The power cord cable supplied by the Celestron Power Tank 17 from OPT did not fit the into to Power Tank 17. I had to use the power plug suppled form Celestron with my 925 Celestron scope.
Works far better than expected, highly recommend this product purchased from OPT.
I've had this battery for eight years now with no problems. It does run down when not in use but I've had no problems with recharging even after months of storage (at room temperature). The battery is not meant to be left plugged in when not in use (as described by another reviewer). According the manual it is dangerous to do so. The battery will last much longer by following the tips in the manual. But it does sound like Celestron's quality control is inconsistent at best.
I have now owned the Celestron 12V 17AH power tank for 2.5 years. During the 2.5 years I have kept it plugged into the wall charger whenever it is not in use. It has never failed me during observing and easily powers my Edge HD 11" /CGEM DX and either my Dew Removers or my camera. The main LED spotlight is very bright and the red light is very useful. The radio does not work very well as there is no antenna. I have used it to jump start my car so this function may be helpful if your car battery dies. At 2.5 years the battery did start to fail but this was expected. I was able to easily replace the battery for about $45.
I bought the larger 17 amp hour Powertank for my NexStar 6SE telescope. It included the DC cable for the telescope, which was a nice addition. I have powered my telescope through long nights of observing and the Powertank handles it fine. It is nothing fancy, but it does not really need to be for the money.
detachable red light is very handy. radio is very poor but still useful. high beam light was covered up, just in case. its very powerful. switch cover is useless. the internal charge limiter is worthless. it never kept the battery at full charge. plus the fact the battery itself had a dead cell and would only go to 11 volts charged. i needed this supply for a long trip and couldn't wait for a return or new unit so i fixed it on my own. when its working right is handy. but if you buy this, plan to charge it for 1 to 2 days right out of the box and test it after it has a stable full charge.