I needed a new portable power supply for my new EQ6AZ mount. Having looked around for a decent power supply, other than the "car jumpstarter" type, I came across this Bush Power unit
http://www.australiandirect.com.au/b...er-pack/BP20AH, which is quite an elegant unit, except for the price. They are certainly a great unit and are probably well worth it, but I just didn't want to spend that amount right now, as I am still trying to recover financially from my 6 week US trip.
I already had a 17AH Celestron Power Tank that died, due to the charging circuit overheating the battery, which was a common problem if left on charge for too long, due to a very poor charging circuit design. This was just left sitting in my back room until yesterday. I was going to ditch it, as part of my thorough spring clean, but then thought that I could replace the battery and just bypass the charging circuit (as previously suggested by an IIS member).
I took it to my local Battery World to replace the battery with something a little better and to see if they could easily bypass the charging circuit by installing a plug that suited my normal car charger.
Battery World did replace the battery with a 21AH battery, bypassed the charge circuit and installed a plug, and they only charged me for the parts; $159 for the battery and the lead (seen hanging out the back in pic below), which is considerably cheaper than the Bush Power unit I was considering. Of course, this is a better option as the Power Tank still maintains all its functionality, apart from the charging circuit. And now, I can leave it on trickle charge with my normal charger, which will maintain the battery charge, ready for use any time.
So, anyone with a Celestron Power Tank that has died, you can replace the battery (with the better 21AH battery) and bypass the charging circuit. Just take it to Battery World.
Cheers Pete