Quote:
Originally Posted by AussieMatt
Thanks for the feedback and aeveryone has given lots of great advice - The reasons for needing the second battery area a few fold -
1. Running two fridges during the day whilst touring, and then they need to run over night ( one will be acting as a fridge the other as a freezer. Running two will flatten the starter battery. Given the remoteness of the areas we are travelling to, having a battery run flat is not a good idea! 
2. with reference to point 1 - the second battery can momentarily act as a starter battery if needed.
3. At the camp sites we may stop for a number of days which then means charging of devices, running fridges and the like, solar may not cope with this
4. i may look to add solar as a top up mechanism at some point when the very large trips occur, not for immediate.
5. the Kids also like their USB disco lights and along with the ability to watch projected films etc, Mainly Frozen and that damn Let it Go Song
(AAAAAAAAAAAAAGGGGGGGHHHHHH) so again lots of power requirements.
6.adding the dual battery also allows for the maximum in storage to be maintained, without the necessity for a battery box etc. |
Sounds more like you need a diesel generator!!
I don't think solar is any help to you - the small panels to keep your battery topped up are typically 10-15 watts - that equates to 1 amp at 12 volts. A larger panel that would be useful (say 100 watts or more) would be bulky and difficult to carry. You could look at multiple, smaller panels through a MPPT charger (much better than PWM).
The traditional "split charge" set up will not allow you to use the second battery to start the car in the event that the primary battery becomes discharged, the relays, switching and cabling etc. are nowhere near man enough for the power involved and hence the second battery is isolated during started. You could use jump leads though.
I think your best bet will be a large leisure battery (or array of them) and a split charge system. It sounds like some of the equipment you will be using may be mains powered, in which case go for a pure sine wave inverter - they're more expensive but more efficient.