12 volt system does not work

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OleOlson

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Mar 9, 2019
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Hello,
I need help in figuring out my 12 volt problem. No 12 volt power to anything at anytime even when hooked up to shore power or with the generator running.

25' 1995 Fleetwood Storm 

History; New House Battery's, two 6 volt wired in series. New upgraded charge controller. 

I have checked voltage with a voltmeter and have 12 volt power to the fuse panel under the fridge. But it does not make it to the fuses themselves.
Only the large red wire shows power not the individual fuses. 

What should I check next?  I am stumped at this point?

Thanks for any help:)
Wes




 
 

Gizmo100

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Welcome to the RV Forum Wes

Sounds like you have a Bad master fuse on the panel. Don't just look at them put the test meter on each side of the fuse and check for voltage.

Best of luck
 

OleOlson

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Hi,
Thanks Gizmo,

I got it figured out sort of, When I changed out the charge controller, it came with a new fuse panel.  But I did not change it out thinking it was not necessary as the old one looked fine. So I stepped up today and changed it out with the new one and wouldn't you know everything came on and now works. Yippee:)

However, I went down through the fuses and checked each one, one by one and the #2 fuse (Bedroom lights) do not show the 12 volts and when I tried to turn those on they dont work.

So why would I not have power to the one line coming into the fuse?  any thoughts?
 

Lou Schneider

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Hi Wes, welcome to The RV Forum!

Remove the bad fuse and double check it's good using the resistance range on your voltmeter.  If it shows continuity, switch your meter back to voltage and check for 12 volts on the fuse pin furthest from the output terminal.

If there isn't 12 volts there, the new fuseboard has a problem.  Make sure it isn't a split feed fuseboard, sometimes you need to insert a wire jumper to get power to all of the fuse sockets.

If the fuse is blown, make sure all of the strands on the wire going into the fuseboard are properly inserted into the terminal and you don't have a stray strand shorting to ground.
 

OleOlson

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Mar 9, 2019
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Hi Lou ,  thank you :)

Yes I did that and put a new fuse in also.

Remember the power is not coming off the wire to the fuse. all the other lines are hot. FYI...>It did this also on the other fuse board, So my guess is its the wire itself?  It runs the two reading lights on the wall next the bed. Not the ones on the ceiling. 

Also, I did go through each wire to make sure there are no loose strands..good thought.  Any other ideas?  I guess I could put in a jumper to test it, I would guess the lights would work.  But that does not solve the problem of the one wire not being hot?

Would it be a bad idea to do a jumper and cap off the wire coming in thats not working? Would that work?
 

Lou Schneider

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Maybe I misunderstood what you're saying, but the power does not come from the wire going from the lights to the fuse, it comes off of the buss inside the fuseboard connecting the converter/battery voltage to all the fuses.  Then it goes through the fuse to the terminal you connect the wire to.

That's why you should see voltage on the fuse terminal furthest from the wire connection ... it comes from the buss, flows through the fuse and out the wire.

If you're not seeing voltage on the terminal where you connect the wire to the fuseboard, there's a problem in the fuseboard.  You can verify this by disconnecting the wire and see if the terminal on the board shows voltage.

If you see voltage on the terminal with the wire connected, but not at the other end (the lights) there's a problem along that section of the wire.

Or you may have lost the ground connection to the dead lights.  Current has to flow into the fixtures through the hot wire, then return via the ground.

Use a piece of wire to connect the (-) side of your meter to a known good ground and see if you find voltage at the fixture end of the wire.  If you do, trace the ground wire side and see if there's a problem there.
 

OleOlson

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I got you, thanks, it seemed the other way around for some reason. Anyway, sounds good ill give that a try. thanks
 

OleOlson

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Bedroom Lights continued;

OK Lou I Was able to get back to the trouble shooting again today:) 

I did what you said and found out that the fuse blows almost right away after trying to turn on the light. before the fuse blows it seems normal with 12 volts on each side on the fuse. Also, I did replace the bulbs with the new LED type, However, I do recall that the lights have never worked to my knowledge.
Should I take apart the lights at this stage? and see if there is a bad connection within the fixture itself?
 

Lou Schneider

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Take a close look at the new bulbs vs. the socket.  Does the socket have two contacts and the bulbs only one pin?  If so, the single pin on the bulb is shorting out the two contacts in the socket.

If that's not it, it's time to take apart the fixture.
 

John From Detroit

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What standard lamp did these take?  1141?  If so look into the socket.

ON that "Single contact" type bayonet lamp there is a washer with a contact in the middle of it. there id a spring behind the washer.  now with LED replacement this does not (Far as I know) happen but if you put in say 1136 lamps (higher wattage standard) it will.. The washer "Cooks" breaks and the Socket shorts.

I'm not "At home" just now so I don't have the party number but.. I have a dozen replacement center contact assemblies (Spring. washer. contact and wire. You can find 'em on line.

I've used 2 of 'em so far. but I'm converting to LED's so....

 

OleOlson

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Thank you, Good tips all the way around. Well check it out asap and let you know how it went. FYI; I did replace most of the lights with the 1141 LED bulb that was recommended to me by the local RV dealer.
 

OleOlson

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Got out to the Rig last night and checked the Bedroom lights and sure enough they are the dbl. contact bulbs. LOL. All the rest are single. Anyway, I will get new LED's asap.

But, Onto another issue.

When I went out to the Rig I had no lights at all anywhere. SO i started to swear a bit..hehe.. Then hooked my meter up to the main Red wire coming into the fuse panel and it showed about 1.5 volts. What the heck!  Went out to the New house battery's and they showed 13.2 approx. volts. 

I plugged in the Rig to let it charge over night. This morning I unplugged the Rig and went to check the volts at the fuse panel and now it reads 12.57 volts with nothing on and when I start turning on the lights it drops down to about 12.45 with all ceiling lights on.

Anyway, Why would the fuse panel show such low voltage after sitting for two weeks even tho the battery's show 13 volts??

Thank you for all your continued help:)
 

Lou Schneider

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Do you have a battery disconnect switch?  If so, try cycling it a few times and see if exercising the contacts improves anything.

Otherwise, look for a  corroded connection between the batteries and the electrical panel.  Corrosion acts as a resistance, it can pass voltage without a load but chokes off the electrical flow as soon as a load is added.

The first suspect is at the battery terminals either between the terminal and the post but it could also be between the wire and the post.  Or where the ground wire connects to the chassis.
 

thelazyl

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I could use some help learning how to use my electrical tester.  I am very much a novice with electrical stuff.  As a starting point I'd like to measure the voltage for internal 12v appliances including at the fuse.  I don't have a problem to fix - this exercise is solely for me learning about how to take care of an RV.

Based on feedback on this forum I purchased the tester below:
https://www.amazon.com/gp/product/B000FCIMFS/ref=oh_aui_search_asin_title?ie=UTF8&psc=1

Greenlee TK-30 Basic Electrical Kit

The issue I have is that the documentation is way above my head - it might as well be in Greek.  There are too many options that can be selected on the tester and I don't know which one to use for the 12v test.  Even if I select the right option on the tester I may not be able to translate what the needle is indicating.

Does anyone have a suggestion for "12v testing for Dummies" type of documentation or youtube?

I also have a simple 12v tester which an alligator clip and a pointy metal pencil looking thing.  I think I know how to use this one.

Thanks in advance.

 

Larry N.

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Taking a look at that kit, not the best for a beginner to work with, I see part of your confusion. It uses "international symbols" instead of words or abbreviations to show what the scales are. So the V~ is AC volts, the V..._ (can't make the exact symbol, but the one to the left) is probably DC volts. I'm not sure what the A..._ is for (DC amps???) . The 9V and 1.5V, with the odd symbol, are probably for battery checking. The batch of yellow on the lower left as 2000k, 200k, etc. are ohm (resistance) scales. I don't know what the WiFi-looking symbol is at the bottom.

With the resistance (Ω or ohms) settings, don't apply them to anything that has voltage on it, or you risk damage to the meter. The white V..._ on the upper left are the scales you use for DC testing, so I'd set it on 20 to check 12V DC. The 2000m is probably 2000 millivolts, or 2V DC scale. The red probe should go on the positive (+) side of, for example, the battery, while the black should go to the negative (-) side.
 

kdbgoat

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I think it was one of the Lou's that did a post on how to read a meter. I wish it was a sticky or in the library. It was a very good, detailed bit of information.
 

John From Detroit

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12.6 is what we call "Full charged resting" 12.57 is 12.6 with meter inaccuracy so that is not a "low voltage" 

But there are several devices (Like propane detectors) that may not even have an OFF switch.  Some devices draw power even when OFF

So sitting w/o charge for 2 week. well batteries will self discharge over time as well.
 

OleOlson

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Mar 9, 2019
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Thanks John From Detroit,

Are you saying I should leave the Rig plug in all the time?  Also, The House battery's. read the 12.6 AT THE batt.  And inside at the fuse panel it read 1.3 or 4 and nothing was working.  That what thru me off. 
 

John From Detroit

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If the batteried read 12.6 at the batt and 1 or 2 at the panel then the batteries are NOT CONNECTED.. meaning either a cable is off. The Disconnect is in the Disconnected/off/store or a fuse or circuit breaker is blown or tripped.

OR as we used to say of one ham I know used to say you have a Connection Now Lose (his call suffix was CNL  He said it meant Connections NOT loose but well.... We knew him).
 
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