How to hook up my 3 RV batteries

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.

phil-t

Well-known member
Joined
Jul 10, 2017
Posts
1,241
Location
Ogdensburg, NY
I can see that all three batteries are connected in parallel. It's a mess for sure. The neg of all three being connected "might" be OK, but if that right hand battery is to be the chassis battery, then it should not be connected to the other batteries POS.
The way I see it anyways. It sure needs to be traced out to tell what's what.
 

Scards

Active member
Joined
Jul 17, 2021
Posts
37
Location
Chino ca
Show us a picture of what you are looking at.. even if it wasn't you that took things apart, the tip of the day, since you are going to become handy, always take pictures of stuff before you take things apart, between your pictures, youtube and this forum, anything can be fixed or resolved (rv related).
Please see my pic, my issue was my batteries died every day. I live in my RV, and currently, im not in a place to plug in. So, my batteries died and id jump start it just to use my water pump and hot water heater etc. I know this has to be a very rookie mistake im making but i do need advice, and this is how im going to learn it. Thank you for any input you have..
I wouldn’t assume. Photos of the batteries and where they go is critical to good advice.

I see so many issues with this installation that if I encountered it with anything I owned I would remove it all and start over. While it may be "functional" as shown it is directly counter to proper parallel battery connection convention, and it is mechanically deficient lacking any kind of battery or cable restraints. It appears the connections made were based on convenience, whatever terminal had room and was closest. The tops of the batteries are a mess, promoting self discharge and terminal/cable corrosion. If "functional" is the goal then this may "work" but it's not something I would consider reliable or durable and in this case, even safe to operate.

Mark B.
Albuquerque, NM
Thanks for the tip, like i mentioned, that pic was before i removed them, and yes many changes are in the works this weekend and im going to clean it up, i just wanted to know if this IS in fact wired correctly, if so, now i can go about making a housing for them and cleaning them up with new connections and wires and the appropriate brackets that secure them safely. Thanks for the input, appreciate it.
 

Attachments

  • Resized_20211013_144103(1)(2).jpeg
    Resized_20211013_144103(1)(2).jpeg
    146.9 KB · Views: 33

Scards

Active member
Joined
Jul 17, 2021
Posts
37
Location
Chino ca
I can see that all three batteries are connected in parallel. It's a mess for sure. The neg of all three being connected "might" be OK, but if that right hand battery is to be the chassis battery, then it should not be connected to the other batteries POS.
The way I see it anyways. It sure needs to be traced out to tell what's what.
So, its not wired correctly?
 

DonTom

Well-known member
Joined
Apr 21, 2005
Posts
4,923
Location
Auburn, CA or Reno, NV
So, its not wired correctly?
Yes, it's wired correctly. Assuming those are all three house batteries and no engine starting battery. Make sure you have one more battery under the hood just to be sure.

Assuming you have three 12 house batteries there, each positive goes to the other two battery positives (+) and the negatives (-) all go together likewise.

See Kirk's "3 parallel" in message #5" above.

Do not be confused by your middle battery being turned around. That let's the wires be shorter between the batteries.

-Don- Reno, NV
 
Last edited:

Ex-Calif

Well-known member
Joined
May 15, 2020
Posts
1,863
Please see my pic, my issue was my batteries died every day. I live in my RV, and currently, im not in a place to plug in. So, my batteries died and id jump start it just to use my water pump and hot water heater etc. I know this has to be a very rookie mistake im making but i do need advice, and this is how im going to learn it. Thank you for any input you have..
OK lets rewind a little bit.

If nothing was smoking and sparking before then the wiring is probably not unsafe and it will power you up if you wire it as it was before.

If all 3 batteries go dead overnight then somehow they are all wired in parallel or you have drains on both the house and the chassis side.

If you are only running a water pump and a few lights you should get a couple days at least out of the battery system. If the water heater is on electric full time you could drain 3 batteries in 24 hours depending on how much water you use.

If the hot water is on propane (not electric) you should still get more than 24 hours. Aside from water, lights and pump are you using any other power to your knowledge?

Also are your lights LED or incandescent? Incandescent bulbs are a pretty big draw.

Just estimating your batteries and if all 3 are in play I would guess you have about 120amp usable power.

Water heater 10 amps X 3 hours = 30 amps
5 X 40w incandescent X 5 hours = 75amps
Pump 1amp X 2 hours = 2 amps

This is pretty much a guess but you can see that even 40w X 12V bulbs use a ton of power. You may have other 12V usage - tv, fridge, laptop.

The point is that a standard battery bank with 1990's technology isn't going to run long without shore power.
 

Kirk

Well-known member
Joined
Oct 30, 2005
Posts
1,260
Location
Full-time , Escapee
So, its not wired correctly?
I would say that it isn't connected in a typical fashion but it is impossible to say for sure with just that picture to go by. If it was working before you took it apart and you are sure that it is back the way it was before, then there shouldn't be any serious problems. One thing does cross my mind is, are you using an inverter to supply 120v power to some things in the RV? If you are, that would explain the batteries running down very quickly as 2 batteries aren't much for an inverter.
So, my batteries died and id jump start it just to use my water pump and hot water heater etc.
Does this mean that the chassis engine doesn't start and it's battery is run down also? If that is the case then clearly all 3 batteries are being used by the coach and that is not proper connection. Proper connections would separate the chassis battery from the coach loads to prevent that from happening so that your chassis engine would start. I have seen many motorized RVs and every one of them have had the chassis battery separated from the coach loads to prevent it from being discharged, thus allowing the starting of the chassis engine for an emergency. There should be a solenoid that connects the output of the alternator which charges the chassis battery to the coach batteries while the engine is running but separates it when the chassis engine is shut off.
 

Gary RV_Wizard

Site Team
Joined
Feb 2, 2005
Posts
74,986
Location
At my Silver Springs FL home
Water heater 10 amps X 3 hours = 30 amps
5 X 40w incandescent X 5 hours = 75amps
Pump 1amp X 2 hours = 2 amps

This is pretty much a guess but you can see that even 40w X 12V bulbs use a ton of power. You may have other 12V usage - tv, fridge, laptop.
Those are extremely unrealistic values for 12v usage. The water heater can't draw 10A of 12v power - that would be the shore power (120v) draw in electric mode. 12v usage is less than 1A/hr. And 12v lighting runs about 1.0-2.0 amps/hr per bulb. The pump draws several amps when it briefly cycles, but doesn't run non-stop, so probably doesn't use more than a couple amp-hours per day.
 

Kirk

Well-known member
Joined
Oct 30, 2005
Posts
1,260
Location
Full-time , Escapee
While the water heater electric element would not be operating constantly, when it does, here are a few numbers for it. I am unable to locate any hard numbers for the amount of on time when no water is being used but based on experience I believe that to be less than 10% of the idle time that it is heating. Even so, it would not take a long time to drain 2 or 3 batteries with it heating.

Most RV water heaters have a 120v electric element of between 10 & 20 ohms. Ohms law tells us that voltage divided by resistance equals current in amps.
120V / 15 Ω = 8a X 120V = 960watts or about 80a from the batteries to supply the inverter.
 
Last edited:

ferfer

Well-known member
Joined
Jul 20, 2008
Posts
409
Location
Arizona
Stacy,

The question IS what are you running on 12 V or propane during the day and at night? Furnace, television (CTR or flat screen), lights etc. Are you running the refrigerator and hot water heater with propane?

It looks like your Duralast 12 V batteries reserved capacity is 96 which calculates to 40 amp hours per battery. Assuming your batteries are fully charged you have 80 amp hours. Since your batteries are dead in the morning and your method of recharging them is ?? to jump start ?? you likely have lot less amp hours available. (Never mind you should only be using less than half the amp hours for health of battery.)

With such low amp hours available you really need your generator to recharge your batteries. If your generator is not working you need to be plugged in.

Oh and how are you charging your batteries?

Jennifer
 
Last edited:

Ex-Calif

Well-known member
Joined
May 15, 2020
Posts
1,863
Yeah I wasn't thinking right about the electric water - head up and locked, eyeballs caged.

Was sort of trying to get the conversation going towards the overnight/24 hour drain which appears to be the original problem. Unfortunately if there is a system drain I am not sure we will be able to talk Scards through isolating it.

She probably needs to find a decent 12V system electrician who makes house calls.

Also (facts not in evidence) she would need an inverter in the system for the water to be on electric and I doubt a coach that old in that condition would have any inverter much less on that size.

Carry on - LOL...
 
Last edited:

Ray-IN

Well-known member
Joined
Mar 16, 2014
Posts
564
Location
North America-somewhere
Everyone is shooting in the dark without a wiring schematic. I suspect DonTom is closest to being correct, but unless phil-t returns we'll never know.
 

phil-t

Well-known member
Joined
Jul 10, 2017
Posts
1,241
Location
Ogdensburg, NY
I'm here - What do I have to do with this? I'm right there with everyone else - guessing. I have never seen 3 12v batteries wired up parallel for an RV setup. I'm betting the battery on the right is supposed to be a single chassis battery and the other two house batteries. There is no charging going on and all three batteries are being depleted.
I've been wrong before though - :cool:
Hope we get the fix and results from the OP. She is definitely in need of some in person help from a capable tech.
 

woof-n

Member
Joined
Jan 19, 2018
Posts
11
Location
Toledo Ohio
Scards
I admire your determination to fix your own camper. Many of us have graduated from same school of hard knocks as you are attending. The real problem as i read this is, the batteries are dead by morning. My electrical trouble shooting plan is to always divide and concour. Charge up your batteries and take a voltage reading. Pull one or all battery out of service for the evening. Check voltage in the morning. If the battery voltage down with no load, the problem is in the battery/s. Reconnect and start the camper, if it doesnt start the battery is bad. If the voltage remains the same then something is draining the battery. So if the batteries are good, then turn off everything in the panel accept for a couple our your most important appliances. Same thing If the batteries are dead in the morning, turn off the entire panel and retest until you locate the problem circuit. Good luck

Dennis
 

Scards

Active member
Joined
Jul 17, 2021
Posts
37
Location
Chino ca
Thank you ALL for your replies, i needed to step-aside and think this out and i visited an actual Ford RV authorized dealer and spoke with a technician and ALL of you were right. My 1 battery was good, 2 were not, and they were just depleted from going empty and recharged over and over, so i need a generator. Who can tell me which one to get. I hear i need 7000 watts to run all my appliances, im interested in a dual fuel, any recommendations?
 

Mr Lars

Well-known member
Joined
Mar 17, 2021
Posts
100
Location
Coleman, TX
Do you not have a generator in one of the basements? Even if it does not work? Is the basement that should contain the generator empty?
If it were me(I know), I would research what size generator was standard equipment for your unit, back in the day when your model RV rolled out the factory doors. And try and find a decent used one as close to that as possible, and have it professionally installed.
 

Kirk

Well-known member
Joined
Oct 30, 2005
Posts
1,260
Location
Full-time , Escapee
I hear i need 7000 watts to run all my appliances, im interested in a dual fuel, any recommendations?
Do you realize how large a 7000 watt generator will be? Are you looing at getting one permanently installed into the motorhome, or a portable one? If you get the least expensive it will be a construction type and also very loud. You could get a Honda 7KW inverter generator for only $4,599 or a Powerhorse 7500/6500 for $3,499.
Either of these will weigh more than 300# and be about 3'X3'X3' in size. If noise doesn't bother you then you could get a construction type Champion 7000 watt from Northern Tool for only $800. Of course, none of those are dual fuel but you could have them converted.
 

uchu

Well-known member
Joined
Sep 9, 2019
Posts
367
Location
Ontario, Canada
This one is dual fuel but, as mentioned, it's noisy and heavy:


My concern is that the issue of the house batteries depleted has not been addressed. Did the person you talk to find out why they got discharged to the point of being trashed? Maybe the converter isn't working?
 
Top Bottom