My RV’s “larger” batteries are dead. Can I replace them with lithium?

Dear Dave, 
My RV’s larger batteries are not working. I am not sure what battery to replace them with. Could I use a LiFePO4 instead of regular battery? Do I need a different monitor? I am not using any solar. —Beverley, 2001 Tiffin Allegro 40 ft. diesel bus

Dear Beverley,
I assume the “larger batteries” you are referring to are the house batteries, and I doubt they are the original ones as they would be 25 years old. I believe the original house batteries were 6-volt Trojan batteries that would look something like these.

My guess is they have been replaced multiple times and most likely with a different brand and maybe even 12-volt batteries.

How much dry camping will you do

My first question when asked about the best batteries is always, how much dry camping do you plan on doing? If you are plugged into shoreline power most of the time, investing in lithium batteries would be a waste of money. There are several cheap lithium battery companies that are flooding the market; however, I know of two that are already out of business and can’t be found.

If you do not plan on doing any boondocking or dry camping and will be plugged in most of the time, I would just get a cheap flooded lead acid (FLA) battery from a discount store. I believe your Tiffin had a large inverter/charger that would provide a constant 13.2 volts to the batteries and will work just fine. These do require more maintenance by checking the cells for fluid levels. Then deciding on 6-volt or 12-volt would not matter other than the cost.

Use AGM batteries for less maintenance

For less maintenance, you could go with an absorbed glass mat (AGM) design that is completely sealed but would be more money. This would also be a good option if you plan to dry camp occasionally.

There have been many articles posted about switching to lithium batteries and understanding what to look for. Here are a few quick points to consider.

Look for a quality LiFeP04 battery, verify your inverter/charger can be set to the proper charging profile of 14.6 volts for approximately two hours, and calculate your power needs to get the right amp hour (Ah) rating. Here is a good three-part article covering all that. This would be a good option if you are planning to do some dry camping and also keeping your Tiffin for an extended period of time as these batteries are often guaranteed for 10 years or more.

What battery monitor will work with RV batteries

The second part of your question is whether the monitor will work or not. That depends on what type it is. I would assume that back in 2001 it most likely was just a light level monitor that did not provide actual voltage or State Of Charge (SOC), which is not very accurate. Once again, if you are not dry camping much, this monitor is fine. However, if you are going to go with lithium, I would recommend getting a better monitor like the Go Power! model.

 You might also enjoy these posts from Dave 

• Can different type and age RV batteries be mixed? Can I add a lithium battery?
• Will RV’s house batteries ‘play nice together’ if I replace chassis battery with lithium?
• Will my RV’s charger be sufficient for new lithium batteries?
• Will WFCO Auto Detect charge RV’s lithium batteries?
• Will WFCO Auto Detect charge RV’s lithium batteries? —Part 2

Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

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