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KS14c 680Wh won't charge (~1.25 yrs old)


mark321

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Can anyone advise me on troubleshooting my KS14c?

I don't have pictures, but I can describe most of what I tried.  First since I have two EUC and two chargers and both work on the other EUC I can assume the charger isn't the problem. Next I checked the voltage coming out immediately after the kingsong's charging plug and it was 67 or so (when plugged into either charger), so that first connection is good I guess. I'm not skilled at tracing these things, but to my eyes it looks like the next place the wire goes is under the blue plastic into the battery pack. On the other side of the battery pack I found what I think are the wires leaving the pack and there the voltage was really low (I forget if it was 42 or 47) and it doesn't change whether the charger is plugged in or not.

And although the charger is apparently supplying 67v, the lights on the charger indicate it doesn't think it's plugged in. On my other EUC the charger light would go red until the charge is done. On the bad EUC the light stays green, same as if the charger wasn't plugged in to anything.

What else can I measure to identify what might be wrong?

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Mark, this has happened to me many times for several different reasons. Its a bit hard to troubleshoot remotely but i will list a coupke of things you can check

1. open the wheel on the charging side . The charging wire going from the charging port to the battery has a connector. Sometimes this connector loses its grip. Move boths parts of the connector around. Unplug it and plug back in and see if anything changes ( if the charger turns red, or the chargers fan kicks in). Also can help to clean the prongs of the connector and sligtly bend them just a little bit to make them fit into the reciprocal part better/ tighter

2. Sometimes, when the kingsong battery gets older it just stops charging, ir stops and starts after a while. This also manifests itself by real low voltage across charging contacts of the battery. Unplug the charger and check voltage across the 2 contacts of the batterys charge wire. If its about 3-5v, tpyou may have a problem.   If its about 8-12v , it is ok. If voltage is like 3-4v, leave the charger plugged in for some 10-20 minutes and see if it just kicks in allof a sudden.

3. Measure the output voltage of both batteries ( i assume you have 2 ) , see if they are both 40 something voltas and let us know

4. Also check is the charge wires inside the wheel are connected to the prongs of the charge port emdpbedded in the plastic casing, they can get loose and disconnect

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1: no change, I've unplugged and re-plugged it several times while poking around. So far the charger never responds when plugged in
2: I guess I should upgrade to a digital multimeter to get better detail, but my analog multimeter looks like it's at 2V on the input to the battery. I have left the charger plugged in for several hours on a few different days, including just now. So far no change.
3: So far I've only opened up the charging side, and that battery looks like 47V. I'm not measuring directly at the blue battery output though, the wire goes into the EUC and comes back out where I'm measuring it. I was about to take the battery completely out, but I don't see how to get that wire out. Tomorrow I'll try to get to the battery on the other side
4: I think this is okay because I plugged the charger in and tested the prongs at the connection we were talking about in #1 and got 67V

Thanks for your help. I had been assuming some connection had wiggled loose. It sounds like you're saying there's a decent chance the batteries have gone bad?

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Ah, now that I've opened both sides I can tell a little better where the wires are going. In fact I've just taken both battery packs out. So let me update all the voltages:

1. Input to the battery on the "charger" side: 4V or just under
2. Oupt from that battery: 80V
3. Input to battery on the "power button" side: barely over 1V
4. Output from that battery: 47V

If I plug the charger directly into the first pack the charger doesn't respond. I'd try plugging into the second pack directly but it looks like I'd need some kind of adapter for that.

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For me this all sounds as one of your packs got into a "deep" unloaded state!

and that's bad...

on Kingsongs the both packs are not connected in parallel to the board...

one of the packs -the first-is charging the other -the second- ...and that second then goes into the board! So forget about about your 80volt/4/1 Volt measurings....

 

try to disconnect both packs...

and then to load each one of it seperatly!!!

Or to check each separately:..

 

but for this procedure At least you have to know what you are doing about +|- !!!!

 

If you are not .....leave this to a electrician!

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53 minutes ago, KingSong69 said:

 

For me this all sounds as one of your packs got into a "deep" unloaded state!

 

How could that happen?  It seems like it would be best to replace the bad battery, or somehow run it with just the good battery and recycle the other one, I don't know, would it need some kind of wiring extension to just run one battery or just put the good battery closest to the board and leave the other side empty.  It would still be as strong as a Ninebot I'm guessing.

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That last set of measurements is with everything disconnected, and testing the two packs individually.

first pack: input 4V, output 80V
second pack: input 1V, output 47V

I just now tried removing the second pack and plugging the first pack straight into the EUC, and things look pretty good that way. The EUC shows 10 bars. Is it possible I've been misinterpreting the charger's lack of response and really the first pack is just fully charged, and the second pack is dead?

It would be a little disappointing to run it on one pack, but better than nothing.

I haven't looked for EUC batteries online yet. I know I saw 840Wh for $600, but that's too steep for repairing an old EUC. Are there sources for getting a 340Wh pack that would be compatible with the KS?

 

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You're voltage reading of 80V must be wrong, because it's a 16s pack, which will never ever hold a higher Voltage than 67.2V for any amount of time. additionally, this is the highest voltage the charger will supply, so there's no way it chould get up to 80V. That would require some rather unlikely rewiring inside the pack.

On the other hand, 47V is really low for a 16s pack, under 3V per cell. But nothing that would damage the cells if it's not left lying around in this state for some months.

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That makes sense that it couldn't possibly be 80V. My multimeter might be too cheap. Now that the EUC is running pretty decently on one battery pack I've loaned it out to a friend so I don't have it to double check right now.

But if that 80V (or more likely 67V) output from the first pack was being fed straight into the second pack and the second pack wasn't taking a charge, does that indicate the second pack is toast? If there's a way I can restore the second pack and get the EUC back to full capacity that would be really nice.

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11 hours ago, mark321 said:

That makes sense that it couldn't possibly be 80V. My multimeter might be too cheap. Now that the EUC is running pretty decently on one battery pack I've loaned it out to a friend so I don't have it to double check right now.

But if that 80V (or more likely 67V) output from the first pack was being fed straight into the second pack and the second pack wasn't taking a charge, does that indicate the second pack is toast? If there's a way I can restore the second pack and get the EUC back to full capacity that would be really nice.

When the 80Volt Measurement is nuts (and it has to be nuts, 67,2 Volt is max!!!) then the 47Volt measurement will sure be false also!

Your multimeter seams to be one of a Kind ;-)

 

Seams some of the cells are dead......or it is completly in a deep deloaded state (but than it must be less than 47 Volt).

The only Thing to find out is to open it and measure each cell on it's own! Not that difficult with a correct multimeter :-)

If just some cells are dead you can replace them...For a "deep deloaded" pack i dont know how to repair or if it is possible...

But i would even more guess, that just some cells are dead!!!

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As @KingSong69 said, it would be best to open the nonresponding pack and check the single cells with a properly working multimeter. Any cell that is under 1,5 V is most likely dead. Cells between 1,5 and 2,5V still may have some life left in them, but have propably already lost quite a bit of capacity. Over 2,5V should be ok. Any deep discharged cells shoud be recharged with a very small current, so the chemistry doesn't get entirely destroyed by 2 A charging current. Try something like C/10 until the cell reaches 2,5 V.

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Is the pack something I'll need to get a professional to reassemble? I expect I can open it and check all the individual cells, but is there any particular method I should use for disassembly to make reassembly easier? Or should I just take everything out and expect to need it reassembled from scratch?

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If you're not comfortable enough around electrics to know for yourself, you shouldn't mess with the internals of a 340 Wh 67,2 V battery. Even if it is mostly discharged, there's still quite a bit of power stored in it, and it's eager to release it upon you if you short something out.

However, I didn't mean to disassemble the pack but rather open it up. Just remove the protective wrapping and see what is inside. Is there an obvious path where some hundred amps flew by? But don't open it yourself, if you don't have a clue how to get it packed up again ;)

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