[raymo]

Hi Markus, there are two ways you can power your gear with ease. One that costs less than $100, and the other that costs between ziltch and $20.
For over 30yrs I have used one or the other.
1. Get a car battery around $90-100, around 60a/hr. This will power all
your gear[ say HEQ5, laptop, and a dewheater or two] for two four or five hour sessions, and if you put it on trickle charge between sessions you'll never have a problem.
2. My favourite method which I have used for the last six or seven yrs.
Auto electrical shops usually have car batteries that have been removed
from cars, but have plenty of life in them. Frequently, four wheel drivers
convert their vehicles to double battery systems, and install two new batteries even when their existing battery is fine.
The last one I got from my local Auto Leccy was an 85a/hr that cost me
$20 and was still powering all my gear five yrs later when I sold everything.
Many members IMHO are needlessly over complicating things, and
spending quite large sums of money quite unnecessarily.[ I'm not referring to heavy usage permanent setups here].
Incidentally, my laptop has worked just fine for yrs using a $25 300w
inverter hooked up to the car battery.
As far as voltage regulation is concerned, most mounts will operate
satisfactorily within quite a wide voltage range, SW mounts such as the
HEQ5 and EQ6 work fine between 11 and 15v, and will give you a low
voltage warning. I suggest that you check your specifications to see what
yours accepts.
raymo