Cg5 on car battery?

[Bennink]

Just wondering if it is a good idea to run my cg5 goto mount on my diesels car battery all night. I'd like to drive home afterwards...

Any thoughts?

[Jessun]

You ask different things of a car battery and a battery for use in the field. The normal car battery is good at giving lots of amps when you turn over, and will do this good - a few times. If you let it discharge completely it can be hard or even impossible to recharge to what it used to be.

In the field you want lower amps but over long time and you want all of it so you'd look for a deep cycle battery, something like a gel cell like they use in electric wheelchairs etc or for instance an Optima Blue Top. These can be pretty much emptied of juice and still be recharged.

My recommendation would be to avoid to use the standard car battery.

[Bennink]

Ok, so the power tanks available at the astro webshops are better suited then my car battery.... Thanks for the advice, I think I'm going to order one. Should I take the 7 or 17ah one? It onyl needs to power a 6 inch newton and a camera......

[Jessun]

They are, and they are practical with the red light and 12V sockets. If you don't mind putting your own kit together I would think that Maplin or similar have cheaper solutions - just not as pretty.

A 7 AH battery can deliver (in theory) 7 amps during one hour. 1 amp during 7hours - and anything in between. As long as you don't use dew heaters or any extras then the 7 will be enough for many hours between charging.

[James]

It's always best to avoid using your car battery - you don't want to risk getting stuck out at a dark site...

Go for the largest battery you can afford/carry. Battery power isn't as straightforward as 7AH meaning 1 Amp for seven hours unfortunately. Most of these batteries shouldn't be discharged that much or their operating lifespan/number of recharges will be reduced. If at all possible I'd aim to not draw down on the battery more than 30-40% and recharge it after every use and every few weeks if not being used - that way you should get many years use out of the battery.

With a goto mount of any sort I'd suggest a 17Ah is a good choice as it should give you 5-7 hours of use without draining the battery too much

Maplin often has a good deal on these batteries (often called jumpstarter packs).

James

[Tribal-Wolf]

Car batteries are only designed for short power bursts as are any battery made for starting a vehicle. You can get mobility scooter batteries that give a good sustainable current but they're not very cheap. There are also car jumper packs but avoid the cheaper units as their batteries are the same and will not sustain a charge for long and take a long while to recharge. I bought a decent booster from halfords because I had used them before in garages I'd worked at for 12v power tools etc. The power tanks are costly for what they are but you know they're made for the job, I doubt I would buy a 7 a/h though. Just one thing about car booster packs.............cheap models are cheap for a reason, I bought 3 different types in my 'cost saving' days and they were all rubbish with a poor lifespan.

[Vega]

I've tried using a smallish car battery with an EQ6 Synscan. A couple hours in and the slewing got clunky. Soon after this, the car barttery was sucked dry. I wouldn't recommend them.

I've since acquired a 110Ah sealed marine battery. This thing is the daddy. I run an EQ6, 2x heater strips + Canon 1000D on all nighters with ease. Next morning the battery is still showing a settled voltage above 12.3 volts. I keep a 5w solar panel on it to top it up during the day (and AC charger if needed in the winter). 110aH is no good for portability tho, the thing ways a ton!

If you need to be portable, I would agree with James and get a 17Ah. No less

Matt

[Bennink]

Perfect! Thanks for the advice. As always, you get what you pay for.

I'll check out my local Halfords first for a good jumperstarter pack and if all else fails buy the 17Ah skywatcher.