Staged Battery Plant for RV

[Haertig]

I am converting a short bus for camping.

Ultimately I plan to install a 48V battery plant, DC heat pump and solar on the roof. I am leaning towards using a 100Ah server battery. I like the build quality and the compact, easy to install, integrated construction that server batteries provide.

But, on an interim basis I would like to install a 12V, 100Ah plant, charged by the vehicle alternator9 to power lower power loads - refrigerator, lighting etc. There will be a separate, protected start battery.

Looking for suggestions on how to stage the build so that the initial 12V plant can be incorporated into the ultimate 48V plant.

Thanks!

-Gray

 

[Dave in AZ]

There is a good use of 12v 100Ah battery in an RV, because the jacks and leveling and tongue and any extenders all are pretty high power 12v usage. So even when you later do 48v, it is good to have that 100Ah 12v to supply these big amp drawa and even out your usage. The 12v 100ah mini is only 19 lbs now and quite small.

Buy one, use it to feed all your 12v lights and fridge and maxxair fan, and RV jack loads. Will still be useful as part of your later system.

 

[Haertig]

Thanks for your thoughts, Dave!

The thread title is perhaps a bit misleading. I'm not really converting the bus to be an RV. When people ask me what I'm going to do, I say, I want a warm, dry box on wheels that I can stand up in with a really comfortable bed. Amenities are going to be pretty thin on the ground. The aforementioned very comfortable bed,; refrigerator (6 cu ft LG with a variable speed compressor); gravity water storage; diesel heater; heat pump (eventually) with the electrical infrastructure to support it; and folding chairs and tables for furniture.

In short, I'm not going to end up with those sort of 12V loads that you mention. I view the interim 12V system as something to get me through the first year and the fridge is really the only significant load (and a few lights and the GF's and my CPAP's). My inclination is to power these and whatever occasional loads I might have with an inverter - I have accumulated several nice 12V ones.

If I can't come up with a way to gracefully incorporate a 100Ah, 12V LiFePO4 battery into my eventual 100Ah 48V battery plant, I will likely just buy a largish 12V AGM lead-acid battery and charge it through a Balmar Digital Duo, which I have in stock, and call it a day.

For those curious, it is a 22', 2007 BlueBird on a 158" wheelbase Ford E450 chassis that has been 4WD converted with a 6" lift.

-Gray

 

[jberger]

One of the cheap 12V LFP's would be a far better choice than a lead acid. LFP will charge up in a fraction of the time and be able to draw down much much lower than Lead in terms of Depth of Discharge (DoD).

 

[Haertig]

Signature Solar made up my mind for me by putting their EG4-WP, 12V, 100Ah battery on sale for less than half price. How can I turn down 100Ah for $239! This is cheaper than I could get a good quality, largish lead-acid battery for.

Such a good deal, I bought two!

-Gray

 

[Brucey]

Signature Solar made up my mind for me by putting their EG4-WP, 12V, 100Ah battery on sale for less than half price. How can I turn down 100Ah for $239! This is cheaper than I could get a good quality, largish lead-acid battery for.

Such a good deal, I bought two!

-Gray

Yes only risk there is it may be discontinued but doesn't sound like that would be an issue.

 

[justinm001]

Connecting the lithium batteries directly to an alternator doesn't sound like a great idea. I think you should have gone lead acid and called it a day for now. Then you can get lithium 48v and everything that goes with it and run a 48/12 dc dc converter which will fill the 12V battery which runs all the loads.

 

[SparkyJJO]

You need a DC-DC charger so you don't destroy your alternator.