Batteries for what?The main purpose of us converting a bus is to have an RV unit that we can afford and that will give us as much freedom travelling as possible. Batteries require some method of charging. We put a lot of research into alternative power sources and we decided to utilize all the roof real estate to incorporate as many solar panels as possible, in our case that was 32 of them. If you missed that post, you can find it here. Obviously we then needed to have some sort of energy storage capacity.
|The roof full of 32 small solar panels|
Deep Cell versus Lithium batteries
We found through personal experience over the last 30 years caravaning that the deep cell batteries have certain limitations.
You can read more about the downsides of deep cell batteries here with quite a bit of technical info about it too but in a nutshell you can only use a part of the rated charge of a deep cell battery. It is all too easy to drain the batteries more than you should and thus drastically shorten the life span of the battery. Another issue is that deep cell batteries are huge and heavy. So we looked for alternate energy storage options and chose lithium batteries.
|one regular deep cell battery|
What are lithium batteries?Lithium batteries are a type of battery composed of Lithium metal or compounds as an anode. It is the lightest metal and the metal that has the highest electrochemical potential. They are also much longer lasting. We have chosen Lithium Iron Phosphate also known as LiFePO4. They are reportedly non-combustible, and thus vastly safer than the original Lithium-Cobalt-Oxide batteries.
|16 of the 32 lithium batteries we went with|
Advantages of Lithium ion batteries
- They are much lighter than deep cell batteries which is a major asset in any RV.
- Can be charged at nearly 100 per cent efficiency, whereas most batteries run at a much lower efficiency.
- They are more compact enabling more batteries in the same area and thus more power, up to 80% discharge.
- These batteries have a better cycle life: 3,000 or more cycles compared to acid batteries' 500 to 1000 cycles.
- Lithium batteries do not restrict solar input thus they use full use of solar input. (The batteries are very greedy) LOL.
- The batteries hold their voltage better.
Practical ApplicationWe expect to be able to run all our appliances on 240v including the domestic fridge, an air conditioner, water heater, induction stove, CPap machine and others, many which are much harder or near impossible on deep cell batteries without a generator. I have a dislike of gas and don't want to have any gas appliances other than a potable butane gas stove. Our lights are all LED lights. Where possible and financially viable we will make any new purchases with an eye to how much power they draw and if an inverter option is available such as the microwave oven, then this is the way we will go. By going with regular 240 volt power also means we are not restricted to expensive RV specialized appliances.
We have installed 32 Lithium batteries under the bus
Want more infoTo understand more I can recommend Technomadia's posts on Lithium batteries. They have had them up and running in their bus now for over 2 years and can speak from both a technical understanding and personal experience. Click here to read their post.
The big nasty debateThere is a lot of debate about Lithium Batteries on some RV forums and some of it quite nasty. It seems as though the lead battery big guns have been steadily undermining the debate to protect their own business interests, similar to the fuel companies pushing fossil fuel over alternate fuels.
First off, I will delete any truly nasty comments rather than genuine constructive comments.
Secondly, I did not go into technical details on this post as that is way beyond my comprehension. I am after all just the glorified writer, it is my hubby that delves into the technical and practical side of the conversion. Rob has relied heavily on research and the advice of others combined with his own knowledge. We do not consider ourselves experts in this and if I have made any obvious mistakes in any of the information above, I am willing to correct it.
Thirdly, because of copyright ownership of some technical details, there is also stuff that I can't reveal within the scope of this post. So with all that under our belts, lets keep all this in perspective. It is just a post stating what we have done and why. It is possible we have made some mistakes in judgement. We have looked into it and believe in what we are doing. In the end, it is all a part of the spice of life, some of it is wonderful and some is bitter.
CommentsWe will value any comments and advice. May I suggest you direct some of the more technical questions to sites such as Technomadia or any RV forums though these seem to be heavily slanted against proper discussions on the merits of Lithium batteries, with some even banning such topics due to some strong negative reactions of a few.
We run 240v power off the lithium batteries 24/7. During our 4 month trip to a cold and mostly overcast Tassie, Summer 2015, we really tested it to the hilt as we free camped nearly the whole time. We only hooked up to power 3 times to charge up the batteries during this time. We are running a household fridge, microwave oven, induction cooker, CPAP machine etc. We are extremely happy with the solar power/lithium batteries we have. We can't divulge details of the battery management system though as we had an agreement with the guy who advised us as it is his intellectual property. He runs a private forum on Lithium Batteries which you may peruse which will help genuine seekers after admittance by invitation only. Be aware there is some opposition to Lithium based on incorrect information. So be discerning of your sources and the currency and relativity of the info.