Rechargeable Power Tanks

[Ralph Stephenson]

Greetings All, Im the new boy on the block, in a quandry, I recently bought a Skywatcher 5" Mak Cass and Im very pleased with it, or will be when the sky clears, here is the problem, does anyone know which is the best buy, the Skywatcher 7Ah or the 17Ah Rechargeable POwer Tank. The difference in price is £58.80 and £102.12. The main thing is the lenght of time they can be used. Many Thanks to all............Ralph:confused:

[pete_l]

Given that a genuine¹ high-quality 17aH 12V SLA battery retails at £40 and a 7aH one for £15 (incl. delivery), somebody's making an awful lot of money from these power tanks!

I've made my own, using said battery and some 6mm plywood for the case and customising it with the number of 12V sockets I need and even some additional 5V ones. For the price quoted above, you could make a couple to your own specification and still have money left over for a charger.

[1] There are an awful lot of fakes around. The only way to tell an honest 7aH or 17aH battery is by weight. Too light and your pwoer supply contains a fake with a reduced capacity.

[Multi-Coated]

Hi & Welcome........... , the 17AH cells will give you more options regarding running additional equipment including as you stated , run time issues. I'd shop around though as i've seen a 18AH unit with some very good accessories for sale at Costco ( cell state metre ) for less than £60.

[dmn21]

Hi,

I'm no expert on the subject, but I bought the 7 Ah version for my EQ5 Synscan mount and it has been fine for the observing sessions I've undertaken so far. Admittedly I've not got a bunch of other accessories draining it and I've only been doing up to about four hours so far.

Depends what you want to do with it really...

Dan

[Multi-Coated]

Dan , if it works for you , it works for you. Additional cells always come in handy if you obtain / run more load.

[Midpoint]

I bought the 17aH tank when I started out as I had the intention of running additional equipment such as dew heaters and I wasn't sure how long the 7aH tank would last. I never did get any other equipment though and so I've never managed to drain the tank significantly. I could have probably made do with a smaller battery. Also, you'll have probably noticed from other people's replies, there are probably cheaper ways of powering your scope.

So although the tanks work perfectly well, if I had my time again I'd probably spend more time looking at the alternatives.

[Bizibilder]

This is all you need:

3in1 Portable Jumpstarter : InCar Battery Chargers and Compressors : Maplin

to get you going. On offer at £24.99 at the moment but sometimes is cheaper! It is 17Ah and has a cigarette socket for the scope to plug in to.

[evilgeenius]

I second the Maplins 3in1 Portable Jumpstarter, I use it all the time.

I've just bought a 4 in 1 extender for it at £5 so i can use more stuff.

[RS3100]

For pretty much the price of the 17Ah "dedicated" power tank, you can also get a Clarke Jump Start 4000 with a 38Ah battery and an accessory socket.

[Multi-Coated]

This is all you need:

3in1 Portable Jumpstarter : InCar Battery Chargers and Compressors : Maplin

to get you going. On offer at £24.99 at the moment but sometimes is cheaper! It is 17Ah and has a cigarette socket for the scope to plug in to.

Sounds a great buy although like all cells their output will be vastly reduced come cold winter nights , cheaper manufactured units more so. You never know though could be a bargain.

[umadog]

I favour buying simply a good deep-cycle battery. It's cheaper because you get more Ahr for your money. Add up the current draw from your devices: if, say, 1 amp, a 7 Ahr battery will last 7 hours. I run my dew heaters via a Dewbuster, which regulates the power they get. This way I get only the heating I need to keep things dew-free and am not excessively draining the battery.