CAMPING THE KIWI WAY

We bought a modern lightweight English caravan a couple of years ago. It was set up for comfortable off-grid camping. We can run most of the caravan on gas ie., the fridge, cooking, water heating and central heating. We found the limiting factor was 12-volt battery power.

Why we wanted more power

Being a modern caravan, it is well insulated and has its own bathroom so we want to extend our camping season out of summer into winter. Winter camping for us means longer time with the lights on at night, using the shower rather going for a swim, watching TV in a warm caravan rather than going on an evening walk. We have also found we are taking more electronic devices and these are using more power than before. We also need more power for our caravan’s facilities, for instance, the gas central heating has an electric fan and there is an electric pump to get water to the shower or sink.

We needed more battery storage

Our goal was to increase our battery capacity to store more power. We opted to go with lithium batteries. These offer two major advantages to us. They are about a third the weight of, and provide about double the usable power of, similar lead-acid batteries. We opted for two 100 Amp hour LiFePO4 batteries to replace our old single 100 Amp hour AGM lead-acid battery. This should give us four times the power storage at two thirds the weight of what we had before. They should also have about double the life span of a lead-acid battery. LiFePO4 batteries are a type of lithium battery commonly used in deep cycle applications. Unlike lead-acid batteries they have smart electronics in them called a BMS (Battery Management System) which protects the battery from damage or catching fire. We were also pleasantly surprised to see that lithium battery prices are now dropping as they become more common and now can be bought at prices approaching those of lead-acid batteries. If you have more than one battery, it is best practice for the batteries to be matched. This means in simple terms that they are the same brand, model and age as each other. Also you should not add additional batteries later on to your existing batteries. For these reasons we bought two batteries upfront, rather just one.

Bigger batteries and bigger electrical loads need to be set up correctly to last and be safe

Unfortunately lithium batteries can’t just be swapped into where your old lead-acid deep cycle battery operated. They have different charging needs and so battery chargers and solar controllers often need to be changed.

Although the batteries were not as expensive as we initially thought, we realised we were heading for a major upgrade of the whole 12 volt system on the caravan. I guess this could have been done in stages but we did it all in one hit. Wayne Ravelich’s article in issue 9 of Camping the Kiwi Way; “Solar basics for dummies” was very useful.

Getting specialist professional help to set up a new expanded system is highly advisable. It is not just choosing the correct charging equipment, but also setting it up safely with the correct fuses and wire sizes. 12 volt systems today have to deal with much greater electric loads and so there is more danger when things go wrong. 

We went to Rigs’n Things in Stratford and worked with the owner, Merv Hooper. Working with Merv was great experience in itself. His workshop is in ex-railways workshop complete with tracks running through it. He invited us to camp inside the workshop in our caravan while the work was being done. He also allowed us to help with the work to keep labour costs down. It also meant we were able to get a more hands-on feel about how everything fitted together and he listened to our ideas. We were concerned that the weight of solar panels could cause our flat caravan roof to sag in the centre. Merv appreciated our concern and so put together a roof rack system for the solar panels to take load on the outer edges of the roof.

Fitting racks to mount solar panels on the roof of our caravan. The racks take the load on the stron

Merv securing solar panel racks with sealant and screws.

Our caravan in the Rigs ’n Things workshop where we camped while the work was being carried out.

Bigger batteries are no use without the means to charge them

Having decided we wanted 200 Amp hours of lithium battery power we needed to look at how we charged them. Solar panels are now much cheaper and better than they used to be, so my advice is to go overboard and put as much up as you have room for. Once installed they provide free power. In our case it was 640 Watts worth. Solar panels also like to be matched to work best. Due to space limitations on our roof we have two different types of panels so we installed two separate solar controllers; one for each type of panel.

We added two further battery charging systems: A new 230 volt mains charger to charge batteries when the caravan is plugged into mains power and a DC to DC charger that charges the batteries from the car’s alternator when we are driving. We went with Victron (brand) Bluetooth components for all our chargers and controllers. This means the different chargers all talk to each other and are able to manage the different stages of battery charging in a coordinated manner. It is all automatic, and we can also see it all on our phones via Bluetooth if we want to.

We also wanted a reliable fuel gauge to see how much battery power we are using and how much is left

We added one more component to the mix in the form of a ‘smart shunt battery monitor’ which keeps track of the power going into and out of our battery by looking at the amps going in and out. The ‘shunt’ provides us with an effective fuel gauge and tells us how full our battery is. Due to the nature of lithium batteries the old voltage-based battery monitors in caravans don’t show how much power you have left. Our shunt has Bluetooth too and so we can monitor our power usage through a phone app.

We are looking forward to getting off grid and not worrying about how much power we have. 🏕️