I've seen a few older forums where people say the Celestron Powertanks aren't worth the silly prices they charge when a cheap car battery does the job perfectly well and actually lasts a lot longer.
I stayed a few nights at an amazing dark site last week (photos attached) and realised that though the skies where I live are far better than what you get in Sydney, there's still a significant benefit to a properly dark site... so am considering a portable battery now. I saw a 30AH battery in Kmart today for $66 and figured it would probably do the job..?
Re keeping it charged, I expect a simple trickle charger will do the trick but I don't know how "smart" they are - is it possible to over-charge the battery and damage it if you don't use it often (I have mains power in my back yard which is where I'll be 95% of the time)?
Re adapters, how exactly do I connect a car battery to the mount? I expect I'll need to make my own, yeah?
Re running a laptop off said battery, is that an option? Also, how long would I get running laptop & mount off a 30AH battery? (I have no ideal what sort of current a laptop draws when guiding.)
A NEQ6 will need 2AH when slewing, less when tracking. If you plan to run all night that battery maybe a little small. You don't want to discharge it too deep, I would not let it get below about 12.5V if you want it to last. Forty AH would be better. You certainy can't run both the mount and a laptop off that battery. When I go to my dark site I take a generator for laptop, hub power, and other AC devices, and a 100AH battery to run the mount and the heaters. Heater controllers usually draw about 6AH. Good luck.
The EQ6 is one VERY thirsty beast. I do have a 7AH Celestron Powertank that is not used for anything more than brief field testing of stuff (as it has 12V output) and a torch (which is does very well!).
As for connecting your mount to the battery, I just bought a 1m cable from Woolies, cut both ends off, connected (quite badly soldered) some clips to one end and put a cigarette lighter head (female) on the other. I have an older 17 AH motorbike battery that will run the EQ6 and one heater strap for at least a few hours without a hitch. I don't know about the health of the battery or how long it lasts because I have never flattened it.
For my dark site I take up a 200 AH (HEAVY!!! at 65kg) deep cycle battery, connect a 360W Pure Sinewave Inverter and run all of my equipment from a 7 port 240V Powerboard. When I decided I wanted to do more up at my dark site I wanted to make sure that I couldn't damage anything electrically so I have a use a pure sine wave inverter, surge protected power board and every device has its own regulated 240V to 12V power supply. Is it over the top? Most likely!
