A recycled portable power supply

Stardrifter_WA · #1 15-10-2013, 07:52 PM

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

JZ (Ross) · #2 15-10-2013, 10:02 PM

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 · #3 15-10-2013, 10:34 PM

Quote:

Originally Posted by 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...

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