Question for the fix-it/mod experts

[labontefan]

When I was on my 10-day camping and racing extravaganza in May, we had some generator problems so we ended up running stuff off the battery. As could be expected, the battery ran down. I had a charger but no place to plug it in. While in Auto Zone to purchase a new spark plug for the generator (hoping that would fix it), I decided it wouldn't be a bad idea to just go ahead and buy a spare battery. (Most of our camping is at the race tracks which have no hookups.) I bought a Group 27 after reading several recommendations for one here. The one that I got with the PU was a group 24.

I would like to mount both batteries on the tongue so it would be easy to switch from one to the other if one runs down. (Also because it would save having to find a place to store the spare.) I have a box for the 27, but obviously it doesn't fit in the brackets that hold the 24. I'm game to try and add another set of brackets that will hold the 27, but where? There's not a lot of space between the tongue jack and the battery, or between the battery and the propane tanks.

You can get a pretty good look at the tongue with the propane tanks and battery here:

http://community.webshots.com/photo/80890745/80891086uzpzeG

I suppose if I could move the crossbars that the battery sits on I could make room. However, those are welded in place and I'm not quite ready to tackle cutting and welding just yet.

Any suggestions? Or should I just keep the spare battery in the storage trunk and pull it out when needed?

If nothing else, I may try moving the brackets on the crossbars (the brackets are bolted rather than welded in place) so that I can mount the box for the 27 and use it as the primary battery.

Any and all advice appreciated!!

[Tim5055]

It may come as a shock, but I have a web page on how I added a battery

Tim's Adding a Battery Page

Now, to the differences of opinion.  I believe that you should run both batteries in parallel, so that they drain together.  Others think this is a bad idea.  I give my opinion on my page.  It' just that, my opinion; take it for what it is worth...


Good luck

[chasd60]

I would say run them separately in this case. To run them together in parallel they should be of the same size and relative age.
 
 
On a separate note, I just picked up two group 27 deep cycle batteries with 115AH cap each for a total of 230AH, and I ordered a 160W solar charging system for my hybrid. I plan on keeping my Group 24 that came with the camper separate and charged. Until my panels/system, arrive I am going to keep the parallel pair in the back of my truck and hook to the camper with jumper cables while I am there and when I leave I will hook the Group 24 to keep things going.
With the batteries in the back of the truck I can use my deep cycle battery charger operating from my inverter to recharge the batteries while I am driving around sightseeing. I have a cap on the back of my truck.
 
I have already tested the invertery/charger combo and it works fine.

[Tim5055]

I would say run them separately in this case. To run them together in parallel they should be of the same size and relative age.

I respectfully disagree on the assumption that batteries used in parrallell need to be the same age/size.

First, from what I have observed folks who use two batteries as separate units tend to use the first one until it "runs down" which generally is over the 50% discharge point.  This is very bad for this batttery.  Additionally, with this pattern the second battery does not get used to it's capability.

I personally violate the rule on mis-matched batteries. I carry both a group 24 and a group 27, but only when dry camping. The common statement about mis-matched batteries is that one (usually stated as either the newer one or the larger capacity one) will try to charge the other when they are connected together.  The only way one battery will try to charge the other is if you connect a discharged battery to a charged battery. Just like water seeking it's level, the charged battery will try to charge the weaker one.  If you connect them together after both are fully charged, no problems should arise.

I have read almost every battery web site I can find. The only caution about mis-matched batteries I could find dealt with charging them. If you charge them connected together, either the group 27 will not fully charge or the group 24 will over charge. For this reason I charge them individually (not connected together) with a quality charger in the garage before and after every trip. With both at 12.7 volts, connecting them together will not cause a mis-match.

Now, my approach requires you to use a separate quality charger, not the converter on the pop up.

If you only charge with the pop up converter, or know you will not follow through with the disconnecting and charging separatly, then stick with  chasd60's advice and get two of the same age/capacity.

[MtnCamper]

I made an extra rack for my battery, from 1" angle. Just cut it to the length I wanted, painted it and pop riveted it onto the frame. Works good, been there for 4 years now, and is still nice and tight. Cost me a couple bucks for the angle and the paint. The new one sits in front of the old bracket. There is a picture of my setup on my website.

Now I can switch between dual batteries or dual propane tanks too. Depending on the weather, and what I think our needs will be.

[labontefan]

Tim and MtnCamper--looks like both of you mount the spare battery next to the propane tank. That means you can have a spare propane tank or a spare battery mounted on the tongue, but not both. With my luck, whichever one I decided to leave in place, I'd need the other one!  

Any suggestions for a way to have both spares mounted on the tongue??? (Yes, I want to have my cake and eat it too.   )

Thanks for all the advice so far!

[MtnCamper]

Tim and MtnCamper--looks like both of you mount the spare battery next to the propane tank. That means you can have a spare propane tank or a spare battery mounted on the tongue, but not both. With my luck, whichever one I decided to leave in place, I'd need the other one!  

Any suggestions for a way to have both spares mounted on the tongue??? (Yes, I want to have my cake and eat it too.   )

Thanks for all the advice so far!

I've been working on a way to do both, problem is just the physical size of my 2 group 27 batteries. I need a toolbox that is 26 inches long, then I could build 2 new rails and it would work. For now, I take the second battery along in it's own box, then parallel them at the campground, leaving the second set on the ground. I haven't given up yet, and may end up with them side by side, running fore and aft. Still thinking..... :confused:

[mike4947]

Gary, IIRC Nick Gattel used a tool box for a twin battery mount. Really sharp looking. If it wasn't Nick It was someone else over at PUX.

[MtnCamper]

Gary, IIRC Nick Gattel used a tool box for a twin battery mount. Really sharp looking. If it wasn't Nick It was someone else over at PUX.

Ya, he did, But I think he has 24's. I can't find one for the 27's. I found one that wsa 26 long, but the ends tapered down to about 24 and the handles were molded into the box. Oh well, Not a big deal, I can run 4 days off of the one battery too. If I need the second, I got room to carry it.