12V Batteries /Jump Start units?

[Poita]

Does anyone know if this 'Jump-Start' pack is any good for running astro gear?

Page 4 of the catalogue.

http://tinyurl.com/kltcz5j

[Astro_Bot]

Not likely. Aside from the battery type, they're usually cheap and nasty batteries inside those things that don't last.

Get a deep cycle battery - Absorbed Glass Mat (AGM) is usually best. Optionally, you can put it in an enclosure or get your own box.

There are many, many threads on deep cycle batteries.

[raymo]

This topic has been done to death on IIS, as there are as many
opinions as options on the best way to power a scope. Having said
that, jumpstarters are not the best way to go, as they are made to
put out very high amperages for a short time[generally 300 to 450 amps]. They generally don't have a large ampere/ hour capacity.
Many purists will advise against it, but I have used a car battery for
this purpose for nearly 35 yrs, and never had a problem. In winter
when using dew heaters etc I use one for the mount, and one for the
ancillary gear.The old ex Corolla battery will run my HEQ5 for three
imaging sessions between charges.
Now wait for all the posts to come in. It's interesting to read all the
opinions.
raymo

[killswitch]

The small SLA battery in jumpstarters isnt designed for deep cycles.

They arent supposed to be discharged past 60-70% of their total capacity because of sulphation. This happens when the cells voltages drop past a certain point. Sulphation permanently reduces capacity and overall lifespan.

AGM battery is recommended because they can be discharged much deeper, around 40-50%.



A car battery is fine because its got a higher capacity to discharge, whereas that cheap SCA jumpstarter only has a 24Ah battery inside.

Jumpstarts die so easily because people discharge them to the point where the voltages are so low even the charger wont detect it.

[Poita]

Thanks for the heads-up, I haven't seen a jumpstarter in the flesh, so wasn't sure what was inside them.

[doug mc]

I picked up a 7ah battery to run the ra. motor on my eq5. The same type of battery you find in motor bikes. It seems to work just fine. The scope is just for visual only. The battery is a gel type. Is it ok you think guys?

[raymo]

It's fine; I used one for years on my old Celestron C-8.
raymo

[MrB]

Yeah should be OK, don't forget to fully charge it after every use before setting it aside, no matter how 'light' the usage.

[The_bluester]

I have used a jump start pack and it was OK for about 18 months before the capacity died through over discharging it. I am using a car battery at the moment, because I had one spare.

Hopefully my observatory plans come to fruition and I can do something better like a regulated DC power supply running off mains with potentially a car battery in the output circuit to float us over any power interruptions. It is that or a UPS to run the DC power supply to achieve the same end.

[Merlin66]

Guys,
I've been using a couple of 20Ah gel cell batteries - the type designed for golf carts/ mobility scooters for the past seven years. They are still 100%, no issues, no drama.
You do need a good triple stage charger....
Highly recommended.