Nitecore UM20 - Help me please

I purchased 2 18650 Panasonic 2900mAh batteries and a Nitecore UM20 charger. I put the batteries in the charger (yes, with the correct polarity) and plugged the USB into my 5v 2100mAh wall adapter. The left side shows 58% battery and flashes about 3-4 times, the right started off at 59% (continually flashes) and has risen to 70% over the last little while(I dunno about an hour I guess). It would appear the left is not charging. I swapped the batteries left to right and again the right side charges and not the left. Is this normal operation? It only charges one at a time. If so this really sucks balls.

I found my answer after extensive searching. Yes... it charges one at a time... lame

Oh and my safety glasses came in the mail today.:wave:

Sounds like it's not get enough power. Try one of those "super chargers" with a 2 amp output and plug that in the UM20

doubleone44 said:

Sounds like it's not get enough power. Try one of those "super chargers" with a 2 amp output and plug that in the UM20

Click to expand...

5v 2100mAh charger...

In actuality this charger I was using is a 2xusb port charger. Info on it says it is 2100mAh. NOPE it's 2x 1050mAh...

If you have an ipad/android tablet charger lying around plug it into that - that *should* supply enough current to charge the batteries simultaneously. If you don't have one but know a friend with an ipad, ask if you can try their charger with your um20.

I believe iphone etc chargers won't supply enough juice to overcome the one after the other problem - most only supply up to 1A

If the tablet charger trick doesnt work, then that should prove your findings - that the um20 is a lame design that only charges one battery at a time.

vk2fro said:

If you have an ipad/android tablet charger lying around plug it into that - that *should* supply enough current to charge the batteries simultaneously. If you don't have one but know a friend with an ipad, ask if you can try their charger with your um20.

If the tablet charger trick doesnt work, then that should prove your findings - that the um20 is a lame design that only charges one battery at a time.

Click to expand...

I am honestly not sure what is going on. I did exactly as you suggested earlier today. It was charging both batteries. When the first got full (I didn't finish charging them last night as I was going to bed and fire hazard) I inserted another one that was at 59%. Checked it about 20 minutes later and it was back to single charging. Took it home, changed nothing and it's charging both. Now they are alot closer only 4% off each other. I'm beginning to wonder if it isn't balancing them.

Was the lower capacity battery charging first?