Maintenance & Restoration

Huck · 07-12-2021, 07:39 AM

My batteries need to be replaced. I'm going to replace with the same model as the space and wiring are tight and using the same model will be the easiest way to go.

My question is on the correct way to disconnect. I believe the solar panels should be disconnected from the charge controller first. Is this correct?

Then once the solar panels are disconnected, I can remove and replace the batteries, and then connect the solar panels back again.

Alex Adams · 07-12-2021, 07:42 AM

Quote:

Originally Posted by Huck

I believe the solar panels should be disconnected from the charge controller first. Is this correct?

That is the way my Renogy charge controller works.

Huck · 07-12-2021, 07:45 AM

Quote:

Originally Posted by Alex Adams

That is the way my Renogy charge controller works.

I have a renogy charge controller.

Alex Adams · 07-12-2021, 07:48 AM

Huck, I put a circuit breaker between the battery and the charge controller. When I am not using the trailer, I trip the breaker manually to disconnect the controller from the battery, then I remove the battery. I think that is safest for the charge controller.

Jon Vermilye · 07-12-2021, 08:23 AM

The safest for the charge controller is to disconnect the panel first, THEN disconnect the controller from the battery. Most manufacturers bury a note somewhere in the manual not to connect the controller to the panels before the batteries.

AlanKilian · 07-12-2021, 08:38 AM

Quote:

Originally Posted by Jon Vermilye

Most manufacturers bury a note somewhere in the manual not to connect the controller to the panels before the batteries.

I made a little box to hold my fuses and switches so I can disconnect each item separately.
My only 12 Volt loads are a foot-operated water pump and a Fantastic fan, so I've got very low current requirements.

Indeed, my panel controller says you MUST disconnect the solar panel first, and connect it last.

My Regony controller failed when I left the solar panel connected and disconnected the battery for a few hours.

BenBark · 07-13-2021, 08:02 AM

Several years ago I purchased a 100 watt portable, solar suitcase panel from Renogy. It works very well. When the first talks of tariffs began, I read that solar panels would be first on the list for retaliatory tariffs from China. So, I ordered a second Renogy 100 watt portable, suitcase panel. Both panels arrived with the controllers permanently attached and wired to the panels. I have to open the suitcase, exposing the panels to the light, before I can get to the wiring to connect to the battery. As Jon said above, my manual says I must connect the battery first. So, I called Renogy and asked just how I was supposed to do that. I was told that for my 100 watt panels it would be perfectly safe to leave my panels connected to the controller all the time, as shipped to me, and connect to my battery last. This setup worked for me for several years with no problems or failures. However, for protection from the weather and to add an extension cable, I have removed the newest Voyager 20amp controller from it's panel and mounted it inside the Casita, near the battery, which makes it easier to connect the controller first as recommended in the manual. My experience has been that it will work either way.

jwcolby123 · 07-13-2021, 09:54 AM

Quote:

Originally Posted by AlanKilian

I made a little box to hold my fuses and switches so I can disconnect each item separately.
My only 12 Volt loads are a foot-operated water pump and a Fantastic fan, so I've got very low current requirements.

Indeed, my panel controller says you MUST disconnect the solar panel first, and connect it last.

My Regony controller failed when I left the solar panel connected and disconnected the battery for a few hours.

VERY nice widget!

gordon2 · 07-13-2021, 10:48 AM

Quote:

Originally Posted by BenBark

... I have to open the suitcase, exposing the panels to the light, before I can get to the wiring to connect to the battery. As Jon said above, my manual says I must connect the battery first. ...

Very simple. Open panels and cover them with a blanket.. that will turn off power to the controller. Then connect battery and remove blanket. Of course if Renogy said you don't have to connect the battery first then you don't need the blanket, but for those who do, thats one way to do it. In fact anytime you are connecting or disconnecting a solar controller from a PV panel its a good idea to cover them with something to block the light. By the way, on the last ISS spacewalk they were connecting new PV panels and waited until the ISS was in the earth's shadow so there was no light before making the connection.. same concept.

Huck · 07-13-2021, 11:11 AM

New batteries are installed, but I'm not sure all is as it should be.

The Renogy PMW charge controller has a solid green for solar panels and solid green for battery charge. That is how it should be.

I have a battery monitor that plugs into a 12v receptacle. On a sunny day like today, it would usually read over 13v. Today, it is about 12.6 and if I turn the fan on, it drops to 11.x and then moves back up to low 12's.

Why might my battery monitor show a lower voltage after replacing the batteries?

Alex Adams · 07-13-2021, 11:25 AM

Huck, try measuring the voltage from the charge output of the controller to see if you are getting full voltage. Does your controller have a screen or just the lights?

Huck · 07-13-2021, 11:52 AM

Quote:

Originally Posted by Alex Adams

Huck, try measuring the voltage from the charge output of the controller to see if you are getting full voltage. Does your controller have a screen or just the lights?

Just the lights. Both are on.

1st led is solar power - On, Solar power is charging the battery
2nd led is battery - On, Battery level is in right range

This is what threw me. The lights indicate charge controller is charging the batteries.

Alex Adams · 07-13-2021, 12:00 PM

Check the voltage at the charge leads on the controller, see what you are getting. That should at least tell you that the proper voltage is being sent to the battery.

Huck · 07-13-2021, 12:41 PM

I unplugged the cables to solar panel and checked voltage. A little over 17v.

Then I checked the voltage where the solar panel connects to the charge controller. About 12.74v

Then I checked the voltage where the batteries connect to the charge controller. 12.73v.

Then I checked the batteries and they were about 12.67v which is just a little higher than my monitor shows.

I wonder if I am seeing lower voltages because the batteries were already fully charged?

Alex Adams · 07-13-2021, 12:55 PM

What batteries did you get? Flooded lead acid, AGM, etc?

100% charge for the different types would be:
Flooded Lead Acid - 12.7+
Gel Battery - 12.85+
AGM - 12.8+

The resting voltage on my AGM battery is 13.0 volts when fully charged. Be sure to measure the voltage after you have given the battery time to "rest" (no charge input and no loads), typically 20 to 30 minutes.

gordon2 · 07-13-2021, 01:04 PM

Quote:

Originally Posted by Huck

I unplugged the cables to solar panel and checked voltage. A little over 17v.

Then I checked the voltage where the solar panel connects to the charge controller. About 12.74v...

If I understand this right, then these first two readings should be very close to the same. Thats assuming the sun didnt duck behind a cloud... you ARE checking in full sun, right?

Huck · 07-13-2021, 01:06 PM

Quote:

Originally Posted by Alex Adams

What batteries did you get? Flooded lead acid, AGM, etc?

100% charge for the different types would be:
Flooded Lead Acid - 12.7+
Gel Battery - 12.85+
AGM - 12.8+

The resting voltage on my AGM battery is 13.0 volts when fully charged. Be sure to measure the voltage after you have given the battery time to "rest" (no charge input and no loads), typically 20 to 30 minutes.

Flooded, lead acid. They are the same model as the old ones.

All my readings were around 12.7v, so I guess everything is working.

Later today or maybe tomorrow morning I will hook up the trailer power cable and see what readings I get when I am hooked up to 110v ac.

Huck · 07-13-2021, 02:09 PM

I plugged into 110 ac and my monitor read over 13v and the charge at battery was over 13v. I guess I can run the fan for a while tomorrow and see if the solar panel is charging the batteries or not. If I seem to be losing charge over the next couple of days, it might be a charge controller problem.