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Help from the road - isolator clicking when on 12v fridge; lights dim when multiple on


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those connections are electrically the same.  voltage doesn't flow or move . it is a difference between poles on the battery. a connection on either end of a wire is the same

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9 hours ago, extech said:

those connections are electrically the same.  voltage doesn't flow or move . it is a difference between poles on the battery. a connection on either end of a wire is the same

Ah shoot. I was hoping it was a matter or correct placement. I'll clean up the connection under the truck that isnt in heat shrink in hopes it might be some corrosion. 

 

I replaced the isolator with the same 4-post one using the same connections as it was. The active "clicking" is gone, but there is still a strange whine literally inside the isolator. I didnt feel the circuit breaker doing anything. Maybe it's time to drive her over to an RV shop.

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8 hours ago, WME said:

Good find, that's about as simple as it gets much easier on paper where you can easily see it.

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2 minutes ago, Maineah said:

Good find, that's about as simple as it gets much easier on paper where you can easily see it.

I'll diagram mine being on a 4 post as well to see if it helps anyone find my gremlin. 

 

On the above one, I'm not seeing the wire that goes back to the dc panel/converter, and there are only 3 posts. 

 

I'll draw it out in a last stich effort and re-check voltage. 

 

 

 

 

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Posted (edited)

So, this is what I have going on as best I can tell.

 

Left battery is starter, right is house. I guess I should triple check that, but it seems to be true.

 

1 - I dont know where the positive (wrapped in black electrical tape - center wire on left battery positive post) wire from the starter to the 80A fuse in box goes afterward.

2 - I cant tell if the negative on the house battery (right battery) to the winch on the bumper counts as grounded. Should the winch be on the starter battery anyway?

3 - I'm not certain about where the red wire on the 1st small post on the isolator is going. It goes to the small silver box in the photo of the setup via the yellow connectors.

4 - Should the second small post's black wire actually hit the body instead of the house battery?

for review.jpg

setup.jpg

silver box.jpg

Edited by wadingthroughlife
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the lead to the house is connected at the battery or at the isolator on the house battery side

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lead to silver box is ignition power source.  house battery ground needs to be to chassis.  the 4 g lead from starting bat goes to......starter

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as long as the small black at the isolator is connected to house bat and it is grounded to the chassis you are good.

   if you kill the house bat using the winch, you can still start the truck the way it is wired now

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2 minutes ago, extech said:

as long as the small black at the isolator is connected to house bat and it is grounded to the chassis you are good.

   if you kill the house bat using the winch, you can still start the truck the way it is wired now

I'll check where the larger ground on the house is going to. I think it was direct to the bottom of the winch. Not sure if that counts as a proper ground depending how it's bolted to the steel bumper.

 

I'll replace the circuit breaker, re-do the connection under the truck for the house battery to dc panel/converter, and check the house battery ground. For the last part, can I check it with the multimeter some how? Electric is not my strong point as has been likely seen.

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Your basic wiring looks OK. This is a 30 min problem for someone who speaks Electron, over the internet small steps are needed

The small red wire to the yellow plugs is the on/off signal wire to the isolator. Check the voltage according to my earlier post.

The diagram I posted is for a 3 post isolator  it is grounded through the case. Your 4 post just adds a separate ground. Ground is Ground doesn't matter how it happened, just that it does.

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I'd be tempted to disconnect the winch - unlikely but possible that the armature is shorting.

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29 minutes ago, neilp said:

I'd be tempted to disconnect the winch - unlikely but possible that the armature is shorting.

Worth a try. 

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Your photo shows a 3 post isolator relay not a 4 then another one shows 4 post? The 3 post is wired correctly. I would cut the black wire short and ground it to the isolator mount not the battery. Due to the voltage drop at the - battery post at the battery with a heavy current draw.

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only reason for voltage drop at the battery is a bad connection.  thats how i check to see if the connection needs cleaning.

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i dont see any pictures of a 3 post relay

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Posted (edited)

I drew the extra post on the diagram borrowed from another reply. I changed the circuit breaker and same issue. I did try the move the small  post ground connected to the battery to elsewhere on the chassis, but then I got zero power to the house 12v items. Moving it back to the battery, I get power to those items again but still a funky electrical sound in the isolator if I turn on the fridge or outside not led light. 
 

If I take the winch power and ground off the house battery, the house battery only has that small ground wire to the isolator. I was worried I’d fry something. if I go isolator small ground to body and also disconnect the winch, then there would be zero ground connecting to the house battery. 
 

I’m checking voltage on the isolator and seeing 11.5 to the post where it connects a small positive to the silver box/ignition source if using the battery as a gound. If I use the body, it gets zero voltage with the key in accessory.

 

With no ignition on, I get matching voltage that I get from each resting battery at each respective post, including the circuit breakers two posts. Ie house was about 12.7 resting and so was the isolator and circuit breaker at the right side of it. The starter was 13.2 and so was the isolator side where it connects. 
 

 

Edited by wadingthroughlife
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Make up another ground wire, (14 ga or so). Connect it from the house battery - to the truck chassis. See what happens with the ignition key.

If the winch is grounded, no harm/no foul. If the winch is floating then this should let the isolator work correctly.

Edited by WME
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1 minute ago, WME said:

Make up another ground wire. Connect it from the house battery - to the truck chassis. See what happens with the ignition key.

If the winch is grounded, no harm/no foul. If the winch is floating then this should let the isolator work correctly.

Thanks. I’ll grab some thicker wire and connect it up tomorrow. 
 

I took videos of all the voltages and also test lights on everything too. Also the awful sound. 
 

I’ll recap the main finding- the house side of the isolator is only getting 9.0x volts resting while the house battery itself is 12.67. 
 

also, the ignition source is getting 0 with ignition off and 11.12 with key in on position. 

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no load====nothing turned on.   voltage at house bat side has to be the same as b+ at the battery.  something wrong with your measurements. 

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16 minutes ago, extech said:

no load====nothing turned on.   voltage at house bat side has to be the same as b+ at the battery.  something wrong with your measurements. 

Hopefully true. I’ll take a video of the process again tomorrow. 

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It seems to be fixed by adding the extra 4g ground from house battery to chassis. No more noise from the isolator using 12v without the engine running. 
 

Thank you all for the input!!

 

The only odd voltage seems to be at the ignition post of the isolator. With the key in the on position, I see 10-11 volts. 
 

 

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Victory😁

Check the ignition post voltage with the engine running.

Edited by WME
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On 4/13/2022 at 7:40 AM, wadingthroughlife said:

 

for review.jpg

 

 

^^^ Is there some sort of diagram like this that is available on this site?  If not, can someone make one as a 'sticky'?  I hate electrical work and would like to know the schematics of how everything is wired up and run.  Also would be nice to include solar setups as well with their additional battery and inverter and etc etc. OK, my head hurts now.

Edited by Toyota_RV_Racer
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On 4/13/2022 at 8:16 PM, extech said:

i dont see any pictures of a 3 post relay

Yes  there was. He took it out and replaced it with a 4 post typical shotgun approach. There is a fair length of small black wire going to the negative battery post for the isolator ground instead of connected to the isolator mount or any decent close ground. The shorter the length of wire at 12 volts the better.

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 I actually ended up grounding the isolator to the chassis as well instead of the battery. I’ll take a pic of the final cleaned up setup with the 4 post soon to share. 
 

 

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Yes my Sunrader is grounded to the chassis and has the 4 pole isolator. That was the way it was set up from the factory. When I bought it it only had 32,000 miles on it and I bought it from the son of the only owner after he passed. Everything was absolutely original

Linda S

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As a WAG 75% of electrical problems on an older RV are ground related. Bad splices, corroded connections, dirty grounds. Tail lights, clearance lights, turn signals the list goes on This is why a cheap volt/ohm meter is an important tool to carry, Learn to use it at home, not broke down at the side of the road or a Wal-mart parking lot.

 

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