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Confused by voltage measurements


agranner

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I’ve been using DarknessBot since my V8S was new (115 miles total as of today). I read that the manufacturer’s apps were really bad before I even got my wheel. However, I’m starting to believe that all the numbers are wrong. Let me explain. 
 

If I charge until the charger LED turns green plus 30-90 minutes (I use the stock 1.5a charger that came with the wheel which I purchased new from Euco) DarknessBot indicates a voltage that fluctuates around 82.7 V (+/- 0.2 V). InMotion app says the same (but they claim 100% SoC, which I know is meaningless). I tested my charger output and it measured exactly 84.2 V steady (I used a Klein CL120 which states an 200.0 VDC accuracy of +/- 1% + 3 digits!). Also there have been no irregularities with charging: I haven’t run more than about 18 miles, I always charge until green plus and then disconnect, voltage charts in DarknessBot seem the right shape. It’s very consistent. 
 

So, I suspect that my charger is working properly. I’m hoping that the battery is ok and is actually 84.0 V when full but the controller is mis-measuring and sending the same wrong value to either app since they agree consistently. How do I test this? Do I have to open the wheel to measure battery directly? And can I trust my meter accuracy? Is it possible the pack is at 82.7 V? Does that mean I have an imbalanced pack that has not been charging properly? If so, why has the passive top-balance not worked for me?
 

The other DarknessBot numbers are also off: current seems offset by -2.7 A as in that’s the displayed value when not moving, very consistent. PWM is nowhere close since I have logged well over 100% but this has a calibration setting. Of course SoC is unreliable but that probably has to do with a bad voltage reading. It’s a little terrifying to watch SoC sag from around 30% to 0 as I try to go up hills. I should say I’m over 6’0” 200 lbs.

 

Any ideas?

 

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If the voltage reading seems off on any Inmotion, the most probable cause is indeed the voltage calibration of the controller. You can reach out to your seller (or possibly Inmotion directly) for Inmotion to remote calibrate the reading. It should actually even give you a tiny bit of additional range in your case.

 Being consistent at 82.7V, and you correctly giving some time for the balancing, I don’t think there is a reason to suspect a lower voltage at the battery itself. The only way to confirm would be, as you wrote, to disassemble and measure the battery pack directly.

I think you should be able to check the charging current from the app a few hours after the charger going green though. If it’s still closer to 0.3A than 0.1A, you actually could have a pack balance issue.

 Regarding any other values, DarknessBot and even EUCw can be a bit slow in adding full support to the latest wheel models, as they don’t get the data transmission protocols from the manufacturer. But “manufacturers’ apps are crappy” is obviously a blanket statement that shouldn’t be trusted much without confirmation.

I personally consider Inmotion’s app to be quite far ahead from the other manufacturers’ apps, especially Gotway’s. I stopped using DB when I got my V11, because for the first time the official app already gave me everything I needed. Besides, I wanted to be able to trust the readings and to be able to adjust the settings, something the DB still doesn’t seem to be doing correctly on the V11, soon two years after V11’s release.

 Regarding the voltage sag though, dropping from 30% to 0% under acceleration is most probably not an issue with the readings. That’s how a pack of that capacity does perform. Inmotion has a pretty long averaging time window for the battery SoC, so a dip like that is simply rounded off. It doesn’t mean it doesn’t happen though. Take it easy on low battery!

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7 hours ago, mrelwood said:

remote calibrate the reading.

How does this work? Are there over-the-air functions? Or do you mean send the wheel back in? 
 

 

7 hours ago, mrelwood said:

But “manufacturers’ apps are crappy” is obviously a blanket statement that shouldn’t be trusted much without confirmation.

I totally agree. I figured there wasn’t much to lose as I sat around waiting for my EUC to arrive. Also seems like DarknessBot is a positive for the community and wanted to support it. 
 

One of the coolest things that’s happened to me since I picked up this new hobby is learning about batteries and EVs in general. These forums have a ton of info and it’s also led me to a bunch of other resources.

It’s easy to get wrapped up in the “EVs are perfect and they’ll save us all” hype but the reality is they are very complicated both for engineers and end users. SoC and range is an example of us comparing them to other modes and it’s just not that simple. I don’t even know what my “range” would be because of progressive tilt-back (firmware), battery voltage sag (hardware), and lower confidence in not cutting out (“driver-ware”) means that almost every mile is a totally different experience. How do you decide when the range has ended? 
 

Anyway, thanks to everyone here. You guys are great!

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8 hours ago, agranner said:

I tested my charger output and it measured exactly 84.2 V steady (I used a Klein CL120 which states an 200.0 VDC accuracy of +/- 1% + 3 digits!)

Which means the real measured voltage is somewhere in the range of 84.2V +/-1.14V ~83.1-85.3V

So assuming some comparable accuracies at the motherboard voltage meadurement the 82.7V are perfectly "sane". The 82.7V wirh +/-1% could mean some 81.9V to 83.5V. So for this example the "real" voltage could be in the range of 83.1V-83.5V.

But one does not know if your voltmeter still is within the specified accuracy and the accuracy for the inmotion voltage measurement was just a guess...

8 hours ago, agranner said:

I’ve been using DarknessBot since my V8S was new (115 miles total as of today). I read that the manufacturer’s apps were really bad before I even got my wheel. However, I’m starting to believe that all the numbers are wrong.

All the apps get the same numbers from the wheel - so there is no difference. Just some 3rd party apps have options for optimized state of charge percent, self calculated and trying to give a more value, precise value.

20 minutes ago, agranner said:

Are there over-the-air functions?

Yes - inmotion can calibrate ota.

8 hours ago, agranner said:

The other DarknessBot numbers are also off: current seems offset by -2.7 A as in that’s the displayed value when not moving, very consistent. PWM is nowhere close since I have logged well over 100% but this has a calibration setting.

Darknesbot had estimated pwm values for inmotion, shermann and begode wheels. Don't know if darknesbot already reads the real value reported from the v11 since some firmware versions by now?

8 hours ago, agranner said:

Of course SoC is unreliable but that probably has to do with a bad voltage reading. It’s a little terrifying to watch SoC sag from around 30% to 0 as I try to go up hills. I should say I’m over 6’0” 200 lbs.

Standard wheel reported soc % values are durectly calculated from battery voltage. So each voltage sag due to burdening a wrong soc is reported.

Afaik euc world estimates/calculates the internal resistance of the batteries and with the battery current he comes to more stable "no load" battery voltage giving more stable soc %.

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9 hours ago, agranner said:

current seems offset by -2.7 A as in that’s the displayed value when not moving, very consistent

The wheel and motherboard always draws some current. Current seems to be measured in both directions - so the zero offset from the motherboard seems to be badly (or not at all) calibrated.

Or does the inmotion app show some different values here?

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@Chriull The two apps do NOT match for “current”. When DarknessBot displays -2.7A, the InMotion app displays -0.2A. They only agree on voltage. I will look into a ota voltage calibration. Has anyone had experience with this? What is the procedure? It sounds very encouraging. 
 

I figured since DB has calibration settings for speed and PWM that those are calculated/derived from other data in the BT stream. There is no in-app settings for voltage or current. I don’t know, obviously what the control board actually holds in registers/memory and what it communicates. I speculate that PWM is a real value in a register on the controller since it’s obviously necessary to control the motor. Similarly, voltage is a real value in a register since it’s necessary for BMS function. I would have assumed it would be up to the off-board apps to calculate current (and power) from those two values. I don’t see the necessity of the controller knowing current (per-phase or total) to function and I speculate that it’s not simple to measure with any accuracy. 

A “no-load” SoC display would be more useful but I think, in general, we just need to learn to live with these things that are not analogous to a tank of fuel. I’m ok with that.

Thanks!

 

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Also, I would hope the Bluetooth power draw would be on the order of 1-2 watts. -0.2A at 84.0V is 16.8W. That seems like a lot to run a couple microcontrollers and a BT radio. But I’m just speculating.

It seems more likely to me that the current measurement (if it is on-board) is +/-x% + y digits so -0.2A could be anything. 

If it is a derived value and the motor isn’t running, it should be 0.

hahaha: this is quickly approaching the limit of my amateur electronics knowledge. 

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26 minutes ago, agranner said:

I will look into a ota voltage calibration. Has anyone had experience with this? What is the procedure?

I have had it done on my V11. Usually you contact your dealer first, and they sort of book an appointment with Inmotion. At a specific time, you are in contact with the seller by phone or chat, battery fully charged. Your dealer relays the procedure between you and Inmotion. They ask you to do some simple stuff with the Inmotion app while connected to the wheel, and they remotely calibrate the voltage measurement OTA. The whole thing is done in a minute or two.

21 minutes ago, agranner said:

Also, I would hope the Bluetooth power draw would be on the order of 1-2 watts. -0.2A at 84.0V is 16.8W. That seems like a lot to run a couple microcontrollers and a BT radio. But I’m just speculating.

You are expecting an amount of precision that the current systems do not reach by a long shot. All values, speed and distance included, should be approached as rough estimates only…

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@mrelwood Thanks! That sounds easy.

I’m also going to try using the InMotion app for a dashboard the next couple of times. I think you’re right: it was much better than I expected it to be. However, I really like the DB ui and features: charts, offline history, and PWM alarms are great! Also Apple Watch is necessary for me because I can’t be seen riding around looking at my phone. I know, a watch isn’t much better, but perceptions matter sometimes.

I really appreciate you all!

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Try leaving the charger connected for a very long time. Like a day. If you get over 82.7v then it probably means it balanced something out. If not, then it probably means that's 84v.

It's not conclusive but can tell you something.

If you can open up the wheel and measure the voltage then that's ideal. (Inmotion V8 can't be measured on the output terminal. You have to measure on the control board while the wheel is turned on. Or split the battery enclosure and measure on the bms. V8 have a very nice enclosure that seals up nicely after opening so you don't have to worry about taking off the plastic seal. The best part about measuring the BMS is PEACE OF MIND. You can quickly measure all the cell groups and feel completely at ease.)

Gotways let you charge while the wheel is on. That's great because you can see in the app what the voltage becomes when the charger gets introduced. = easy to see if it rises or not.

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I’m tempted to open the wheel and take a look. I suspected that it was well put-together. That’s one reason I picked this one. 

I’m not keen to leave the charger connected for a long time. As I understand, the charger maintains as much current as necessary to have a constant voltage, even well past when most of the cells below the 3%C charging threshold from the data sheet. Even if the BMS is shunting through a bypass resistor, there is still some current going through the fully charged cells which the manufacturer clearly recommends against. Obviously it’s a trade off: we have to accept some (hopefully mild) trickle charging in order to get a balanced pack. As I understand, this is the key why people say to charge to full every time as a balanced pack can be removed from the charger soon after threshold and not trickle the cells.

A charge monitor sounds like a great idea! You could have a really good idea of how long you are trickling. Gotta look for one of those.

BTW, it seems the wheel is “on” as long as the charger is connected and I do get Bluetooth data. The problem is my voltage readings on-board are wrong (I suspect) and can’t be trusted. I’m going to call EUCO service and see what they say. 

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22 minutes ago, alcatraz said:

you can see in the app what the voltage becomes when the charger gets introduced. = easy to see if it rises or not.

Oh, I see what you mean. It always seemed to me that the voltage reading didn’t rise much with the charger connected even in “red light mode”

I’ll look more closely the next time I charge from a lower SoC. Usually, when I get home from a daily commute cycle I’m at around 75-77V. Should I see a noticeable increase between on/not-moving and on/charging? 

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50 minutes ago, agranner said:

 I’m not keen to leave the charger connected for a long time. As I understand, the charger maintains as much current as necessary to have a constant voltage, even well past when most of the cells below the 3%C charging threshold from the data sheet. Even if the BMS is shunting through a bypass resistor, there is still some current going through the fully charged cells which the manufacturer clearly recommends against. Obviously it’s a trade off: we have to accept some (hopefully mild) trickle charging in order to get a balanced pack. As I understand, this is the key why people say to charge to full every time as a balanced pack can be removed from the charger soon after threshold and not trickle the cells.

While I understand your concern, keep in mind that balancing is pure guess work on our side. We have no idea how long it needs to do that, yet alone know if it's balancing at all.

The balancing current is a few milliamps. It's basically nothing. I theorize that this is why we have no problems for a few years then all hell breaks loose. It's because the balancing provided is nearly useless. It's not needed at all for years while cells are in good condition. As soon as they deteriorate the balancing current is almost immediately overpowered and rendered useless.

So the balancing time could be something like this:

Year 1: 0min

2: 0min

3: 1min

4: 30min

5: 1000min.

6: 1000000000min.

That's why these 60-90min on the charger rules to me sound a bit like a joke.

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Tickle charging Li Ion isn't a good idea, that's pretty much universally accepted. A question remains: how much is too much? My only data point is my 9 year old laptop which sat on charger 24/7 for yes, 9 solid years. I don't know when it started to go 'bad' because it was rarely used on battery power, but after 9 years the laptop would only last about an hour on battery power whereas it started life at around 4-5 hours. So from my experience, if you leave your wheel on charger for 9 years, you're for sure going to want new batteries. On the other hand, if you don't balance them you may well be shopping for batteries in year 2 or 3.

Edited by Tawpie
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8 hours ago, alcatraz said:

While I understand your concern, keep in mind that balancing is pure guess work on our side. We have no idea how long it needs to do that, yet alone know if it's balancing at all.

Correct.

8 hours ago, alcatraz said:

The balancing current is a few milliamps. It's basically nothing.

Incorrect, there is no specific “balancing current”. Passive top balancing works by slowing down the charging (ie. lowering the voltage) of the high cells. Low cells continue charging as usual. The bigger the difference is, the faster the difference decreases.

8 hours ago, alcatraz said:

It's not needed at all for years while cells are in good condition.

Doesn’t seem like that though. On one of the S20 demo units the cell voltage difference was already closer to 0.2V. The provided charger probably didn’t allow any balancing to happen, but still, the wheel hadn’t been charged but a few times.

8 hours ago, alcatraz said:

As soon as they deteriorate the balancing current is almost immediately overpowered and rendered useless.

“Balancing current” is probably the misleading part here, since there is no specific current that does the balancing. Another is “balancing time”. Balancing starts when the first cells’ surface voltage reaches 4.2V, but balancing doesn’t really stop unless  the BMS completely interrupts the charging which only happens if the difference is very large to begin with.

As the cells deteriorate, the low cells will get burdened more as the pack is used. That slowly increases the voltage difference, ride after ride. The sooner the voltage difference is taken under control, the smaller the difference in the rate of deteriorating is. So even if the balancing was very ineffective, it is enough to keep the pack in good health as long as it’s used continuously right from the start.

8 hours ago, alcatraz said:

That's why these 60-90min on the charger rules to me sound a bit like a joke.

To me it seems like the reason they sound like a joke to you comes from slightly misunderstanding the balancing process.

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I've studied dozens of balancer specs for diy batteries for a long time. ~90% of them offer very small balancing currents like 30-60mA.

When you have a couple of cell groups that deviate and do so in an accelerating fashion, those cell groups of several thousands of mAh are going to very quickly take a long time to be set straight.

It makes me think that the provided bms' are designed to only cope with deviations of new matched cells. As soon as they age a few years it's anyone's game.

If you've worked with hobby balance chargers you can see there how they usually work. Charge the whole pack until the first group reaches 4.2v, and then bleed that one group, then charges the whole pack again. If you have one cell much lower than all the others it's a painstakingly long charging process. It also wears out the healthy cells by constantly charging and discharging them until the weak group gets up to level.

These hobby packs are also way smaller than most wheel cell groups. The simple popular chargers have tiny balancing currents too. The very expensive chargers have proper currents.

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58 minutes ago, alcatraz said:

When you have a couple of cell groups that deviate and do so in an accelerating fashion, those cell groups of several thousands of mAh are going to very quickly take a long time to be set straight.

Sure, which is exactly why I have had the best results keeping them in the line from day one.

 

58 minutes ago, alcatraz said:

If you've worked with hobby balance chargers you can see there how they usually work.

Ah, I haven’t. And the difference may be in that on EUCs the charger is happily unaware of any balancing. It’s 100% the responsibility of the unique BMS design.

 

58 minutes ago, alcatraz said:

It also wears out the healthy cells by constantly charging and discharging them until the weak group gets up to level.

That’s not what the EUC BMS does though. And doesn’t sound like small “balancing currents” even could discharge the healthiest cells very fast either.

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I'm with @alcatraz on this one... most GW/BG BMS we're seeing today have a 120R bleed resistor for each 10,000mAh cell group, which drains just 35mA at 4.2V. A very slow effect.

Older wheels from ~2016 had faster balancing circuits, like 75R and 56mA per 5,000mAh group... 

(I can see an argument for keeping the balancing currents small- because the BMS is buried inside a padded and sealed battery pack, and balancing will cause heating of the bleed resistor. With our in-pack BMS, there's basically no place for the heat to go, so let's minimize it.)

This "weak top-balancing" approach does seem to work for most EUC owners... hard to criticize it too much, since it's been pretty effective for us. 

12 hours ago, alcatraz said:

So the balancing time could be something like this:

Year 1: 0min

2: 0min

3: 1min

4: 30min

5: 1000min.

6: 1000000000min.

Right. @Chriull did a lovely demonstration... 

TL;DR:   Charging longer helps correct under-voltage cells. And powered-off resting time after disconnecting the charger helps correct over-voltage cells. 

 

On 3/19/2022 at 9:52 PM, agranner said:

I always charge until green plus [some time] and then disconnect, voltage charts in DarknessBot seem the right shape. It’s very consistent. 

That's all it takes to convince me :) 

Further investigation is only to satisfy your inner curiosities, enjoy.

If there are real problems, the EUC won't let you finish a charging session. The voltage would rise steadily, then step down in a sudden ~1V drop and not permit further charging. 
(Instead, yours seems to rise to a plateau and stay there, when the charger is connected. That's good.)

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It depends on what you have but it should work along these lines. If balancing starts at 4.18v and the overcharge limit is 4.25v and you have one group at 4.00v, others at 4.18v.

How many times are you going to hit that limit? You're trying to bleed off 4.25v to 4.18v, and then charge all cells up so you hit 4.25v again, etc etc.

There is little charge needed to go from 4.18 to 4.25v. For that weak group at 4.00v it would maybe get to 4.01v after one cycle. Then repeat. Bleed 19 groups back to 4.18 then activate the charger, get back to 4.25v etc. 

The older the pack, the more cycles needed etc. All cells except the bad ones are being micro cycled, hitting the overcharge limit repeatedly, hundreds/thousands of times.

For a community that tries to avoid trickle charging, it's ironic how the bms' charges/discharges 99% (the healthy portion) of the pack up to the brim 4.2x volts, hundreds of times to straighten out 1-2 weak groups. It's almost like it's trying to AGE the good goups faster to match the weak ones. (The smart bms' with good currents, charge a big capacitor from the highest group and deposits that charge into the weakest, so it doesn't keep cycling the good groups.)

In China, cells and bms' are relatively cheap and simple. They don't plan 10-20 years of life. They put in the minimum needed for hobby use, for a short ownership. Then swap in a new pack after a few years. Us westeners like long lasting stuff so we better update the bms', or have some sort of plan B.

I'm no expert but I'm 99% sure that most/all of the supplied bms' can't be trusted. It's a lottery, if you have a wheel that still charges fine after 5 years then you won the lottery. There's still the question of communication between packs etc. Is the protection still working after 5 years? Maybe you're overcharging half the pack unknowingly to reach the 100% you're seeing. There are a lot of ifs.

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19 hours ago, agranner said:

Oh, I see what you mean. It always seemed to me that the voltage reading didn’t rise much with the charger connected even in “red light mode”

I’ll look more closely the next time I charge from a lower SoC. Usually, when I get home from a daily commute cycle I’m at around 75-77V. Should I see a noticeable increase between on/not-moving and on/charging? 

Here’s a screenshot showing 60sec of voltage from DarknessBot. Clearly shown increase of ~0.4V is when I connected the charger (stock 1.5A charger) showing red light.

It also seems like voltage is increasing about 0.4V per minute. I have no idea what the rate of voltage rise should be. I’ll keep an eye on it to see what I can learn.

I understand the “charger voltage” will increase during the constant currant phase up to the constant voltage set point when current is reduced to maintain voltage. I have to assume that the voltage being measured by the controller (and sent to phone) is the same main battery terminals’ value as this “charger voltage”. What else could it be?! But both charge and discharge go through the BMS. Now I know I’m not going to be satisfied until I open the pack and probe all over. Still want a charge monitor. 

138C5451-2E71-41A7-B4D8-906A4174AFC2.png

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10 hours ago, alcatraz said:

It depends on what you have but it should work along these lines. If balancing starts at 4.18v and the overcharge limit is 4.25v and you have one group at 4.00v, others at 4.18v.

How many times are you going to hit that limit?

Once. Then the BMS interrupts the charging, and doesn't continue until you disconnect, and reconnect the charger once the overvoltage has been removed.

But even before it cuts off, your example situation doesn't seem to be hitting the cutoff voltage at all:

10 hours ago, alcatraz said:

You're trying to bleed off 4.25v to 4.18v, and then charge all cells up so you hit 4.25v again, etc etc.

This is not what happens. If balancing starts at 4.18V, the charging current for the highest groups is simply 35mA smaller (per @RagingGrandpa's calculations) than for the low groups. In the mentioned case (4.18V / 4.00V) the charging current is still 250-1250mA per cell (depending on the charger and the pack configuration). 35mA decrease only slows down the charging, it doesn't bleed off anything until the total charging current is down to 140-210mA, which is only after the charger has displayed a green light for a while already. Which is btw a situation the pack never even gets to if any of the cell groups reach 4.25V.

A good read is the Li-ion cells' "polarization voltage", ie. surface vs core voltage. It is one part of smoothing out the cell voltages at the end of the charging process, and prolonging the CV phase of the charge.

10 hours ago, alcatraz said:

There is little charge needed to go from 4.18 to 4.25v. For that weak group at 4.00v it would maybe get to 4.01v

If the 4.18 groups would get to 4.25 in a giffy, the 4.00 group would get to 4.07 in the same time perioid, wouldn't it?

10 hours ago, alcatraz said:

after one cycle.

The charger and the balancer are different entities, and the balancing process doesn't work in cycles, as described above. The charging is not stopped to do the balancing, then continued. The charging is constant.

10 hours ago, alcatraz said:

Then repeat. Bleed 19 groups back to 4.18 then activate the charger, get back to 4.25v etc.

It never bleeds any of the groups "back to 4.18V". If one group is at 4.00V on a 20S pack, the average for the other 19 groups is at maximum 4.21V. That makes the total pack voltage to 84.0V, and that's all a healthy charger gives.

10 hours ago, alcatraz said:

All cells except the bad ones are being micro cycled, hitting the overcharge limit repeatedly, hundreds/thousands of times.

Again, hitting the overcharge limit cuts off the charging completely until disconnected and reconnected once the voltage has dropped. It doesn't "cycle".

10 hours ago, alcatraz said:

the bms' charges/discharges 99% (the healthy portion) of the pack up to the brim 4.2x volts, hundreds of times to straighten out 1-2 weak groups.

Your math doesn't add up. If the high groups are charged worth 0.2V, so are the low ones. If the difference is 0.2V, hundred times that would charge the low cell groups to 24V each. We all know that doesn't happen.

 

10 hours ago, alcatraz said:

I'm no expert but I'm 99% sure that most/all of the supplied bms' can't be trusted.

If someone is 99% sure, I'd surely call them an expert. :lol:

10 hours ago, alcatraz said:

There are a lot of ifs.

These are not general if's of the industry or li-ion battery science, but aspects that are just not clear to you yet. I'm not saying that everything is clear to me either, but it does seem that you could ease some of your worries by reading more about the subject, or directly investigating how the BMS on an EUC functions.

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I’m second guessing what I thought about charging. @alcatraz and @mrelwood Have given me a lot to think about. I assumed that leaving the charger connected overnight would be not good because it’s not smart enough to turn itself off. So I’ve only charged until going to bed as this is always after the green light comes on.

Now, I’m thinking that may mean I have never given this pack a full charge including the day it came in it’s box.

So if the charger puts out as much current as necessary to maintain 84.2V then ideally the pack voltage rises to 84.2 and levels off. Once it is no longer rising no charging or balancing is happening and if any cell reaches 4.25V, the BMS opens the charging circuit and the current from the charger should fall to zero. Maybe the stray current people have noticed long after green isn’t going to the pack at all and is just in the BMS.

This means it should be ok to leave the charger on overnight. For me that would be about 10 hours past green. As long as I ride some in the next day or two.

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10 hours ago, agranner said:

This means it should be ok to leave the charger on overnight.

I guess it should be ok, yes. But I don’t think it would achieve much. The total charging current generally tapers down to minuscule amounts in just a few hours. So even if you aren’t worried about keeping the wheel in the charger overnight, I can’t really think of a situation where it would be specifically beneficial. I rather just be determined about charging for an extra hour or two every single time I charge the wheel.

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1 hour ago, mrelwood said:

 

I guess it should be ok, yes. But I don’t think it would achieve much. The total charging current generally tapers down to minuscule amounts in just a few hours. So even if you aren’t worried about keeping the wheel in the charger overnight, I can’t really think of a situation where it would be specifically beneficial. I rather just be determined about charging for an extra hour or two every single time I charge the wheel.

Perhaps not for the euc, but for the person doing the charging, he would be more at ease as to when he can start charging the euc, since there is no compromise in cycle life if he can unplug it whenever it is convenient, ie. when he gets up in the morning. 

For myself, if I have a new wheel, and after many positive recharging cycle experience, and the battery is still in tiptop shape, I don't mind leaving the charger plug in over night. Mind you I still try to get all the charging done before I go to sleep. But if I can't, now I know I have an option.

 

 

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