2024 Micro Minnie 2108FBS solar questions

[TriGuy-WO]

Hey all, looking for some information. I picked up a new 2024 2108FBS trailer about a month ago. I just upgraded the battery to a 300ah lifepo4 and all seems good. The converter auto detected it and setting the go power solar controller for the new bat was easy as can be.
We occasionally dry camp at trail races, the longest one is 4 days without water or power hookup at Run Woodstock. So i'm just trying to make sure it will do it without having to fire-up the generator.
Last Sunday (with it plugged unto my house) I turned on the fridge then Monday night at 4:45 pm I unplugged the shore power and left the fridge running. Bat was at 100%, left for work at 7am Tuesday and it was at 88% I don't think that's to bad. But was hoping for better of course.
We had ok sun, a little cloudy. Trailer has the OEM 200 watt panel on top. I was hoping that it would at min maintain the charge thru the day but sadly when I checked it at 5pm it was down to 85%. So with the solar it lost 15% in 24 hours. Using the app for the battery I was watching in real time and the solar was only putting in 1.2 amps, and when the fridge turned on it went to a negative 2.4 amps.
This morning it was down to 72%.
I'm thinking of adding a portable panel to plug into the Zamp plug on the side of the trailer to help boost it and allow me to adjust for the sun since at woodstock I'm usually under a tree.
My question ( I know almost nothing about this) is, does the panel have to be rated at 12v? some of them I'm looking at say "Operating Voltage 38.8V±5%". Is that a problem? Not sure if the controller will knock that down as needed or what.
Thanks for the help.

 

[creativepart]

It depends solely on what you have on your roof now. Panels are sold in "nominal" voltages - 12, 24, 48 etc. But a 12v "nominal" panel is very likely to put out 17v to 20v even as high as 22v. The same is true for the higher nominal voltages. 24v is 30+v and 48v is 52+ volts.

You want your portable panel to be relatively close to the same nominal voltage you have on your roof now. Do you know the nominal voltage of your current panel? I know some Winnebago's are 12v nominal and others are 24v nominal.

You can tell buy reading any literature that came with your panels in your TT. Failing that, you can just use a voltage meter (a multi-meter) to take a reading either on the roof where you panels are plugged in. Or at the solar controller where the wiring from your roof attaches to your charge controller. If your controller has a screen it will likely show you the voltage from your roof panels, too.

Next you need to know how the portable port on the side of the TT is wired. Sometimes it's wired into the charge controller and sometimes it's wired directly to your batteries.

Again, using the multi-meter check the DC voltage on the two prongs of the solar port on the side of the TT. If it reads higher than 14v it's likely wired to the solar charge controller and if it reads 13v or less it's likely wired to the battery. This assumes you are parked in the Sun, of course.

This is important because if it's wired to the battery then you must buy a portable kit with a built in or additional solar charge controller. But, if it's wired to your exiting charge controller then you need to either buy a portable panel without a built in solar charge controller or you need to remove such a controller if you get a panel with a solar charge controller.

Also, be mindful of the plugs. The plug on your TT is likely a SAE plug, especially if it says ZAMP on it. Most solar panels come with MC4 plugs. You'll need to buy a MC4 to SAE adapter to make the switch. Some are even sold as MC4 to ZAMP, though ZAMP is not an official standard, just very common.

And, just one more thing to be aware of - SAE plugs have a "male" and a "female" connector. Make sure that the "gender" of the SAE cable you get is the same as the side of your TT.

I know that all sounds like a lot. But honestly, it's rudimentary and you'll get the hang of it easily. Just take it a step at a time.

 

[creativepart]

One more thing. Don't always count that your Solar will always replenish your batteries. From what you've reported it looks like you can run that fridge for 3 or 4 days or more on the solar you have now. Which is great.

 

[TriGuy-WO]

Thank you for the help. When I got home it was at 67% and the rooftop solar was putting out 2.4 to 8 amps depending on the clouds.

I looked at the gopower control and it was showing 22 volts. I checked the outside plug and it was reading 13.5 which is what the bat was saying. If I'm understanding you that would mean the outside solar plug is not going to the controller but straight to the battery.

So no matter what panel I get it must have it's own controller. That makes me think that it then does not matter if the panel is 12v or 46v as it's going to be a stand alone unit and just going to the battery. Is that correct?

 

[creativepart]

So no matter what panel I get it must have it's own controller. That makes me think that it then does not matter if the panel is 12v or 46v as it's going to be a stand alone unit and just going to the battery. Is that correct?

Yes... I hadn't thought of it that way, but yes. Just be sure the Solar Charge Controller on the Portable Panel, or the one you add to a panel without a controller is for charging 12v batteries.

One benefit of the higher voltage is you can use a longer cable since will will not need to be such a heavy gauge. (Higher voltage is fewer amps so you don't need heavy gauge wiring.)

 

[Dragicm1]

Solar controller

One more thing. Check if the GoPower solar controller is a PWM or MPPT controller. An MPPT controller will be more efficient at charging your battery. We updated our GoPower PWM to a Victron SmartSolar MPPT.

 

[Wmlunt-WO]

X2 on the Victron, 30 amp.
I replaced the go power and added one in the pass thru for the portable. 200w external.
We have the same model and year.

 

[TriGuy-WO]

Thanks, I'll look into that.
I have to say though, I'm impressed with the unit so far. I'm in west MI and we have not had that much sun the past few weeks. With the fridge running, I ran the slide in and out and the awning out and back in. It took 6 days for the battery to hit 40%. I doubt the solar got sun for much more than 4 hours a day.

 

[FredL]

TriGuy, if you happen to check back on this thread, curious what make 12v fridge you have.