GP-FLEX-200 System Additional Panels

turbopilot

New member
Had a nice sunny day on the central coast of California so I decided to "stress test" the 500 watt Flex panel system on my Unity. Was able to get 20.3 amps out of the panel at noon on the 17th of February. Not bad. These panels may be putting out more than their rated output. It was also 82 F when this screen shot was taken so the panels on the roof were pretty warm.



By June with the sun directly overhead these panels should at least put out their rated output around 28 amps, if not more.

Feeling pretty good about this when all of a sudden the solar controller "crashed" with a blinking screen. Got on the phone with GoPower tech support (very good experience) and we worked through a number of steps to reboot the controller. Nothing was working so they said they would send a new controller.

Then I thought I would explore the wiring from the solar controller to the + side of the DC bus in the house battery box. I found that LTV ran a #8 wire from the solar controller down to the battery box. This is good news as the documentation only calls for a #10 wire, so there should be less loss.

Then in the battery compartment I discovered that LTV had spliced the #8 wire to a #12 wire with a fuse holder containing a 15 amp fuse. The fuse holder #12 wire then attached to the house DC buss on the house side of the 200 amp fuse from the house battery. I also found that the 15 amp fuse was blown, which makes sense since the panels were generating 20.3 amps when the controller crashed.

Here is the original installation. You can see the red #8 wire coming in from the right where it was spliced to the yellow #12 wire.



So I pulled out the yellow fuse holder and replaced it with a Blue Sea Systems 285 30A Circuit Breaker.


Here is the final installation:



So if you have the factory installed 200 watt GoPower Flex solar panel option and you want to add additional panels to your Unity, make sure you update the wiring to support the additional load form the expansion panels.
 
Yes. It needs 12 volt from the battery to work. The controller reboots if you disconnect both the panels and the battery for 10 seconds. After putting in the new circuit breaker I rebooted the controller and all is well.
Could you just bumped up the fuse size??
 
No, for a 30 amp controller you need at least a #10 wire to the bus. Fuse holder was a #12 wire. Thought about just getting a #10 fuse holder but the Blue Sea Circuit Breaker is a better fit for this application.
I figured that was the case so did you replace the #12 wire and was that hard to get at? I plan to add one or two panels so I'll need to do this.

Thanks, Bob
 

turbopilot

New member
I figured that was the case so did you replace the #12 wire and was that hard to get at? I plan to add one or two panels so I'll need to do this.

Thanks, Bob
No just pull the house batteries out. You will see yellow fuse holder wire spliced into red #8 wire. Snip the junction, put a terminal on the red wire that goes to the Blue Sea C/B. From the other side of the C/B run a #10 (or #8) your choice down to the + terminal on the fuse block.

GoPower installation manual says #10 wire fine for 30 amps. That's what is so nutty. LTV runs a #8 wire down to batteries then runs the connection through a #12 wire to DC bus.
 
No just pull the house batteries out. You will see yellow fuse holder wire spliced into red #8 wire. Snip the junction, put a terminal on the red wire that goes to the Blue Sea C/B. From the other side of the C/B run a #10 (or #8) your choice down to the + terminal on the fuse block.

GoPower installation manual says #10 wire fine for 30 amps. That's what is so nutty. LTV runs a #8 wire down to batteries then runs the connection through a #12 wire to DC bus.
Thank you. That IS weird to oversize then undersize... I'd probably just go with #8. Hardly cost much more.
 

Eugene Rider

2016 Unity TB
One of the modifications in the factory building of my 24T is to have wires from the controller area run down to the battery area so I can install 400 watts of portable solar panels so I can park in the trees and run a 10 or 12 gauge extension cord to get my solar panels into the sun. I asked for 10 gauge wire, Dean told me code required 8 gauge wire.
Will include pictures after I get the RV and all my upgrades done. All I want in life is to be the envy of turbopilot:professor:
 

turbopilot

New member
One of the modifications in the factory building of my 24T is to have wires from the controller area run down to the battery area so I can install 400 watts of portable solar panels so I can park in the trees and run a 10 or 12 gauge extension cord to get my solar panels into the sun. I asked for 10 gauge wire, Dean told me code required 8 gauge wire.
Will include pictures after I get the RV and all my upgrades done. All I want in life is to be the envy of turbopilot:professor:
Don't know about code but the bigger the better moving DC amps.

 

jackfish

Active member
That table is darn near worthless. Percent voltage drop? While our RV electrical systems are considered nominal 12 VDC, my panels output 17.7 volts and my batteries want 14.7 volts in bulk charging. Better to use one of the many wire sizing calculators available on line to get things a little closer to reality.

I've got 635 watts of PV for 36 amps and 10AWG from panels to combiner box and 4AWG from combiner to controller on about 15 feet of run. That's less than 1.5% of voltage drop. I have 2AWG between the controller and the batteries, which are in close proximity of each other; voltage drop there is virtually nothing.
 
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Was it fairly easy to find a spot on the body to screw in the circuit breaker? I worry about whats on the other side where the sharp screw is going to come out.. ;-) At this point I'm only looking to add a third panel which may not be too much for the fuse but for $40 bucks why not just replace the fuse and 12# wire...


Had a nice sunny day on the central coast of California so I decided to "stress test" the 500 watt Flex panel system on my Unity. Was able to get 20.3 amps out of the panel at noon on the 17th of February. Not bad. These panels may be putting out more than their rated output. It was also 82 F when this screen shot was taken so the panels on the roof were pretty warm.



By June with the sun directly overhead these panels should at least put out their rated output around 28 amps, if not more.

Feeling pretty good about this when all of a sudden the solar controller "crashed" with a blinking screen. Got on the phone with GoPower tech support (very good experience) and we worked through a number of steps to reboot the controller. Nothing was working so they said they would send a new controller.

Then I thought I would explore the wiring from the solar controller to the + side of the DC bus in the house battery box. I found that LTV ran a #8 wire from the solar controller down to the battery box. This is good news as the documentation only calls for a #10 wire, so there should be less loss.

Then in the battery compartment I discovered that LTV had spliced the #8 wire to a #12 wire with a fuse holder containing a 15 amp fuse. The fuse holder #12 wire then attached to the house DC buss on the house side of the 200 amp fuse from the house battery. I also found that the 15 amp fuse was blown, which makes sense since the panels were generating 20.3 amps when the controller crashed.

Here is the original installation. You can see the red #8 wire coming in from the right where it was spliced to the yellow #12 wire.



So I pulled out the yellow fuse holder and replaced it with a Blue Sea Systems 285 30A Circuit Breaker.


Here is the final installation:



So if you have the factory installed 200 watt GoPower Flex solar panel option and you want to add additional panels to your Unity, make sure you update the wiring to support the additional load form the expansion panels.
 

turbopilot

New member
Was it fairly easy to find a spot on the body to screw in the circuit breaker? I worry about whats on the other side where the sharp screw is going to come out.. ;-) At this point I'm only looking to add a third panel which may not be too much for the fuse but for $40 bucks why not just replace the fuse and 12# wire...
No problem finding a spot to attach a the Blue Sea C/B. 3 panels should get you 16.86 amps at noon on a sunny day on June 22. So you need to protect the circuit against that number.

In my experience these panel ratings are based on sea level measurements. If you travel at high altitudes on a sunny day you will get significantly more output. I am worried that 30 amps may not be enough for my system which is rated at 28.1 amps. I am getting 20.3 amps in the middle of February at sea level. So I am guessing I will get more the 28.1 amps on a sunny day in June at 12,000' in the Rocky Mountains.
 
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Kind of off topic but does anyone know the likely lifespan of these Flex solar panels? LTV must have had good reasons for switching to them but my understanding is that when panels heat up their efficiency decreases. Raised, glass solar panels have air circulation behind them where the Flex panels do not and they cost more. I hope that they are good for at least 15 years as that will take care of me but they will be a bear to replace....

Thanks, Bob
 

turbopilot

New member
Kind of off topic but does anyone know the likely lifespan of these Flex solar panels? LTV must have had good reasons for switching to them but my understanding is that when panels heat up their efficiency decreases. Raised, glass solar panels have air circulation behind them where the Flex panels do not and they cost more. I hope that they are good for at least 15 years as that will take care of me but they will be a bear to replace....

Thanks, Bob
For the RV application I doubt temperature makes much of a difference. Performance of the panels will decline above 25C. But typically panels that get really hot are seeing full overhead sunshine. You will be making so much power in those circumstances you will never miss the reduced output associated with temperature. As to panel lifetime time will tell. I would guess the UV will ultimately win working on the plastic matrix of the panel before the solar cells themselves give out.
 

surfbum

New member
turbopilot, are you doing okay so far with your standard 200amp batteries? I keep hearing people wanting to upgrade and add two more to have a 400amp setup. What are your thoughts on this? I would mostly dry camp - almost never go to the RV parks. Also, does LTV offer Lithium batteries like Pleasureway and Roadtrek right now or no?
 

turbopilot

New member
turbopilot, are you doing okay so far with your standard 200amp batteries? I keep hearing people wanting to upgrade and add two more to have a 400amp setup. What are your thoughts on this? I would mostly dry camp - almost never go to the RV parks. Also, does LTV offer Lithium batteries like Pleasureway and Roadtrek right now or no?
I don't have enough experience yet. 2016 Unity house batteries have 232 ah. I upgraded mine to AGM's instead of the standard flooded battery. Many threads and posts on this subject if you look around this forum.

At this point I am going to treat the rig as having 332 ah (house + cab) of battery storage. I am also going to take my batteries down to 20% (or what ever state of discharge will still start the generator) when the need arises. The trade off to run the batteries below 50% is battery life. But even replacing the AGM's every two years is far cheaper and a lot less hassle than going to Lithium batteries.

Given 500 watts on the roof, with primarily summer operation all but assuring 100% charge on the batteries by sunset, I don't think there is any doubt we can make it through a short summer night most often using less than 150 ah.
 

Peter Tourin

2020 Unity RL, ex 2012 Unity MB
+1 about using AGM's hard and replacing them more often. It's a good point, considering how much Lith batteries cost! If you go down to 20% the batteries should be around 11.5-11.6 under load - it's down there but most things should still run. I don't know if the generator would start, but you can always start the RV for a short time when you want to start the jennie. AFAIK, LTV has made no statements about considering going to Lith batteries. It turns out not to be a simple change - the Lith batteries need a very different charging routine, and the issue of combining/isolating the house and chassis batteries is more complicated. There's also the low temperature issue - you can discharge Lith batteries below freezing (battery temp, not ambient temp), but you can't charge them. So it's a pretty different world.
 

wade5979

New member
Turbo,
1-Did you use any screws when mounting your extra panels or just adhesive and how many tubes for 3 extra panels?

2- Did you consider upgrading to an MPPT charge controller?

You've done a great deal of solar research and you thoughts are appreciated
 

turbopilot

New member
Turbo,
1-Did you use any screws when mounting your extra panels or just adhesive and how many tubes for 3 extra panels?

2- Did you consider upgrading to an MPPT charge controller?

You've done a great deal of solar research and you thoughts are appreciated
I just copied the way LTV installed the first two panels. They used adhesive on the panels and screws to hold down the Renology Y adapters. I used one tube of adhesive per panel. Panels are solidly attached to the roof.

So far the output of the panels has done better than I thought as the sun is getting higher. Got 20.2 amps at noon on a sunny day in mid February. No reason not to believe they will not reach or exceed max output of 28.2 in the middle of June. If the current controller delivers or exceeds max output of the panels not sure I see the need for a MPPT charge controller.
 

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