12V Power Problems

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grubbie

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Sep 27, 2021
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9
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FDL, WI
Update: I installed the new solenoid, and the problem continues. I took pictures and wrote myself a note to make sure I hooked it up properly.

It is back to the way it was before I started trying to fix this. The battery still checks out, so we are back to square one.
 

Kirk

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Oct 30, 2005
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1,013
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Full-time , Escapee
I installed the new solenoid, and the problem continues.
When you replaced the solenoid, did you also replace that relay that is shown in the picture you posted?
image0-jpeg.149376

If you did not, I would tend to suspect that it would be the cause of your problems, assuming that it comes from this solenoid. Are the 2 fuses that can be seen at the bottom(lower right of this picture) a part of the solenoid and replaced with it?

Have you determined exactly what this solenoid is and what it does? If in the battery box next to the battery then I would suspect it may be a battery isolator. An easy way to eliminate that device would be to put both the lead from the battery and the one from this device on to the same terminal, which would have the same results as the solenoid being closed all of the time.

Have you been able to measure voltage on either side of the solenoid while the 12V is missing from the RV? If not, as soon as the problem happens again, measure to see if it is passing through. Measure from first one terminal to ground or to the battery negative post and then the same from the other terminal.
 

grubbie

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Joined
Sep 27, 2021
Posts
9
Location
FDL, WI
auto reset breaker in your 12 volt supply line that is tripping
Are these what you are talking about. As we were checking the wires we found a lose connection on this bad boy.

What does this do? Is it consistent with the problems I have been describing?
 

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grubbie

Member
Joined
Sep 27, 2021
Posts
9
Location
FDL, WI
When you replaced the solenoid, did you also replace that relay that is shown in the picture you posted?
image0-jpeg.149376

If you did not, I would tend to suspect that it would be the cause of your problems, assuming that it comes from this solenoid. Are the 2 fuses that can be seen at the bottom(lower right of this picture) a part of the solenoid and replaced with it?

Have you determined exactly what this solenoid is and what it does? If in the battery box next to the battery then I would suspect it may be a battery isolator. An easy way to eliminate that device would be to put both the lead from the battery and the one from this device on to the same terminal, which would have the same results as the solenoid being closed all of the time.

Have you been able to measure voltage on either side of the solenoid while the 12V is missing from the RV? If not, as soon as the problem happens again, measure to see if it is passing through. Measure from first one terminal to ground or to the battery negative post and then the same from the other terminal.
When I searched the part number it was sold as an entire unit, so everything in the picture is brand new.

I am not 100% sure what it does, but the best we can figure is it is a battery isolator, because it is in the battery compartment and you can hear it switch over when the main power switch is flipped.

We have measured 12V on it, but it seems to only work when it isn't actually attached to 12V power. For example, when shore power is plugged in, before we installed it, but as soon as we hooked the battery back up and tried to use 12V power in the RV, it stopped working.
 

John From Detroit

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Apr 12, 2005
Posts
25,274
Location
Davison Michigan
What an auto -reset circuit breakers does. (or a manual one for that matter) is open if the current is too high. Now turns out there are 3 kinds and with some minor differences they all look much alike

Manual reset (High current turns it off, push a button to reset)
(Note these can be magnetic or thermal... Magnetic the current flows through a magnet and when it's too high CLICK, thermal it heats a bi-metal strip. Same thing)

Auto-Reset (Far as I know always thermal) A good example is some turn signal blinkers,, the ones that specify the number of lamps... In the old days.. Too much current heats them up and CLICK, then they cool off and CLICK power restored.

Finally there is the "Short Stop" Current through the bi-metal strips trips it but then there is a finer high resistance wire wrapped around the bi-metal strip that continues to heat it (at much lower current) till you stop the current either by turning it off or removing the load... One of those drove me crazy for a while till I figured it out. I doubt you have that type.

An automotive 12 volt test light (Any auto store or auto dept)

Clip the clip to any solid known good ground (Start with the battery negative) and "probe" connections You might find a long coil of flexible wire (And an additonal clip or 2) same source, useful.. Probe out along the positive lead starting with the battery positive..
Every connection touch. Light Bright, GOOD,, Dark Not good
Problem exists between Bright and Dark

(Note DIM is an option tool. also not good I had one of those)
 

CharlesinGA

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Oct 6, 2017
Posts
461
Location
50 miles south of Atlanta, GA
Finally there is the "Short Stop" Current through the bi-metal strips trips it but then there is a finer high resistance wire wrapped around the bi-metal strip that continues to heat it (at much lower current) till you stop the current either by turning it off or removing the load... One of those drove me crazy for a while till I figured it out. I doubt you have that type.
Read the printing on the side of the auto reset CB in the second pic above, it says SHORTSTOP. Is that what you are talking about?

That tiny breaker is 50 amp, personally I would prefer a better quality CB than that for that high of a current, something like this.

Eaton Bussmann 285 Series Resettable Circuit Breakers Surface Mount up to 150A

eaton-bussmann-cb285-50-surface-mount-circuit-breaker-50-amps__5599_580.jpg

Charles
 

grubbie

Member
Joined
Sep 27, 2021
Posts
9
Location
FDL, WI
Are the two types of circuit breakers designed to do the same thing? The RV has one similar to this
If they are designed to do the same thing, why would there two of them?

The one that says shortstop that I pulled out of the RV looks like the wires go into the to power the house side of the RV. The Bussmann looks is hooked directly to the battery and then the wire runs the length of the RV and then disappears when it goes into the RV under the drivers seat.

Does it make sense to upgrade the shortstop to something more durable?

Thank you yet again.
 

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