Recent content by utsi

Thanks! As a matter of fact I already ordered and received this exact charger. What confused me was how inaccurate it seems to be - when measuring with a multimeter it's 0.1V off. And after searching the web I found no way to calibrate it, unlike the SkyRC version. Is this as expected? Maybe I...

That's an excellent suggestion, I'll ask him if he's willing to do that! You are correct, thanks for pointing that out! I had forgotten to mention that upon opening the pack it became clear that the aliexpress seller had pulled one on me and given me cheaper cells than what the listing said -...

The voltage on the bad group is dropping steadily, now it's at 3.93V while the others are at 4.09V. The BMS has been disconnected the whole time so it's not the problem. I found a repair shop in my country who can fix batteries. The seller gave me a couple of alternatives: 1) I can give him...

That makes sense, the problematic group is the first/last one. But the charging cable had also fallen off that same group before(?) winter storage so it was probably way off the first couple of times I used the pack before I discovered the problem. I did, at least 48-ish. It does, ~0.1 vs...

Oh crap!😱 Will store it outside tonight!

The charger seems to stop (or go into extremely slow mide) when one group reaches 4.1V. The rest of the groups were at 4.09V, except the bad one which I later charged separately until it was 4.12V. But it didn’t stay there, it kept falling. Was nearly at 4.0V when I started charging it again...

So you're suggestion would be to use the battery and see what happens and charge the low group separately if it is considerably lower than the others after a ride? I'm just a little worried that using the pack could somehow make matters worse :confused:

I looks like it stops charging when a couple of the groups reach 4.1V, the rest stays at 4.09. The lagging group remained at 3.65V before I charged it manually with a single cell charger. Having said that, I never left it charging for more than 9-10 hours after the regular charger had "finished".

Hi! I recently had a problem with my 72v 21ah triangle pack when a charging wire had fallen off one of the cell groups. After soldering it back on, it seems degraded. All the other groups can hold their voltage (or drops ~0.01V after charging), while the said cell group drops by a whopping 0.1V...

My voltmeter battery was out, so the readings were way off. I have started to charge the low voltage cell group with a 18650 charger for dual cells, 4.2V. Feels like I’m charging a Tesla with an iPhone charger, it will take days😅 Where can I find a good charger for scenarios like this?

Thank you very much for your help, sir! You were absolutely right, a wire had fallen off so I soldered it back on. I find poking around in the pack a little scary so I probably wouldn't have done it if it wasn't for your advice :) Now the 1-2 connector voltage is 3.8V and all the rest is...

My 72V China battery says it's fully charged but stops working after a few minutes usage. I opened the pack and started measuring the small wires from the BMS connector to the battery. Here are the results: connector 1-2: 0V connector 2-3: 0V connector 1-3: 7.2V connector 3-4: 4.2V connector...

I will probably go the safe voltage route when I'm ready to throw the things away and find somewhere to deliver them. But if I can make one good battery with to bad ones, how long do I have once they start getting weak, is it a linear curve or are they degrading rapidly?

That's interesting! I won't be able to use the em3ev battery because it's 52V, but I do have an old li ion battery with the same problem as this one, but it's a different size, 12Ah instead of 20-ish. Could it still work? I may have to get a little creative in regards of placement since I don't...

So I got the wattmeter from from hobbyking and a new motor from aliexpress. It turns out that you were right @dogman dan, the battery seems to be getting tired. I also read about your battery fire now, so sorry to hear about it. My battery is very similar and bought around the same time. Thank...