Lithium (LiFePo4) batteries

This is probably not worth reading unless you are interested in Lithium batteries!

There is an update to this post:

As mentioned in previous posts I wanted to set up the caravan and LandCruiser with LiFePo4 batteries. There were different reasons for the LandCruiser and the Caravan.

Springers gave me a quote of nearly $900 to set up an 80AmpHour AGM battery in the engine compartment for the Engel fridge/freezer. I had heard that AGM batteries should not be fitted near the engine due to heat problem. Also I figured for that kind of money I should be able to get a LiFePo4 battery providing considerably more usable storage. I decided on a 100AmpHour LiFePo4 battery and installed it prior to arriving at the Castlemaine gathering. This gives almost three times as much usable storage compared to the 80AmpHour AGM proposed by Springers.

The 3 x 120 AmpHours AGM batteries are 8 years old and definitely have lost storing capacity. Replacing these batteries with similar AGM batteries would only give me similar capacity. In my opinion the most significant disadvantage of AGM batteries is the fact that after they have been charged to 80%, the charging rate is reduced to almost nothing. Especially when charging with the generator, it takes forever to charge to 100%. In contrast, charging of LiFePo4 batteries can be pushed at full blast until they are completely charged. Of course LiFePo4 batteries can also be discharged a lot deeper than AGM. We would also reduce weight and increase storage space by going with LiFePo4. The cost of LiFePo4 batteries is higher but for me the advantages far outweighed the additional cost.

We didn’t have much experience with the new system before we arrived in Castlemaine. However from this limited experience, I was not happy with the charging rate from the alternator. Terry investigated the problems and after many hours, the battery charger was replaced with a soft start charger: a CTEK charger. This resolved the problem and everything went fine.

One of the main problems of replacing the AGM batteries in the Kedron with LiFePo4 batteries was the removal of the now dysfunctional AGM batteries. These batteries are so heavy that it seemed impossible to just lift them out. There were 4 of us discussing many options – these included star picket fence posts and a lever system to lift them out. At this stage a farmer from up the road stopped and talked to us. We explained what we were working on. He had a look at it and said ‘at this angle it is impossible to remove the batteries’. We removed the hatch cover to give better access to the batteries. Once the access was easier, he grabbed one of the batteries, lifted it up and handed it to one of us. This was more than what the person expected, almost dropping it to the ground. At last the first battery was out. Not much later the second battery was out. The farmer now had a nick-name: The Crane!

Fortunately my setup already included a Plasmatronics PL40 regulator. This regulator is programmable and can be set up for the requirements of LiFePo4 charging. Together with Terry’s black box, the charging can be set up to cut off all charging (solar on roof, foldable solar panel, battery charger and from alternator in car while driving) if the cell voltage gets too high. Once the LiFePo4 batteries were connected, it was relatively simple to set up the system.

We now have two independent systems: The LandCruiser and the caravan have their own batteries and each system can control the charging of the batteries in that system. But if the two systems are connected, they act as one.

All my testing proved to be successful. The two systems work well individually and they also work well when connected together.
– when the car is connected to caravan, the solar charges both systems
– when the car is connected to caravan, the battery charger in the caravan charges both systems
– when the car is connected to caravan and no input from either solar nor battery charger (at night), the two batteries end up with the same overall voltage.
– when caravan is not connected to car, battery charging works well
– when caravan is not connected to car, solar charging works well
– when car is not connected to caravan, alternator charges battery in car
– when car is not connected to caravan, the 100 Amp battery seems to keep Engel running for quite a few days.
– when the car is connected to caravan after either of the systems has been fully charged, the system that has higher voltage charges the system that has lower voltage.
– regardless whether the two systems are connected, I can use a foldable solar panel to boost charging either or both systems.

I haven’t much experience with the new system yet – I have full confidence that my experience to date will be confirmed over the coming months.

All in all I am very happy with everything. Many thanks to Terry for all his help.

The battery box in the caravan takes up much less room. The batteries are also considerably lighter.

Battery box with lid off. The straps are to make removal of cells easier.

Connection to LandCruiser. Don’t look at the dirt, please! I still have to make up an extension cable to allow the car to be parked a bit further away.

Inverter and battery charger between drawers and cargo barrier.

Battery box contains battery as well as the controlling black box and other regulating gear. The belt you can see is for lifting out the cells from the battery box.

The width of the battery box fits exactly in the hatch that the Engel sits in. In foreground the lid of the Engel.

This entry was posted in 2013 - 7 months zigzagging across Australia and tagged , , , , . Bookmark the permalink.

4 Responses to Lithium (LiFePo4) batteries

  1. Wayne says:

    Looks like a really good system have been thinking of this my self need to get a lot more info yet

  2. Martin says:

    Thanks for sharing, looks good and I know you will be happy with them!

  3. Peter says:

    Looking good Erich. I am still a long way behind your setup. But still learning. These batteries have never ceased to amaze me in there performance. We stayed at Tocumwal till Saturday and had usable power all the way. That was 5 days, no shore power no genny and minimal solar (tree). We don’t have a big solar system yet, but even Raena is impressed with them. Safe travels.

  4. Pingback: Lithium (LiFePo4) batteries | nussbaumerweb

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