House Battery Blues?

[Gooseberry]

Originally Posted by MountainBikeRoamer

My bad? Yargghhh. Perhaps its the fat red wire that runs off to the house fuse block, and not the black one? It's late, and it's possible that my brain's electrical connections are as unreliable as my battery's voltage readings. Let me go re-check this.

That makes more sense and you might want to fuse that smaller wire or move it to the fuse block.


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[MountainBikeRoamer]

Originally Posted by Gooseberry

That makes more sense and you might want to fuse that smaller wire or move it to the fuse block.

UPDATE:
Yep, not sure what I was thinking. (or clearly wasn't thinking...).

Here's the actual hookups at the house (RV) battery:
Negative Terminal:
FAT BLACK WIRE: Is definitely a major chassis ground wire. It runs for a total length of only about one foot, and is a direct connection in between the house battery negative terminal and a bolt that secures it as a ground to the metal floor of the van.
SKINNY GREEN WIRE: Still no idea what this is. It runs off and away under the carpet to.....somewhere.

Positive Terminal:
MEDIUM-WEIGHT RED WIRE 1: Runs off and under the floor...to somewhere.
MEDIUM-WEIGHT RED WIRE 2: Runs to the RV-electricals fuse block.

[boywonder]

Originally Posted by MountainBikeRoamer

FAT BLACK WIRE: Is definitely a major chassis ground wire. It runs for a total length of only about one foot, and is a direct connection in between the house battery negative terminal and a bolt that secures it as a ground to the metal floor of the van.

So is the black cable connected to the van body or van chassis? The body is sitting on the frame with rubber pucks sandwiched between them......you want the black wire connected to the frame......even if it's connected to the body.

[MountainBikeRoamer]

Originally Posted by boywonder

So is the black cable connected to the van body or van chassis? The body is sitting on the frame with rubber pucks sandwiched between them......you want the black wire connected to the frame......even if it's connected to the body.

Hey, I follow ya.
(and I've had a good night's sleep too...)

This is getting interesting.

The fat black wire that runs from the house battery terminal is **definitely** bolted to the floor. In fact, the SMB-installed carpet in this area has a very-deliberately-sliced-open window made to allow the end of said black wire to bolt directly to a shiny/clean area of the floor (it looks like it's the forward edge of the rear (driver-side) fender-well.) And it looks like quite a few other electricals share this same ground point.

Photo of the not-exactly-house-beautiful area shown here:



(*** also shown in this pic: Skinny green wire running over along the floor on the right, and out/under the wood paneling (grouped with a bundle of skinny red wires) --- this is the previously-mentioned "skinny green wire" that also runs from the house battery negative terminal.)

AND SO --- if that big black wire is indeed bolted to the *body of the van*......
....then am I correct in now seeing it....that it's likely one of two possibilities going on here?

THEORY 1:
For this fat black wire to be grounded to the body of the van, there must also be a similarly-sizable second wire (somewhere) that grounds the body of the van to the frame? (Thus completing the ground circuit?)
**I did look** under the outside of the van (directly under the area where those ground wires bolted down to the floor) but didn't see anything other than the other end of the bolt....so I'm guessing for this possibility to work, I've got to head to the engine bay....)

**OR**

THEORY 2:
The second, small green wire running away (and off:under the carpet somewhere unknown) from the house battery terminal - is it possible that THIS is the chassis ground instead? (looks a bit skinny to handle that duty IMHO however....)

[86Scotty]

What I see is pretty typical for 95, and it's not bad, it's just old and needs updating and cleaning up. I would pull all of those grounds loose and clean up every terminal and using a wire wheel (on a drill) to polish the floor really good, both sides if you can get to the underside. Then I would add a foot or so of 4 gauge grounding cable on the other side of that big ground bolt from the bolt/underside of body to the frame near it. Don't forget to clean up the frame where you bolt to it. No drilling required probably, just wire brushing on the frame. There are a million available holes in the frame from the factory. You can surely find one close. You CAN'T over do your ground, you can only help. Spray over all of your new shiny connections with some kind of cheap spray paint or something so they don't rust.

[boywonder]

Originally Posted by 86Scotty

I would pull all of those grounds loose and clean up every terminal and using a wire wheel (on a drill) to polish the floor really good, both sides if you can get to the underside. Then I would add a foot or so of 4 gauge grounding cable on the other side of that big ground bolt from the bolt/underside of body to the frame near it. Don't forget to clean up the frame where you bolt to it. No drilling required probably, just wire brushing on the frame.

You CAN'T over do your ground, you can only help.

^^^^what he said......you'll need to remove the paint on the frame around the hole that you are going to use.....and use a lockwasher to bite into the metal.....for bonus points remove the paint on both sides of the hole and use a lock washer one both sides......star type lock washers are best for grounds...lots of teeth.

Well.......you can overdo grounds in the car stereo dept........and create ground loops...they show up as hum in the speakers.

That small green wire does something but I doubt it's your chassis connection.....

[MountainBikeRoamer]

Originally Posted by boywonder

^^^^what he said......you'll need to remove the paint on the frame around the hole that you are going to use.....and use a lockwasher to bite into the metal.....for bonus points remove the paint on both sides of the hole and use a lock washer one both sides......star type lock washers are best for grounds...lots of teeth.

Well.......you can overdo grounds in the car stereo dept........and create ground loops...they show up as hum in the speakers.

That small green wire does something but I doubt it's your chassis connection.....

Thanks you guys........

Hey -- while I'm doing all of this, is it advisable (or worth it?) to also replace the house-battery-to-chassis black ground wire pictured in the most recent photo? (Or....is that unnecessary, and do those RV-electrical-related wires not typically have much performance loss (over the span of 20 years) in their protected, inside-the-van environment?)

I ask only because I grew up in the East (New York State and Michigan)....and know that on the 20-year-old cars I had back there, the original underhood battery cables didn't stay pristine (or perform very well any more.)

[daveb]

Corrosion can cause intermittent issues with connector surfaces and the crimps. Even vibration can loosen a standard pressed crimp or bolted connection. They don't have to look bad to actually be failing.
BTW There are a number of (different sized) frame to ground jumpers on my van. You want the battery grounds to be rated for the correct amperage. Whether or not to replace is questionable but cleaning and inspecting while you're in there or close to it is always a good idea.

[86Scotty]

Originally Posted by MountainBikeRoamer

Hey -- while I'm doing all of this, is it advisable (or worth it?) to also replace the house-battery-to-chassis black ground wire pictured in the most recent photo? (Or....is that unnecessary, and do those RV-electrical-related wires not typically have much performance loss (over the span of 20 years) in their protected, inside-the-van environment?)

It looks good to me but replacing would be cheap insurance. If you replaced you could just go with one through the floor to the frame.

[capnkurt]

Originally Posted by boywonder

...that would be voltage.......

measure the voltage across the house battery with the engine revved up a bit.

Consider replacing your isolator with a Blue Sea Separator....won't suffer from the .7V diode drop and these don't have coils to heat up and burn power.


I used this one....basic...actually came with a manual switch as well...called an "add-a-battery" kit



The ML-ACR style ones are really popular here...they have a number of nice features/functions but are about twice the $$ as the one above

Hey Mike, sorry to hijack the thread here, but I figured this is a question that you probably would want answered in case you find that the isolator has become faulty...so, can these battery separators that Boywonder linked to be located under the hood? Specifially, if someone were to be interested, let's say, in mounting it in exactly the same spot at the original surepower isolator on the radiator core support/front bulkhead?

capn