Solar charge when chassis power off?

[N1ven]

Hi - just traded 2008 Voyage 33V in on a 2018 Era. New to solar (and posting here) so silly question: The rooftop solar is charging but does it continue to charge when I leave the unit parked outside and shut off the chassis power switch? Kinda like guessing whether the fridge light goes out when the door closes. If it does stop charging, might I be better off not shutting the chassis isolator switch off?

[powercat_ras]

Generally the solar charge controller when added after a coach is new is wired directly to the coach battery from a device called a solar charge controller thru a protective fuse or circuit breaker, so it should work with the chassis isolater switch set either way. However if it is Winnebago factory installed solar I can't say for sure.

That said are you sure the switch you are referring to is a CHASSIS disconnect switch and not a COACH battery disconnect switch. Generally Winnebagos with only 1 disconnect switch have only a COACH battery disconnect switch. Once again if added after coach is new they generally go straight to the batteries, buit if Winnebago OEM I can't say for sure.

When you are parked without shore power and with generator off in sunlight you can measure coach battery voltage, if solar is putting charging into the batteries you should see something above 12.7 volts if it is not the voltage will be in the 12.2 to 12.6 range.

The voltages I state above assume you have either flooded lead acid or AGM batteries.

[Winterbagoal]

I have a 2018 Navion, and the ERA is probably similar based on the ERA OM available at www.winnebago.com as a downloadable .pdf file.
I have 300W of solar on the rooftop, a Zamp ZS-30A PWM solar charge controller, with a status display at the monitor panel area, and a coach battery enable/disable switch down at ground level near the side entry door. Your ERA probably has a similar setup.
I leave the Navion parked outside all year round, with the coach battery switch enabled, because it powers the Zamp ZS-30A display in the systems monitor display area. The panels provide charge to the coach batteries when the sun shines, and I can check the state of charge by looking at the ZS-30A display.
So, yes, the solar panels charge the coach (not chassis) batteries when the sun shines, but in order to see what's going on at the batteries, leave the coach battery enable/disable switch enabled, so your ZS-30A status display stays on. You don't have to, but it's what I do.

[Morich]

Originally Posted by N1ven

Hi - just traded 2008 Voyage 33V in on a 2018 Era. New to solar (and posting here) so silly question: The rooftop solar is charging but does it continue to charge when I leave the unit parked outside and shut off the chassis power switch? Kinda like guessing whether the fridge light goes out when the door closes. If it does stop charging, might I be better off not shutting the chassis isolator switch off?

No question is too silly if we are actually trying!
But then it may be a case of using different terms or maybe not understanding some of them?
Most think of our RV as having three different but interconnected electrical systems. So maybe the problem with your questions is just a slight difference in terms or maybe missing the difference in what we like to call things?

We have the parts most of us call the chassis 12VDC that is normal with any car or truck. Chassis battery, starter, alternator to run and charge that battery and the things normal for car or truck.

A coach system that runs the things specific to RV like inside lights, fans, water pump, etc. That system has a set of batteries and can get charged several ways. Most often we think of these batteries as charged from a converter getting it's input from the cord or generator. with solar it can also be charged that way. Or when driving, there is a connection made to get charged from the chassis alternator as well!

So that brings your question of the chassis battery disconnect?
Did you mean the chassis which charges from the alternator is other provisions are not made? We often would not expect solar to charge the chassis if something has not been added to make it happen. So did you possibly mean getting the coach battery charge from the solar?

Part of the question may be if you have a chassis battery disconnect or are you speaking of the coach battery disconnect?

Possible some good info on checking the battery charge is on page 4-9 of the owners manual as it has some details on how to avoid being confused by surface charge if we have been charging recently.

Short answer, while ignoring some possible confusion on terms is that I would assume the coach battery should be left on when wanting to charge coach batteries from any source. whether that source is solar or converter, the disconnect will likely cut off the charge to the batteries!
To get charge to the chassis battery, there would need to be some small changes made after the OEM design! Possible previous owners may have made this change but I would not assume it true without checking.

[N1ven]

Yep, I meant the COACH battery disconnect right by the side door when I enter the coach. I was thinking 'engine battery' and 'chassis battery,' so my bad. I was guessing the rooftop solar only charged the batteries when the coach disconnect was on (and I could see the charging status on the Zamp PS-30A display). So then it's a tradeoff between which is greater: the benefit from the 200W solar panel charge during the day, or the drain on the batteries 24 hours a day from all the little things that run in the coach? Not sure the charge is greater than the drain, especially during the shorter days of winter. But, it the solar charges regardless of the coach disconnect, then that is great news. BTW, I'm getting a 140W portable panel from Zamp to plug into the side port.
Thank you all for the help!

[Morich]

One small point that often snags folks when they are thinking of how they want to leave the disconnects?
There is a bit of confusion often built in when we see a "battery disconnect" as it makes us think we have actually disconnected ALL the load on that battery! WRONG!

Some details from drawings will show what I mean that can snag us!
This drawing sheet 3 which is "chassis electrical box"
https://www.winnebago.com/Files/File.../000024293.pdf

The problem being that I may want to change my answer on how your solar is wired and possibly left on when disconnect is OFF! Constant surprises if I don't actually look to verify things!!
For help, we have wires stamped and ID'd on them to match what is on the drawings.


Decoder chart/list here:
https://www.winnebago.com/Files/File...ical_guide.pdf
""From" column on left and "to" on right?

Your chassis electrical box ( under pass. seat!)
Click to see better or go direct for big picture?


A lot of important stuff under there and it does tend to give trouble as the solenoid contacts may burn!
On left is the solenoid where the chassis battery comes in on left(red) to meet coach power on big lug on right (yellow). The blue wire LR brings power from cash area, either from ignition hot or when we push a dash switch. Power goes through coil to ground and out on wire FM. That closes makes the red and yellow contacts close as we drive!

But then the power goes across to the battery disconnect relay controlled by the switch by door!
See how GJ goes to fuses BEFORE the disconnect relay and KKF and generator starter feed has to go through the relay? Some get cut off, some not!

If we look up GJ on the chart, it is feed to solar and things left on!


This is how it gets done.


GJ stays hot as it avoids the disconnect, while KKF has to go through the relay!

There are a couple options down in lower left involving solar but I now think it will stay connected when disconnect switch is turned off! Normally I think of the safety items like CO and propane detectors as being left on!
But that may need tested/checked before trusting too far!!

Lots of devil in the small details!

[N1ven]

Thanks, Morich. I'm a radio engineer and extra class amateur, so you are speaking my language. I agree that the solar input might not be effected by the coach disconnect. I'll do some testing (just wish the batteries weren't in the most god-awful place - liked under the steps in my Voyage) and verify. The light goes out on the controller - I think but haven't looked at in the dark yet - so how to keep the controller on (because it needs to be operating to adjust charging voltage) but the display off is interesting I'll let you know.

[Morich]

Okay, Considering experience, maybe I should say, sorry for the too complete process!
One of the hazards of not knowing who and what experience level we need to work!

When I was sloping down to retirement from my first main job, I wound up dealing with a situation where the work was getting way to close to being a board changer for me, so as a way to keep me around, I let them loam me out to different offices where new folks coming out of sales, accounting and desk jobs were moving into what we termed craft jobs!
Often they were very capable of learning the tricks of passing tests but had no idea how to keep their fingers out of the socket!
So that left me almost paranoid of not explaining some of the electrical stuff we need to know.

[N1ven]

I very much appreciate the helpful replies. I'm also a CPA so like to obsess on details.

[N1ven]

Confirmed today... the solar panel is charging even with the coach power turned off. 13.6V in batteries and controller shows charging when I checked on my rig today. Good to know. Can't wait to try my new portable panels when in the daylight -plugged in the Zamp 140W panel last night in the dark and plug fits perfectly in the side of the rig, but sadly no moon energy was detected. Thanks again guys.