The Aldi one has 17.2 amp hr battery, Although at $79 its a good by
Mine has 38 amp hr,
It is SCA brand from Super Cheap Auto and they often have specials on these.http://www.supercheapauto.com.au/online ... 41#details
Only Half the capacity is really usable and the Recharge Me light will start flashing at 50%
You need to work out how much battery capacity you might need.
Charging from the 12 socket in the car is a very slow process and even the 240volt charger
is an overnight job.
Our recent 2 week trip we managed to barely get through the 2 weeks using it mostly
for low power stuff like iPods etc, heaviest use would have been the portable DVD player
We made sure we hooked it up to recarge in the car every where we went by the 10th day
and even had a 1.3 watt solar panel plugged into it
Other trips of a week or less we had plenty of capacity