Engine batter not charging while on shore power.

tommymsw · 03-13-2018, 12:14 AM

I have a 2000 Adventurer 35B (new to me) and I just noticed that the engine battery is not charging while on shore power. The house batteries do.

My old crappy '84 Chevy class C did charge the engine so I figure this one would also.

Now... I "feel" like it used to? When I was plugged into shore and checked the voltage, it would read 13.8 (while charging) just like the house batteries.

But now all I see is 8.6!

Was it never set to charge and I was wrong? Or could I have messed something up?

70ChevelleSS · 03-13-2018, 07:37 AM

From the factory chassis battery will not be charged by the converter. You can install a Trik-L-Start type device that will charge the chassis battery once the coach batteries are charged. Winnebago should have added this at the factory or at least provided a chassis battery disconnect switch. My 1994 Bounder had disconnect switches for both chassis and coach batteries.

rk911 · 03-13-2018, 09:25 AM

we’ve had 3-winnebago class a motorhomes and none of them were equipped to charge the chassis battery while hooked to shore power. i installed a TRIK-L-START Starting Battery Charger/Maintainer which took care of that. but 8.6 is indicitive of a dead battery. i’d also have that tested and replaced if need be.

Old Crows · 03-13-2018, 10:30 AM

That's the way about 99% of modern RV's work. Genny & shore power only charge the coach battery bank. The engine alternator charges both coach and chassis batteries.

Solar? You got to check your manual. May charge both or may only charge the chassis batteries.

l1v3fr33ord1 · 03-13-2018, 01:27 PM

tommymsw-

According to a wiring diagram for your coach (link here), it has a BATTERY MODE SOLENOID inside the electrical box "above the step" (PDF page 2, which is drawing sheet 1, Zone D-4). If that solenoid is wired the usual Winnebago way, it will be activated when the coach engine is running,or when the DUAL BATTERY (a.k.a. "AUX BOOST" or "AUX BATT" or "BATT BOOST") switch is pressed. So, underway the alternator will charge the house batteries, if everything works as designed.

The diagrams do not appear to show any factory-installed connection or equipment that would charge the chassis battery from the house battery charging system(s). My reading of the diagrams could be incorrect.

Your coach is old enough that someone may have added a device (such as the Trik-L-Start) to allow the house battery charging systems to charge the chassis battery. A logical place to look for one would be near the BATTERY MODE SOLENOID.

The two posts of the BATTERY MODE SOLENOID are convenient places from which to measure the chassis and house battery voltages.

tommymsw · 03-13-2018, 03:15 PM

I think why I read a charge on both sets of batteries before was from the 10W solar panel on top. It must charge both sets? However, when I looked at night, only the house batteries were charging. So I am guessing the shore did the house and the solar did both or just the engine battery.

I know 8.6 is BAD, but the battery "was" fine for the last month or so. But I have been fixing and repairing the RV, so taking a lot of short trips in town and sliding out the slide out and testing the leveling hydraulics (I think uses chassis battery). I wasn't worried because I assumed the shore power charged it. Now I know!

tommymsw · 03-13-2018, 03:19 PM

That Trik-L-Start seems amazing! I ignored it because I figured it would be a pain to install... Thinking it replaced the current charging system. I am glad I clicked on the link RK911 placed and saw how easy it was to install. Genius idea by somebody! I will install one!

70ChevelleSS · 03-14-2018, 07:22 AM

Our solar panel only charges the coach batteries. When it's going to sit for a while I jumper the coach batteries to chassis battery. With the coach batteries disconnected the solar panel will keep all the batteries charged up.

BobC · 03-20-2018, 10:30 PM

When I install solar, I'm going to install a controller that will support two battery banks.

Tom-NC · 03-26-2018, 06:42 PM

Hi,

My 2014 35P charges both coach batteries and chassis batteries. It normally charges the coach batteries but when it senses the chassis battery is low it also charges that.

To be safe as the electronics may cause a problem I installed a trickle charger and I don't have to worry about any of the batteries.

Good Luck!

tommymsw · 03-28-2018, 10:47 AM

So I ordered the Amp-l-start. Now, would anybody be willing to help me figure out where to install it? I was just going to install it at the batteries (easy) but it says it is better to install "to terminals on your battery isolator or emergency start relay". I get what they are saying, I just have no idea where those are... My small class C was EASY to find things.
I see "to" and "from" relay on the schematics, but I do not see the actual relay location. I'd like to know where both locations are so I can decide what place is easier and better.

While I can read these a "little", I am no expert! http://www.winnebagoind.com/diagram/2000/131755.pdf

tommymsw · 03-28-2018, 06:57 PM

Never mind.... I noticed it was CLEARLY labeled INSIDE the RV. I love Winnebago! (No idea how to delete my last post)