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Sherman Charger Issue ?


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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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