Converting to LiFePO4 batteries and Sailor Man's LiFePO4 Build

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Well-known member
Sep 7, 2008
Ontario Canada
This is an excellent article about changing from Lead-Acid House batteries to LiFePO4. It's written for the boating community, but the principles are the same for us. It delves deep into charging considerations and the issues with using a common lead-acid charger (converter). Also what a "drop-in" LiFePO4 battery really means.

Lots of good info on the differences in usable charge between the two types.

Its a couple hour read, so maybe make a pot of coffee first.

I also posted this link in the Resources section under House Systems.
Thanks for the link. I have not yet had time to digest it all yet. It was great timing because I am starting to get requests for an upgrade to LiFePo4 from the owners that I have done work for in the past.
Now.....if Coleman (or anyone else) could re-introduce a rooftop 6,000 btuh cooling air conditioner, I am thinking I could make my wife happy by using that unit at night at modest settings and maybe get some air conditioning out of a lithium setup. I would reduce the area to be cooled by shutting the bathroom door. I have no rear AC unit, merely a crank up vent with fan. Word on the street says "no" to a boondocking system unless you can go crazy with batteries and charging methods. I like "simple". Like no airconditioning, which I did no grow up with anyway.....BUT.....trying to keep her happy. I would pre-cool the interior using the Onan, then shut that off snore away with "some" modest cooling with a smaller A/C unit, like Coleman used to make (I think it was the Polar Cub or something like that)......I am interesting in a lithium setup and have been following the DIY approach to creating your own battery pack.
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I am upgrading my 1976 Coach and have a completely different approach. Among all LiPO4 batteries, only one has a UL certificate. It is Lithionics, maunfactured in Clearwater, FL.
I am also upgrading by undertaking a complete energy conservation upgrade. As a result, I have (2) different batteries, one 13.6v and one 51.6v.
I have also remove the Onan 6000 generator and replaced it with a Firman inverter generator dual fuel (yes lpg too).
I am removing the highly inefficient rooftop ac units (one with resistance heating) (SEER 5.5-7) with (2) 12,000 btu Mini-split heat pumps (SEER 33).
I am replacing the inefficient stock 12v alternator with (2) Balmar alternators (12v & 48v).
With LiPO4 batteries allowing 100% withdrawal of power (Lead acid 50%), my enhanced electrical storage is 11.5 times the current capacity.
Electrical Hot water eliminated by replacing with lpg tankless hot water heater.
All glass is to be tinted with ceramic film (blocks 95% of solar ac load).
Sorry, I forgot to talk about the roof. It will be very slick. I am removing the bulky (2) advent ac units and a storage box. They are being replaced by (2) YMGI 48v dc Mini-split ac units in a custom enclosure above the rear bumper.
I am adding (12) semi-flexible SunPower 110w solar panels (1,320w).
Also, Cliff Golby has fixed the terrible dashboard air conditioning system. it now blow strong and cold. I am replacing the engine driven air conditioning compressor with a 12v dc compressor (16,000 btu max). Then I will have (3) direct current cooling systems running solely off the batteries. (12,000+12,000+16,000 = 40,000 btu).
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Not sure that covering rotational power to electricity, then back to rotational power with your 12V dash AC compressor will net an increase in efficiency.

Keep us up to date with your work!
Sorry, the 680 watts are need for 24 hours not 12 hours. These LiPO4 batteries are good for a minimum of 3,000 recharges, so they will outlast 3 to 6 replacements of lead acid batteries. If viewed from an initial cost perspective, it is a quite expensive project. however, if viewed from a life cycle cost perspective, it is quite inexpensive, Also, no maintain ace vs. lots of maintenance makes a considerable difference. Also, Lithionics batteries have a "Never Die" feature. They will give you 90% of the power and then shut down. You think the battery is dead, but it is not. Press a button on the battery and it gives you the last 10%.
I am using an indel 195 Combi Refrigeration/Freezer. It is powered by both ac and dc. I am primary using dc power. There is no lpg connection. This unit comes with (2) compressors, one for refrigeration and one for frozen food and much more handsome. It has a larger storage capacity that other ones I have seen in the GMC Motorhome.

It is actual two separate units stacked on top of each other. It is all Stainless Steel. It is Marine grade.

Indel estimates a 24 hour electrical use of only 680 watts for both the refrigerator and freezer, if you don't keep the door open too long.

In addition, I am installinging another Indel unit. There is always an issue with having a supply of ice. So I am installing a separate Drawer 16, under the Combi that can be used for either refrigeration or as a freezer, I plan to use it exclusively for ice storage.

I haven't found a way to attach the pdf file, so will please have all that are interested, please send your email addresses to

I have designed a separate ventilation system to use outside air to cool the condensers. Unfortunately that is not the case for the Drawer 16. This quite small unit uses almost twice the power of 195 Combi, but I love my ice.

I have all my projects on CADD using ArchiCAD.

Things are seeming to be coming to a head. I may be getting the Lithionics LiPO4 batteries in about 3 weeks. Their usual capacity is about 12 times the originally installed storage capacity.
I forgot to tell you. There is an additional accessory to the Indel units that I have purchased. The direct current compressors gam be fitted with a special compressor controller that matches the dc motor speed to the load. This can save 30% to 40% of the already small electrical power use. It is worth the money.

For the faint of heart, given how large a percentage of battery use comes from refrigeration, this expenditure is worth it, These frig/freezer are with the cost.

In addition to the refrigeration, I am removing all existing air conditioning systems and replacing them with much more efficient direct current heat pumps. Gone is the furnace and electrical resistance heat. So is the electrically heated tanked water heater.
Do you have any plan to heat when the OAT gets below 40°F??
The original furnace, unused for decades was still in the coach. I removed and trashed it.

The only heat in the coach was one resistant electrical coil in the 15,000 btu Advent. The newer 12,000 btu Advent had no heat.

Both of them will be trashed.

I am installing (2) YMGI 86 12,000 btu solar ready Mini-split heat pumps. There is no backup resistance heat.
Working outdoor temperature ranges are: Heating: 15°F - 75°F
Cooling 23F - 104°F

Each unit provides 12,000 btu cooling and 13,000 btu heating.

So there will be a total of 26,000 btu of heating in the coach, using battery power almost all of the time.

Since the dashboard air conditioning system is being converted to 12v dc, the 455 does not have to run. The new electric spiral compressor has a maximum rating of 16,000 btu, but I don't expect to use all of it.

Therefore the total cooling & Heating capacity from batteries is:
Cooling Heating
Electric Dashboard AC: 16,000 btu
Salon YMGI 86: 12,000 btu 13,000 btu
Bedroom YMGI 86: 12,000 btu 13,000 btu
Total Capacity 40,000 btu 26,000 btu

I hope I have answered your question.

With the 1,320w of solar panels on the roof, the effective SEER of these units approaches 33 . The Advent rooftops, like all the other ones has a SEER pf 5.5-7, when new. Of course, in the real world, they are much worse causing the gasoline guzzling Onan 6000 labor to run the roof top air conditioners. No wonder gasoline mpg is so bad.
It is unfortunate that you did not offer the heater to others. A lot of people have houred out heaters.

I will be interested to see how well this works out for you. I read a lot of people and hope that they all succeed.

So you have 1320 watts of solar panels on the roof, but that is the output of the panels when the sun is perpendicular to the panel.
What will be the average power available from the panels considering they are mounted flat on the roof and do not track the sun across the sky? I know this will vary throughout the year as the sun's azimuth changes with the season, but lets say best case scenario for the USA is at summer June 21.
Just wondering.
Sailor man, I like the look of those A/C units. I’d love to be rid of my roof A/C unit too.
It looks like each unit draws about 600W. If you leave one on overnight you could easily use 3 to 5 kWh of charge overnight. Your rooftop solar will take 3 to 4 hours to recharge your batteries assuming you turn everything off and get 100% efficiency. Thats not reality. My feeling is you need a lot more solar.