Reply
 
Thread Tools Display Modes
Old 07-23-2014, 10:33 AM   #1
Old Ram Guy
 
Avenger61's Avatar
 
Join Date: Jun 2014
Location: Chambersburg, PA
Posts: 129
Wiring two 12 Volt Batteries

I had the dealer add a second 12 volt battery to my 2015 Shamrock 23IKSS Hybrid. Once I got it home I noticed that the negative wire on one of the batteries was hanging out of the battery box so I opened it up and the wire had come loose from the connector to the battery. It looked like they just failed to crimp the connector tight enough, but I also noticed they wired the batteries in series instead of in parallel. The battery disconnect switch I had on one battery wasn't working at all either. I've read many posts on this that says they should be wired in parallel, so I rewired the batteries in parallel with the battery disconnect on the negative post of the first battery. The battery disconnect still doesn't work so I'm figuring that the two negative wires going from battery 1 to battery 2 are still getting a connection even with the disconnect turned off. Two questions I have are: Is wiring two 12 volt batteries on a travel trailer the best way to wire them or is the series method better? Also, do I need two battery disconnect switches (one for each battery) for them to work? These are two brand new Interstate 12 volt batteries and I want the best configuration I can get to make them last without screwing something up.
__________________

__________________
Marty, Jenice and DD
Avenger61 is offline   Reply With Quote
Old 07-23-2014, 10:39 AM   #2
Phat Phrog Stunt Team
 
TURBS's Avatar
 
Join Date: Aug 2011
Location: Iowa
Posts: 34,337
Negative to negative.
Positive to positive.

"sabre owners united!"


turbs
__________________

__________________
TURBS is offline   Reply With Quote
Old 07-23-2014, 10:42 AM   #3
Junior Member
 
Join Date: Jul 2014
Posts: 27
You would only wire the batteries in series if you have 24VDC system. Series will double the voltage...Parallel will double the available current while keeping the voltage at 12VDC.

As far as the disconnect switches....It would depend on the location of the switch in circuit, but I would be willing to bet that the disconnect switch is not rated for the potential current draw you could get from 2 batteries in parallel. I would install a second switch or get a DPST switch rated for the current on each battery individually.

As a side note..If they hooked up the batteries in series and you have a 12VDC system...you may be in trouble and might want to check out the DC side of your system. At best you could have blown a fuse...At worse you could have fried all of your 12Volt appliances...
__________________
Bmbrady77 is offline   Reply With Quote
Old 07-23-2014, 10:49 AM   #4
Member
 
Join Date: May 2014
Location: Pflugerville, Texas
Posts: 40
I run two 12-volts parallel. First, if what you say about the dealer hooking them in series is true, it may have caused other problems since that would increase the voltage output to 24 volts and may have overloaded the system.

Just keep the coaches positive and negative wires connected to battery no. 1 and run one jumper wire from negative on battery no 1 to negative no 2 and one jumper wire from positive on battery no 1 to positive no 2.

Only one battery disconnect is necessary. It may have burned out or blown a fuse somewhere near it if the dealer hooked up in series. Worth checking.
__________________
TheBennetts is offline   Reply With Quote
Old 07-23-2014, 10:56 AM   #5
Old Ram Guy
 
Avenger61's Avatar
 
Join Date: Jun 2014
Location: Chambersburg, PA
Posts: 129
My mistake I said series but actually the dealer wired the batteries as shown in figure 2 of this link: Battery School | Batteriesnorthwest.com | Connect Your Batteries for Optimum Efficiency it seems like the best way is what is shown in figure 1 correct? I will go get a second disconnect switch and see it that works.
__________________
Marty, Jenice and DD
Avenger61 is offline   Reply With Quote
Old 07-23-2014, 11:14 AM   #6
Member
 
Join Date: May 2014
Location: Pflugerville, Texas
Posts: 40
Either way will work as depicted in the schematic and, although picture one is more efficient, I still like method #2 for simplicity. I know if I don't keep it simple, sooner or later I will mess something up.

Even though there is less efficiency it's not noticeable to me.
__________________
TheBennetts is offline   Reply With Quote
Old 07-23-2014, 11:14 AM   #7
Junior Member
 
Join Date: Jul 2014
Posts: 27
The only electrical difference between Fig's 1 and 2 are that Fig.1 eliminates one small leg of wire to the total circuit. This "in THEORY" makes the circuit more efficient because any wire on the circuit is added resistance, thus you will lose a small amount of potential available current via heat dissipation through the resistance of the wire.. So the "MOST EFFICIENT" claim is technically true BUT..

In reality..it's really not going to be a noticeable difference unless the wires are undersized in the first place...
__________________
Bmbrady77 is offline   Reply With Quote
Old 07-23-2014, 12:56 PM   #8
Old Ram Guy
 
Avenger61's Avatar
 
Join Date: Jun 2014
Location: Chambersburg, PA
Posts: 129
Thanks, that helps a lot. I think I'll keep it the way the Dealer wired it then (figure 2) and just add the second battery disconnect switch. Seems like they would just have the factory installed disconnect take care of disconnecting everything but I'm sure there is a reason why they don't. For me I need to disconnect the batteries or some neighborhood kid will play with the buttons on that automatic jack for sure. I always have to make everything kid proof and that leads to me having to learn stuff that isn't fool proof.
__________________
Marty, Jenice and DD
Avenger61 is offline   Reply With Quote
Old 07-24-2014, 07:16 AM   #9
Site Team - Lou
 
Herk7769's Avatar
 
Join Date: Oct 2009
Location: South Eastern PA
Posts: 21,169
Quote:
Originally Posted by TheBennetts View Post
Either way will work as depicted in the schematic and, although picture one is more efficient, I still like method #2 for simplicity. I know if I don't keep it simple, sooner or later I will mess something up.

Even though there is less efficiency it's not noticeable to me.
FYI, in this case "Less Efficient" and "simpler" is unhealthy for your battery bank.

The battery closer to the positive and negative leads from the camper will work harder due to its lower resistance and have more and deeper charge/discharge cycles than the one with the connecting wires in the circuit (whose resistance is added to the battery's internal resistance).

See the attached article for additional information.
__________________

Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW
Herk7769 is offline   Reply With Quote
Old 07-24-2014, 08:46 AM   #10
Senior Member
 
Campster's Avatar
 
Join Date: Aug 2010
Posts: 248
Make sure the switch is wired up in the right place. My switch is wired between the chassis ground and the battery that has the cable going to the chassis ground. With the switch in the open position there is no ground connected to both batteries thus no path for the current to flow (disconnected). With the switch in the closed position the chassis ground is connected to both batteries thus there is a path for the current to flow (connected). This setup works great for me, once hooked up never a problem. My batteries are wired like the top diagram in the above link with a switch between the negative terminal on the battery on the left and the chassis ground.
__________________

__________________
Campster is offline   Reply With Quote
Reply

Tags
12 volt, wiring, battery

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



» Virginia Campgrounds

Reviews provided by




ForestRiverForums.com is not in any way associated with Forest River, Inc. or its associated RV manufacturing divisions.


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 06:11 PM.