House batteries not charging from chassis (SOLVED)

[BruceMc]

2016 Sunseeker 2250S (Forest River) on Chevy chassis:

Last year all was fine - the house batteries were being charged from the chassis any time we were underway.

We have a 2 1/2 week run coming up shortly, and I'd like to fix this issue before we depart...

This year, we've had two trips, and while I don't know if this was an issue on the first run over a weekend but we noted the following on our recent 5 day run:

We boondocked the first 3 nights, and noticed the chassis battery voltage was running in the 12.2 to 12.0 range where it should have been 12.8 to 12.4.
I ran some tests and found the batteries were not being charged while underway - the chassis was running at 13.8 to 13.4, yet the house batteries never increased.

Only when we plugged into shore power did they come up to the (charging) values in the 13.* ranges, then standing charge after several hours off shore power was 12.8.

Something is wrong.

The 2250S Sunseeker has a Precision Circuits 00-10033-300 FR BCC, of which I can find no documentation or troubleshooting information.

Even the relay was not clicking when pressing the emergency start switch located on the base of the drivers seat - we found that a fuse had not been plugged into the correct socket (apparently during assembly). Once a fuse was installed in the proper circuit - we now have a functioning emergency start.

The circuit breaker under the hood is not tripped - we have 12v from the chassis at the BCC. When pressing the emergency start - the house voltage jumps up & matches the chassis.

There seems to be no voltage on J12 labeled "Ignition In" while the engine is running, even after several minutes.

We tried jumping power to J12 but the system shut down. I had installed a volt meter last year in the convenience center so we could monitor the actual voltage - it and all other 12v items disconnected. Interesting.

There has to be an ignition in to tell the BCC to connect the two systems...

Here's the panel:




If you experienced this issue, what did you do to correct it?

I've posted this note on forestriverforums.com - Sunseeker as well to see if I get assistance there - if so, I'll report back here on results.

[mchero]

Good job, thanks for the writeup.

[BruceMc]

Success! I found a switched lead in the uplift wiring (ambulance, RV, etc) cavity behind the drivers seat; it was right next to the orange that had been snipped from the connector. Odd that I never found a fuse for it....

All has been buttoned up and is in working order. I learned a lot, and hope that it will help others with a Precision Circuits BCC/BIM. There's a lot going on in that box, but with a little understanding of the theory of operation, it's much easier to troubleshoot & fix.

Thanks everyone!

[BruceMc]

Update: After further discussion with the tech, I learned the following:

The left side of the circuit board cuts out when ignition is present. This side includes things like the slide (or slides, if you have more than one. This panel supports 4 slides!), and the electric awning. (wouldn't want a child to deploy the awning while you are underway, right? hee hee)

Given that information, I tested this theory. The small relay(s) I hear are the slides/awning circuits. All lights and other items work fine while this terminal has 12v.

Next test: jumper the panel, start the engine and wait for the time delay. I've been running fans all day to reduce the house battery voltage; it has been at 10.6 for several hours now.

Once I've proven the BCC, all I need to do is find the issue with the chassis ignition source, or find a new one... That's all I need to do.

[BruceMc]

Precision Circuits Tech replies:

"You are correct about the orange wire. It should be connected to Ignition just as you describe. Without the Ignition signal, you will have exactly the problem you describe, the House battery will not charge."

Therefore that is confirmed. I need to find another source of switched ignition or find the issue with the chassis connection.

Second, but more important, is what happens when jumpering chassis voltage to J12.
The tech hasn't replied on that one, but kudos to them for replying this late in the day!

[enblethen]

Here is a later version of your battery control center. I can see that there are insulated studs passing through the housing.
Battery control center

[BruceMc]

It appears to go to ground, but that's an isolated terminal. Both batteries use the same isolated terminals, only much larger.

The terminal on the green wire is the converter/charger.

[enblethen]

Why do I see a green wire from circuit breaker going to ground?
Looks like the potted device on the right could be the battery charge controller.

[BruceMc]

I've chased the wires. Gray/Tan go to the loom where they are tied to yellow/green which is connected to the emergency start switch.

Red jumps from the circuit board to the BIM.

Orange goes to red in the loom, which then follows the orange/green pair. It enters the cab just behind the drivers seat in the filler on the left. At the base of this filler, there is an uplifter loom, near as I can tell. The red is spliced into a small orange in the factory loom.



I checked this lead - no voltage while the ignition is on or when the engine is running. All fuses in both the underhood panel & under drivers seat panel check ok; none are blown. (both panels are difficult to get to & the underhood one is particularly difficult to remove the covers. Be sure to remove the short one on the left, then the main one. shame on GM....)

While tearing into panels & under the floor mat, I found a ton of assembly scrap - shame on Forest River.

So, other than knowing where the wires are run to, and which wire does what, I'm no closer than I was. I have two specific issues:

1) No ignition power on the orange.
2) A jumper from chassis power to J12 shuts down the 12V branch - all goes dead until I remove the jumper. One of the small relays clicks solidly when I jumper the connections - but not the large solenoid.

I need to find a chassis schematic to see where that orange heads off to... and perhaps build up a new charging solenoid with a different brand.

However, I'll contact Precision Circuits with this info - perhaps they have suggestions on the setup. They won't know about the chassis to loom wire, but they should know the function of the orange in the BCC.

Fun.

[Ivylog]

There is a BIRD in the system that tells the Isolation relay when to engage...usually after the engine batteries get to 13.4 V. May be made by Intelatech.

[MEXICOWANDERER]

One snap-to-install Sure Power battery isolation relay cures the turks head knot of wire snarl forever.

[pnichols]

The relay can be closing just fine, but the house batteries still not hardly charging when driving.

The has happened to us a couple times in the last 10 years. The problem was corroded contacts on the relay such that a too-high resistance in the contacts was drastically reducing the charging current going into the house batteries.

Our solution was to install a new relay to solve the problem both of those times.

I now have a meter right on the cab dash that shows me when this is happening so that I don't get surprised by this happening any more.

[BruceMc]

Bobbo wrote:
You need a switched, fused hot wire run to ES. You may need to trace the factory wire to find where it is broken or has a blown fuse.

This is my opinion as well. There has to be 12v on the ignition in circuit!

Yet when trying to work around the issue by jumping power from the chassis positive to the ignition in, the house 12v system shut off as if it was in fault condition.

I'll pull the ignition wire & test if it has voltage while disconnected, and will try the jumper test again. My friend was doing the tests on the BCC so I want to validate them firsthand.

[BruceMc]

I wondered if my wording might confuse... I'm as guilty as the next person when I read - I need to completely read & understand before responding.

The relay is working - it clunks/closes with the emergency start switch after we moved the fuse into the correct location, and the voltage jumps up to match the chassis.

Here's the complete sentence in the original post:
"Even the relay was not clicking when pressing the emergency start switch located on the base of the drivers seat - we found that a fuse had not been plugged into the correct socket (apparently during assembly). Once a fuse was installed in the proper circuit - we now have a functioning emergency start."

[Bobbo]

If the relay had failed, the emergency start switch would not work. But I agree that it has lost power from the engine.