, but battery resisted and spit it out again.

Maybe this is something to try?
https://support.euco.us/article/256-my-euc-doesnt-charge-to-full

EDIT: I just got my WheelLog working and checked. It seems to stay at 83% when battery is full and light is green. I tried to put it on while it's green for another 30 minutes, but it got stuck at 83% and 79.70v

Edited April 27, 2023 by Yffisch

[Chriull]

4 hours ago, Yffisch said:

Maybe this is something to try?
https://support.euco.us/article/256-my-euc-doesnt-charge-to-full

Yes. Details depend on how the additional cells are connected. If you have for example three packs try one after another to find the bad one.

If after some charging the packs have too different voltages do not reconnect them again!

Be careful or do not ride with just one (or two) battery packs. They could get overburdened?

@RagingGrandpaonce did research which wheels packs are endangered if used with just one pack.

4 hours ago, Yffisch said:

EDIT: I just got my WheelLog working and checked. It seems to stay at 83% when battery is full and light is green. I tried to put it on while it's green for another 30 minutes, but it got stuck at 83% and 79.70v

Once the charger turns greens this is because one battery packs bms stopped the charging process for all battery packs.

Leaving the batteries on the charger won't change anything as they are offline

[RagingGrandpa]

9 hours ago, Yffisch said:

It seems to stay at 83% when battery is full and light is green. I tried to put it on while it's green for another 30 minutes, but it got stuck at 83% and 79.70v

Danger here!
Don't continue riding it.
You need to find and fix the problem; or dispose of the batteries.

https://forum.electricunicycle.org/topic/22351-what-to-do-battery-not-charging-to-100/

[alcatraz]

If the charger is indeed outputting 84v then you should stop riding your wheel.

If the charger has this 2v drop issue that's happening to a lot of V8 chargers (that look oddly similar to the tesla charger) then you need a good charger. However since you're experiencing a 4v drop it's one more warning against riding.

Measure the charger please.

[DavidB]

"Maybe I should send the wheel back to the seller for checking it out."

Don't send the wheel anywhere! Yes, ring the seller. He obviously has enough electrical know how to advise you as he was able to upgrade your wheel from 1020Wh to 1500Wh and it was good for 5000km.

I think Marty Backe had a wheel like this that he got from China (Aliexpress dealer?). (edit: checked and yes he did)

The battery manufacturers warrant the cells to have at least 80% capacity after 500 charging cycles. Marty got 50 miles (80km) range so your 5000km is only 63 full cycle charges. So that is not the cause which means you definitely have a problem with the battery pack and I don't mean just getting 83% charge, you might lose your house/apartment or worse.

If there is an issue with one cell it can go into thermal runaway and start a cascade which will be impossible to put out. I don't know how the exta cells were intergrated in this wheel and guess it is possible one pack has been disconnected electonically (broken connection?) but you must check it out.

 

[Yffisch]

11 hours ago, RagingGrandpa said:

Danger here!
Don't continue riding it.
You need to find and fix the problem; or dispose of the batteries.

https://forum.electricunicycle.org/topic/22351-what-to-do-battery-not-charging-to-100/

When I said 79v, it was the number from my WheelLog app. Not from charger. I will buy a multimeter today and measure output of my charger!

5 hours ago, alcatraz said:

If the charger is indeed outputting 84v then you should stop riding your wheel.

If the charger has this 2v drop issue that's happening to a lot of V8 chargers (that look oddly similar to the tesla charger) then you need a good charger. However since you're experiencing a 4v drop it's one more warning against riding.

Measure the charger please.

I have no tools so I will buy today and see where the problem is. I will not ride the wheel until problems are resolved. Should I leave the wheel charged at 83% as I have it now? Or shall I use it a bit so it's not "fully charged without being used". Since I was reading that if you're leaving your wheel for a long time, keep it around 40%.

1 hour ago, DavidB said:

"Maybe I should send the wheel back to the seller for checking it out."

Don't send the wheel anywhere! Yes, ring the seller. He obviously has enough electrical know how to advise you as he was able to upgrade your wheel from 1020Wh to 1500Wh and it was good for 5000km.

I think Marty Backe had a wheel like this that he got from China (Aliexpress dealer?). (edit: checked and yes he did)

The battery manufacturers warrant the cells to have at least 80% capacity after 500 charging cycles. Marty got 50 miles (80km) range so your 5000km is only 63 full cycle charges. So that is not the cause which means you definitely have a problem with the battery pack and I don't mean just getting 83% charge, you might lose your house/apartment or worse.

If there is an issue with one cell it can go into thermal runaway and start a cascade which will be impossible to put out. I don't know how the exta cells were intergrated in this wheel and guess it is possible one pack has been disconnected electonically (broken connection?) but you must check it out.

 

Ok, I have contacted him now and waiting for response. I checked my app and it has actually done 6300km, but still - it's not 500 cycles.
I have this flame proof bag over my wheel now. At least it might save my house from burning down, even though it may be contaminated by the smoke and chemicals etc...
https://iwheel.se/products/safe
 

[Chriull]

10 minutes ago, Yffisch said:

Should I leave the wheel charged at 83% as I have it now?

Yes.

With ~79V you could have a cell group (4.2V) dead and some others already degrading. Riding can reverse charge dead groups which leads to even greater stress for these cells.

Very likely it's just one pack with bad cells -so best to follow your sellers instruction to identify this pack.

[alcatraz]

I have a Tesla V1 with 13.000km and going strong with the original pack and bms's. 

If you have the older cells 18650 style, they're quite reliable (Panasonic). So just opening up the side panel with a philips screwdriver and taking a picture are enough to get some preliminaries. 

But yeah you need a simple multimeter and a screwdriver. 

When you get it measure the charger with VDC (dc voltage). It should show 84.5v thereabout.

[mrelwood]

Besides not riding the wheel, it would be best not to try to charge the wheel either at this point. Having the battery (or some cells) full for a week or two is not an issue. Measure the charger output voltage and wait for the seller’s response.

Like a few people said already, the battery lights do not represent the battery capacity. So even if the pack were at 1000 full charge cycles, or even if one pack was disconnected, the lights should all light up after a charge. And the voltage on the app should be close to 84V. The fact that it is not, means that either the charger no longer puts out the correct voltage, or at least one of the packs has failed. My guess is for the latter, unfortunately.

@Yffisch, out of curiosity, have you usually charged the battery to full, or have you disconnected the charger before the battery reached 100%?

Edited April 28, 2023 by mrelwood

[Yffisch]

10 minutes ago, mrelwood said:

Besides not riding the wheel, it would be best not to try to charge the wheel either at this point. Having the battery (or some cells) full for a week or two is not an issue. Measure the charger output voltage and wait for the seller’s response.

Like a few people said already, the battery lights do not represent the battery capacity. So even if the pack were at 1000 full charge cycles, or even if one pack was disconnected, the lights should all light up after a charge. And the voltage on the app should be close to 84V. The fact that it is not, means that either the charger no longer puts out the correct voltage, or at least one of the packs has failed. My guess is for the latter, unfortunately.

@Yffisch, out of curiosity, have you usually charged the battery to full, or have you disconnected the charger before the battery reached 100%?

99.5% of the times, when I charge the wheel I have always charged it to 100% (or at least when charger displays a green light).
This specific issue kind of started after not using the wheel over the winter. I left it without use for around 2-3 months, but I charged it once a month anyways. Very soon after that when I started using it again, this happened. I don't know if it's related or not. 

[mrelwood]

7 minutes ago, Yffisch said:

99.5% of the times, when I charge the wheel I have always charged it to 100% (or at least when charger displays a green light).

That’s good. That means that you have the BMS cell balancing a good enough possibility to keep the cells balanced.

7 minutes ago, Yffisch said:

This specific issue kind of started after not using the wheel over the winter. I left it without use for around 2-3 months, but I charged it once a month anyways. Very soon after that when I started using it again, this happened. I don't know if it's related or not. 

If the wheel was charged up to 100% for 2-3 months, the batteries definitely have degraded a bit during that time. Storing at 40-60% would’ve been much better. But even so, it shouldn’t have caused a severe battery failure like this.

I do wonder if the additional pack used the same cells and BMS that the original packs use. Combining different cells could cause a severe voltage drift that the balancing function might not be able to keep up with.

[Yffisch]

9 minutes ago, mrelwood said:

That’s good. That means that you have the BMS cell balancing a good enough possibility to keep the cells balanced.

If the wheel was charged up to 100% for 2-3 months, the batteries definitely have degraded a bit during that time. Storing at 40-60% would’ve been much better. But even so, it shouldn’t have caused a severe battery failure like this.

I do wonder if the additional pack used the same cells and BMS that the original packs use. Combining different cells could cause a severe voltage drift that the balancing function might not be able to keep up with.

Well, I remember that guy saying that the cells he was looking for was out of stock, but he said "I can put these instead, they are even better". So could have something to do with that. Although, he has a very good reputation and probably knew what he did.

Btw, another question. If I'll plug out the packs to see which one makes the charger turn red (which means I've found the broken one), should I really do this at the same time while the wheel is charging? Or shall I plug/unplug the cables to the blue packs while charging is off, and then start charging it to see what color it will be? It feels a bit risky to keep it charging while plugging in and out those cables?

[mrelwood]

 

2 hours ago, Yffisch said:

"I can put these instead, they are even better".

That does sound a bit strange. It sounds plausible that he didn’t know to take in consideration all the parameters of the new cells. Because if they are “better”, they are different somehow, which is usually bad.

2 hours ago, Yffisch said:

If I'll plug out the packs to see which one makes the charger turn red (which means I've found the broken one), should I really do this at the same time while the wheel is charging?

Definitely not. The battery connectors are usually very tight, and attaching/detaching them often causes an intermittent connection for a while. You don’t want to do that while charging. Only operate in a disassembled wheel when the charger is disconnected.

But remember, this is very important: Always measure the battery pack voltages before connecting them!!! They need to be at the same voltage, within like 0.5V or so, preferably even closer.

 If you detach a failed pack, it’s voltage can drop on it’s own within seconds, making it unsuitable for connecting back up.

Edited April 28, 2023 by mrelwood

[Yffisch]

I just checked charger with multimeter and got 84.6v. So that means there is nothing wrong with charger.

Edited April 28, 2023 by Yffisch

[mrelwood]

14 hours ago, Yffisch said:

I just checked charger with multimeter and got 84.6v. So that means there is nothing wrong with charger.

Yep, charger seems fine. Sounds like it’s a battery pack failure. I hope the seller gets back to you soon.

[Yffisch]

Does those pictures make any sense to anyone?

[mrelwood]

7 hours ago, Yffisch said:

Does those pictures make any sense to anyone?

What do you mean? Looks normal to me. What is surprising though is that there doesn’t seem to be an extra third battery pack like I assumed from your earlier posts. Maybe the seller installed new packs altogether?

[Chriull]

3 hours ago, mrelwood said:

What is surprising though is that there doesn’t seem to be an extra third battery pack like I assumed from your earlier posts

Seem to be two 20s2p packs.

With 21700 5Ah cells that's 80*3.7*5=1480Wh.

The "rub marks" on one of the batteries do not look nice

[alcatraz]

This is not the same config as the 1500 v2 that was found a couple of years ago. I'm surprised they got this pack to fit. The problem was to get the 70 x 2 mm clearance between the trolley handle rods. (21700 cells, 21x70mm)

By squeezing such a large pack in, I'm thinking maybe a couple of cells got scuffed (wear through the heatsink and damage their casing) and that could explain them discharging. Also, we don't know what cells you have. Are those SF sticker the only info?

Disconnect the packs and measure them individually. Mark them 1/2. Charge them individually (by disconnecting one at a time, including its extra singnaling cabling) for a couple of minutes and see if you can figure out which of them won't charge. You can usually see the charger light turn green prematurely on the bad pack.

With a charger at 84.5v it is indeed a pack problem. Maybe one can be removed and replaced to fix it. If it shows that you have M50T cells, you probably shouldn't ride any of them. If you have other cells and one pack charges fine, then you could just replace the bad side and have a working wheel again.

Repairing a pack is tricky.

Edited April 29, 2023 by alcatraz

[Yffisch]

On 4/29/2023 at 7:30 PM, mrelwood said:

What do you mean? Looks normal to me. What is surprising though is that there doesn’t seem to be an extra third battery pack like I assumed from your earlier posts. Maybe the seller installed new packs altogether?

Yes, now it makes more sense to me. He removed the speaker part to be able to fit the whole pack. I understood it from him like he will keep original and add a 3:rd pack where the speaker is located. But apparently not

On 4/29/2023 at 10:47 PM, Chriull said:

Seem to be two 20s2p packs.

With 21700 5Ah cells that's 80*3.7*5=1480Wh.

The "rub marks" on one of the batteries do not look nice

Yeah, might be since it's so stuffed in there.

On 4/30/2023 at 12:12 AM, alcatraz said:

This is not the same config as the 1500 v2 that was found a couple of years ago. I'm surprised they got this pack to fit. The problem was to get the 70 x 2 mm clearance between the trolley handle rods. (21700 cells, 21x70mm)

By squeezing such a large pack in, I'm thinking maybe a couple of cells got scuffed (wear through the heatsink and damage their casing) and that could explain them discharging. Also, we don't know what cells you have. Are those SF sticker the only info?

Disconnect the packs and measure them individually. Mark them 1/2. Charge them individually (by disconnecting one at a time, including its extra singnaling cabling) for a couple of minutes and see if you can figure out which of them won't charge. You can usually see the charger light turn green prematurely on the bad pack.

With a charger at 84.5v it is indeed a pack problem. Maybe one can be removed and replaced to fix it. If it shows that you have M50T cells, you probably shouldn't ride any of them. If you have other cells and one pack charges fine, then you could just replace the bad side and have a working wheel again.

Repairing a pack is tricky.

I think he wrote he would put Samsung 50E, but then I remember he called me and told about some other batteries on the phone that I don't remember.
Those stickers was the only thing I could see. I'm still awaiting response from seller so I might ask when he responds.