Furnace / Battery Problem

[Gerry]

Me again with the same old problem.
Furnace works on shore power but not on battery, (cold night spent out a few nights ago)
I just spent $225 to an RV dealership to cure this problem and they will not make it right so I will have to work it out myself with all your help. (popping high blood pressure pills by the handfull)
I have my battery on the tongue sot he run to the furnace is a good 10 ft of # ??? (original wire in 1980 Boler 13 ft)
I have re wired from where it comes in all the way back so I know this is #8 wire but that weak link may be from the tongue into the shell.
What is the proper size wire should I run all the way back so this hook-up will work?
Leaving next week for a week in northern Maine and temps will be down in the 30s so I need to get this going.
Gerry the canoebuilder

[Brian B-P]

I find it hard to believe that this is a wire gauge issue. There isn't a bit of wire in my Boler larger than 10 ga, and Boler didn't put in much of that. With a good battery the furnace works fine.

I would put a voltmeter on the power to the furnace when it is (trying to) run - running the fan - to see if there's enough there; if there is, then look for another problem, and if there isn't, check out the battery. What's "enough"? Whatever the furnace manual says...

[Gerry]

I find it hard to believe that this is a wire gauge issue. There isn't a bit of wire in my Boler larger than 10 ga, and Boler didn't put in much of that. With a good battery the furnace works fine.

I would put a voltmeter on the power to the furnace when it is (trying to) run - running the fan - to see if there's enough there; if there is, then look for another problem, and if there isn't, check out the battery. What's "enough"? Whatever the furnace manual says...

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Thanks again Brian. After haveing my $9.95 voltmeter forever I am finaly learning how to use the thing (other then for continuety) and how to read all the scales with the proper dial setting.
I think I found the problem and it was just a loose connection on one of the butt connectors they put on.
I replace and furnace lit right up on Battery
Keeping fingers crossed as it seems every time we take Lady-Bug on the road one thing or another goes wrong.
Gerry the canoebuilder

[Greg A]

RV dealership $225.00

Gerry the Canoe builder with a $9.95 voltmeter----- PRICELESS!

[Brian B-P]

Keeping fingers crossed as it seems every time we take Lady-Bug on the road one thing or another goes wrong.

This means that after enough trips, everything in the trailer will be fixed, and Lady-Bug will be perfect! Hang in there, Gerry.

[Pete Dumbleton]

Anyone shooting trouble where there is insufficient power should remember to also check the ground or return cabling; the entire circuit, out and back, must be OK for the whatever to work!

[Gerry]

Anyone shooting trouble where there is insufficient power should remember to also check the ground or return cabling; the entire circuit, out and back, must be OK for the whatever to work!

Pete
I have a heavy green wire going from my converter down to the frame.
I also have a white wire that is considered the ground going thoughout the trailer from my Battery.
Is all the whatevers, useing the white wire or the frame, or both, as the ground path back to the battery, via the converter????
Gerry the canoebuilder
Brian: I am trying to hang in there but the only thing that worked great the day dealing with the RV dealers was my hand going into my wallet handing them cash.

[Alf S.]

Hi: Glad to hear that I am not the only "Loose connection" out there!!! In Nfld. Canada there is a saying that goes kinda like "Ya pays yer money and ya takes yer choose". Sounds like you will be warm n toasty... What's next???
Alf S. North shore of Lake Erie

[Brian B-P]

I have a heavy green wire going from my converter down to the frame.
I also have a white wire that is considered the ground going thoughout the trailer from my Battery.
Is all the whatevers, useing the white wire or the frame, or both, as the ground path back to the battery, via the converter????

A green-insulated wire from an AC wiring enclosure to anything is likely a protective ground connection, which is never expected to carry any current except in the case of an insulation failure or other accidental connection of power to the something which not supposed to have power.

All of the devices ("whatevers") in every moulded fiberglass trailer wiring diagram I've seen (Boler, Scamp, Trillium) use a (normally white) wire - not the frame - to complete each circuit.

The connection of converter to frame may allow a circuit to be completed via the frame, but the trailer wiring was designed to use the white-insulated negative/return/ground wiring. If only for your own sanity, or as a favour to the next person who tries to maintain the trailer (because old Bolers never die, they just get passed on and renovated...), I suggest consistently sticking with the return path via the white wire.

[Pete Dumbleton]

As Brian said, the green wire is the ground for the 120VAC circuits (black is hot, white is neutral). Indeed, it should be connected to the frame.

For the 12VDC system, where the return/negative/ground wire may need to carry a combined load from several uses (could have brakes, brake lights, running lights, battery charge and reefer all running at same time, for example), the power (+battery) wire is usually red and the return (-battery) wire is usually black, but some RV techs may follow the AC codes and use black/white, so it's not always a sure thing.

[Gerry]

As Brian said, the green wire is the ground for the 120VAC circuits (black is hot, white is neutral). Indeed, it should be connected to the frame.

For the 12VDC system, where the return/negative/ground wire may need to carry a combined load from several uses (could have brakes, brake lights, running lights, battery charge and reefer all running at same time, for example), the power (+battery) wire is usually red and the return (-battery) wire is usually black, but some RV techs may follow the AC codes and use black/white, so it's not always a sure thing.

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So putting a ground strap from - post of battery to the frame will not help the conductivity of the negative side of the appliances. (Because they, are not hooked to the frame??Right?)
So far so good, My wife has me start the furnace daily to "just make sure it runs" but as we all know one trip down a bumpy road and all H-E- double toothpicks can break out.
The white ground / black POS system is as said throught the trailer until it gets to the furnace or other appliance where other owners have turned Black or White into a rainbow of blues, reds, browns, orange, yellows.
One of the first problems I was faced with in 05, with Lady-Bug was the exterior lights not working and a friend helping told me the hitch was not makeing a good ground connetion.
I insisted as I had believed and was told, the Boler did not use the frame as a ground BUT... when he stepped on tongue it all worked.
That being the case I would think a grounded frame is important if it effects the lights.
Gerry the canoebuilder

[Pete Dumbleton]

Each of the appliances should have its own return path to the 12VDC fuse block, which in turn is typically connected to both the converter and battery, which in turn are connected to white wire in the 7-way Trailer Connector, and thence to the TV frame and thence to the TV battery. I recommend a wire directly from the TV connector to the TV battery, also attached to the frame.

On my trailer, I beefed up the wire between the battery and the fuse block (I don't have a converter). Good wires and connections mean less wire loss and better use of the battery for lighting things, not heating wires...

[Brian B-P]

So putting a ground strap from - post of battery to the frame will not help the conductivity of the negative side of the appliances. (Because they, are not hooked to the frame??Right?)

Yes, that's right, at least in my case.

[Brian B-P]

Each of the appliances should have its own return path to the 12VDC fuse block...

"Fuse block" for the return wiring...
In my Boler - and my case it not unique - the white wires come together somewhere in the nest of random wiring and connect to each other with a variety of crimped-on wiring caps (circles in my diagram, below). There is no bus bar anywhere for the negative side.



The white-insulated wires in the trailer are shown as grey in the drawing (so you can see them).
Decoding the wiring to make the drawing took a while...

[Pete Dumbleton]

Brian, the fuse block that I pulled from my Magnatek converter is a board with a common connector on it for terminating the negative/ground/return lead(s) for each fused circuit... But, to be clear, I did NOT mean to imply that a negative/ground/return wire should be connected to a fuse or the fuse bus.

Here's an example of something like it:

12 Circuit Fuse Block with Negative Bus

Note that the upper terminals on the block are negative and the lower terminals are fused positive.

[Pete Dumbleton]

In my Boler - and my case it not unique - the white wires come together somewhere in the nest of random wiring and connect to each other with a variety of crimped-on wiring caps (circles in my diagram, below). There is no bus bar anywhere for the negative side.

My Scamp is wired something like that but the white wire eventually comes back to the (-) terminal on the fuse block board. This can be seen in the Scamp Wiring Diagram in Helpful Documents.

Any circuits I added have a 'home-run' negative lead as well as the fused positive lead, just as done in 120VAC wiring -- Easy enough to run the negative wire when I'm running the fused positive one. I'd rather have a few extra wires with connections only on the ends than have connections buried in the runs -- Makes for less trouble, easier troubleshooting and no worries about resistance loss.

If I were wiring from scratch, I would have every internal circuit set up with two wires on a fuse block like the one in the post above and would probably have terminal strips for external lighting as well to increase reliability and aid troubleshooting. However, I can understand why manufacturers wouldn't go for the extra equipment and labor.

[Brian B-P]

Pete, I know you didn't mean that there was a fuse in the negative connection... it's the whole idea of Boler supplying a nice negative bus bar that's hilarious. We're lucky they even followed a colour code.

I agree that the "home run" wiring approach is more reliable. In addition to the mess in my drawing, the negative wires have lots of buried connections in the middle of the runs; since I have yet to find all the bad ones, some of my clearance lights are erratic.