Lithium (LiFePo4) batteries

My LiFePo4 post from 2013 (https://nussbaumerweb.wordpress.com/2013/04/17/lithium-lifepo4-batteries/) on this blog still receives a lot of views. More than 3 years later it is seriously out of date. For a starter, the Kedron was sold together with the LiFePo4 batteries back in 2014. In fact the lithium batteries helped us to sell the Kedron.

When we returned from our trip in September 2013, we decided to upgrade our caravan. There was nothing wrong with the Kedron and it had served us well. But over the time we used it, we realised that a different layout would suit us better.

We looked into replacing the Kedron with a new caravan – but everywhere we looked, ended up in a dead end. We looked at various manufacturers, did factory tours of quite a few. Nobody wanted to manufacture a caravan and then allow us to install a Lithium battery. They told us if we installed our own battery system, it would void our warranty for the whole van. We couldn’t agree to something like that.

Therefore the solution was to buy a second hand van that didn’t come with any warranty at all…

2014 was a busy year for us as we had sold our house in Brisbane and were building a new home at RV Homebase in Tinana near Maryborough. While the new house was being constructed we spent the time at Standown Park Caravan Park located between Gympie and Tin Can Bay. During our stay, a Davidson built caravan which met most of our criteria came on the market. Caboolture Caravan Repairs was the original builder of the Phoenix Vans which had an excellent reputation for a quality product and the Davidson family is well known for their expertise in caravans. However, the Phoenix brand had been sold many years ago and the three vans built by CCR in 2011 could not bear the Phoenix name, hence they are Davidson RVs. The van advertised was the last caravan ever built by Caboolture Caravan Repairs – they now concentrate on their repair business. We jumped at the opportunity and purchased the van with the intention of replacing the AGM batteries with LiFePo4 batteries.

I grew up in Switzerland and Do It Yourself was never part of my upbringing. In fact, DIY was frowned upon, being viewed as “cannot afford to have it done properly”. Having built the LiFePo4 system in the LandCruiser and having been heavily involved in building the LiFePo4 system in the Kedron, I felt I should be able to complete the install in this new van. When we purchased the van, we didn’t really know how to do the changeover as the original AGM batteries were mounted external to the body of the van on the rear of the A-frame in a protective enclosure which was not suitable for the Lithium battery. After extensive discussions with LiFePo4 experts, we decided to install 400 amp hours of LiFePo4 batteries on a slide in the front tunnel boot.

The first challenge (and probably the biggest challenge) was to figure out how the van had been wired in the first place. The documentation we had received didn’t help and the manufacturer of the van couldn’t provide a wiring diagram either. In order to regulate the charging of the LiFePo4 cells, it is essential to separate the charging circuit from the consumption circuit. With the help of a multimeter and hours of removing panels and crawling around on the floor, I figured it all out. Unfortunately, it turned out that the charging and the consumption circuit were joined a long way from the battery. This meant installing a new run of cables from the back of the van to the tunnel boot in the front of the van so that the solar and the mains battery charging circuit could be separated from the consumption circuit. I hesitated (Lesley would say I procrastinated) for a long time before deciding on drilling the holes and pulling the cable through to reach the batteries on a separate run. The cable is mostly in cupboards, but I had to run it from the top to the bottom – not exactly nice, but it is hidden from the main area of the caravan.

Similarly the charging circuit that was charging the batteries from the tow vehicle needed to be separated from the consumption circuit. This was a major challenge for me as it involved drilling holes, connecting very heavy cables to existing runs and soldering cables to achieve what I wanted to connect. I removed the solar regulator, feeding the solar panels voltage straight to the batteries, via the T1 Lithium charging regulator

Having completed this rewiring, time came to install the fridge slide, construct the battery box and mount the LiFePo4 battery in the box – fortunately I have a neighbour who assisted me with this part of the build. Then the charging components needed to be installed on the front of the battery box. The main component, the T1 Lithium charging regulator, which is the brain that ensures the cells do not reach critical voltage, was supplied by T1 Lithium with connectors clearly labeled so that it was relatively easy to connect it all up. This time I also installed a Victron battery monitor which allows us to keep track of State of Charge. This was all fairly straightforward as it was similar to the install in the Kedron. Having a better understanding how it all works also helped.

This photo shows the battery box mounted on a slide in the tunnel boot, allowing easy access to the components.

This photo shows the cells – normally they are protected by a plywood cover. This prevents dropping anything onto the top of the cells.

The control panel.

The changeover was completed just in time for our six month trip to Western Australia. If you are interested, check out our blog from the day we left: https://nussbaumerweb.wordpress.com/2015/03/29/leaving-rv-homebase/

During this trip we had a Xantrex 1800W inverter installed. This allowed us to utilise the vastly increased capacity of our new LiFePo4 system. We were very happy with the new system. It takes some time to get your head around the capabilities of this increased capacity. Having a State of Charge of 50% means we still had as much useable capacity as we had on the previous system when it was fully charged. So while we were enjoying the benefits of the new system, we didn’t take advantage of some of the capabilities during the 2015 trip.

We did a few short trips in 2016, including a 6 week trip over Easter. We had purchased an induction cook top which Lesley used a few times during this trip, taking advantage of the free energy.

Prior to our 4 month trip to Western Australia in 2016 (https://nussbaumerweb.wordpress.com/2016/05/31/day-1-to-calliope-campground/), we also purchased an additional 2 x100W semi flexible solar panels, but only used one, as the other one is defective. I use the panel to provide additional input into either or both batteries (van/tug batteries). After our 4 month trip to Western Australia, I can report the following performance:

  • on travelling days, the alternator/DC-DC charger together with the solar panels mounted on the roof of the van, supplied sufficient input to keep the batteries full by the end of most days
  • when stationary, the solar panels provided sufficient input to keep the batteries full on most days
  • the challenge was to keep the batteries full on very hot days. The compressor fridge runs continuously when the temperature is above 40 degrees Celsius inside the van. To keep the batteries charged, the 520 watts of solar panels on the roof of the van were insufficient. Even when augmented by a 120W moveable solar panel the battery charge decreased. However with the new 100W flexible solar panel, the 740W of solar panels in total managed to keep the batteries fully charged. I find that the moveable panels are so much more efficient than the stationary panels on the roof of the van because they can be positioned for maximum input by correctly angling them to the sun.
  • Worst scenario was continuously cloudy, hot days when stationary. We struggled to keep the batteries fully charged under those conditions and reverted to using gas for the hot water system, probably erring too much on the cautious side.

We do not carry a generator – which obviously would assist in keeping the batteries fully charged during continually cloudy days when camped in one spot. During this trip, I ran the engine of the LandCruiser only once to charge the batteries from the alternator while we were stationary. I think the decision to not carry a generator was a wise one – we only needed the additional charge once – and the LandCruiser could provide the necessary charge, probably with less noise than a generator.

We have installed an 1800W Xantrex inverter on the circuit that is wired to the 240V inlet. The inverter is auto-switching when we connect to an outside supply, such as in a caravan park. We use the coffee machine and milk frother every day. The hairdryer is also frequently used. We use an electric kettle for our cups of tea in the morning. We use an electric sandwich maker. We use a toaster. When the batteries get full early in the day, we use the electric hot water system to heat our water. We have an induction hot plate that we sometimes use for cooking. The stick mixer and the food processor are used occasionally. We carry a vacuum sealer to seal food in plastic bags, however we didn’t use it on this trip. The airconditioner can be run on this inverter, but we have never used it. I think it would drain the batteries too quickly but again we are probably being over cautious.

On a separate 240V circuit we have a 300W inverter that is always switched on when we are stationary. We use it to charge phones, tablets, laptops, electric toothbrush, electric clippers, vacuum cleaner and camera batteries. When Lesley does the washing in our twin tub, it is also plugged into the 300W circuit. Two satellite receivers run on this circuit as well. The television runs on the 12V Circuit.

All lights are LEDs and are wired to the 12V circuit. Our 4 fans are also wired directly into 12V.

I also changed the setup in the LandCruiser considerably. We still have a 100Ah LiFePo4 battery used primarily for an Engel Fridge. To charge this battery while driving, we installed a Ctek DC-DC charger. Whereas previously the LandCruiser battery was always connected to the van batteries, this connection is now only active while we are stationary combining the two batteries to effectively become one system that is charged and discharged in unison. While driving, the van batteries are being charged via a Redarc DC to DC 40amp charger in addition to the solar panels on the roof of the van.

The changeover between the stationary and the driving configuration is achieved by changing the connections via Anderson plugs.

We are very happy with our setup.

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2 Responses to Lithium (LiFePo4) batteries

  1. Pingback: Lithium (LiFePo4) batteries | nussbaumerweb

  2. Great report, I will probably upgrade to Lithium when my batteries need replacing. Any chance of a post with what hardware you used, prices and any other technical details.

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