Replacing Gp 27 battery with active rooftop solar

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podwerkz

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Joined: 11 Mar 2019
Location: Texas
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Topic: Replacing Gp 27 battery with active rooftop solar
Posted: 21 Mar 2021 at 6:19pm

Some controllers will simply flash an error code on the display when re-connected to a battery if the solar panel is active when you do so.

Lots of controllers on the market today are compatible with 2 or 3 battery voltages and need to 'learn' the battery voltage (be connected to the battery) before they have solar input.

r･pod 171 gone but not forgotten!

offgrid

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Posted: 21 Mar 2021 at 6:08pm

If that is the recommendation of your solar charge controller manufacturer then for sure yes, but it really should be self protected from damage under that condition.

1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold

Pod_Geek

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Posted: 21 Mar 2021 at 11:08am

Originally posted by offgrid

...So disconnecting the battery with a switch or simply by removing the negative conductor is ok for a few weeks but if your trailer will be out of service for several months and you can’t assure it’s charge will be maintained (either by grid power or solar) then it’s best to remove the battery and store it where you can maintain it with a charger.....

But I'd have to disconnect the solar panel from the controller as well, yes?

2020.5 R-Pod 195 Hood River
2018 RAM 2500 6.4L

offgrid

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Posted: 21 Mar 2021 at 7:39am

Yep if they left your solar module in the shade with the battery connected for a couple months then its toast. There are parasitic loads in the trailer that will discharge the battery unless either disconnected or maintained on a charging source. It will also self discharge even if left disconnected with no charging source for a long period. It’s actually the opposite of what your are thinking, self discharge is faster in hot weather than cold weather, but will happen either way eventually.

So disconnecting the battery with a switch or simply by removing the negative conductor is ok for a few weeks but if your trailer will be out of service for several months and you can’t assure it’s charge will be maintained (either by grid power or solar) then it’s best to remove the battery and store it where you can maintain it with a charger. A cold concrete garage floor is fine, that’s another common misunderstanding. In fact the battery will last longer if you store it in a cool place, it won’t freeze if it’s charge is maintained.

1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold

Pod_Geek

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Posted: 20 Mar 2021 at 1:40pm

No disconnect switch.

2020.5 R-Pod 195 Hood River
2018 RAM 2500 6.4L

Ricktoon

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Location: Montana
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Posted: 20 Mar 2021 at 1:19pm

Pod_Geek does your R-pod have a battery disconnect switch? If the wires for the solar are tied to the batteries through the R-pod the battery disconnect should shut off flow to and from the batteries.

Rick and Ellen B
2019 Chevy Colorado
2021 Rpod 196

Pod_Geek

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Posted: 20 Mar 2021 at 12:57pm

This was in response to my Go Power GP-PWM-10-SQ throwing a 601 error (Battery Disconnected or less than 3.0 volts). None of the 12V appliances/features/lights worked.

So I had my SO climb up on the roof and cover the panel with a big black trash bag and a rubber mat on top of that, and the controller went dark. Changed out the battery, and the R-Pod was back to being itself.

Took the battery to the place that I had bought the new one. 1.2V (aka "Dead as a doornail"). Fluid levels were fine. Dang thing was theoretically only 15 months +/- old.

Hmmm...R-Pod had been in the shop for two months from December 7 to about February 7. I wonder if they had it indoors or otherwise out of the sun when temperatures got well below freezing such that it discharged and froze. Possible?

2020.5 R-Pod 195 Hood River
2018 RAM 2500 6.4L

GlueGuy

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Posted: 20 Mar 2021 at 11:39am

Many, if not most solar charge controllers advise to connect the batteries first. Probably because many of them will handle multiple different voltages (12, 24, 48). I would just disconnect the positive lead from the solar to the charge controller, then connect the battery.

bp
2017 R-Pod 179 Hood River
2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost

offgrid

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Posted: 19 Mar 2021 at 7:42pm

It really shouldn’t hurt a property designed solar charge controller to connect the solar module first but if you cover a solar module with an opaque cover it’s dead. Or better, just disconnect one of the solar module leads at the controller, connect the new battery, then reconnect the solar module. No need to be on the roof.

1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold

Pod_Geek

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Posted: 19 Mar 2021 at 6:46pm

Ok, so I have a dead/dying Group 27 battery. Bought a new one but I know I need to be really careful changing it out due to having rooftop solar. My research suggests never disconnecting the battery while the solar panel is actively supplying power to the controller/battery system.

What is the easiest way to do this? Cover the solar panel such that it can't supply power to the system and then disconnect the old battery and replace it?

Figure out how to disconnect the panel on the roof?

Turn one or more breakers off? (Assuming there are breakers that can cut power from the panel to the controller)

Find a fuse between the panel and controller and temporarily disable it?

I would do this at dusk if I could, but the storage yard closes well before sunset these days.

2020.5 R-Pod 195 Hood River
2018 RAM 2500 6.4L