Hi Peter,
It's great to chat with someone who has what is probably the identical (original) system who will understand my queries!
Yeah, this is a 21-footer. Our bed is toward the back and is east/west with the shower in one rear corner, the toilet in the opposite corner and a cupboard in between. The door is at the front and you enter straight into the kitchenette/dining area. The area labelled "Couch (Electrical Cupboard)" is where all the electrical gubbins are at present and where the new stuff will go. Immediately behind that is a cabinet that contains the compressor for the split-system air-con (took me a while to get my head around that - I thought the A/C was just a window-rattler!)
I'm assuming that everything "after" the step-down transformer is 12V? If I can identify where the wires go, I should be able to run those through a fuse-panel? Or is there already and existing fuse-panel somewhere. I'm looking at a Blue Seas Systems 12-fuse panel if I need one.
Just to explain, we've just sold our house, so I had to move the van out to our sons place as it was taking up most of the front lawn and doing nasty things to the grass! We're moving back to our unit in a couple of weeks and I'll bring the van back and get into the reno's with a vengeance. We're planning on heading off on a three-month trip in May, so time is short!
The existing inverter system setup is amazing. It has a 1,000W pure sine wave inverter which was being powered by a couple of 12V lead-acid batteries that were mounted, wait for it......, on opposite ends of the rear bumper bar! The voltage-drop on the dinky little wires he was using must have been epic!
I've decided not to install an inverter at this stage. I'm aiming to keep it (relatively) simple and stick to a pure 12V system. The only thing the 240V will be used for is to run the A/C when hooked up to the mains.
There are a couple of old, mismatched and rather small solar panels on the roof which will be replaced with something in the 400-500W range. Whether these will be 12V or 24V, a couple of large panels or multiple smaller ones, house or RV panels, or what exactly, is all up in the air at the moment. I'm planning on having a decent sized Victron MPPT charger, so I will have a bit of headroom. I need to get up on top of the van and measure it all up and work out what I can fit up there. I know there are a few vents here and there.... hopefully they won't interfere too badly.
The other option, and probably worthwhile for the longer off-grid stays, is adding a decent folding panel as and when required. I was thinking I could mount an Anderson Plug on the drawbar so I can put the panel either side and move it around as required. I'm not sure if I would run that through the Victron MPPT or just keep it simple and use the inbuilt regulator on the panel and hook it straight up to the positive bus bar. At least that way, I could use if for other purposes, such as trickle-charging the car battery.
What battery are you running? I was originally going to install AGM's but have now decided on a couple of 100Ah Lithiums. The advantages are huge and whilst expensive initially, the lifetime cost is much lower than AGM. Our main current draw will be a 138 litre Brass Monkey 12V fridge that only draws a peak of 3.8A. Other than that, it'll mainly be the water-pump, LED lights, USB charging points and a couple of small 12V fans.
I'd initially planned on having a 240V charger to keep the batteries topped-off, which would be ideal for the AGM's, but apparently Lithiums are happier being left at around 50-60% when not in use for extended periods. If completely disconnected from the system, they consume next to nothing, so can be left unattended for months. Even if they do discharge, the battery won't be damaged - might just need to be "woken up".
I am fitting a Victron DC-DC charger via Anderson Plug from the car. When actually on the road, I'd expect to pull into camp each night with a fully charged battery bank, what with the 12V from the car and the solar panels.
Anyway, enough of my blathering! I look forward to further discussions!
Take care,
Dave
