Advice for a battery

[Suzy I.]

I need advice on what kind and size of battery I need to get for my 13 footer. It currently has a fridge and two lights. I will be putting in a Fantastic fan and probably adding some little reading lights, and MAYBE a water pump for the sink. We will probably go on trips of one to two weeks at a time, with no hook-ups.

The previous owner wired it to work with an extension cord plugged into the regular house plug. It currently has no battery at all. Also, what is the best place to put the battery? The tail lights/brake lights have a 4 pin flat type plug to plug into the truck..I don't know if this has any bearing on anything, but just thought I'd throw it out there!

If you assume that I know nothing about batteries, amps, voltages etc and word your answers accordingly, then we'll be off to a good start! Thanks!

[David Tilston]

Suzy,

The first thing you should understand is how the capacity of a battery is specified. The unit is Amp Hours. Basically how many amps for what number of hours it can supply. This is a bit confusing, but you should never go below half of the full charge. Your battery will last a lot longer that way. So if you get a 100 amp hour battery, you should not use more then 50 amp hours.
Your battery requirements are dependent on your usage. Putting LED bulbs in your lights is a good start.
You wont run your fridge on batteries, so that should not affect your decision. Also, the pump typically wont run very long, so again not part of the decision.
The fan will be your biggest draw. At 3 amps draw at full speed, you would want to recharge after about 16 hours of operation. The low speed consumes 1.86 amps. So, with the same battery, you should not operate at low speed more than 27 hours.
Solar cells could extend this indefinitely, if your power requirements are modest.
I have two Group 24, (the physical size) batteries on the tongue of my trailer. They are rated at 95 amp hours each, for a total capacity of 190 amp hours. Costco is a good place to buy batteries. They sell what is known as a golf cart battery for slightly less then $100. These are 6V batteries, so you need two of them. I think that these are rated at 240 amp hours.
Batteries require ventilation because they give off explosive gasses when they charge. It is not as bad as it sounds. You would have to charge your batteries very quickly and have very little ventilation for a dangerous situation to happen. The ventilation requirement is why so many people put the battery on the tongue of the trailer. If you do that, you will need a box to put it in and a way to secure the battery. My trailer has a platform welded to the tongue with straps to hold the batteries.

[Rene]

^^^All great advise there David. I'll just add that if you need more than 1 battery and really plan to boondock without hookups for 1-2 weeks at a time, You WILL need a solar panel and solar charge controller preferably with a battery/system monitor. Your fantastic fan would then run mostly during the day when you had lots of power avaliable and also easily charge your batteries up every day.

[Perry J]

Keep it simple, go to Wal-Mart and buy a group 27, 29 if they have one, deep cycle battery.
There are Wal-Marts everywhere if you should have a problem.
You will not use very much electricity with a 13 footer
I never camp with hookups.
My overhead camper battery is 5 years old and my Lil Bigfoot battery is 3 years old.
Before I added a 50 solar panel I could go 3 or 4 days before using my generator.
If you are traveling daily and have a charge line from your vehicle to the trailer battery it will charge up as you travel.
Change all of your incadescent lights to LEDS which are available on ebay for a reasonable price.

John

[Denece]

We went with a group 27 gel battery based on our experience using them on our sailboat. Gel does not gas so you don't have to be so concerned about ventilation We have a small solar panel for short term boondocking. We changed the lights to LEDs which draw next to nothing and don't have much else in the way of draws
The gel cells cost more but our experience with them has been that they are worth the extra up front expense.
There are solar sites that will help you calculate what you need. Ie: how much battery draw for how much light, stereo water pump, etc. they are very helpful in deciding how much storage capacity you actually need based on your usage

Best of luck

Denece

[Suzy I.]

Thanks for the info, and especially for the education, David! I had been thinking about solar panels, but I wasn't sure how big the panels needed to be. I'll search for one of those sites that will help me figure out what I need. As always, the cost comes into the equation, too!

Another question though, David. If my fridge is not running off of the battery, then what is supplying the power?

Thanks again for the info everyone.

[Byron Kinnaman]

OK here's my story and I'm sticking to it.
We have a 13' Scamp. I've replaced the interior lights with LEDs. I do have a furnace to take the chill off on cold nights. Rarely I dig out the "Constant Breeze" fan, a portable box fan that runs on 12 volts. I have turned of the converter, no charging when plugged to 120 Volt. Rarely plugged in since the only thing that I run from the 120 Volt is the fridge, otherwise it runs on propane.

My 12 volt system is powered by a single 80 amp hour group 24 battery. When in one place for several days to weeks, I carry a 65 Watt Solar panel, which gets used about every 3 to 7 days depending on how much the furnace runs. The solar panel is portable and plugs directly into the battery with enough cable I can follow the sun. When the battery is charged it goes back into it's storage place in the bed of truck.
I have a solar charge controller mounted to the frame of the solar panel. With the way I'm using it there's no need to use the "monitor" feature. This has worked quite well for us for about 4 years.
Typical trips for us. 90+ days every winter, with 3 to 4 weeks in one place, no electricity.

One of the things to consider is to try to keep your power usage to a minimum. Use light only when needed. Use fans and furnaces at little as possible.

When staying in one place for 2 to 3 weeks or more the bigger problem is water, both fresh and gray. I carry a 2.5 to 3 gallon collapsible water jug. Any bigger become difficult to handle. My fresh water tank is 12 gallons, and the gray water tank is 26 gallons. I don't know how long I can go without emptying the gray water tank, I haven't managed to fill it completely yet. The fresh water tank needs more water after 10 to 12 days. There are ways to conserve water, but that another topic.

Good luck

[Byron Kinnaman]

Originally Posted by Suzy I.

Thanks for the info, and especially for the education, David! I had been thinking about solar panels, but I wasn't sure how big the panels needed to be. I'll search for one of those sites that will help me figure out what I need. As always, the cost comes into the equation, too!

Another question though, David. If my fridge is not running off of the battery, then what is supplying the power?

Thanks again for the info everyone.

When not connected to shore power the fridge should be run on propane. Attempting to run the fridge on battery power will soon run the battery down.

[itlives]

All good advice - as usual for this crowd!
If you do go to solar, look for a charge controller that has a divert. After the battery(s) are charged, the divert sends the electricity to whatever you hook it up to. I had it wired to my fan in a greenhouse.

Edit- Did a quick search -here's one. This site has lots of info if you want to start thinking solar -which is a good idea IMO
http://www.solar-electric.com/tracc6060amp.html

[David Tilston]

Originally Posted by Suzy I.

Another question though, David. If my fridge is not running off of the battery, then what is supplying the power?

As Byron said, propane is what you use when not connected to your tow vehicle, (TV). 12 VDC is only for when you are running your TV. 120 VAC when you are plugged into shore power.

Depending on your tank size, your propane may last a couple of weeks when running the fridge. Unlike batteries, running you propane till it is gone is no problem.

[Suzy I.]

Originally Posted by David Tilston

As Byron said, propane is what you use when not connected to your tow vehicle, (TV). 12 VDC is only for when you are running your TV. 120 VAC when you are plugged into shore power.

Depending on your tank size, your propane may last a couple of weeks when running the fridge. Unlike batteries, running you propane till it is gone is no problem.

Aaaah, that explains it. I think my fridge is just a regular mini fridge, not one of those 3-way ones. My trailer has no propane; there's no stovetop, which I actually prefer, because it gets too hot to cook inside and I just use my portable stove outside. By it not only doesn't have propane, all of the gas lines/vents etc have been removed, which again I was ok with cuz I didn't plan on putting a stovetop in.

Hmmm...so I would have to put that all back in, and those 3-way fridges are kind of pricey...I may just have to do an ice chest for a while. I'm finding this trailer is like an onion; the more layers of things to fix that you peel off, the more layers you find that need fixing!

Again, thanks to everyone for all of the info.

[David Tilston]

Suzy,

Are there vents on the side of your trailer where a fridge would go? The attached picture shows the type of vents I am referring to. These are necessary for a propane fridge If not, you may want to look at a Norcold 12VDC fridges.

If you do have the vents, there seems to be a bit of a glut on the market of old Dometic RM211 three way fridges. These were popular in tent trailers in the 70's and 80's. These trailers are now being scrapped because of rotten canvas, or mice, or what ever. They just don't last as long as an egg. So people salvage the fridge, stove, and furnace from them and then convert them to a utility, or flat deck trailer. I got an RM211 for free. They were original equipment in a lot of eggs as well.