# Dry Camping Battery Pack



## egregg57 (Feb 13, 2006)

Appliance or Accessory / Estimated Amps
Aisle Light 1 Amp
CO Detector 1 Amp
Fluorescent Light 1-2 Amps
Furnace 10-12 Amps
LP Gas Leak Detector 1 Amp
Overhead lights (Per Bulb) 1 Amp
Porch Light 1 Amp
Power Roof Vent 1.5 Amps
Radio/Stereo 4 Amps
Range Hood (Fan & Light) 2-3 Amps
Refrigerator (LP Gas Mode) 1.5- 2 Amps
TV Antenna Booster <1 Amp
TV Antenna Booster Up to 8 Amps
Water Pump 4 Amp

I did some math and some research. It looks like (unless you have another 12V device not listed) the maximum current draw while dry camping is about 45 Amps per hour. That is saying that you have everything running 100% of the time. In that case you would need a 2,160 amp hour battery&#8230;&#8230; Not happening! Really just kidding,

You should never even come close to about 200 amp hours over a weekend (2 days). BUT it is a good idea not to exceed 50% capacity of a battery without topping it off. It shortens the battery life if you do. So 300 amps is probably pretty good.

So I put together a battery pack. Each battery is 2 1/2 " W X 6" L X 3 3/4" D. A box will need to be made, 15 1/4"L x 12 1/2"W x 10"D (inside dimensions this will accommodate 24 x 12VDC 7.0 Amp hour batteries delivering up to 168 Amp Hours. Charger will be a 13.5VDC Trickle charger that could plug in to a generator or the converter panel charger would charge the pack while plugged into shore power. I have to check dimensions of available space because 2 of these would be required, I would need ventilation, cooling, etc.

Two of these will provide 336 AH of power at 12VDC. Hmmmm

The question is, how many amp hours is an average, run of the mill RV battery capable of?


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## Insomniak (Jul 7, 2006)

egregg57 said:


> Appliance or Accessory / Estimated Amps
> Aisle Light 1 Amp
> CO Detector 1 Amp
> Fluorescent Light 1-2 Amps
> ...


A group 24 battery generally provides around 85aH, while group 27 gives 115-135aH. Paralleled together you would have approximately 170-270aH. Two 6 volt Trojans wired in series will give you about 220aH with better deep-cycling characteristics.

Did you just inherit a small battery factory, or are you piddling around in your garage?


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## Dan Borer (Feb 6, 2009)

Sounds like a lot of work and expense. I put 4 Costco 6V golf cart batteries in my Mountaineer and have in excess of 400AH available. We recently returned from a 4 day dry camping trip and still had over 50% power available. There were 3 of us and we weren't shy about using the interior and exterior lights, TV and satellite since I carried along the generator just in case the batteries ran low. I did remove 1 bulb from each double bulb light fixture and still had more than enough light. Batteries are permanently mounted in the forward compartment and use the factory installed battery vent system. Quick, simple, relatively inexpensive and more than adequate!

Dan


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## raynardo (Jun 8, 2007)

We spent two nights this past weekend boondocking in the desert. I have two Costco 6v golf cart batteries to run things. But I also have a 85 watt solar panel to keep everything charged up, so I never had to turn on generator at all. Watched a ton of TV (via an HD satellite dish, a HD DirecTV DVR, and a Naxa 24" HD TV) on Saturday - football games, movies, probably 10 hours in all waiting until the midnight hour so I could go outside to watch the Leonid meteor shower (a bust - only saw 6 in an hour).

I'm sold on a properly installed solar system!

Oh yeah, ALL my interior lights are LED's so I'm not too concerned with their power consumption.


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## KTMRacer (Jun 28, 2010)

Insomniak said:


> Appliance or Accessory / Estimated Amps
> Aisle Light 1 Amp
> CO Detector 1 Amp
> Fluorescent Light 1-2 Amps
> ...


A group 24 battery generally provides around 85aH, while group 27 gives 115-135aH. Paralleled together you would have approximately 170-270aH. Two 6 volt Trojans wired in series will give you about 220aH with better deep-cycling characteristics.

Did you just inherit a small battery factory, or are you piddling around in your garage?
[/quote]

x2 on the 6V golf cart batteries. Talking to a Trojan rep, and looking at Trojan data, going to 50% discharge on Trojan golf carts is a very mild discharge for camping cycle life. In fact even discharging to 20% of capacity (80% discharged), T-125 trojan golf cart batteries are good for hundreds of charge discharge cycles. I have set that has been charged at 65-90A and discharged usually to 30-40% or capacity (discharged 60-70%) and they are going strong after 8 years. Cycle them probably 50 times/year. BTW don't try to discharge 12V batteries, even trojan deep discharge below 50%, they will quickly loose capacity per the Trojan rep.

the biggest and easiest way to extend battery life is to swap out the often used incandescent lights for LED lights. Current draw will be 1/10. I can turn on all the lights we need for a nice bright living area in our 295RE, which is big and only draw 2A for the lights. And the LED lights actually put out more lumens than the incandescent they replaced. Even in the spring and fall with the furnace running the AM and evening we can easily go 3 days withought charging the batteries.

Your estimates are pretty accurate except for the CO LP detectors and TV amp. they are around 0.1A as is the radio in standy. Antenna booster is <0.1A in standby, 0.3A when operating. Fridge is about 0.5A normally, pushing 1.5A when the cooling fan kicks in.

And battery capacity is strongly dependent on the current draw. For example the Trojan T-125 is rated at 240AH over 20H (12A draw) at 2.6A draw AH capacity increases to 270AH, and at 25A draw it drops to 200AH.

the trojan 12V group 27 is 115AH at 20H (5.7A) goes up to 128AH at 1.2A and drops to 90AH at 19A draw.

So, in general when you double the number of batteries, you will more than double the AH capacity and run time because each bank is suppling less current and moves up on the AH capacity curve.

Course the downside to a flooded lead acid battery is weight. Each Trojan T-125 weighs in at 66lbs. But true deep cycleflooded lead acid batteries take a great deal of abuse. With a good charger you can charge them at 1/3 AH capacity without much life degredation and discharge them at the same 1/3 of AH capacity without much life degredation as long as you keep them watered and don't discharge them more than about 70% for 6V golf carts and 50% for 12V batteries.


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## egregg57 (Feb 13, 2006)

The plant I work at uses all sorts of NiCad batteries. They are changed out frequently and on a very conservative rotation. There is a lot of batteries that are available for a person to get a custody sheet for and reutilize. Cost = labor to walk them out to my truck. The largest being vehicle size batteries @ 75AH currently I have a stack of 12 12VDC @ 7AH and 16 12VDV @ 3AH batteries in my shop. That does not scrape even the surface of the battery recycle bin. Across the hall there are 4 APC UPS battery packs wired to deliver 108VDC each at 27AH.

I have a ready supply of batteries. I just need to make something convenient to change them out periodically. Additionally , the tags identifying the batteries, stay on the batteries. When they are exhausted I can bring them back in to work and have them disposed of properly. It's a pretty good deal.

Additionally, I had posted this on Outbackers and a member there had brought up the Solar Panel charging (which I had not even thought of...I don't know why..). Panels set up on the roof would take care of charging needs and swapping to LED's where applicable also saves.

I don't do a lot of dry camping. In fact it has been a long time since I have. Maybe it's a little bit of disaster preparedness on my part that has brought this idea around. Some recent storms have made me think about what I can do in case something bad happens and I need to get out of dodge.

We were spared the brunt of Sandy. But had the high pressure system not been where it was, driving Sandy into New York and New Jersey..Massachusetts / NH / Maine coastal areas would have suffered the same devastation. Although I am about 15 miles in from the coast, the effects from a storm like that..well I know what would happen to my area.

In anycase this is all good input! Thank you all so far! I think I am going to give this a shot. And you are right KTMracer, weight is going to be something to consider. I am guessing, picking one of these batteries up (12VDC 7.0AH NiCad) is about 2+ lbs each. A battery pack the size I am talking about is going to be heavy. AND I need the dimensions of the space I have for storage of it.

Ehh! something to keep the juices flowing during the long cold winter months!


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## KTMRacer (Jun 28, 2010)

egregg57 said:


> The plant I work at uses all sorts of NiCad batteries. They are changed out frequently and on a very conservative rotation. There is a lot of batteries that are available for a person to get a custody sheet for and reutilize. Cost = labor to walk them out to my truck. The largest being vehicle size batteries @ 75AH currently I have a stack of 12 12VDC @ 7AH and 16 12VDV @ 3AH batteries in my shop. That does not scrape even the surface of the battery recycle bin. Across the hall there are 4 APC UPS battery packs wired to deliver 108VDC each at 27AH.
> 
> I have a ready supply of batteries. I just need to make something convenient to change them out periodically. Additionally , the tags identifying the batteries, stay on the batteries. When they are exhausted I can bring them back in to work and have them disposed of properly. It's a pretty good deal.
> 
> ...


Looks like a great opportunity for some experimentation Let us know how it works out. NiCADS are pretty easy to charge and can deliver lot's of current when needed. Worth a try given the price and availability!!


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## cdawrld (Jul 31, 2011)

With the sub c class NiCad you could create battery packs that fill the rear bumper or under the sofa or in the frame rails. Put the weight where you want it. Think Tesla.


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