Upgrading our electrical

[herd of turtles]

We have a T@b teardrop. The biggest problem is the refrigerator is 12V and sucks the battery dry within a couple of days. From extensive reading on this forum we are going to replace the battery with an AGM group 27, 120HA.
Still considering solar as well. We have no way of knowing what level our battery charge is at. Is there something we can buy to attach without having to dig the battery out of the bottom underneath the closet? A gauge perhaps. Any suggestions on what we can do to not constantly run down the battery would be most appreciated.

[deceiver]

I'm no expert in this so others can chime in but connecting a voltmeter in parallel with the battery will give you it's charge. Checking it with a load (while the fridge is running) will let you know how much was used. Full charge tests at about 12+ volts. When it hit's around 10 volts it's time for a charge.

[parnold]

The simple and inexpensive way it to read the voltage on the battery after is has been sitting for an hour or so without any draw. The voltage will tell you pretty accurately what is left in the battery in percentage. There is a chart in the sticky section that I use with mine.

The expensive way is to buy a Doc Wattson meter. It tells you how much draw you have at any moment, as well as what the peak draw was, and how many amp hours you have consumed. It cost $60.00.
http://www.powerwerx.com/tools-meters/doc-wattson-meter-dc-inline.html

I use both methods to track my battery as I'm often without power where I camp, and use battery only. Even though I have lights on the interior of my tear, I use a battery lantern to conserve the big battery. My main use is the fan, and portable DVD player. Three nights camping I drained my battery to 75% of capacity. Fan on one entire night, watched two DVD's and the other two nights the fan was on less than half an hour.

[bobhenry]

Wire in one of these little guys

http://www.batteryspace.com/batterymonitor12von-boardbatterypowermonitor.aspx

[parnold]

Wire in one of these little guys

Now that's a handy little gadget at a good price!

[Shadow Catcher]

A simple way to monitor charge is to monitor voltage.

Wet "maintenance free" or AGM/Gell cell
Rest voltage 12.80=100% 12.60=75% 12.40=50% 12.00=25% 11.80=0%

[eamarquardt]

Another option is to use an inexpensive multimeter to monitor your voltage.

All HF stuff is suspect, but you could "calibrate" one of their meters with a better meter and determine its accuracy or buy a better meter and use it.

http://www.harborfreight.com/catalogsea ... multimeter

Cheers,

Gus

[herd of turtles]

Thanks for all the advice. This site is awesome

[dh]

I'm late on this one, but walmart has a voltmeter that plugs into a cig lighter. You could simply plug it into a 12V outlet. I think its $15.

[Frog]

Herd:

I don't know how much greater capacity an AGM battery will give you. 12 volt refrigerators just consume a hugh amount of electricity. You might get an extra day out of the new battery at best.

A 75 watt solar panel would provide about 5-6 amps max per hour in direct sunlight. If you get "sunlight" from 8-6, 10 hours, you might average 4 amps per hour. That would give you 40 amps a day which would go a long way toward keeping your battery up, but on a long trip without adding alternator generated juice to the battery, the fridge will ultimately kill whatever battery you have. A second panel would double the input.

You have a few choices:

Dump the refrigerator and get either a gas/electric fridge or an ice box.

Add one or two solar panels. Two would probably keep ahead of the demand on most days.

Use a generator; those noisy, smelly beasts.

Plug into 110 power.

Hook up the car and recharge the trailer battery off the car which would take a few hours a day of burning gasoline.

Add a second battery, or ideay two golf cart 6 volt batteries in series.

Conserve all other forms of electrical consumption as best you can, i.e. lanterns instead of trailer lights.

If the fridge is out of the sun, you might try running it during the day and cutting it off or back for a few hours at night or run it on a timer so it's on an hour, off an hour so its on and off a total of 12 hours for each.

Probably not much help, but good luck on your problem.

Everything I've read about the 12 volt refrigerators is that they do use a lot of power.

[Engineer Guy]

See practical experience here from astrotrailer, et al...

http://tnttt.com/viewto ... c&start=30