Rockwheel GR16 won't power on/charge after 5 months of storage

[parchedpirate]

Would love it if anybody could give me a clue on some things to check on my rockwheel,  I pressed power button and got nothing, so I figured I just need to charge it.  When I plug in the charger, the indicator light on charger stays green.  I unplugged the charger and pressed power button, and I have a fading beep sound and charge indicator drops to empty almost immediately.  Any ideas, I left it on charger for 30 minutes, light remained green on charger the whole time and when unplugging and then pressing power...same thing.  Battery seems to not have charged more than the beeping and light that immediately goes off. 

 

By the way, the battery was great before and still was holding full charge.

[esaj]

You didn't store it fully charged by any chance? Still, even if the cells are degraded, I'd expect it to take in at least SOME charge, sounds like it isn't charging at all. Try checking the wiring from the charge port to the battery pack

[parchedpirate]

I will definitely check that....as I have never cracked it open , can you give me a little bit of a hint as to what I should be looking for...btw thanks a lot for the fast reply.

 

(and yes I think it was fully charged as well when I stored it ...yikes, what does that mean?)

[esaj]

49 minutes ago, parchedpirate said:

I will definitely check that....as I have never cracked it open , can you give me a little bit of a hint as to what I should be looking for...btw thanks a lot for the fast reply.

I've written a bunch of info on the batteries (but not that much about the charge ports) here:

If you open the casing, you should find two wires running from the charge port to the battery through some connector. Check that the wires and the connector are firmly connected. If you poke around the battery, it's not super dangerous, but take care of not short-circuiting it etc, as mentioned in the above post. If you have a multimeter, you can try measuring the voltage of the battery to see if there's any charge in it (I think the older Rockwheels used 16S-packs also, so the voltage should be somewhere between 48V for very much empty pack, up to around 67.2V for full pack), but if you feel uncertain about it, maybe better leave it alone.

 

Quote

(and yes I think it was fully charged as well when I stored it ...yikes, what does that mean?)

The cells "age" faster when kept at high voltage, storing in full charge is pretty much the worst option, especially if the storing temperature is high (above room temperature). Mostly this seems to show up as permanently declined maximum charge, how much of the capacity was lost depends on the time in storage, temperature and the cell voltage.

More or less "ideal" storing environment would be cool (but not freezing) and the cells should be kept at about 30% charge (around 3.6-3.8V per cell, for a 16S pack that's about 57.6-60.8V), and only charged if necessary (ie. they start to drop towards 3V or so). If the voltage drops too low (2.5V per cell or below, around 40V for 16S-pack) for a longer while, the cells can start forming metallic "dendrites" inside themselves, and should not be used anymore, as they can cause internal short circuits.

As usual, take all of the above with a pinch of salt, I'm not a battery expert, this is just based on what I've read (and measurements from some more or less worn 18650-cells I have laying around, as well as higher quality 16S-packs I have in storage).

[parchedpirate]

Ok I cracked it open finally but doesn't really look like anything as far as the connectors is loose.  they sure use a lot of hot glue or whatever that stuff is on  all of the connectors.  Its so frustrating, i wish I had more knowledge of these internals. 

[meepmeepmayer]

9 minutes ago, parchedpirate said:

Its so frustrating, i wish I had more knowledge of these internals. 

I know how you feel

I only have one idea: get a voltage meter and check if the battery still works (make sure not to accidentally short anything, maybe ask around here on details how to do everything) so you basically disconnect the battery and connect it to the meter to see what's going on.