The caravan was purchased in January 2013. It was built in 2000. Well looked after by one owner.
It came with a small 40Ah battery and an antiquated built in charger. The charger had a reverse current drain of 60ma when powered off, so would flatten the battery in a few days. I purchased a 10 Amp Ctek charger, and rewired the power circuits through a Narva 10 way fuse panel. The reverse current of the Ctek is negligible.
To reduce 12v power drain I replaced all the internal 12v incandescent globes with LED. Current drain is about 20% of that with regular globes. I purchased a pack of 10 from “Beach Lovers Leds” in Queensland. I prefer pure white rather than warm white.
Next came a larger battery. The Van has 2 single beds and the battery was under one of the beds. I purchased a surplus Fiamm 100Ah battery, total weight of 36Kg and measures 100 x 400 x 300, which lays neatly under the rear seat. This meant running heavy duty cable back to the charger and distribution panel. a 50Amp circuit breaker was fitted adjacent to the battery. A merit plug was wired under the floor direct from the battery via a fuse to provide 12v power under the van for a fridge or other appliance.
Who gets sick of hand pumping the water from the on board tank. I think we all do. Next modification was a 12v pump. Now if you look on Ebay they can be picked up for around $30. You can pay a lot more for the same thing at a shop but that is up to you. A proper tap was purchased and fitted in place of the old hand pump. The sink now has 2 taps. One for the 12v pump and another when connected to mains water. I guess you could mess around with switching one tap for both but I did not. Select the plastic hose with care and make sure it is food grade or the water will have a plastic taste. The pump was fitted in a cupboard under the sink.
We now have most things running on battery power, well not the range hood. Out came the range hood, a large 12v fan was fitted and a 12v globe here as well.The original fan and light switches were still used but rewired for 12v. After the first trip the globe worked loose and fell out of the socket. A small dob of silicon now holds it in place.
The microwave still needs 240v but that is all and we can happily camp for many days with no mains available. The 3 way Electrolux fridge runs happily on gas.
Whilst talking of the fridge, there are many websites discussing proper operation and ventilation of the 3 way fridges. I repacked insulation around the sides, blocked up holes in the fridge enclosure that was leaking hot air into the cabin. The rear of the fridge needs to act like a chimney so air is drawn up over the condensers. I decided to fit 2 small computer fans at the top of the fridge, just inside the top vent. This helps circulate the air better and I hope aids the fridge operation. The fridge fans and water pump both have a switch fitted. The pump switch to stop draining the water tank in the event of a leak. The fans so that they are only used in warmer conditions.
A portable 120 watt solar panel keeps the internal batteries topped up.