I just removed two 6v batteries from my fifth wheel rv. I'm going to replace them with two 12v batteries. When I removed the 6v batteries, there was one wire running from pos to pos on the two batteries. There were two large white wires from the rv and going to the neg post of one battery. There was also two large black wires going from the rv to the neg battery post of the other 6v battery. With the one wire that was running from pos to pos of both batteries, that tells me that they were both wired in parallel? Am I right? What confuses me is if they are both 6v batteries, wouldn't they need to be wired in series to get 12v in an RV that is 12v?My fear is installing the two new 12v batteries. I don't want to wire the same only to find out it's wired in series. I don't want to screw things up with 24v.Can you help me out? Thanks

installing 12v batteries +to+ -to- will give you 12 volts.

MSGTRETIREDCSP wrote:I just removed two 6v batteries from my fifth wheel rv. I'm going to replace them with two 12v batteries. When I removed the 6v batteries, there was one wire running from pos to pos on the two batteries. There were two large white wires from the rv and going to the neg post of one battery. There was also two large black wires going from the rv to the neg battery post of the other 6v battery. With the one wire that was running from pos to pos of both batteries, that tells me that they were both wired in parallel? Am I right? What confuses me is if they are both 6v batteries, wouldn't they need to be wired in series to get 12v in an RV that is 12v?My fear is installing the two new 12v batteries. I don't want to wire the same only to find out it's wired in series. I don't want to screw things up with 24v.Can you help me out? ThanksTwo 6 volt batts need to be wired pos on one batt to neg on the other batt to make up a 12v batt.Then the load pos and neg goes on the other batt posts not being used.Reading your description it is impossible. The two black (pos) wires should have gone to the pos post of one of the 6s not the neg post. The two white wires should have gone to the neg post of the other battery, which they did.I can't figure out how you ever got anything as it was. Perhaps you didn't need to swap 6v for two 12s, but just got the wiring right on the 6s.

This is diagram from google search on how the 6VDC and 12VDC are wired up.Roy Ken

Your 6V batteries could not possibly have been wired as you described or they would NEVER have worked. Period.

We'll after reading all your replies, I think I did a stupid when I removed the batteries. The one wire I said that was running from pos to pos may have been running from pos to neg. I just looked at the one battery and assumed they were both installed the same direction when they were sitting side by side. I didn't pay attention to see if maybe the other battery sitting beside it was turned around. Duh. If so, then the one wire running from pos on one battery would be to the neg on the other battery. Because I was in a hurry, I did't look at both batteries the way I should have.When I go out tomorrow, I'll run a cable on neg to neg and pos to pos. I'll connect those two white wires from the rv to the pos and the two black wires from the rv to the neg. hopefully that'll do it. I'll let you know. Thanks for helping me get my thought process to going.

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MSGTRETIREDCSP
Explorer
Mar 06, 2014
BillyandKris wrote:
Why are you switching to 12V. We are going the other direction.

No particular reason. Most of the time, we are hooked up to 120v. I've always had two 12v batteries in past rv's so I just wanted to stick with 12v batteries. I doubt there will be a next time, but if there is, I'll remember the way things were hooked up before I get started. :S
BillyandKris
Explorer
Mar 06, 2014
Why are you switching to 12V. We are going the other direction.
MEXICOWANDERER
Explorer
Mar 06, 2014
Case Number 101,733

TAKE IMAGES WITH A CAMERA OR PHONE BEFORE TOUCHING THE WIRING ON A BATTERY BANK.
MSGTRETIREDCSP
Explorer
Mar 06, 2014
Just an update. Everything hooked up and working great. Beside the smell of burning wire, everything is good. Just kidding on the burning smell. Thanks for all your advice/help. :)
beemerphile1
Explorer
Mar 06, 2014
RJsfishin wrote:

...Sometimes, if you want it done right, DON'T do it yourself. :)

:B
RoyB
Explorer II
Mar 06, 2014
MSGT wrote:

Ok, thank you for that info. It saves me from making some sparks. I'll try that.

Just getting one little SPARK will most likely blow your close to the battery IN-LINE fuse as well as two "REVERSE POLARITY" fuses back in your 12VDC Power Distribution Panel.

Try not to 'SPARK' your battery system even for a short second haha...

Its not fun tracking down why you are not getting 12VDC from your batteries when that happens...

In the RV world the BLACK CABLE is usually HOT +12VDC and the WHITE CABLE is GND -12VDC.

In the AUTOMOTIVE WORLD that most of us are used to the RED CABLE is HOT +12VDC and the BLACK CABLE in GND -12vdc.

Since the battery connections are used in both RV and AUTOMOTIVE WORLDS you sometimes find both wiring schemes being used. Just be aware.

When messing with battery cables I always take a picture with my cell phone or mark the HOT +12VDC cables with RED FINGERNAIL POLISH...

When you purchase AUTOMOTIVE items like maybe a JENKINS 12VDC Radio setup they usually come with RED and BLACK 12VDC cables. When you install these in the trailer you sometimes end up with a RED WIRE on TOP of BLACK Wire in the 12VDC Power Distribution Panel... This sometimes makes old timers like me turn over in the graves haha...

Roy Ken
wolfe10
Explorer
Mar 06, 2014
I would NEVER use color or wiring to determine positive and negative. The cost of connecting with reverse polarity can be high.

Trace the wires. One will connect to chassis (metal) ground, the other to the 12 VDC breaker box (with or without a large breaker between battery and breaker box).
RJsfishin
Explorer
Mar 06, 2014
Whew !!! Scary at best !
Sometimes, if you want it done right, DON'T do it yourself. :)
BTPO1
Explorer
Mar 06, 2014
Peg Leg wrote:
I like to put some elec tape near the connectors on my batt cables. Black tape on my neg cables and some red on pos ones. I see the tape and know I've already checked where the wires are supposed to go. I do this no matter what color cable it being used.

I agree with you on this, I always tape my leads with the proper color coding to prevent any mistakes.

Be sure to check and make sure which cable is which. The one that is going to or attached to the chassis is the ground or negative. JMO
bikendan
Explorer
Mar 06, 2014
suggest you Google "12 Volt Side of Life part I and II"

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