Electrical Problem

[paul65k]

First of all Merry Christmas everyone!!

So I really am perplexed!! Let me start by saying that I have a 2001 (built in 2000) 36 FDDS.

I leveled the coach the other day after I moved it back into it's spot after putting in all new batteries and a Victron 712. I had no issues with the HWH system leveling it and even ran it up and down multiple times just to get it where I wanted the coach. I then plugged the coach in to the 50A outlet here at the house.

Today (3-5 days later) I was going to remove one of the dinette benches (minor remodel) and went to put out the front slide......turned the key to aux (all batteries were fully charged and I was plugged in) the slide went out about 2" (on bottom) and HWH turned itself off

So I started the coach and it started right up, tried to turn HWH back on and while it did turn on as soon as I tried to move the legs manually it not only turned off but killed the engine

Many more iterations and finally it worked long enough to get the main slide in. Here's the deal.......when I turn off Shore power it won't start at all....appears completely dead even though the starting batteries are at 13.2V resting and will handle a load showing in excess of 1000 CCA

Now here's the weird part.......house batteries are also at 100% and around 13.3V resting and all of them individually not only test good but also do not fall off when under load.

So I checked all the cables, all of which I just made new and they all test good......however when shore power is off both the house batteries and the starting batteries won't do their respective jobs inside the coach/engine start. I can't even get the fluorescent lights to come on when not plugged in, but they do try and you can see that the lights are dim but won't "Fire"......turn the shore power on or start engine and they go right on.

I also realized the bedroom slide (electric) was out and went to bring it in and it wouldn't budge even with the shore power on.......started motor and had shore power and got it to come in......at least the coach can now be driven

Checked all the 12V fuses as well as circuit breakers and all good, batteries are fully charged.

Anyhow I am stuck.......I afraid to drive it anywhere cuz if it stalls it isn't gonna start again......tried to start the generator and it wouldn't fire either. I hear a loud click from the fuse area in front of passenger whenever I put a load (HWH) or try to start without shore power.....Solenoid maybe???

I hesitate to open the front slide as the HWH system is all but inop and if I need to drive it somewhere that would be a problem.

Is it a ground issue???.......if so why does is it diminished by both Shore power and engine power.......damn am I confused

Has anyone run into anything like this????????

[twinboat]

Double check the cabling on the chassis battery, its not doing anything.

Things are working on the chassis, thru the isolation solenoid ( same as boost solenoid ) when the house batteries are being charged.


Pull the plug and the charging stops, the isolation solenoid opens and the chassis has no power.

Remove and reinstall any cables that goes to chassis ground.

Try a jumper cable to by pass each cable. One must not be connecting.

You say you made new cables. Did you solder them, crimp them with a big crimper, or hammer them closed.

Proper crushed crimps or solder can be trusted, smacking them with a hammer, not so much.

[paul65k]

Originally Posted by twinboat

Double check the cabling on the chassis battery, its not doing anything.

Things are working on the chassis, thru the isolation solenoid ( same as boost solenoid ) when the house batteries are being charged.


Pull the plug and the charging stops, the isolation solenoid opens and the chassis has no power.

Remove and reinstall any cables that goes to chassis ground.

Try a jumper cable to by pass each cable. One must not be connecting.

You say you made new cables. Did you solder them, crimp them with a big crimper, or hammer them closed.

Proper crushed crimps or solder can be trusted, smacking them with a hammer, not so much.

Thanks so much for getting back to me!!

OK I'll check but having trouble understanding why the House side is also having an issue.

I made the cables with pretty high quality components from Windy Nation 1/0 wire with their connectors (closed end) and a hydraulic crimper then used shrink wrap to cover the connectors.

I also added the Victron Shunt and put the previous Ground line on the chassis side and made a new one to the battery side. Grounds from both banks terminate at this location.

[paul65k]

PS.......Also Getting an engine light and the info panel will blank out, then reset as well.

[paul65k]

Everything worked perfectly after installing the batteries.....engine fired right up and everything worked fine both 12V as well as the inverter.

Now when I put a load without shore it just fails....there has got to be a common point of failure here that affects both the 12V side and the chassis side???

[ralph0808]

Did you ground both chassis and house batteries through the Victron shunt? I think only the house batteries go through the shunt. Maybe I misunderstood what you said about the ground hook up of the shunt.

[KSagal]

I don't have your same RV and don't know what a Victron 712 is, but I do work in a technical capacity as an elecromechanical Engineer.

From what you describe, I would offer that you have a cable or connection that is faulted. Your testing is done with low current and tests fine, but the loads you apply (slide motors and the like) require heavy current, and that is when your connection fails.

On my RV, this occurred at a ground on the engine. It tested great with a multimeter, but once I removed the bolt, wire brushed the connections, applied a bit of conductive grease, the system worked much better. The multi meter said I did nothing. However, now all the systems that were funky or intermittent started working as they should.

In the past, in a car, I had a battery cable that went bad inside a crimpped on connector from the factory. All components worked fine, until I tried to start the engine. Then all went dead. And stayed dead. Then I would open the door, and the dome light would come on in the totally dead car, and all components (lights, radio, beepers) would work, unless I tried to start the car again.

The heavy current draw caused a fault in that bad cable. A light current draw would return it to the appearance of function again, until the next heavy current draw.

You have previously been advised to check all the cable connections, and the grounds, and I endorse that suggestion. Another good suggestion was to use a jumper or bypass on each cable and connection until you find the fault, and again that is a good one.

There is also one other tool I use. Look at what was worked on, since the last time the system worked as it should. I am sorry to say that the last thing touched before the fault, is often the smartest place to look when a new fault occurs.

One last thing to consider. If you have multiple batteries or cables, it is possible that they are wired wrong. If you have 4 batteries as an example, and 3 are wired correctly, and one is wrong, the effect will be that the bad one cancels out one good one, and your multi meter will show 2 good batteries, or the proper voltages, but when you apply a high current load, your results will vary.

Again, the best place to start is the last thing you changed before the fault occurred.

Good luck.

[paul65k]

Originally Posted by KSagal

I don't have your same RV and don't know what a Victron 712 is, but I do work in a technical capacity as an elecromechanical Engineer.

From what you describe, I would offer that you have a cable or connection that is faulted. Your testing is done with low current and tests fine, but the loads you apply (slide motors and the like) require heavy current, and that is when your connection fails.

On my RV, this occurred at a ground on the engine. It tested great with a multimeter, but once I removed the bolt, wire brushed the connections, applied a bit of conductive grease, the system worked much better. The multi meter said I did nothing. However, now all the systems that were funky or intermittent started working as they should.

In the past, in a car, I had a battery cable that went bad inside a crimpped on connector from the factory. All components worked fine, until I tried to start the engine. Then all went dead. And stayed dead. Then I would open the door, and the dome light would come on in the totally dead car, and all components (lights, radio, beepers) would work, unless I tried to start the car again.

The heavy current draw caused a fault in that bad cable. A light current draw would return it to the appearance of function again, until the next heavy current draw.

You have previously been advised to check all the cable connections, and the grounds, and I endorse that suggestion. Another good suggestion was to use a jumper or bypass on each cable and connection until you find the fault, and again that is a good one.

There is also one other tool I use. Look at what was worked on, since the last time the system worked as it should. I am sorry to say that the last thing touched before the fault, is often the smartest place to look when a new fault occurs.

One last thing to consider. If you have multiple batteries or cables, it is possible that they are wired wrong. If you have 4 batteries as an example, and 3 are wired correctly, and one is wrong, the effect will be that the bad one cancels out one good one, and your multi meter will show 2 good batteries, or the proper voltages, but when you apply a high current load, your results will vary.

Again, the best place to start is the last thing you changed before the fault occurred.

Good luck.

Great advice Karl............I've been sitting here thinking about this all night and agree with the approach for sure.

I will try again in the morning and completely agree that you're spot on with the idea of a compromised cable/connection.....seems to be the only thing that makes sense.

I'm going to start with the connection of the main ground cable.....I crawled under there and it is kind of dirty......I'll take it off and clean the connections to start and if that doesn't work I'll check all the other connections working back from the "Last touched" per your suggestion.

Thanks!!

[paul65k]

Originally Posted by ralph0808

Did you ground both chassis and house batteries through the Victron shunt? I think only the house batteries go through the shunt. Maybe I misunderstood what you said about the ground hook up of the shunt.

Hi Ralph,

This is the way it was cabled at the factory (without the shunt)....all grounds terminated at a single battery and then to the chassis for both sets of batteries and this is also consistent with the wiring diagram located in the battery compartment.

I also removed the shunt from the circuit completely at one point today when I was troubleshooting so I think I have eliminated this as a potential failure point.

Thanks for taking the time to respond......Merry Christmas.

[Tom and Patty]

I had a similar problem after replacing my batteries. Slides wouldn’t work and other problems that I don’t recall. Checked all the batteries and even took all 4 out and load tested them.
I had the negative connection only hand tight at the red circle. I chased the damn thing all night. Everyone called it too. One of my connections.

[DrDaveMA]

If you are having problems with both battery banks look to what is common to both, the ground (common) connections. As mentioned above a bad ground will NOT carry current.

[paul65k]

Originally Posted by DrDaveMA

If you are having problems with both battery banks look to what is common to both, the ground (common) connections. As mentioned above a bad ground will NOT carry current.

Thanks DrDaveMA!!

Yup....it's all making sense, that's where I'll start in the morning.

Actually have that same placard in my compartment.

Here's the picture of the finished product....you can see all the negatives terminate near the front left and then a short cable to the Shunt......going to try working back from all the Negative cables in the morning see if I can pin it down.

[twinboat]

You can try to create the loss of power and feel every cable connection. A warm one will be a bad one.

[paul65k]

Originally Posted by twinboat

You can try to create the loss of power and feel every cable connection. A warm one will be a bad one.

Good idea...thanks!