# Dual Batteries



## Orvillefor4 (Aug 8, 2007)

Help. I'm going out West to Yellowstone campground for a week and they don't have electric hookups nor do they allow generators. So my problem is I need power for a week, and I think I need two 12 volt batteries to give me enough power, even though I'm not expecting to really run anything. 
Can I run two 12 volt batteries in trandem, or do I need to get two 6 volt batteries? Will that get me through for a week of dry camping?


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## Troy n Deb (Aug 31, 2009)

I think you should be OK as long as you go sparingly. You can always charge by the truck for a few minutes. I have 2 12 v marine batteries together and they will easily run the furnace throughout the night. Never dry camped that long Good Luck


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## thefulminator (Aug 8, 2007)

Just be sure you hook them up correctly.


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## Oregon_Camper (Sep 13, 2004)

Can always add a solar panel to help add power back during daylight hours.


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## hautevue (Mar 8, 2009)

We camped at Flagg Ranch last year--it's north of Grand Teton Nat. Park, and South of the south entrance to Y'stone. Flagg had full hookups.

At Glacier N.P. we had no hookups, and by being very careful we made it 4 days. We discovered what a lot of folks do--some took a battery into the bathroom and put a charger into the hair dryer outlet and charged their batt for 4 - 5 hours! We saw cell phone chargers, laptops being charged, and so forth! The magic time was, for that bathroom, 8:45 am. That's when the N.P folks arrived to clean the bathrooms and so at 8:30 a lot of folks were seen removing the stuff. At 9:15 they were back! So you might be able to take a batt into the bathroom and charge it. You will run into the problem of the low batt sucking power from the fully charged one, but that's better than running out completely.

Dry camping things we learned: go really easy on the lighting. We found we really didn't need all the lights on. We entered the park w/full propane so the reefer was no problem. At Glacier we needed the heat on overnight (it was down to 45) but we kept the temp set to 55 and made do. The sitters found the bathroom a bit uncomfortable, but they survived. The furnace blower motor will suck things dry if you run it a lot.

We turned off the power to the stereo. It's only a few watts, but every little bit helps.

We made it 4 days and at the end of the fourth day one could see the voltage was dropping as the lights got dimmer. So we closed the slide at the end of the 4th day and split. Imagine having to crank the slide back in manually. Ugh. We left about 6pm and went outside Glacier and paid $25 for a full hookup campsite. It was worth it to not fret overnight whether we could get the slide closed electrically the next morning.

We have two 12 volt batteries, and were fully charged when we arrived.


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## forceten (Nov 14, 2008)

I had my first experience sort of dry camping this year. 6 days outside of dc (greenbelt park). They had a 10pm no gen rule. We only had one battery and weren't use to not having power hookups or being able to run our genny when we wanted. We ran the battery down the first day to 1/3rd and then started learning to be a bit more careful after that. We used the gen every day some to charge the battery up to full.

The host at the park also said right up front - no plugging things into the bathroom to charge (like cell phones and I guess batteries)

I am gonna intall a 2nd 12v battery now.

I am interested in solar though. What setup to you guys use, and is there one that will keep two batteries charged up without plugging in at all?


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## Oregon_Camper (Sep 13, 2004)

hautevue said:


> ............ Imagine having to crank the slide back in manually. Ugh. We left about 6pm and went outside Glacier and paid $25 for a full hookup campsite. It was worth it to not fret overnight whether we could get the slide closed electrically the next morning.


Even if your battery is 100% dead, you can still back the truck up to the trailer..plug in the connector and you'll have enough power to bring the slides in and do any aother last minute stuff that requires power.


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## Oregon_Camper (Sep 13, 2004)

forceten said:


> I am interested in solar though. What setup to you guys use, and is there one that will keep two batteries charged up without plugging in at all?


I bought this set up from Costco ($300) after talking with Nathan about how he had this setup installed on his last RV. We dry camp 90% of the time (2x6v batteries) and I only bring my generator on trips over 6 nights. I want this set up to eliminate the need for a gerneator.


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## outback loft (Sep 22, 2008)

forceten said:


> I had my first experience sort of dry camping this year. 6 days outside of dc (greenbelt park). They had a 10pm no gen rule. We only had one battery and weren't use to not having power hookups or being able to run our genny when we wanted. We ran the battery down the first day to 1/3rd and then started learning to be a bit more careful after that. We used the gen every day some to charge the battery up to full.
> 
> The host at the park also said right up front - no plugging things into the bathroom to charge (like cell phones and I guess batteries)
> 
> ...


I have put together a setup of my own, which includes 6 solar panels and it covers almost all of my open roof space. I have also changed out my converter/charger to a 4000 watt inverter/ charger, then there is a bank of 4 deep cycle marine batteries feeding that. At this time I can get away with running the a/c for a few hours off the solar setup.

I am actually out at the campground now and have no generator running with my a/c going at 72 degrees. I love it being able to sit here without the generator, or the need for an electric site and still have all the features of the trailer. Granted I have gone way overkill on my setup, but I am working for a solar company on the side, so I have access to some nice technology that allows me to do this.


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## Tangooutback (Apr 16, 2010)

outback loft said:


> I have put together a setup of my own, which includes 6 solar panels and it covers almost all of my open roof space. I have also changed out my converter/charger to a 4000 watt inverter/ charger, then there is a bank of 4 deep cycle marine batteries feeding that. At this time I can get away with running the a/c for a few hours off the solar setup.
> 
> I am actually out at the campground now and have no generator running with my a/c going at 72 degrees. I love it being able to sit here without the generator, or the need for an electric site and still have all the features of the trailer. Granted I have gone way overkill on my setup, but I am working for a solar company on the side, so I have access to some nice technology that allows me to do this.


I am impressed solar technology has got to the point of being able to power a/c unit. How long does it take to charge up the 4 marine batteries assuming you have full sun? How big is each solar panel and how much does it cost?

I've heard advertisement of motorhome built on Sprinter (Mercedes) chassis being able to run a/c on gel cell battery, which is charged up by its diesel engine. I've often wonder how valid is that claim.


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## CamperAndy (Aug 26, 2004)

outback loft said:


> I have put together a setup of my own, which includes 6 solar panels and it covers almost all of my open roof space. I have also changed out my converter/charger to a 4000 watt inverter/ charger, then there is a bank of 4 deep cycle marine batteries feeding that. At this time I can get away with running the a/c for a few hours off the solar setup.


A set up like that must have cost $3000.


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## forceten (Nov 14, 2008)

$3,000 might be worth it if it can really power the entire rv with no gen needed or shore power.


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## thefulminator (Aug 8, 2007)

I really like what this guy did. Be sure to watch the videos. Now we just have to get it mass produced.


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## john7349 (Jan 13, 2008)

Oregon_Camper said:


> I am interested in solar though. What setup to you guys use, and is there one that will keep two batteries charged up without plugging in at all?


I bought this set up from Costco ($300) after talking with Nathan about how he had this setup installed on his last RV. We dry camp 90% of the time (2x6v batteries) and I only bring my generator on trips over 6 nights. I want this set up to eliminate the need for a gerneator.









[/quote]

Jim
Do you have any pics of this in operation? Looks great!


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## Oregon_Camper (Sep 13, 2004)

john7349 said:


> I am interested in solar though. What setup to you guys use, and is there one that will keep two batteries charged up without plugging in at all?


I bought this set up from Costco ($300) after talking with Nathan about how he had this setup installed on his last RV. We dry camp 90% of the time (2x6v batteries) and I only bring my generator on trips over 6 nights. I want this set up to eliminate the need for a gerneator.









[/quote]

Jim
Do you have any pics of this in operation? Looks great!
[/quote]

I'm still waiting for it to arrive from Costco.com. I ordered it on Tuesday. I'll document the installation process and post it here once I get it done.


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## Orvillefor4 (Aug 8, 2007)

Thanks guys for the advice. Actuallly, right after I posted my question I went back and read the article about batteries and saw how two 6 volt batteries provided so much more amp hours than two 12 volts. So I went and got 2 6 volt batteries at Sams Club today and installed them on my rig. I also reduced the number of days at yellowstone to 3, because my wife didn't want me telling her we couldn't turn on anything for fear of draining the batteries. I'm also looking forward to this dry camping thing. Haven't really done it yet. Gone with out water & sewer 2 yrs ago outside of DC, but that was easy. Just filled up the water tank and used water sparingly so the black & gray tanks didn't fill up too quick. I think it was 5 or 6 days. Anyway, thnanks f rall the posts. Well see how 2 6 volts do. I may try solar next to see how that fits into the mix. If its really hot and no electricity, I'm not prepared for that.


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## forceten (Nov 14, 2008)

So 2 6 volt batteries last longer then 2 12v ones?


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## CamperAndy (Aug 26, 2004)

forceten said:


> So 2 6 volt batteries last longer then 2 12v ones?


Typically but you have to try and compare apples to apples. You can get 12 volt batteries in group 24, 27, 29 and 31 sizes. You can get 6 vdc batteries in 3 or 4 sizes also. A pair of group 31 batteries will last longer then a pair of 105 Trojans but the Trojans are better suited to deep discharge and re charge. The thing is most people only get a pair of group 24 batteries and just about any 6 volt pair will be higher rated and do better then those.


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## outback loft (Sep 22, 2008)

CamperAndy said:


> I have put together a setup of my own, which includes 6 solar panels and it covers almost all of my open roof space. I have also changed out my converter/charger to a 4000 watt inverter/ charger, then there is a bank of 4 deep cycle marine batteries feeding that. At this time I can get away with running the a/c for a few hours off the solar setup.


A set up like that must have cost $3000.
[/quote]

It was a bit more than that, but to be able to go completely without the generator I will need to add some more batteries. (at least to run the a/c) I just got back and I had the a/c running through the night last night, it was set to 72 degrees. I had the fan set to low, and to automatically shut off when it reaches temperature. I woke up at 5 am this morning to my battery bank at 11.5 volts, but taking in 500 watts of solar power. I generally have no issues with getting sun since I do spend a good portion of the time out on the beach, and can charge my bank of batteries in about 5 hours.


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## Oregon_Camper (Sep 13, 2004)

outback loft said:


> .................... Granted I have gone way overkill on my setup, but I am working for a solar company on the side, so I have access to some nice technology that allows me to do this.


Care to share the love and help an fellow Outbacker with an upgraded invertor?


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## outback loft (Sep 22, 2008)

Oregon_Camper said:


> .................... Granted I have gone way overkill on my setup, but I am working for a solar company on the side, so I have access to some nice technology that allows me to do this.


Care to share the love and help an fellow Outbacker with an upgraded invertor?





























[/quote]

I believe it is a Xantrex charger/inverter. I will have to look the next time I am at the trailer. I have two display panels for my setup, on is for the solar charge controller, and the other is a display controller for the inverter. Between the two displays I know what my voltage is, remaining amp hours, inverter draw, solar input, etc.

I am not 100% sure on the model of the inverter, but will check. The solar company I am doing some work for has set me up with what I need to do this. The owner of the company has an Airstream that he has setup the same way, so I knew it worked before I went through the work of putting it all together.


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## Nathan (Jan 2, 2007)

Oregon_Camper said:


> I am interested in solar though. What setup to you guys use, and is there one that will keep two batteries charged up without plugging in at all?


I bought this set up from Costco ($300) after talking with Nathan about how he had this setup installed on his last RV. We dry camp 90% of the time (2x6v batteries) and I only bring my generator on trips over 6 nights. I want this set up to eliminate the need for a gerneator.









[/quote]
Here's a picture of them (45W worth) on the roof of an OB:


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## Patty (Mar 4, 2010)

Nathan,
Do you leave them up there all the time or do you take them down and store them? How did you install them? Screws in the roof? I bought a 45W panel that is 24x27 off ebay for $125 and will probably order a charge controller online too. They have them for$40~. It is small enough that it is easy to handle and I will be able to store it. I will be dry camping for 5 days in July. I'd like to have a setup on the roof that I can put it and then remove for travel and storage. Does 45W keep the batteries topped off if you are careful? Questions, questions!

Outback loft, that sounds like a primo setup. I would also like an inverter/converter. I think that is what allows you to use all your outlets with battery.


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## Nathan (Jan 2, 2007)

We tend to be careful with power, but in Yellowstone we had young kids (read can't stay covered) and it was cold at night (~40deg) so the furnace ran some. We also were camped in a wooded area. The panels therefore only helped extend the battery life.

With the OB (the picture I posted), I screwed them right to the roof. Well, then I sold the OB, and the panels went with it. With the 5'er I got the 60W set and just set them up there. The advantage was that I could move them around, or even tilt them using slides, A/C, etc for support and maximize the solar input. I never ran low on batts this way, but it also was easier because that trailer had a ton of storage and a ladder and walkable roof. For the new trailer I'm going back to the screw down approach for simplicity.

BTW, if you crew them down, run them lengthwise due to the roof crown. Also, start the screw, squirt some dicor around it under the panel. Then run it home and dicor the top as well.


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