> Do you connect the batteries direct to the -/+12V lines or do you feed
> them into the voltage stabilizers (7812/7912) in the power supply

I sold all my g6 racks in order to finance the new case.. ; )

In this, i dont use any circuitary between the batteries and the modules.
In order to use the regulators, i believe youd need some headroom, about 3
volts extra or so.

The batteries in question dont (at least commonly) come in 15v versions, so
its not possible to use the regulators.

Another negative point of using regulators with batteries: the excess
voltage is disipated by heat. Fine for a mains powered system, but with the
finite resources of a battery, its a bit too wastefull for me.

> I have to carry this system with a ribbon over my shoulder for two hours
> and around 6-8 kilometers, so "just they get heavier" is definitely a
> matter for me ;-)

As for weight - i can carry my 12u system, its power source, my modded 606,
and all relvent accessories, single handedly to the bus stop a few streets
away. I wouldnt like to have to carry it any further ; )

The main weight though is probably the aluminium used in the subrack and
module fronts. The batteries, strapped on my back, i probably dont feel as
much...

You should be able to work out what sort of size youd like from the module
power requirements, and your expected playing time between recharges. I
went for the larger batteries not so much for extended time, but more for a
more stable output over time. But, as you said, this isnt important for you
in the same way.

Julian