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House battery not charging from alternator

Posted: Wed Dec 30, 2009 7:16 pm
by OnTheRoad
My house battery is not charging from the van's alternator. This is in a 1990 b190.

The alternator itself is working fine and is keeping the chassis battery charged up. Also I can use the generator to charge the house battery.

I was looking through the old yahoo forum, and saw someone else reporting the same problem but didn't see a resolution.

Any ideas on where to look to fix this? I was looking for the battery isolator, and in the engine compartment found the starter solenoid which is right next to the chassis battery and works like an isolator, but I'm wondering if there is another isolator hidden elsewhere on the van that might need to be fixed/replaced.

Posted: Wed Dec 30, 2009 10:04 pm
by skater
In theory there'd only be one isolator - a second one wouldn't make a lot of sense. In mine, I'm pretty sure it's right above the coach battery, but of course there's no reason they'd have to keep it in the same place between years...

Posted: Thu Dec 31, 2009 5:04 am
by OnTheRoad
Ah, I see what you're talking about. There is a relay connected to the coach battery mounted in front of the van.

I was expecting to see a box connected to a large battery cable for charging, so was trying to trace some of the other electrical cables. In my van this relay connects the + side of the coach battery (thick cable) to something like a 10 gauge cable going through the relay.

Hopefully this will be easy to trace from here. I did a quick check and see the relay itself is (apparently) working -- at least it makes a loud click if I connect the signal side to the battery.

Posted: Thu Dec 31, 2009 10:35 am
by skater
OC Eli wrote:Ah, I see what you're talking about. There is a relay connected to the coach battery mounted in front of the van.

I was expecting to see a box connected to a large battery cable for charging, so was trying to trace some of the other electrical cables. In my van this relay connects the + side of the coach battery (thick cable) to something like a 10 gauge cable going through the relay.

Hopefully this will be easy to trace from here. I did a quick check and see the relay itself is (apparently) working -- at least it makes a loud click if I connect the signal side to the battery.
When you do find the problem, please let us know - it's very strange that this has happened to two people now (and IIRC the other one was a '90, too). I'd start the camper and check for +12 volts at the relay on the wire coming from the engine's power. Unfortunately I'm not sure where that wire actually physically comes from in the engine bay.

I'd also consider disconnecting the coach battery and unplugging the camper so that you only have one source of +12 volts DC (the engine battery)...

Posted: Thu Dec 31, 2009 8:05 pm
by OnTheRoad
Fixed!

The battery isolator in front of the coach battery has three connections.

On the left, a connection to the + terminal of the coach battery

On the back, a connection to a small wire that goes to a harness connection and is charged when the ignition is on (this triggers the relay)

On the right, a connection to a thicker wire that goes to the same harness as the ignition wire, and connects to the alternator

My problem was the alternator signal was going from the alternator to the harness, but not from the harness to the battery isolator.

I think the harness also serves as a 30 amp fused connection for the alternator wire. I think this because of the 3 on the harness, the coach has a 32 amp charger, and the alternator wire looks to be 10 gauge which is also ok for 30 amps. In any case it's not a replaceable fuse.

I went to a few auto parts stores looking for a replacement 30 amp fused harness connector, but no luck finding anything that matched and nobody recognized the connector. To fix it I bought a 30 amp in-line fuse for the alternator wire, cut off the harness connector, connected the ignition wire directly to the back connector on the battery isolator, and connected the alternator wire directly to the to right connector.

Then I fired her up, and sure enough the coach battery is back to being charged by the alternator.

Posted: Fri Jan 01, 2010 9:28 am
by skater
Good find! I'm glad you were able to fix it.

Posted: Mon Feb 28, 2011 11:38 am
by jimi
Coach batter Relay on 1996 b190 is behind driver side headlight

they hide the relay under the main battery; however you can access it by removing the driver side headlight.
I checked mine, it was bad, I replaced it and all is well. now 14+ volts
I traced the Two battery leads one goes to distribution block and back to cabin. the other (the one you want) leads under main battery, but only accessible by removing headlight, having small hands, and patience.
Not sure what years beside 1996 this location applies to.

jim

House battery not charging from alternator

Posted: Wed Sep 28, 2011 2:34 pm
by baggydew
Does anyone have a part # or supplier for that battery isolator? I have a '94 model

Posted: Wed Sep 28, 2011 6:11 pm
by Planck
Your local Ford dealer should be able to provide the part number.

Re: House battery not charging from alternator

Posted: Sun Oct 13, 2013 10:02 pm
by VanDownByTheRiver
UPDATE: an Airstream dealer said the relay is a continuous duty Cole Hersee 24106 (haven't confirmed). To be clear, the relay I'm talking about is located behind, and accessed by removing, the driver's side headlight.

I'm also wondering if anyone has a part number or supplier of this relay. No luck looking for similar ones at Autozone or Pepboys today.

Thanks for saving me tons of time tracing the problem to this hidden relay guys!

Re: House battery not charging from alternator

Posted: Thu Aug 02, 2018 11:00 am
by Fmedina771
Hey I am having the same problem, I removed the solenoid behind driver side headlight to test and it seems to be working just fine. Seems like I am not getting 14v from alternator cable that goes to big post of solenoid. Anyone know where problem could be? Is there a fuse?

Re: House battery not charging from alternator

Posted: Thu Aug 02, 2018 11:58 am
by tdashmike
Fmedina771 wrote:Hey I am having the same problem, I removed the solenoid behind driver side headlight to test and it seems to be working just fine. Seems like I am not getting 14v from alternator cable that goes to big post of solenoid. Anyone know where problem could be? Is there a fuse?
Look at the update from OnTheRoad above. It looks like the harness has a built in fuse that is not replaceable that you will need to bypass.

Re: House battery not charging from alternator

Posted: Fri Aug 03, 2018 4:44 pm
by Keystone
I had this problem in my 94, and found the solution in Planck’s old thread called,Secrets of the 92-96 auxiliary battery set up. “https://b190.com/viewtopic.php?f=4&t=714
Don’t know if it’s the same in your ‘90, but this thread is worth a read. Planck found a fuse box in the engine compartment that had a blue 60-A fuse in the T-slot. Unfortunately the links to his terrific photos are gone now, but following his text description you might find that fuse in your rig.

Here was my outcome as posted back then:
Keystone wrote: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
Good luck!



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Re: House battery not charging from alternator

Posted: Fri Aug 03, 2018 11:27 pm
by Fmedina771
Keystone wrote:I had this problem in my 94, and found the solution in Planck’s old thread called,Secrets of the 92-96 auxiliary battery set up. “https://b190.com/viewtopic.php?f=4&t=714
Don’t know if it’s the same in your ‘90, but this thread is worth a read. Planck found a fuse box in the engine compartment that had a blue 60-A fuse in the T-slot. Unfortunately the links to his terrific photos are gone now, but following his text description you might find that fuse in your rig.
Thank you so much for this, Ive been searching like crazy!!! Thought I was onto something with the solenoid, took grill and front cover apart twice with no luck. Turns out the 60amp fuse for aux battery was missing, put one in and both batteries now charging!! I no longer have to drive with generator to get house battery charged. Solar is coming next.... Im new to RVs, this b190 is my first camper, I love it and very happy to be apart of this awesome community. Thanks!!!

Re: House battery not charging from alternator

Posted: Sat Aug 04, 2018 4:29 pm
by Keystone
Fmedina771 wrote:
Thank you so much for this, Ive been searching like crazy!!! Thought I was onto something with the solenoid, took grill and front cover apart twice with no luck. Turns out the 60amp fuse for aux battery was missing, put one in and both batteries now charging!! I no longer have to drive with generator to get house battery charged. Solar is coming next.... Im new to RVs, this b190 is my first camper, I love it and very happy to be apart of this awesome community. Thanks!!![/quote]

Hey Fmedina771, that’s great news! If only all our problems could be solved by replacing a $10 fuse, right? Welcome to the b190 club. Like you, my b190 is my first ever R.V., and though I love it, I’d have given up long ago if not for this great forum. Next time you repair, replace, rehab or innovate something in your new rig, please post your stories and pics here for the rest of us.

Thanks to Skater for keeping the forum alive!

Keystone (aka Cécile)