A recycled portable power supply

[Stardrifter_WA]

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. :D

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

[JZ]

Hi Peter,
Thanks for the interesting comment on the Power Tank. I got one second hand recently with a scope I bought and find it very good to use but I was a bit dubious about the charger. It has the US plug so I have to use an adapter. The previous owner had it sitting around for some years so the battery was dead. He replaced it but I have been thinking about the best way to keep it in good condition. After reading your experience I am going to go ahead and ditch the charger and do a connection for a good trickle charger. I think I'll get rid of the jumper leads too as they get in the way. One of the first things I did when I got it was to remove the halogen globe from the spot light so it can not blind anyone if it accidentally gets switched on on the observing field!

Cheers,
Ross... :)

[Stardrifter_WA]

Hi Ross,

Yeah, be very dubious about the charger, as I know they had quite a few failures, due to the PT charger continuously giving a full charge, when left on charge too long. I knew that quite a few of these were disposed off, due to this particular problem, which is a pity, as the problem was easily rectified, as it turns out.

I like to spot, great for checking out that I haven't left anything behind. Once it is set up, it is then left alone, and it would be hard to accidentally turn it on anyway. :)

Cheers Pete