Adding batteries

[steve_buckman]

Has anyone added additional batteries for dry camping?
I'm thinking of adding 2 6volt deep cycle batteries in parallel with the original 12 volt battery and isolated with a dual battery switch. This would give me plenty of capacity but I have some charging concerns.
I tow with a 02 Chev Duramax and if all batteries are low when the truck altenator kicks in will it blow a fuse in the truck? Same question for the factory installed converter/charger in the 5th wheel?
I have a 2011 3250 TS and there is room where the current battery is for all three if I install them without battery boxes. Seems like there is plenty of ventalation in that compartment to do that. Any thoughts?
What have other people done to add battery capacity?

 

[GOTTOYS]

Connect the 2 6 volt in series then connect them in parallel to the 12 volt. I wouldn't isolate them with a cut-off switch just let them all run at the same time. I would put in a cut-off switch to turn all the power off for storage purposes. Can't imagine the truck having a problem with the charging. In my opinion though..I would use 12 volts batteries of the same capacity as the existing. If you look at the difference in capacity it really isn't much. Then they will all charge and discharge the same amount. I ran 2 group 24 12 volt on my last rig. Worked fine. When I traded it I kept the new batteries. Plan to install then with my existing group 24 and have all three working in parallel. I would use a vented battery box for any additions just like the factory did I'm sure they did that for a reason. I'm going to install mine in the front storage compartment then put a tee in the existing vent hose and vent them out that way. Don't need anything going boom! Make sure you tie them down. JMHO..Don

 

[grizzlygiant]

Connecting two batteries (two 6V in series = 1- 12V battery) in parallel will give you more amp-hours of power, true. But since the internal resistance (age) of each battery is different charging rates will be different. I would install a selector switch which would allow me to separately charge as well as discharge each battery individually.

 

[GOTTOYS]

Sounds like a lot of extra messing around to me. I would like the largest combined battery capacity as opposed to running out of power in the middle of the night and having to go switch over. I guess I like to keep things simple. Don

 

[watchthebox]

I wouldn't recommend mixing 12 and 6 volt batteries like that. I'd either add another 12 volt like the existing battery or take out the existing 12 volt battery and replace it with two or four 6 volt batteries. Your truck and converter won't be damaged by this change, although it will of course take longer to charge the new battery bank given the greater capacity.

 

[chief190]

most charging circuits from truck are limited to a 30 amp circuit. If batteries on trailer are dead low voltage when plugged into truck charging system it is possible to blow fuse if charging system in truck batteries are fully charged. the other possibility of trying to operate high amperage items ie slide pump with discharged trailer batteries with blow fuse in truck if circuit useage is above charge fuse rating. this happens more than you may think as I have had to change charge fuse for trailer maytimes for people who bring truck in for no charge of trailer circuit. I am a senior master Ford technician and have a little better than average knowledge of the systems on the truck side.

 

[newbie]

I took out my original 12v and put in two 6v in series. It worked good when dry camping but I still wished I had longer run time. A couple months ago I was able to obtain four 12v UPS batteries and 4/0 battery cables free. The batteries are huge and top of the line commercial grade UPS batteries. I had to modify the battery compartment and build a new box with a side out tray. I also added a digital panel ammeter (actually two, the second monitors the converter amperage) and a voltage meter. I am really happy with the new set up.

Now the down side. They are heavy. The batteries and metal box weigh close to 500 lbs. For me, the extra weight was manageable since we are weekend campers.

So far, I haven't had any problems. We do use the generator once a day during peak power usage which also helps top off the battery bank.

John

 

[hoefler]

Never mix batteries of different size, voltage, capacity, or age. You will never fully charge one battery and you will over charge another. Make sure the jumpers between batteries are the same size or bigger than the lead feeding the coach or inverter. When modifying your battery box, especially if you have a plastic box in a compartment, that the venting is directly to the out side of the compartment. The off gassing that occurs as the batteries are used and charged, will cause corrosion with in the compartment they are in and anything else stored in there with them. If allowed to go on improperly vented long enough, you will have a explosive environment as well.