2000 watt inverter and solar charging.

The need for an inverter stems from not being on hook up or not having the generator handy or wanting to run it early in the morning for a cup or two of coffee, morning coffee is so important!

I looked at various options and decided the best route for our needs was to leave the habitation batteries alone and look at a single large capacity battery to run the inverter, nothing wrong with that except I struggled to find a battery of sufficient capacity I could fit, in my desired loaction, under the passanger seat. Another consideration was the battery needed to be of the sealed variety as it was to work in close proximity to the other electrics, namely the inverter and the solar panel regulator more of which I will discuss later.

The first task was to measure and research batteries, I decided that it would be best to use two smaller batteries connected in series to provide 24v, this allowed for smaller gauge cables and also a neater installation, components were easier to source as they were more readily available at the lower amperage the 24v system worked on, I say lower amperage but we are still looking at a mighty 80amp at full load.

I settled for two 95 a/h LV26MF sealed batteries from Numax these compact batteries are 302mm long, 175mm wide and 225mm high, there are numerous leisure batteries on the market but these were more than adaquate for the limited use they would have.

Weight is always a consideration, the batteries alone are around 42kg, add everything else in and we are looking at a fair slice of our payload. The size and weight of the solar panels had to be considered as well, in the end I chose again to go for the semi flexible 120 watt panels, the same as I used for the habitation batteries, the two panels weigh in at around 5kg compared to 20kg with conventional panels and mounts.

 

Initial trial layout for batteries etc

Initial trial layout for batteries etc

The photo above shows the basic layout of the two batteries, the inverter and the solar regulator, now I only have to fit in the circuit breaker the remote relay and the 25mm cross setion cables! I had intended to use a 100amp thermal circuit breaker that could double as an isolator switch but eventually opted for a remote relay to allow complete control from the cupboard the coffee machine and 240v outlet are located in.

 

The twin outlet with one being on mains hook up and the other the inverter.

The twin outlet with one being on mains hook up and the other the inverter.

I was initially quite smug and pleased with this set up, one socket connected to the van 240v circuit and the other to the inverter, the twin 240v outlet from CBE fits in with the other similar plugs and outlets around the van but I soon realised I needed the solar wiring to run up to this point as well as the remote switch, so it all had to come out agan, what is the saying? prior planning and preparation!!!!!!!!! ah well at least now I know how it comes apart!

 

Batteries and carriers mounted along with the inverter.

Batteries and carriers mounted along with the inverter.

Happy with the basic layout I started to make things permanant, the battery carriers are screwed to the floor, the batteries fitted and clamped securely, the inverter mounted and the earth lead attached, almost done then!

Almost finished the wiring.

Almost finished the wiring.

At the left of the batteries is the 100 amp relay that is used to switch the inverter on and off, the eagle eyed might be shouting “where is the fuse” well as mentioned above I was going to use a thermal circuit breaker but instead I opted for a cube fuse. This is a very neat and compact unit that fits between the battery positive terminal and the main feed cable, the benefit is that it is small, very compact and protects all of the live cabling as it is at the battery post. The cables used are all very short and that is essential to minimise voltage drop and hence keep the loads to a minimum.

100 amp relay.

100 amp relay.

The 100 amp relay has a separate fuse to protect the wiring going to the remote switch in the coffee machine cupboard, it has a 3 amp fuse and is conected to the switch using 8amp twin core cable that is very easy to run to where it’s needed. As the cube fuse on the battery post is only designed to accommodate one cable terminal the charge feed from the solar regulator is connected to the live side of the relay, if there is a problem or short here the fuse in the fuse box next to the solar regulator will provide the necessary protection.

Installation of the solar regulator.

Installation of the solar regulator.

Another set of fuses are used here to protect the solar regulator and the batteries, one is the feed from the solar panels at 44v and the other is the charge supply to the batteries 24v @ 10amp or so.

Solar regulator and fuse box.

Solar regulator and fuse box.

The big question is does it work? Hell yes is the answer, we had a two week trip in Germany along the Rhine and Moselle rivers staying at sites we chose without hook up, we used the coffee machine every morning and Tracey was able to use her hair dryer and tongs without any trouble. The batteries never went below 60% and were charged via two series connected 120 watt solar panels on the roof. The two 12 volt batteries (connected in series to give 24v) do not have a dedicated mains charger so they rely solely on the solar panels, they provide the charge via an MPPT solar regulator that is optimised to run at the higher voltages of around 44 volts, the German summer sun was all we needed.