House charging while driving

n0ukf · 05-11-2018, 11:10 AM

I have seen mention in other forum topics saying that the boost relay gets energized to charge the house batteries when the engine is running but looking at the wiring diagrams ('96-97 Adventurer) I can see nothing connecting this to the ignition. In fact, I can't even find the ignition switch or alternator on any of the automotive diagrams. Where are they?

70ChevelleSS · 05-13-2018, 11:24 AM

Not sure on the wiring diagrams. As far as engine alternator charging the house batteries, yes it should. Once the chassis battery is full charged then it should start charging coach batteries.

n0ukf · 05-13-2018, 06:43 PM

We tested this yesterday and it does charge, but I still want to see a diagram that includes the ignition and automotive charging system.

70ChevelleSS · 05-15-2018, 08:10 AM

You have a battery control circuit board somewhere, typically close to the batteries. This is where the battery disconnect solenoid(s) are as well as the boost solenoid/relay. House and chassis batteries are connected to opposing sides of the relay. Find the battery control center and see what type circuit board you have. Then you should be able to find a schematic for it.

l1v3fr33ord1 · 05-15-2018, 03:21 PM

n0ukf-

Your initial post covers two topics.

1) Location of automotive wiring details
The Winnie Automotive Wiring Diagram (typical for 1997 Adventurer 34 here) is intended to show wiring that Winnie provides once it has picked up the signals from the chassis builder. Put another way, the Winnie diagrams are not meant to take the place of the chassis builder's design and service documentation. Note also that the Winnie diagrams can cover multiple chassis builders in a single diagram set.

2) How the AUX BOOST (AUX START) solenoid gets ignition-switched power
The place to always start looking is the AUX BOOST solenoid. On the Automotive Wiring Diagram listed above, for the Chevy chassis the solenoid is on Sheet 1, Zone C-3 (note: Sheet 1 is page 2 of the PDF). The "pickup" signal for the solenoid comes on circuit "LR." (How would you know? It always comes on circuit "LR." The secret decoder ring- link here- says so.) Follow "LR" and you'll eventually come to the AUX BOOST/AUX START switch. That switch has two leads. One, "LS," comes from the chassis batteries. The second, "KE" is an ignition-switched chassis battery source. Follow "KE" and you'll eventually see where it gets its 12V- often from a fuse in the chassis-supplied fuse panel.

So, the switch works this way: In one position, "KE" supplies "LR" when the ignition is on, activating the "AUX BOOST/AUX START" solenoid and tying the two battery banks together. In the other position, 12V from the chassis batteries via "LS" supplies "LR," with the same effect. One has to assume the switch is in default position for "KE," and momentary for "LS," to make things work as expected.

Although "KE" may have a different source for each chassis (Chevy, Ford, Freightliner, etc.), the circuit is the same once it hits the switch.

powercat_ras · 05-15-2018, 10:36 PM

On a 96-97 there should be a large battery isolation relay (BIR) that is controlled either by manuall forcing to operate from a dash switch labeled battery boost or similar, and by a control module that is voltage based. If there is charging voltage over 12.8 volts or so on one side and the other side does not have charging voltage ( 12.6 volts or less ) then the module will operate the BIR. You likely have heard the loud "clunk" it makes when it operates and when it releases, that you may be able to find it by following the sound.

Generally, Winnebago locates the BIR and the control module within a Chassis Electrical Box that has large number of circuit breakers on the front of the box.

l1v3fr33ord1 · 05-16-2018, 04:51 AM

Randy-

Neither the wiring diagrams nor the owner's manual for the 1997 Adventurer indicate there is a "control module" that connects house and chassis battery banks for combined charging.

You are correct in that there is a large solenoid, which you call a "battery isolation relay" and I call an AUX BOOST/AUX START solenoid in post #5. As described in that post, the solenoid gets its activation signal from the switch, only.

Modern coaches often have cross-charging electronics. Given the OP's coach is 20 years old, it's possible a prior owner has added an aftermarket cross-charging device to his coach.

n0ukf · 05-18-2018, 02:28 AM

I know where the AUX START and house battery disconnect relays are, "under the hood" on the driver's side. I've had the box open once so far to add a connection for solar panels at the front end of the coach. I'm planning to also add a solar connection to the rear end to give us placement options (which end will be pointing south?) when boondocking. No, we are not going to mount fragile solar panels on the roof where hail can get at them. On the ground we can quickly move them under-cover if needed, and store them in the basement off-season.

jerichorick · 05-25-2018, 08:27 AM

Could you please give us a bit more info about your rig? What model is it? What Model Year? Be specific since there are so many 34' models to look at wiring diagrams on.

tderonne · 05-25-2018, 09:55 AM

Quote:

Originally Posted by n0ukf

I know where the AUX START and house battery disconnect relays are, "under the hood" on the driver's side.

The AUX START relay is the isolator/connection relay. It's triggered by the aux start switch, or ignition power, it's that simple. They are known to fail, so good to know where it is.

As for where you find them in the diagrams. The Ford wiring is not in the Winnebago drawings. But you should be able to find a wire from the relay, looks like it'd be circuit LR that powers the relay from the aux switch. Circuit KE, ignition power, is at the switch when it isn't pressed.

n0ukf · 05-26-2018, 07:40 PM

Quote:

Originally Posted by jerichorick

Could you please give us a bit more info about your rig? What model is it? What Model Year? Be specific since there are so many 34' models to look at wiring diagrams on.

'97 Adventurer 34WA ('96 Chevy chassis, 7.4l TBI)

Quote:

Originally Posted by tderonne

The AUX START relay is the isolator/connection relay. It's triggered by the aux start switch, or ignition power, it's that simple. They are known to fail, so good to know where it is.

As for where you find them in the diagrams. The Ford wiring is not in the Winnebago drawings. But you should be able to find a wire from the relay, looks like it'd be circuit LR that powers the relay from the aux switch. Circuit KE, ignition power, is at the switch when it isn't pressed.

I can find the relays on the diagrams (body and chassis) but I have not seen any ignition switch or alternator (or other engine side wiring) on the chassis pages.

GearJerker · 05-26-2018, 10:00 PM

Quote:

Originally Posted by powercat_ras

On a 96-97 there should be a large battery isolation relay (BIR) that is controlled either by manuall forcing to operate from a dash switch labeled battery boost or similar, and by a control module that is voltage based. If there is charging voltage over 12.8 volts or so on one side and the other side does not have charging voltage ( 12.6 volts or less ) then the module will operate the BIR. You likely have heard the loud "clunk" it makes when it operates and when it releases, that you may be able to find it by following the sound.

Generally, Winnebago locates the BIR and the control module within a Chassis Electrical Box that has large number of circuit breakers on the front of the box.

Randy can you speak a bit more about this? My 2018 hasn't been charging the house batteries except for the first start of the morning and now I wonder if this is the culprit. Are you saying that if the coach batteries are more than 12.6v, the solenoid will not engage? I've had situations with lower voltage where I started and ran the engine for a bit and after dumping when I restarted the engine the coach batteries didn't receive a charge.

GJ

jerichorick · 05-29-2018, 08:57 AM

Quote:

Originally Posted by n0ukf

'97 Adventurer 34WA ('96 Chevy chassis, 7.4l TBI)

I can find the relays on the diagrams (body and chassis) but I have not seen any ignition switch or alternator (or other engine side wiring) on the chassis pages.

Thank you. Look at these two diagrams: http://www.winnebagoind.com/diagram/1997/123182.pdf

http://www.winnebagoind.com/diagram/1997/123808.pdf

I believe the BATTERY MODE relay is the failing component. This is what I found at Amazon that will work for you: https://smile.amazon.com/DB-Electric...minal+solenoid

Have had to replace a couple of these on other coaches.

Switchflicke · 05-30-2018, 03:37 PM

My 'Boost' solenoid failed last year. It made the clunking sound and would on occasion allow the house battery to get a bit of a charge. Mostly it would not though.
I replaced mine with an Echlin ST-95. If I remember correctly there is another Echlin ST-?? with gold contacts and a bit higher amp rating. Good thing about the Echlin is you can get one fairly locally
Stan