Considered the bee’s knees in battery terms, lithium still is a hot topic re bang for your buck. So we ask, are lithium batteries worth the money?
On several occasions we have written about the latest technology in 12-volt batteries, Lithium Iron Phosphate or LiFePO4. In this feature, we look at what it is actually like to live with lithium batteries in the real world and how they compare with their lead-acid ancestors.
The downside of lead acid
In our case, we have a Roadstar Safari Tamer off-road caravan that was designed to be completely self-sufficient so we could free camp away from mains power for extended periods of time. To that end, we had a 12-volt system that was based on two 120Ah Fullriver AGM batteries. Now anyone familiar with the 12V RV scene will know that Fullriver batteries are among the best you can buy. We were, for the most part, very happy with them, but like all lead-acid batteries, they had a number of flaws.
First and foremost is the weight of these things. Each battery weighed in excess of 40kg. That’s over 80kg in batteries alone. In the battle to keep our caravan weight down, this was a big issue.
The second problem with lead-acid batteries is they don’t like being discharged to below 40 percent state of charge. In other words, even though we had 240Ah of battery capacity, we could only use 140Ah before we started to damage the batteries.
The lowdown on lithium
Lithium batteries overcome both these issues. For a start, they are much lighter. The 200Ah Pro Power lithium batteries we replaced our AGMs with weigh just 35kg. Immediately we saved 45kg. The second advantage lithium batteries have is they can be discharged to much lower levels without sustaining any damage to the cells. Pro Power recommends not to discharge them below 10 percent state of charge. In other words, you can run your caravan or camper electronics for longer between recharges for the equivalent amp hour rating.
If there are any disadvantages to lithium batteries, apart from the cost, it is that they do not like to be charged at higher than 13.8 volts. Lead-acid batteries can cope with charge voltages as high as 14.3 volts. In the past this would have necessitated changing both the 240 mains charger and the solar charger to ones that have a lithium charging profile. Pro Power batteries get around this problem by having inbuilt battery management systems that limit the charge voltages regardless of the source charger. That said, it is still preferable to have a charger that can either have the maximum charge voltage limited to 13.8V or has a lithium charge profile.