Chassis Battery Help

[lacamastraveler]

Okay, fellow Solera owners, perhaps you can help me solve a mystery. Typically we take our 2015 24R to our Arizona winter home, but this year (and perhaps future years) we plan to leave it in storage, where I have no electrical hookup.

I'm not concerned about the house batteries because the solar panel keeps them charged.

But I decided to disconnect the chassis battery and connect a small windshield mounted solar panel. (I did try using the red disconnect switch, but as some of you have reported, it didn't do anything).

So I disconnected the black negative cable (as shown in the attached picture) and . . .I still had power. Headlights worked, etc. Huh?

I toggled the red switch a few times, no change. In frustration I reattached the negative cable, removed it, and as I thought would happen the first time, the power went off (headlights, dash, etc.)

Any idea what happened? I did not attach the portable solar panel (picture included) for fear I might hook it up incorrectly. I would assume negative to negative and positive to positive, but the fact the battery at first continued to supply power with the negative detached concerned me.

What am I missing? Thanks

[JLeising]

Some observations and “swags”:

First, wth no connection to the chassis negative terminal, as your picture shows, that battery was not supplying any electricity. If your headlights lit, they were getting power from a different source.

Now some SWAGs (Stupid Wild-A... Guesses) -

I believe solar connected to your house batteries will fully charge the house batteries, then the battery control circuit will start charging your chassis battery. This is my most probable guess as to your observation- the BCC (I think also sometimes called the BIRD circuit) had engaged to charge your chassis battery from your solar system. This, in effect, connected your house batteries to your chassis battery. When you pulled the chassis negative the house batteries were available to power your lights.
The power used by the lights likely quickly dropped the house battery voltage low enough that the BCC then disconnected the two batteries- so the next time you tried it, the lights did not illuminate.

I also use solar to maintain my batteries while in storage. Have not confirmed that the chassis battery gets charged, but it has always been fine, even after two or three months storage. If I am correct, no need for your second solar dedicated to the chassis battery.

[lacamastraveler]

Jleising ~ that makes a lot of sense. So I should probably reconnect the negative terminal. We are still a few weeks away from winter departure so I will monitor the battery voltage. Thanks for the info.

[ipolyihh]

did your solar panel come with an additional 12v plug?

the socket at the bottom of the center console is always "live"

should be no problem charging thru that, but make sure it's still live when the switch in the drivers footwell is in disconnect

also the consumers are very minor, I had no problem starting after a month of sitting idle

ps you can also run the generator to start the vehicle or recharge the cab battery, just be sure it runs long enough for the relay to start sending power to the cab

[davidlayton]

Hi all, will the engine 12 volt system also charge the house batteries on my 2015 solera with the engine running? Thanks David

[Mikegjax]

Originally Posted by davidlayton

Hi all, will the engine 12 volt system also charge the house batteries on my 2015 solera with the engine running? Thanks David

Yes.

[KatanaPilot]

Originally Posted by davidlayton

Hi all, will the engine 12 volt system also charge the house batteries on my 2015 solera with the engine running? Thanks David

If your 2015 Solera is similar to my Forester MBS, then as stated previously - yes. There is a battery control center located behind a panel on the left side as you enter the step well from the outside.

Here is a link to a picture and some more info as to functionality.

The BCC will also charge your coach battery when on shore power or Onan generator.


Additionally, there are multiple ground and power paths due to the additional wiring installed at FR. This is why you can disconnect the battery ground and still have chassis power being supplied to the coach. At least that's true on my Forester MBS.

[elob_tx]

I had a similar issue recently when I needed to replace my 6 year old chassis battery with a new AGM battery. I was trying to be careful and not short anything out so I removed the battery disconnect by the accelerator pedal and still had power like you did. So I unplugged my shore power and turned off the coach battery disconnect switch. Still had chassis power. I traced the wiring from the chassis battery + back under the drivers seat and discovered that there is a inline fuse that connects the battery management controller to the chassis battery for charging. No way to disconnect it without causing some sparks. I plan on adding another Blue Sea Systems battery disconnect switch under the drivers seat to allow disconnecting the tie in to the battery management controller to make battery maintenance easier and safer.