Celestron 7AH Power tank charging

[Alan_B]

Hi - I have the celestron 7AH power tank and I have recently had to charge it from the "charge required" state (LED came on). I duly put it on charge and the red charge LED started to flash, waited a few hours and eventually it was steady. However the green "charge complete" LED never came on even after charging for 5 days.

I have measured the voltage at the red/black screw connectors at the rear and I get 12v and the light works OK. I have charged it a few times since with same result

I have read that you can use a motorcycle battery charger to recover the battery . i have one of these (an Acumen Acumen Electronics Platinum Black Charger - 20110 ).

Question - if I want to charge the power tank with this charger do I have to remove the battery from the power tank or can I just connect to the red/black screw terminals at the rear . If so what position should the on/off/charge switch be in ?