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Sherman Charger Issue ?


Adel

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I notice that the charger makes periodic clicking noise, also accompanied by corresponding LED flicker as you can see from the clip below. I also noticed the same behavior from a replacement charger. If you have a Sherman, does your charger behave the same way, is this normal or sign of a problem with the charger or the wheel ?

 

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Yes mine does the same thing. Usually near the end of charge. I'm sure it's something to do with the battery reaching end of charge voltage, and then dropping when the charger disconnects, then it just goes back and fourth. 

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5 hours ago, Fiori said:

Yes mine does the same thing. Usually near the end of charge. I'm sure it's something to do with the battery reaching end of charge voltage, and then dropping when the charger disconnects, then it just goes back and fourth. 

Great. Thanks for confirming.

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I noticed mine doing this more often now. I checked the voltage when it was happening and it was hovering between 101.2V and 101.3V(which is too high), the flicker happens when it switches between the two. I am assuming this is triggering the HV cutoff on the Sherman BMS. It's not normal for that to happen IMO. 

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Mine does that, as well as a fast charger for the 16S.
It fades off as the batteries are saturated and dont drop some voltage at charge stop. The charger goes to solid green and spin the fan for a little while more (balancing?) before going entirely silent at 100.5V.

( @Fiori yes that is too high, but could be the measurement that is off, AFAIK they are all a bit off. Try confirming with a multimeter?)

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@nullJust measured charger port with multi-meter this morning: 101.00V. Not extremely high, but still over what it should be. I'm sure it spikes a little when charging too. 

 

Will probably end up sending charger back to ewheels(we are in talks now), but I'll see what they say. 

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7 minutes ago, Fiori said:

@nullJust measured charger port with multi-meter this morning: 101.00V. Not extremely high, but still over what it should be. I'm sure it spikes a little when charging too. 

 

Will probably end up sending charger back to ewheels(we are in talks now), but I'll see what they say. 

Indeed, if a second source reads it as too high it probably is.
In general chargers can be adjusted with a small potentiometer inside, but if you have a plan with eWheels good for you.

Edited by null
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@null I agree I think it's a bit too high. I thought this might have that adjustment screw but wasn't sure. I wanted to avoid ripping open a brand new(2 week old) charger if possible. If they let me keep this one and send a new one I may open it up and see if I can do just that(or they may instruct me to open it up and do that, we will see). 

Edited by Fiori
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I am sending back the charger and getting a replacement. 

Out of curiosity I measured voltage at the pins of the charge port on my Sherman: it was 96.7V. 96.7V scared me a bit as 23X4.2 = 96.6(aka bad series group of cells).Charge port should show 100.8V(or close to it) when full. Value did not change whether wheel was on or off. With screen on Advanced mode screen on the Sherman says 100.3V. But I am told there are diodes on the charge port that could effect the voltage reading at the port.

So I removed the top cover and measured voltage at the xt90 for the battery pack on each side: both packs were equal(yay) and at 99.7V, which is good news. I do feel this has something to do with why the charger wont turn off.  I am assuming bad charger with higher voltage(101V-101.2V) is triggering HV cutoff of the bms prematurely and not allowing the charger to properly ramp down and fully charge the battery. I will see if new charger does any magic.

 

EDIT: BA and BU screens of the advanced section of the Sherman screen both were equal and showed 111 as a value. From what I can tell, this is good. 

Edited by Fiori
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Update: new charger came. Output voltage on new charger is 100.8v, much better. However the flickering issue still happened at least once, but way less often with new charger. I'll keep watching it and report. 

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  • 3 weeks later...

New Update: It rained for a few days here, and then I went out of town for the weekend. I left my sherman plugged in this entire time. When I came back the shermans fans were running, and the sherman screen was cycling on and off saying "No conn".  Charger light was green and sherman battery was reduced to about 50 percent. I am assuming the fans and sherman screen drained the battery over this long period of time. 

I will send yet another message to ewheels and update with the results...

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4 hours ago, Fiori said:

New Update: It rained for a few days here, and then I went out of town for the weekend. I left my sherman plugged in this entire time. When I came back the shermans fans were running, and the sherman screen was cycling on and off saying "No conn".  Charger light was green and sherman battery was reduced to about 50 percent. I am assuming the fans and sherman screen drained the battery over this long period of time. 

I will send yet another message to ewheels and update with the results...

Interesting it went down to 50%, if anything it is for the better, trickle charging is bad for the cells.
It is not recommended to leave it unattended, especially for days, as there is a higher chance of something going wrong when charging.

Edited by null
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7 hours ago, null said:

Interesting it went down to 50%, if anything it is for the better, trickle charging is bad for the cells.
It is not recommended to leave it unattended, especially for days, as there is a higher chance of something going wrong when charging.

It was plugged in for about a week(which I understand is a long time). It was monitored by camera/alarms in a safe area. Built tons of 18650 batteries and know the bang bang boom capabilities all too well. 

It definitely didn't discharge itself like that on purpose. The screen was cycling on and off about every 10 seconds, it would show the 'no conn.' message and then repeat the cycle. Sherman software had some type of glitch I'm sure, whether or not its caused by the flickering light on the charger I do not know. 

I definitely don't want it to trickle charge by any means. I just wanted to make sure it has ample time plugged in while charged so that the balance function can do its job. Balancing a pack this huge takes forever. I'd like to know if the BMS on the Sherman actively balances or does so only at the upper end of charging(I hope its active, but i'm doubtful). Most of these only balance when close to full(around 4V) and plugged in to the charger. Usually at super slow rates like 5-20mA.

 

EDIT: Also I do not plan to leave the Sherman plugged in by itself even with cameras/ fire alarms after this incident because it's clearly not setup to safely do that. 

Edited by Fiori
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2 hours ago, Fiori said:

I definitely don't want it to trickle charge by any means. I just wanted to make sure it has ample time plugged in while charged so that the balance function can do its job. Balancing a pack this huge takes forever. I'd like to know if the BMS on the Sherman actively balances or does so only at the upper end of charging(I hope its active, but i'm doubtful).

It has passive balancing as all the other wheels - balancing a bit at the top by resistors in parallel.

2 hours ago, Fiori said:

 Most of these only balance when close to full(around 4V) and plugged in to the charger. Usually at super slow rates like 5-20mA.

And this is "trickle" charging plus. Imho at the end this passive balancing gets more ineffective and stresses the cells more than everything else.

My thoughts by now for balancing would be some consectutive charge cycles with just very low discharge so balancing is repeated.

Imo an unbalanced pack can in most cases not be balanced by one cycle with passive balancing. Passive balancing is designed to just balance a "little" bit each time.

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On 2/3/2021 at 6:23 AM, Fiori said:

t definitely didn't discharge itself like that on purpose. The screen was cycling on and off about every 10 seconds, it would show the 'no conn.' message and then repeat the cycle. Sherman software had some type of glitch I'm sure, whether or not its caused by the flickering light on the charger I do not know. 

Yes “no conn” happened now and then on mine for no clear reason as well.

Edited by null
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Hello, my sherman came 2 days ago with yz450 charger and at 79% of charge when i plug the charger it makes same on/off clicking and sounds... Anyone using any type of “smart chargers”? Wondering if other chargers are better....

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23 hours ago, rdo1 said:

Wondering if other chargers are better...

Yes that is a good question, I have spent some time trying to investigate. Except that YZ seem to have fairly shabby build quality, there is nothing to know if a producer is better than another. The little feedback there is are the faulty units (everyone has some) but there are no details on electrical design or build quality. Even Chargery who make a very feature rich 15A charger have their share of issues. On top it might not do balancing on the Sherman.

The only charger that is (supposedly) sure to be of quality is the Grin Cycle Satiator, which is very expensive and not that powerful at 100V..

Frustrating situation, with all the e-vehicules we could have thought someone knowledgeable would do some reviewing, but no.

edit: I am making an overview of the main brands / models, hoping to gather some info there. Photos of the inside of the models I have if you have any electricity knowledge to judge from.

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11 hours ago, null said:

 On top it might not do balancing on the Sherman.

Balancing is always done via battery pack bms so it should balance with any charger that reaches the correct full voltage. 

Looking forward to your findings. To be quite honest it's my opinion that this charger sucks and is very cheap. I'm hopefully there are higher quality 100.8V chargers to be had, they just don't seem to be super common. 

Edited by Fiori
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On 2/12/2021 at 12:01 AM, Fiori said:

Balancing is always done via battery pack bms so it should balance with any charger that reaches the correct full voltage. 

I know, hence I don’t see what could be the reason if this is true. @houseofjob might get us some more info.

it’s expensive but could be worth it as a « rule them all » for a bit into the future with its 15A. If it truly is reliable, and balance the Sherman. (Again I don’t see why it shouldn’t, but sometimes smart functions can conflict I guess. Or it’s just a setting issue.

edit: as for chargers in general I lack knowledge to judge, but will try to do information central as I’m into the question at the moment.

edit 2: I give up on the Chargery, of the little first hand experience I can find there are to many failures and lack of support. It is also impossible to get to know whether there should be a way to charge the Sherman with balancing. 

Edited by null
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  • 3 weeks later...

Finally got around to fully charging my new Sherman, my onboard screen indicated a full charge at around 85% via the EUC World app, now my charger has turned off (green light) and the EUC World app says it's charged to 94%, my voltage per EUC W is at 98.9 volts.  Does this sound right?  Sorry if it's been covered...

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EUCWorld calling 98.8V 94% charged sounds ok, but the charger turning off at that voltage isn’t expected. Does EUCWorld still show negative current (still current going into the battery)? If so, the charger is still finishing the job and the green lite is lying to you.

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Just now, Tawpie said:

EUCWorld calling 98.8V 94% charged sounds ok, but the charger turning off at that voltage isn’t expected. Does EUCWorld still show negative current (still current going into the battery)? If so, the charger is still finishing the job and the green lite is lying to you.

Hmm, the fans turned off and the green light was on, it stayed at that 94% for an hour before the red light turned green.  I guess I can plug it back in, it had only been green for a few minutes.

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19 minutes ago, Tawpie said:

If the charger really thinks it’s done at less than 100.8ish volts (this battery isn’t old or damaged is it?) I’d try another one to see what happens. If two chargers stop at 98.8...

Ahh, I will try another charger I guess.  No, it's a brand new wheel with 27 miles on it.

Edit: Just tried my Nikola+ charger (100v wheel) and it lit up green immediately.  I guess it's a discrepancy on the EUC World app?

Edited by RetroThruster
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Maybe? Haven’t heard of that discrepancy but that doesn’t mean anything. I guess if the Sherman display says 100.8, then I’d believe that but do expect that EUC World displays exactly what the Sherman is telling it... I would be very surprised if the app changed that number. Does the Sherman agree with EUC World?

It’s important to know the true end-of-charge voltage because not being able to charge to 100.8ish can be a sign of a worn or in your case, a defective pack.

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