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We just bought a fifth wheel! Several questions ...

jornvango
Explorer II
Explorer II
We just bought a used 2009 fifth wheel to put on our land and live in while we build. The one thing that doesn't work on the fifth wheel is the battery so the first thing to do is to replace that.

Before we start buying stuff for the fifth wheel, we have a few questions that hopefully someone can help us with.

1) Since there is plenty of room in the battery storage compartment, we can pretty much fit whichever battery group size. Does the group size matter? In our old Casita trailer, we only had very limited room for 1 battery so of course we had to buy the correct group size. How does this apply to the fifth wheel?

2) The fifth wheel only as one battery (which is dead). We'd like to put at least two or three 12V AGM batteries. I assume we can connect the RV to one of these three, and connect the batteries in parallel (positive to positive, negative to negative) to keep the batteries 12V?

3) We're going to hook up a Renogy solar panel (with built-in controller). Do we simply connect the solar panel to one of these three 12V batteries?

Thanks!!
11 REPLIES 11

StirCrazy
Traveler III
Traveler III
jornvango wrote:
Thanks!

We won't have access to shore power. The house will be off grid and run on solar.

I'm thinking one or two batteries in the RV to charge with Renogy. I can monitor and add panels if needed.

We are thinking about getting a Jackery with solar panel separately to place in the living area to charge our phones and laptop.

Heating will be catalytic so no RV battery needed. Or perhaps a diesel heater once I can get around to taking on that project.


What kind of electrical appliances are you thinking of running? coffee pot, toaster, microwave? That is really what you need to know to size your battery bank and the type of batteries. how cold does it get.

for example, in my 5th wheel I have four 6V batteries and 480watts of solar. that will let me run the microwave and if I limit that to 10 min a day and only run the Keurig in the morning and once after supper, keep tv down to a reasonable amount and it is sunny I don't have to worry about not having power, that's even with running the propane furnace, but 2 6V will not let you draw as deep on the inverter before you get low power alarms due to the initial draw down of the battery. Four allows you to go a bit deeper while adding capacity at the same time. going to a different type of battery say LiFePO4 gives you a large capacity still and less of an effect on voltage drop but if the battery is going to get below 0C or 32F you must take that into consideration. price wise for the same usable capacity LiFePO4 is cheaper if you compare it to quality lead acid batteries, for example I just replaced my four 6V batteries in my rv with cheap batteries (220cdn each and that's cheap for decent batteries up here and that even includes the discount from where I work) good batteries say something like rolls Surrett are almost 500 each after tax but you won't find a higher quality 6V battery.

Going back to my cheap ones which was the point after tax, it was about 1000cdn to put 4 in and that gives me 220 usable AH. To compare that to the price I think I can get two 100AH LifePo4 batteries for 337.00 each. Yes, they are eco worthy and cheap, but cheap LFP is still better than cheap lead acid. so, I could get 3 for the same price giving me 300 usable AH and 4 times the life, so when that cycle life is factored in, they become less than 1/4 the price of the lead acid.

The other thing that will let you do more is your solar. solar panels are ridiculously cheap if you source them yourself. What I try to do is size my system to replace all the power I used in the evening and overnight by noon the next day and then run everything I use during the day maintaining my batteries at 100% until the solar charging drops off. so, on my 5th wheel I have 480 watts and it works for me as we are pretty careful about when we use the inverter and when we don't, but I can't say leave the bar fridge in the outdoor kitchen plugged in, so I am looking at doubling my solar and converting the batteries to LifePO4 with a much larger capacity to be able to do this.

If you can put in the house solar system and depending how you're setting up the battery storage if you can set that up and the inverter, you can just plug into that system.
2014 F350 6.7 Platinum
2016 Cougar 330RBK
1991 Slumberqueen WS100

cptqueeg
Explorer II
Explorer II
jornvango wrote:
Thanks!

We won't have access to shore power. The house will be off grid and run on solar.

I'm thinking one or two batteries in the RV to charge with Renogy. I can monitor and add panels if needed.

We are thinking about getting a Jackery with solar panel separately to place in the living area to charge our phones and laptop.

Heating will be catalytic so no RV battery needed. Or perhaps a diesel heater once I can get around to taking on that project.


It seems like you're going in a 100 different directions at once. I'd back off a second and look for a single solution to power both the rv and house off the same system.
2024 Chev 3500 CCLB Diesel
Four Wheel Camper Granby Shell

laknox
Traveler
Traveler
jornvango wrote:
We just bought a used 2009 fifth wheel to put on our land and live in while we build. The one thing that doesn't work on the fifth wheel is the battery so the first thing to do is to replace that.

Before we start buying stuff for the fifth wheel, we have a few questions that hopefully someone can help us with.

1) Since there is plenty of room in the battery storage compartment, we can pretty much fit whichever battery group size. Does the group size matter? In our old Casita trailer, we only had very limited room for 1 battery so of course we had to buy the correct group size. How does this apply to the fifth wheel?

2) The fifth wheel only as one battery (which is dead). We'd like to put at least two or three 12V AGM batteries. I assume we can connect the RV to one of these three, and connect the batteries in parallel (positive to positive, negative to negative) to keep the batteries 12V?

3) We're going to hook up a Renogy solar panel (with built-in controller). Do we simply connect the solar panel to one of these three 12V batteries?

Thanks!!


Check out my cousin's YT channel, BeginningFromThisMorning, where they detail the build-out of a '64 GMC bus into an RV that is 99% solar. Almost 3500 watts of solar and 2800 ah of battery storage via a Nissan Leaf battery. If you have questions, don't hesitate to contact them as they're very good about answering. Might take a day or two, though. Juan, cousin's hubby, keeps up on the latest in solar, so even though his rig is already getting "dated", he can probably answer questions about the latest stuff.

Lyle
2022 GMC Sierra 3500 HD Denali Crew Cab 4x4 Duramax
B&W OEM Companion & Gooseneck Kit
2017 KZ Durango 1500 D277RLT
1936 John Deere Model A
International Flying Farmers 64 Year Member

pianotuna
Traveler II
Traveler II
Spend more money on solar panels and add batteries as necessary.

Start with an energy audit. Do panels for 125% of the load.

I would choose one company for the solar--and other electrics--such as victron. I would definitely use a hybrid inverter charger even if there is no shore power.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

valhalla360
Traveler
Traveler
If you will be off grid for months, can you put in the house solar system first and feed the rv off that?
Tammy & Mike
Ford F250 V10
2021 Gray Wolf
Gemini Catamaran 34'
Full Time spliting time between boat and RV

Veebyes
Explorer II
Explorer II
When living off the grid battery power, along with water capacity is king.

Good choice with going with AGM batteries. Put in as much as you have room for. Most RVs don't have much room for batteries so measure up and see what will fit. The more amp hours the better.

You likely have enough room for 2 group 27s, maybe 2 group 31s, a single 4D, possibly an 8D, or 2 6V GC batteries.

We have been using a single AGM 4D. The first one had a lifespan of nine years. The second has been in since 2018. Going strong. Don't anticipate replacing it until 2027, if we are still travelling.

There are some advantages of the AGM, in addition to their longevity. They self discharge at about the rate of the wet cells and while in use they hold their voltage longer, giving more useable amps per cycle than the wet cell. The better battery comes at a cost however. For the serious dry camper well worth it.
Boat: 32' 1996 Albin 32+2, single Cummins 315hp
40+ night per year overnighter

2007 Alpenlite 34RLR
2006 Chevy 3500 LT, CC,LB 6.6L Diesel

Ham Radio: VP9KL, IRLP node 7995

jornvango
Explorer II
Explorer II
Thanks!

We won't have access to shore power. The house will be off grid and run on solar.

I'm thinking one or two batteries in the RV to charge with Renogy. I can monitor and add panels if needed.

We are thinking about getting a Jackery with solar panel separately to place in the living area to charge our phones and laptop.

Heating will be catalytic so no RV battery needed. Or perhaps a diesel heater once I can get around to taking on that project.

JRscooby
Explorer II
Explorer II
Building without shore power?
If have power on site I would just hook to that and don't worry about a battery until ready to go mobile with the RV.

wildtoad
Explorer II
Explorer II
A good read on setting up batteries in parallel. https://www.impactbattery.com/blog/post/how-to-charge-marine-and-rv-batteries-in-parallel
Tom Wilds
Blythewood, SC
2016 Newmar Baystar Sport 3004
2015 Jeep Wrangler 2dr HT

valhalla360
Traveler
Traveler
If you have shore power there is no purpose in upgrading the battery bank, beyond a single cheap 12v battery.

AGM are for planes or boats that do not stay level, since the acid won't spill. They offer no advantages in an RV, doubly so if it stays parked.

If you don't have shore power, 6v golf cart batteries are a good traditional approach, alternatively lithium are becoming more cost competitive but make sure your charging system is compatible.
Tammy & Mike
Ford F250 V10
2021 Gray Wolf
Gemini Catamaran 34'
Full Time spliting time between boat and RV

corvettekent
Explorer
Explorer
I would use two FLA 6-volt golf cart batteries wired in series.
Yes, if your solar panel has a built-in charge controller you can wire it the batteries. You are going to need a few hundred watts of solar.

Are you not going to have 120-volt power to build the house?
2022 Silverado 3500 High Country CC/LB, SRW, L5P. B&W Companion Hitch with pucks. Hadley air horns.

2004 32' Carriage 5th wheel. 860 watts of solar MPPT, two SOK 206 ah LiFePO4 batteries. Samlex 2,000 watt Pure Sine Wave Inverter.