Adding more batteries

As long as they are in use just leave them connected is fine. Only time to separate is storage with no float or to diagnose an issue. I also recommend 100 to 200+ watts solar.

If you went with 27 AGMs in there you could take them down to a much lower SOC which is like having extra AH.

However the inverter 11v low voltage alarm might be heard in the morning. To beat that you can run the truck engine when the inverter is on, so the 7-pin holds the voltage up temporarily. ISTR that is what SoundGuy does.

These claim you can take them right down many times without wrecking them, for instance:

http://www.hespv.ca/hesproductspecs/HES/Stark_Battery_TD_ENG.pdf

I think a switch is the easy solution, don't want to mess around with booster cables. I can't fit 6v in the battery compartment or I would have went that way in the first place.

Honestly it's not very often that the 2 grp 27's can't keep up. I have 300w of solar to charge them back up it's just that by the time the furnace runs at night and then using the inverter in the morning it can bring them down.

Before getting to crazy just change out the 2 12v batteries for 2 6volts. You would be surprised at how much longer they last. You can also add in a good solar panel or two the charge it up if you don't want to use a genset. Not sure if you guys have a Rocky's battery down there or not. I picked up two 6v batteries for my toy hauler in the fall for $300. I don't believe the Trojan brand is any better these days and cost way more.

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Get a Sure Power 200 ampere model battery divider solenoid and a 120- amp rated flat mount circuit breaker. No 6 AWG wire is plenty big enough. Pass wire under the truck sheathed in 5/8" heater hose or black spiral wrap nylon sheath. Buy a hull pass through fitting from West Marine. This stuff is a Do-it-Yourselfer's Paradise and ends fiddle------- around with switches and crystal balls. BERG and POLLACK both make 2 conductor no-screw-around socket and plug for truck to camper disconnect.

Such a system will allow your truck alternator to pass a 90 amp charge rate to the GC220 batteries. You do want to recharge them from the truck during ypur lifetime, right? Wouldn't hurt a bit to add a 2nd breaker on the camper side of the plug.

I've installed multiple systems like this and no way in hell is manual switching better. My bus has 2 group 31 starting batteries a 4 L16 house batteries. I forget they are there. The Sure Power charge divider RELAY does all the work automatically.

It would be of help to know what chassis you have. Ford, GM and MoPar alternator regulator voltage set points are different.

If batteries don't work parallel, how does anybody
Boat, RV, off grid home, get by with multiple batteries

Matt. .. You know better than that

Yes it takes matching batteries of the same chemistry for best results

If I was placing batteries someplace with very limited access
I would be getting AGMs not flooded cells

Matt_Colie wrote:
Hedge,

Lead/Acid batteries do not play nicely in parallel.......

Oh, I almost forgot, carry baking soda to clean up the acid spill when one of then (probably a Gr 27) explodes.

Matt

Could you please show us where you got that info on parallel batteries.

Why would one of the Gr 27 explode?

You don't need a switch. Before you leave the campsite to go home, you disconnect the jumper cables.

After you get home, the camper is slid off the truck, the stands go under it, and the truck bed battery set goes into the garage to be recharged and then maintained on a Float there (with a battery charger for that) until the next camping trip.

Now you have your truck back for other jobs.

The camper battery set gets recharged in place and then left on the camper's converter to Float with shore power from the stick house.

Hedge,

You actually got very similar answers from both BFL and Chuck. The executive summary could be:
Lead/Acid batteries do not play nicely in parallel and the more different the less nice-nice.....

I will bet you dollars to donuts that one of your current 27s is weak. (Hint, this is a sucker bet that I already won because you have used them and parallel jars will never equalize while strapped together.) Now, when you mix that with the T105s of any golf cart batteries that are true deep cycle/

BFL has a good plan, and it will work, but it is a recipe for excitement because you would now have 3 different batteries in parallel in your case. To survive this, you need to do three things. Put in the switch so your separate (3) banks can be charged to full density individually, Separate all three banks with some gunga-mama fuses (like make charge rate *1.5). And the last is tough.... THINK. You can discharge all three banks in parallel for short bursts. But, do not leave them that way for longer than you must.

Oh, I almost forgot, carry baking soda to clean up the acid spill when one of then (probably a Gr 27) explodes.

I did a lot of boat work before the depression. I got to clean up more than a few of these. I always had soda and gloves in my kit. I like doing these job for insurance coverage, it is nasty but it pays good.

Matt

batteries do not like different battery types or sizes

and not to crazy about different ages of batteries.