View Full Version : How long should batteries last while dry camping?

08-06-2007, 01:21 PM
Finally got out for longer then 2 nights this weekend, I moved the trailer out on Thurday night, stayed overnight, went to work, so no one in trailer all day, wife and I moved in on Friday night for the long weekend, now we don't use much power (I thought). Water pump is on for dishes breakfast and dinner,a wash up morning and night, no shower, furnace was turned off, had the fantastic fan on for 1 hr tops, the fan over the stove for mabey 1 hour and use the one floresent light for a couple of hours a day. On Sunday morning, I had to take a battery home and throw it on the battery charger to get enough power to make the day, and this morning I had to hitch the truck up to have enough power to make it through breakfast.
I had 2 interstate 12 volt deep cycle batteries installed when I bought the trailer and this is the 4th time we have used it. The trailer was plugged in to shore power untill we left, so should have had a good charge.
My old camper that I had only had one battery but I never ran out of power, that was when the kids were small so there would be 3 showers a night, plus all the extra dishes etc, lights were on constantly. I had more trouble trying to keep enough water for the weekend, never worried about the battery.
My question is, how long should my batteries last. Its summer, its warm, I have windows open to keep it cool, when the temp drops, and the days get shorter, so I'm using more lights, how long am I going to be able to go.
We like dry camping, quite often we are in the trees so solar is not really an option.
I don't really want to buy a generator, but.......
Thanks in advance for any replies

08-06-2007, 01:57 PM
Even the cheaper 12 volt group 24 batteries that came with our trailers (2 of them) lasted longer than that. Our 6 volts do even better if we don't run fans to keep cool. Do you shut the radio completely off when using it? The Kenwood radios have an off position then a really off one--if the light that says off is on, it's not off! :D Do yoi keep your batteries topped off with water? We haven't really pushed our batteries to see how long they can go--I do remember 3 days use with no problems. For extended dry camping I take omy laptop along to input info into my genealogy program, so we usually put the generator on every day for a few hours--I don't have much battery capacity on the lapton and my DC plug to power it isn't working right.

08-06-2007, 02:48 PM
In earlier camping days (BG — before generator), we often nursed two series 27 AC Delco deep cycle batteries for a week or more (with kids), even using the furnace on occasion. That's with very little lighting (lantern use) and no radio, no showers, and a trailer before safety devices (which use amps). But from what you describe, you should easily be getting more amp/hours than what you did. On the other hand, if you are going to use the furnace very much, be prepared to buy a generator to keep your batteries up. For now, check your batteries — should be at least series 27 size.

08-06-2007, 04:08 PM
We had the CD player on for a few hours one night, but that is about it, i know that when I swapped the batteries out the radio went into standbye mode all by it self, so it was on standbye for an hour or so before we noticed. The dealer made sure to tell us about the radio and to make sure that it was in fact turned off and not just in standby.
How much power do all the alarms and such draw, I really can"t see them causing such a drain.
How well does the charge wizard charge the batteries, should I be taking the batts out and giving them a proper charge and then just let the charge wizard keep them topped up.
I haven't looked to see what size the batteries are, I'm not very well versed in deep cycle, I work more with group 8D's and the like for starting heavy equipment.
Can you test a deep cycle the same way that you would check a conventional battery?
I just think that I should have gotten more time out of what i have. If this is kind of the normal amount of time, well I guess that I will be in the market for a cheap generator in the near future:D

08-06-2007, 04:54 PM
Hay we just came back from Willow campground in WY for two weeks with our 22 GQ we did dishes outside2 showers a day no lights, no radio, the only thing we ran was the water pump and refrigerator Our battery's lasted 3days each.

Wehadourbattery charger with us and charged onebattery using the other...How with a power converterplugged into the cigarette lighter

08-06-2007, 08:31 PM
Hidden battery drain possibilities:

1. Leaving your 12v TV plugged in all the time, even when "OFF," because it really stays on so the clicker will work. How about your CD player, does it have a clicker?

2. Leaving the TV antenna gain on (check for the green light)

3. Sounds like you have the radio figured out

4. Was the water pump running once in a whilewhen you didn't have the water turned on? Maybe a water leak.

5. Alarms don't use much juice except when they go off. You can pull the fuse when in storage.

6. Any outside lights on?

08-07-2007, 10:48 AM
trekout2 wrote:
Hay we just came back from Willow campground in WY for two weeks with our 22 GQ we did dishes outside2 showers a day no lights, no radio, the only thing we ran was the water pump and refrigerator Our battery's lasted 3days each.

Wehadourbattery charger with us and charged onebattery using the other...How with a power converterplugged into the cigarette lighter

The inefficieny of creating AC from DC, then going back to DC from AC, results in a net LOSS of power,rather than any significant "recharge" of a battery.

08-07-2007, 12:02 PM
I have not dry camped but your problem is one faced by boaters when anchored away from shore power and I am familiar with that. The first step to understanding and solving your problem is to calculate the energy used and compare that to what is available from the batteries.

I suggest that you prepare a spreadsheet which accounts for everything that is used in a day. Estimate the hours of useage in a day for every electrical device. Look up the amp draw for each device and multiple that by the daily hour useage. That will give you the daily amp-hours for everything. Then add the amp-hours to get the daily total and compare that to the amp hours available from your two batteries.

The rule of thumb is that marine batteries can be drawn down to 50% charge without damage and true deep cycle batteries down to 80%. It is sometimes difficult to know which type one has. Group 27 batteries contain 85-105 amp hours.

So, let's estimate that you have 95x2 = 190 amp-hours total and can safely use 95 of that before recharging. Divide by the number of days and that is your daily budget.
When you compare that to your calculated useage you can see if you are in balance or not.

If things should be ok but are not (as I suspect you will find in your case) then there is a mistake either in useage or supply. As has been suggested an electrical draw may have been missed or the batteries may not have the expected capacity for some reason.

I hope this helps. I am a numbers kind of guy and quantifying this problem is the way I would go in order to get to a solution.

08-07-2007, 05:43 PM
I spent some time talking to other people who were out camping this weekend, sounds like I'm not out of line running out of power when I do, one of my coworkers said that he only got 2-3 days out of his twin 12's but when he switched to 2 golf cart batts, he is up to a week now.
I don't have a TV, use the cd player sometimes, we go out to get away. The laptop stays at home, just the cell phone in case of emergency, thats it. I use the weekends to catch up on my sleep, and I have found that I sleep really well in the trailer.
I'm thinking that I will pick up a 1000 watt genset, and just run for several hours to keep the batts charge up.
We don't use the A/C or microwave, so should work OK.
I should be good for a 2 day weekend, but any longer the that and the genny goes on.
Thanks for all of the responses.

08-07-2007, 06:47 PM
You might think about getting a solar panel, but instead of mounting it to the trailer roof, add 20-30 feet of wire to it and some stands. Then you can park in the shade but put the panel out in the sun to recharge the batteries. You would have to find a place to store it while traveling though. In the long run it is cheaper when compared to fuel prices.

Gordon Ford
08-08-2007, 06:35 AM
Brian - you seem to have a problem. We get 4 to 5 days out of a pair of fully charged 12volts in the summer. Do you have your trailer plugged in to household power for at least 24 hours to fully charge the batteries? What voltage does your trailer converter put out? Check with your dealer as you may have a faulty converter that does not fully charge your trailer batteries.

Charging your trailer batteries from your truck alternater is not very efficient as you likely have a significant voltage loss in the wire that runs from your trucks charging system through the trailer plug to your trailer batteries. (Check to see if you have 13 +volts at your trailer plug wire that goes to your trailer batteries when your truck engine is running. Unlike Ford, GM apparently does not put the fuse for your trailer feed in the fuse block .)

08-08-2007, 04:24 PM
Hi Gordon.
I leave the trailer plugged in all the time, I had to leave it next door last week, had the roofers in to replace the roof, so wanted the trailer far away, so it was unpluggeg for a couple of days before we left, but every thing was turned of, save for the fridge and it was on propane.
I'm going to put the batts onto a trickle charger tonight, will see how it goes this weekend, but we are only out for 2 days again.
I have been so busy with work, that no time to do any checks, thats why we bought new, so that we could enjoy instead of repairing, if you know what I mean.
About mid september I should have some time to get at little things like that.
Thanks for the reply

08-08-2007, 08:11 PM
I was out moving batteries around tonight and I noticed 2 wires coiled up under the one battery box, they are a #10 red and black wire. They go into the trailer just infront of the front cross member, the #6 white and red go in behind the cross member.
What would these wires be for, and why are they not conected????
Could this be part of my problem?


08-08-2007, 08:49 PM
Those are the solar panel wires. They are not connected to anything. They are there if you decide to put solar panels on the trailer.

08-09-2007, 04:02 AM
The "phantom" draw on my trailer is about 0.8 amps with the fridge and water heater on propane, the cost of auto ignition and the popane/carbon dioxide detectors

So 0.8x24= 19.2 amp hours, with 200 amp hour of hattery capacity and limiting discharge to 100 amp hours 5 days if you don't use any other power.

I have and link 10 meter, flourecent ligths, led lights and a lcd TV and typical use in warm weather is about 30+ amp hours is we are carefull more than double that in cold weather and running the furnace

08-09-2007, 07:11 PM
Who Knew????
Would that be what that little sticker just inside the door that say Solar Ready is all about;)
Heading out Friday night for the weekend again, if I can remember, I'll bring my amp meter and see what I am getting for a reading.

08-14-2007, 07:55 PM
In the summer I wouldn't think you should have any problem with power for 4 to 5 days if you aren't using a TV, lights or radio and have 2 batteries! Anytime we have run out of power in 2 days, it has ended up being dirty or loose battery cables.

08-15-2007, 11:33 AM
Doc wrote:
I use two 12v batteries, in parallel in our 24.5N. Same voltage, but more current. Last longer dry camping and the two big current users, landing gear and slider, work faster.

Except that I suddenly found both batteries discharging, completely, while the coach is stored. Being the methodical engineer type, I started with the batteries; both checked good. Next I went through all the switches and various things that draw current while we are in the coach to see if something that seemed to be "off" was really "on".

And I called Good Guy Tom at Northwood Mfg and got the wiring diagrams and prepared for the tedious chore of tracing wires to an accidental ground.

But first, I put my trusty Fluke (pro-level volt/amp meter) in series at the batteries. I was drawing a whopping 1/2 amp (500 milliamps) with nothing turned-on! (It should be under 20 milliamps.)

So I began, one at a time, pulling fuses, hoping to isolate the problem. The first one, the 7.5 Amp Accessory fuse did it. The current flow went from 1/2 amp to next-to-nothing.

The Accessory fuse monitors the 12v outlet, the antenna amplifier, the slide-out switch (not the slide out motor-the switch), and...the Kenwood radio.

I pulled the radio chassis and checked the wiring. Everything was okay. I put it back in and replaced the fuse. And the little panel said "Off". Looked in the manual. On this radio, "Off" means "Standby". "Off" draws a 1/2 amp of current. "Off" runs your batteries down in three days!

To turn the radio Off Off, hold the Off button down until that screen goes blank.

I called Good Guy Tom at Northwood. I could hear him, on the phone, doing the "Wisconsin Salute", you know, the sound of a guy slapping his forehead with the heel of his hand, like the "I coulda' had a V-8"?

Your batteries should stay up for months in storage.

Unless you leave your radio "Off".


I wrotethe abovea while back. I doubt if your radio is really "off". With an amp-meter in series at the battery you should see just a miniscule drain, .2 or less. .5 amp is too high and will discharge your batteries in twoor three days, by itself. Just hook up themeter and start pulling fuses until your assistant says "hey there!" or something more appropriate. (I'm still betting it will be in the 7.5 miscellaneous fuse). Doc'

08-15-2007, 12:08 PM

I don't want to be picky, but I am trying to understand what an acceptable draw when everything is "off" is. Do you mean it should be below 0.2 amps (200 milliamps) or 0.02 amps (20 milliamps)?

08-15-2007, 06:02 PM
We were out last weekend, friday to sunday. The weather was nasty so spent lots of time inside with the lights on, radio, the works, my sister and family were in the spot next to us in a tent so they spent a lot of time inside with us, extra dishes and I even forgot to turn the fantastic fan off on Saturday night, (must have been that last glass of wine;)) and still had lots of batts left on sunday when we pulled out.
I don't know what the problem was the weekend before, but everything was perfect this time.
Now if they could just do something about the weather that we have been having

Gordon Ford
08-15-2007, 07:33 PM
The first day of rain after 5 days of sunshine is called Saturday. Thank your lucky stars you bought a 4 seasons unit.:cool: Happy to hear your battery problem is resolved:).

08-16-2007, 05:45 AM
The first day of rain after 5 days of sunshine is called Saturday. Thank your lucky stars you bought a 4 seasons unit.:cool: Happy to hear your battery problem is resolved:).

Ah yes, the joys of living on the WET COAST;)
Heading over to Powell River this weekend, going to spend a few days at my Brother in laws cottage. Once again the weather report is not to my liking, going to need a wet suit if I decide to go skiing (how do you spell that???)
Have a good weekend every one. I'll be thinking about you when I'm huddled around the camp fire trying to get warm. (Thinking about my brand new Fox, with the nice bed, the nice awning, the heater if you need it, a toilet the flushes...... need I say more:D)