Re-chargable batteries or jump starter?

[Ceti Alpha V]

Hi SGL

For all the time I'd be at a dark site, it maybe more cost effective and less maintenance to get re-charge batteries over a jump starter for powering a Skywatcher alt-az mount.

Are re-charge batteries up tro the task? If so, what type? Probably for powering for 2-3 hours max at a time or are re-chargable batteries no good and only a portable power unit, like a car jump starter will do.

Just thinking it would also be more convenient to charge AA batteries as and when than the almost constant charging a jump starter need and their relative short use life.

You views and opinions appreciated.

[davew]

It's cold and fairly damp in Aberdeen I'm told so..... Option three, a proper leisure battery that will power the scope all night, run dew heaters and maybe a Netbook if required and may last for years. Unlike option one or two

It doesn't have to be the biggest battery in the shop mind.

Dave.

[JamesM]

Nothing worse than running out of power. As mentioned by Dave above, especially when its cold. I would second the idea of the leisure battery as it gives you so many options, (hairdryer for secondary?) comes with a handle and job done.

James

[Merlin66]

I go for a collection of 20Ah gel cell batteries (easier to handle!) and an electronic charger - will outlast a power pack every time.

[Ceti Alpha V]

Thanks for all the replies.

I hadn't considered a leasure battery. Found this, but how do you connect it to the scope/ devices and regulate the power? What/where do I get connections?

I suppose a normal car battery type charger is used to top up the batteries.

[Psychobilly]

Rechargeable batteries have a lower voltage than their Zinc or Alkaline counterparts typically 1.2V instead of 1.5V...

Where a piece of kit might be happy running of 8 Alkaline cells for a Nominal 12V it really needs 10 Ni-cad or NiMH cells to provide the same voltage...

It gets a bit more complicated under load due to the internal resistance differences of the various battery technologies..

Most "professional" kit that runs off 12V from batteries is setup for 10 cell use and comes with two dummy batteries if you really need to run it of Alkaline or Zinc Carbon cells...

Gel battery and a decent charger is the way to go... or if portability isn't an issue go for a leisure battery.. remember Lead acid batteries must be recharged as soon as possible after use.. leaving them in a discharged state will lead to there premature failure

Billy...

[WayBig]

I used to get several hours usage of a nexstar 114 on 8 aa rechargables - found I more convenient than a power pack as I already had the charger and some batteries....if that helps