If you do a lot of dry camping then LiFePO4 lithium batteries are a
great choice. They are lightweight (always a good thing in a GMC).
You can cycle them deep (over 80% of their capacity). They charge
fast while the generator is running (assuming that you have a big
enough charger) so you do not have to run the generator as long to
top the batteries off.
But if you spend most of your time plugged in. Or your GMC spends
most of its time in storage, then LiFePO4 is probably not a good
choice. A set of deep cycle golf-cart batteries are a much better choice.
We use our GMC about six weeks out of the year. Maybe two of those
are dry-camping. I have an electric fridge, inverter (for microwave,
toaster, coffee maker etc.). I have been getting about ten years life
out of each set (4 x 220ah) of golf-cart batteries. I typically use
100Ah/day and run the generator 3-4 hours/day (usually while cooking)
when dry camping.
The key to long battery life is to understand the nature of the
battery that you are using and to keep it within its limits. One of
the best resources I have found on LiFePO4 lithium battery systems is:
http://nordkyndesign.com/category/marine-engineering/electrical/lithium-battery-systems/
This set of articles is targeted toward the marine market but the
issues are pretty much the same when using LiFePO4 batteries in an
RV. I highly recommend reading these articles before spending the
money on a LiFePO4 lithium battery system.
The LiFePO4 batteries are expensive, easily damaged by misuse and
very different than lead acid batteries. For example, leaving them
fully charged shortens their life whereas a lead acid battery is best
kept fully charged. LiFePO4 batteries need to be floated at about a
20-30% charge state if they are not being cycled. Overcharging the
LiFePO4 battery shortens their life whereas a lead acid battery needs
to be overcharged occasionally to keep the cells balanced. LiFePO4
battery chargers sense current to determine when to quit charging the
battery. Lead acid battery chargers sense voltage to determine when
to quit charging the battery.
So my suggestion is to learn as much as you can about LiFePO4 lithium
battery systems and then decide if it is a good fit for the way that
you will be using your GMC...
For now I am keeping the golf cart batteries in the GMC. But I am
working on a bus conversion for full-time off-the-grid use. That one
will have an LiFePO4 lithium battery system installed...
Dave M.
>My House batteries are at the end of their life and I need to
>replace them before the winter traveling season.
>
>A year ago Jerry Work did a presentation at Western States and GMCMI
>about Modern LiFePO4 lithium batteries with on-board electronic
>controls for use
>in our GMC's. Have any of you done this conversion? Which of the
>three packages did you use? How easy to install? Are you glad you
>did the Lithium
>conversion?
>--
>Larry
>78 Royale w/500 Caddy
>Menomonie, WI.
>
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Dave
Ann Arbor, MI.
73 Sequoia (26'/455/EbH/RwI/ThH/HEI/TBI/160°/3.42/100A/Q55G)
99 Gillig (36' work in progress)
