I use 2 Li-ion batteries. One is a Tracer and costs way other too much, but I bought it some years ago when it was simply expensive not as now stupidly expensive.
The other is a "cheapy", similar to the Talentcell ones but half the cost, search ebay.
The problems. They start out as 12.6v I think, they drop fast to about 1v less say 20 minutes later thyey are 11.5v (lets use simple rounded numbers) and 1 half think 11.5 will be too low for consistant operation. My scope is an old ETX-70 that operates on 9v and takes 12v happily so whatever I am over 9v.
Mine is 4800mAh you can get 6800mAh likely better, I intend to buy one soon.
Talentcell do a bigger one that may be worth considering, I forget the mAh specification, but a fair bit more. Still however 12v area. Search one out and read the details.
Now the "12v" problem. Really you want one that starts at 13+v and then drops to 12+v.
Shido make a Li battery for a motor bike, and vehical batteries are 13.2v.
Thinking one may be a suitable solution, as in start at 13.2v and drop after time to 12.2v. Then all happy.
So again search out Shido and motor cycle battery. Search "Li motor cycle battery" in general.
The Shido batteries are "small" as in 4Ah, seen one at 5Ah but cost increases exponentially.
I think the problem is not getting something, it is getting something that will still be doing the job after 30 minutes. Assume that whatever the rating they will last half the time. So a 4Ah Shido I would say expect 2 hours safe usage - IF the output is maintained. My 4800 has done 2 hours happily but little slewing around the sky, 90% or more just tracking.
The small ones like Talentcell will sit on the base under the scope, but sit on at the front. The rear of the scope and battery collide it the battery is on the rear of the base area.
Edited by sg6, 11 August 2019 - 11:44 AM.