Help with batteries

[Kid211986]

hi I got a nitecore um20
Dual 18650 charger and had a set a batteries in one of my mods for a few days and when I went to charge them my charger is just reading EE on the display what does that mean

 

[AzPlumber]

Battery is inserted backwards or voltage on battery too low.

 

[AlB53]

What kind of charger?

 

[AzPlumber]

What kind of charger?

uhm, pretty sure it's the Nitecore UM20 that was mentioned in the OP

 

[Beeker]

EE means Reverse Polarity (Battery in backwards); if not the battery may be open internally or was discharged so low it appears that way to the charger.

 

[Baditude]

What kind of charger?

I agree with the above answers. Make sure the batteries are not inserted upside down. With many of today's flat top batteries, it can be easy to insert them the wrong way if you aren't paying attention.