DC power issues- any advice?

I know this is not suitable for you as you say you are isolated. But when you return to civilization, take a run by the hardware store and purchase a pair of plastic lamp bases for household screw-in light bulbs.

Next, head for a NAPA store. Purchase (2) 100-watt TWELVE VOLT light bulbs. You are going to GANG the two lamp fixtures together (parallel), then lead a pair of 14 gauge wires to use as test probes. The diameter of the conductor of 14 gauge is good size. You need to STRIP a half inch of insulation from the end opposite you connected to the lamp base. Then solder over the kitchen stove burner with Radio Shack solder. This makes the stripped copper wire ends stout.

The two bulb bases need to be ganged. Run a SPUR wire from the primary base you connected the two test lead wires to. The SPUR connects to the 2nd base. It connects the 2nd bulb in parallel.

Make the test leads just long enough to be comfortable. So you won't be yanking the bulb bases around when you move the probes from place to place.

Next, go grab your jumper cables. One of the two clips is going to be clamped to a proven ground. A good negative somewhere. No sense in making the lamp tester test leads so long that they snarl.

Clamp one jumper cable to a good ground. Good grounds are not easy to find. You may have to run the cables out of the entry door and clip them to a scraped shiny piece of steel hooked to the chassis. Whatever works.

Why this and not a simple test light?

Well, you're going to clip the loose end of the battery jumper cable to one (doesn't matter which) test lead. Now that test lead is grounded.

Let's go to work.

The loose (unconnected) test lead end now can create a SEVENTEEN AMP LOAD when you touch the tip to any 12 volt live surface. The positive connection of any device, buss bar, fuse, you name it. If it has power, when you touch it with that test lead, you create a 17 amp load, and those two light bulbs can be seen for a half mile at night. A rude load test with unmistakeable signal.

If you touch something and the lights do not come on, or there is a spark, then the lights flash on then off, you have a BAD connection somewhere.

AND BECAUSE OF THE 17 AMP LOAD when you touch anything, good or bad, the test lead tip WILL MAKE AN ARC. This is good. Jab the test lead tip rather than drag it across a connection.

This cheap to make (and easy) tester has found I would have to guess, more than a thousand bad, and almost bad connections, over the years. It is phenomenal.

BUT BUT BUT BUT BUT BUT

Do not check tiny wires DOWNSTREAM of a fuse or breaker rated less than 20 amps with this critter. It'll blow the fuse. This tester is for primary feeder and branch circuits.

When you're done, unscrew the bulbs and put both of them somewhere safe. The PLASTIC lamp bases you bought are hard to break.

And yes, your eyes do not deceive. If you "test" a circuit and the bulbs glow dim in some spots but not in others, Houston You Got's A Problem.

LOAD TESTING is the only way to really test a circuit. I've seen it all with my own tester: Bright lights that grow dim or go out after a few seconds. This critter finds problems, the problems do not find you (at a campsite). New rigs, old rigs, the tester is B.S. proof.

"But that has never given me a problem" some owners complain after I found a problem while testing everything.

Then I uncover a burned or loose connection. "Wow!" the owner would say "That was ready to fail!"

Total cost? Under 20 dollars. You supply the jumper cables, or make up your own ground wire extension. Use a savage grade crocodile clip to connect to the frame.

Good hunting. This is preventative maintenance. If you don't go through your rig and test all higher power circuits, don't worry. The problem will show up sooner or later and you sure will "know it" when it does. This isn't a Pie In The Sky type of test.

The number of bad connections you will find before they find you is shocking.

As has been mentioned, but I'll mentioned it again since it is very important: Decimals Matter! 12.6 to 12. 7 is fully charged. Around 12.4 is 80% and 12.2 about 50%. (That is at rest with no current draws or charging happening)

To see if you have a bad battery let them sit for several hours (no load or charging) then measure voltage at each battery. Should be equal, and if fully charged, about 6.3 to 6.4 Volts. If there is a difference, one is bad. A fully charged lead acid cell is in the range of 2.1 volts.

Hasn't been mentioned and you may want to just check---the breakaway switch for emergency brakes.

If your testing lit the lamp, one or more of those circuits may be passing current for alarms, circuit boards, and radio.

WylieWanderings wrote:

Vroadracer wrote:
1. I made a tester with a 12 volt signal light by putting a clip lead to the positive wire of the signal light and another clip lead to the ground wire of the signal light.

2. Next turn the 12 switch off at your fuse box. Then remove all of the fuses (keep up with the position they were in before they were removed) and check to make sure they are all good and that none of them are blown?

3. Then disconnect the ground cable from the battery that is grounded to the frame of the 5th wheel. Now take your tester and connect one lead to the end of the disconnected ground cable and the other clip lead to the ground terminal of the battery.

4. Now you can insert one fuse at a time back into the fuse holder. After you put the fuse back in, go look at the test light bulb. If it is glowing, then that circuit is drawing current from your battery. The brighter the light the more current it is drawing. You can test the circuits one at a time so you can tell if you have more than one circuit that is drawing current from your batteries.

That is the way I found that I had a malfunction in my Arctic Pac on my 5th wheel as it would draw my batteries from 12.6 volt down to 10.5 volts overnight with nothing powered by 12 volts being turned on at the time.

I hope this helps you to find your problem.
Vroadracer
Dickson, TN

Great explanation- we will definitely give this a test!

Thanks for the tutorial! We found 4 circuits that appear to have shorts and are drawing down...now to track down the cause!

Also our Progressive converter limits power to 10.5 volts when it detects a problem, which is why it appears to be a significant draw down.

With the problem fuses removed, the converter puts out well over 12 to the rig. This explains why it appeared to draw down so quickly. The batteries are fine- it's the converter that throttled the power because a problem was detected.

You said Six volts hooked in parallel... Graphically that means

-Batt+6V
-Batt+6v

What you should have is six volt in SERIES,, Graphically that is
-{Bat}T{ery}+12V *the T in the middle is a jumper wire*

If you typed correctly that is your problem.

Note: there should not be any six volt batteries in an RV, Just 12 volt batteries which, as in the 2nd diagram, come in 2 pieces (six volts each when OUTSIDE the RV, but 12 volt when properly twinned inside the RV).

Why use six volt in series instead of one big 12? Well I'm over six feet tall and over 300 pounds. I routinely pick up 200 pound loads and set them on package trays and such.. I COULD NOT lift even half that big 12 volt battery off the ground onto the tray when lying under the coach (Thankfully the battery store kid was able to do it and then I slid it into position) Them suckers are HEAVY.

I was able to lower the slightly smaller (220 amp hour v/s 230 amp hour) decade old ones off the tray with only minor injury (one band aid)

Sometimes there is a 3rd position called Gas or Propane. If there is, then try and switch there.

Almot wrote:

WylieWanderings wrote:
When on battery power, the Dometic fridge will drain power very quickly...

What mode the fridge is in?

Auto- It's a 2 way Dometic...gas or shore power/generator

WylieWanderings wrote:
When on battery power, the Dometic fridge will drain power very quickly...

What mode the fridge is in?

Vroadracer wrote:
1. I made a tester with a 12 volt signal light by putting a clip lead to the positive wire of the signal light and another clip lead to the ground wire of the signal light.

2. Next turn the 12 switch off at your fuse box. Then remove all of the fuses (keep up with the position they were in before they were removed) and check to make sure they are all good and that none of them are blown?

3. Then disconnect the ground cable from the battery that is grounded to the frame of the 5th wheel. Now take your tester and connect one lead to the end of the disconnected ground cable and the other clip lead to the ground terminal of the battery.

4. Now you can insert one fuse at a time back into the fuse holder. After you put the fuse back in, go look at the test light bulb. If it is glowing, then that circuit is drawing current from your battery. The brighter the light the more current it is drawing. You can test the circuits one at a time so you can tell if you have more than one circuit that is drawing current from your batteries.

That is the way I found that I had a malfunction in my Arctic Pac on my 5th wheel as it would draw my batteries from 12.6 volt down to 10.5 volts overnight with nothing powered by 12 volts being turned on at the time.

I hope this helps you to find your problem.
Vroadracer
Dickson, TN

Great explanation- we will definitely give this a test!

1. I made a tester with a 12 volt signal light by putting a clip lead to the positive wire of the signal light and another clip lead to the ground wire of the signal light.

2. Next turn the 12 switch off at your fuse box. Then remove all of the fuses (keep up with the position they were in before they were removed) and check to make sure they are all good and that none of them are blown?

3. Then disconnect the ground cable from the battery that is grounded to the frame of the 5th wheel. Now take your tester and connect one lead to the end of the disconnected ground cable and the other clip lead to the ground terminal of the battery.

4. Now you can insert one fuse at a time back into the fuse holder. After you put the fuse back in, go look at the test light bulb. If it is glowing, then that circuit is drawing current from your battery. The brighter the light the more current it is drawing. You can test the circuits one at a time so you can tell if you have more than one circuit that is drawing current from your batteries.

That is the way I found that I had a malfunction in my Arctic Pac on my 5th wheel as it would draw my batteries from 12.6 volt down to 10.5 volts overnight with nothing powered by 12 volts being turned on at the time.

I hope this helps you to find your problem.
Vroadracer
Dickson, TN