Secrets of the 92-96 Auxiliary Battery Set-Up

Electrical issues, both 12 volt and 120 volt
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Planck
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Secrets of the 92-96 Auxiliary Battery Set-Up

Post by Planck »

I have read all of the great posts in the electrical section and have not seen this issue discussed. Hopefully you will not run into this problem, but if you do, maybe this post will speed up the solution and fix. I recently "upgraded" from a perfectly fine 91 model(except for the rust around the bottom perimeter up about a foot) to a 1993 pretty rust free model 190. I traded in at a dealer and did not realize the extent of the house battery problems until we got home and I started going through the various systems. Anyway, it had 3 batteries, with the 3rd being added under the folding bed/seat which others have done. The strange part I discovered after getting home was that the vehicle battery was also tied into the house system, making 3 house batteries, one being shared to start and run the engine. Niether of the house batteries were any good, thus the reason for the jumper to the vehicle battery(see picture with jumper wire disconnected).

Image

The Delco group 27 marine battery under the seat is dated 1999 and will not take a charge(no surprise there). The auxiliary battery under the hood is not a deep cell battery but a conventional lead acid that fits in the narrower space. There is no liquid in any of the cells. I have decided to go with just a sealed group 27 under the seat and eliminate the house battery under the hood. I have removed the jumper wire from the main vehicle battery that tapped into the house battery terminal(more on that in a minute). A disconnect switch had been added to the vehicle battery and I found out why after not disconnecting it. The battery will drain in about 4 days. Put an ammeter on the battery and it is drawing .25-.30 amps somewhere. I disconnected the house jumper and the amp draw dropped way down to what I would consider normal(radio time and pre-sets, etc.). So something in the house is drawing .25 amps all the time. Maybe a detector as in a previous post. I think it was the 12 year old group 27, because after removing it the current leak went away. I assumed someone(possibly dealer) tapped into vehicle battery to avoid needing to replace the house batteries. Further testing revealed no power to the house batteries with engine running.

Fortunately the first thing I did when I got home with this 93 unit was to order the 3 volume set of factory workshop manuals. Behind the drivers(left) headlight is a auxiliary battery relay(see picture).

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After removing the headlight I tested this relay and it works when the engine is running. But there was no 12+ volts coming into the relay from the alternator with the engine running. Further review of my manuals(needed to go back and forth between two of them to get all the info) revealed that fuse T in the engine compartment fuse panel is between the alternator output and the auxiliary battery relay. Fuse T is a 60 amp fuse( a big blue jobbie)! I located the engine compartment fuse panel between the engine and master cylinder, under the coiled brake lines(see picture).

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The cover is a little tricky to get off(had to pull up on the brake lines and move another larger hose out of the way). The fuse locations are identified and I quickly found slot T. Had to use a pair of soft nose pliers to pull it out. Sure enough, it was blown. So tomorrow I will head to local auto parts store in search of one of these big blue fuses.

It is now tomorrow and I have 2 new 60 amp fuses. Put one in slot T and now have charging power to both house batterie locations when engine is running.

I have also ordered the converter upgrade from BestRV to replace the Megatek unit and fuse panel.

Now I have a favor to ask of you 93-96 owners. Under the hood on the left fender well by the firewall is a two terminal block that the auxiliary(house) battery cable attaches to(see picture).

Image

I assume this was added by Airstream. Does you 190 have this? My auxiliary battery cable attaches to the forward terminal(along with the main battery patch cable). There are two cable leaving the rear terminal going down under the firewall. One of these goes to the converter(in my case also to the house battery under the seat). I have not been able to determine where the other one goes. Anyone know where it goes? I checked the trailer connections and it did not go there.

I will add some more pictures showing how I removed the battery cables from the auxililary battery location under the hood, and ran the cable from the auxiliary relay directly to the terminal block. This way there is no chance of anything wearing and shorting out at the unused battery location.

So, now you may know a little more about how and where charging power gets to your house batteries, plus, in a pinch you can jumper to your engine battery to get house power.

And thanks to Skater for teaching me how to post pictures.
Keystone
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Post by Keystone »

Belatedly, I can answer one of the questions posed in your May 5, 2011 post.

Quoting you: "Now I have a favor to ask of you 93-96 owners. Under the hood on the left fender well by the firewall is a two terminal block that the auxiliary(house) battery cable attaches to. Does your 190 have this? My auxiliary battery cable attaches to the forward terminal (along with the main battery patch cable). There are two cable leaving the rear terminal going down under the firewall. One of these goes to the converter(in my case also to the house battery under the seat). I have not been able to determine where the other one goes. Anyone know where it goes?"

Yes, my 1994 has this same terminal block, and wiring to it is configured the same way ad yours--the forward terminal wire comes from the coach battery, and the rear terminal has the two cables that go under the firewall. Sorry, I do not know where they go.

Your post and pictures are so helpful as I try to puzzle out why the coach battery in my vehicle is not charging. Neither does it charge from the converter when plugged into shore power nor, apparently, does it charge from the alternator. I'm not sure if it would charge from the generator because genset is not starting for some reason.

So, I am going to try to look at that fuse that you identified to see if that's it. I can live without the converter in the short term b/c I now have a new battery charger specifically designed to charge my AGM coach battery, so I can top it off before and after short trips. I have yet to camp where there is shore power. But alternator charging would be, uh, nice.

Back to the converter, I am thinking of installing the converter upgrade--maybe a fall project...sigh. There seem to be two out there: the Best that you used, (45-A appears to be the smallest) and the InteliPower PD4635 (a new product that comes in a 35-A rating). My converter, and I suspect most of ours in the early 1990's, was a 32-A Magnetek 6332. I wrote to InteliPower to ask if their unit would work for me, and they said, "The 6332 is not listed because the PD4635 is a 35 amp output charger. We cannot list a higher output charger to replace a lower output unit, because of the different wiring requirements and the danger of fire."

Is this just CYA? Hmmm... I suspect you are using a 45-A upgrade, and Skater, IIRC, is using a 60-A upgrade. Did you replace all the wiring to match the current carrying capacity of the upgrade? Somehow, I can't believe that the 3A difference from 32 to 35A is that big a risk, but I am interested in your opinion(s).

Thanks again for such a great post. Love the pictures!




[/quote]
Keystone
1994
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Planck
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Post by Planck »

I did not replace any wiring with the Best upgrade, nor did they advise to do so. That is pretty heavy wire already being used. Can't imagine there being a problem. Good luck getting the alternator to charge the coach battery. Hopefully it is just the fuse. I would make sure the coach battery is pretty well fully charged once you get the alternator problem fixed, before testing, as there is a possiblity of two low batteries, which could put quite a load on the alternator.
Keystone
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Post by Keystone »

Good to know. I'm not going to worry about the wiring; will likely buy the 35-A model for the converter upgrade when I'm ready for that project, and I will make sure the batteries are both pretty full before I implement the possible alternator problem fix. Thanks for the help.
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skater
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Post by skater »

Keystone wrote:Is this just CYA? Hmmm... I suspect you are using a 45-A upgrade, and Skater, IIRC, is using a 60-A upgrade. Did you replace all the wiring to match the current carrying capacity of the upgrade? Somehow, I can't believe that the 3A difference from 32 to 35A is that big a risk, but I am interested in your opinion(s).
No. The 60 amps is the maximum amount of DC power (12 volts) the converter can theoretically produce. It's not like you're adding a ton of 12 volt accessories to the van that will suddenly start drawing that much more power, and the accessories are already fused* to the amount their wires can handle.

In practical terms, the converter still only produces the amount of power (in terms of watts or amps) required to run the lights/appliances being used, plus charging the battery. Ergo, no wiring upgrade should be necessary.

* - Some aren't in mine, like the captain's chairs. Sigh.
1991 Airstream B190 - bought, 2005; sold, 2011; bought 2017
1995 Airstream Excella 30' trailer

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chadseld
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Post by chadseld »

Here is what I figured out while installing my solar system in my '93.
There are two cables that come off the positive terminal of my under-hood house battery.
The first cable snakes under the main starter battery and I assume connects to some circuit for charging via the vehicle alternator.
The second cable runs to the terminal block you mentioned. From the terminal block, there are two cables, both of which run under the firewall.
The first of these cable goes to your converter panel under the couch. The second goes directly to the generator, for starting the generator.

When installing my solar system, I could not fit a large deep cycle battery under the hood so I put one under the couch. I used an AGM battery and a battery box to be safe.
I left the house and generator cables attached to the terminal block under the hood, so that I can still use my new deep cycle battery to start the generator. Only now the power takes a bit longer to get there :)
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Planck
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Post by Planck »

Aha - the second wire goes to the generator. Thanks for finding that out. I always wondered where it went.
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skater
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Post by skater »

chadseld wrote: The first of these cable goes to your converter panel under the couch. The second goes directly to the generator, for starting the generator.
Slight correction here - not only is it used for starting, but the generator for some reason must see 12 volts on that line while it's running or it will shut down. I don't know why, but that's how mine works. If you start the generator, then disconnect the battery and shut off the breaker for the converter, the generator shuts down. (I forget why I was doing this. But I had a good reason at the time!)
1991 Airstream B190 - bought, 2005; sold, 2011; bought 2017
1995 Airstream Excella 30' trailer

WBCCI #13270, Washington, DC Unit
Keystone
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Re: Secrets of the 92-96 Auxiliary Battery Set-Up

Post by Keystone »

Add my name to the list of grateful "Fuse T replacers". That 60-A fuse blew recently, resulting in no alternator charging of the coach battery for about 600 miles. Was completely dead-on-arrival at campsite since we'd been (or thought we were) running fridge on 12-V. Sigh...Once again, I've been saved by Planck and his handy pictures and narrative in this thread that saved me hours of tracking down this issue. Thanks!! -Keystone
Keystone
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Planck
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Re: Secrets of the 92-96 Auxiliary Battery Set-Up

Post by Planck »

Keystone
Actually you have been saved by Skater and this great, but small forum he maintains for us B190 owners and caretakers. Without his efforts, none of this info would be available. A great resource!

Thanks Skater
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Re: Secrets of the 92-96 Auxiliary Battery Set-Up

Post by PeterH-Airstreamer »

Reviving and older thread. I found my solenoid behind the drivers side headlamp to be non functioning, ordered a replacement continuous duty solenoid to fix my coach battery charging problem (COLE HERSEE 24106-BX - 24106).
I noticed a second solenoid just forward of the chassis Battery . Does anyone know what this Solenoid does. The S terminal is not hot with ignition on. 1 terminal has leads to: 1. Alternator 2. chassis Battery 3.the solenoid behind the headlamp
the other terminal has no power and I can't follow where it goes, it seems to disappear under the dash
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Planck
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Re: Secrets of the 92-96 Auxiliary Battery Set-Up

Post by Planck »

You don't mention what year you have. That does not look like a solenoid to me, maybe a large terminal connector. Could be wrong about that. Sold my 92 last week and all the Ford manuals went with it, so hopefully someone else can help figure it out.
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Re: Secrets of the 92-96 Auxiliary Battery Set-Up

Post by PeterH-Airstreamer »

Planck wrote:You don't mention what year you have. That does not look like a solenoid to me, maybe a large terminal connector. Could be wrong about that. Sold my 92 last week and all the Ford manuals went with it, so hopefully someone else can help figure it out.
its a 1996. It definitely is a solenoid with 2 main post and the small S terminal
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con5
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Re: Secrets of the 92-96 Auxiliary Battery Set-Up

Post by con5 »

Hello all, new here with a recent purchase of a 1998 b-van. Where is the stock auxiliary battery located. I can’t seem to find it but it is working! It’s too hot right now in Texas to keep poking around.
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Millennial Falcon
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Re: Secrets of the 92-96 Auxiliary Battery Set-Up

Post by Millennial Falcon »

con5 wrote:
Sun Aug 30, 2020 5:03 pm
Hello all, new here with a recent purchase of a 1998 b-van. Where is the stock auxiliary battery located. I can’t seem to find it but it is working! It’s too hot right now in Texas to keep poking around.
I believe it is in the same spot on all the years? If so, when you open the hood there should be two batteries. The battery on the PASSENGER side is the Coach Battery (for all the lights and stuff in the "house" part of the van). The battery on the DRIVER side is your engine's battery, used for starting the engine and running your car radio.
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