Hood mounted solar panel (1 Viewer)

[NYC570]

Am I reading this correctly or is there a typo? $429 for a 90w panel?

@TonyP is right, you want airflow under your solar panel if possible. Panels lose efficiency as they heat up. Your metal hood gets hot. Even a small airgap in this case isn't ideal, you really want a few inches at least. Roof rack mounting is better if you have the space.

Panel angle will make a difference in output as well. If they are mounted flat you lose 10-30% of output depending on time of year, location on the globe, etc.

Also shading any part of the panel will really hurt. Even a small amount of shade will drastically reduce output. So on your hood might be OK if the sun is directly above but if it's partially behind the truck and a part of the panel gets shaded by your roof, RTT, etc it'll seriously drop the output.

Panels are in my experience about 50% efficient. So a 100W panels will get you about 50W at peak. Maybe 60W if you're lucky. You'll get much less when the sun is low (~20W). I don't know how much power an ARB fridge draws over the course of the day, but you might be better off getting one or two flexible panels but NOT attaching to your vehicle and instead attaching and repositioning them when you park to camp then putting away when you drive.

Also keep in mind the force of wind doubles every 10 mph, so your panel needs to be mounted TIGHT or else it'll rip off. I have a friend who had a pair of flexible 100W solar panels on his trailer roof. They were taped down using Eternabond. If you've never used that stuff it's like duct tape and 3M VHB on steroids, and it makes a water tight seal. Still the airflow across the roof caused his panel to pop loose on the highway at 75 mph one trip, at which point the panel became a sail and broke away at the MC4 connectors. Not sure how it happened but we think some water got underneath which loosened the tape

Moral: I wouldn't try to mount a flexible panel to your vehicle with any sort of air gap under it. Just sayin'

I agree with everything except efficiency. In my experience, foldable and flexible panels have achieved 60% to 90% of their claimed wattage with a MPPT controller. Rigid panels have achieved up to 100% of their claimed wattage. Of course this depends on your location and time of the year. Also, if the panels are split cell design, covering part of the panel won't affect them as much up to a certain point.

 

[linuxgod]

I agree with everything except efficiency. In my experience, foldable and flexible panels have achieved 60% to 90% of their claimed wattage with a MPPT controller. Rigid panels have achieved up to 100% of their claimed wattage. Of course this depends on your location and time of the year. Also, if the panels are split cell design, covering part of the panel won't affect them as much up to a certain point.

I speak from personal experience of two different solar panel installations as well as discussions with others who have done solar primarily on their travel trailers (a couple friends as well as some folks on the Lance Owners forum). I've seen situations where panels output (post-controller) is close to 75% but those are fairly optimal situations (panels tilted, full sun, but moderate outdoor temps). In most cases 25-50% output during the day seems to be much more typical.

• Installation 1 was a pair of Renogy 100W flexible monocrystaline solar panels installed directly on an EPDM trailer roof with 3M VHB and Eternabond. <20' total 8ga wiring and WindyNation PWM controller. Highest output (measured post-controller) I ever saw was *maybe* 50% @ ~14.4V - in Moab in August.
• Installation 2 was a pair of Newpowa 175W rigid monocrystaline panels installed on feet which result in about 2" of space between the panel and the trailer roof. <20' total 8ga wiring and Renogy MPPT controller. Highest output I've seen was a bit over 200W. (I have a photo somewhere I can dig up but it was a bit over 14A @ ~14.5V). That was in July at the Great Sand Dunes in CO this summer, bulk charging a battery that was below 80%. Panels were not tilted. (I can tilt them in one direction about 20 degrees but the sun was facing the wrong way for this).

I've never seen any panel in any situation output 100% of stated wattage. I'm sure it's possible, but unless the manufacturer is understating the potential output I don't see how you could actually achieve it unless it was a fixed mount and positioned to track the sun. If you have some links or info on a mobile install that comes anywhere close to 100% I'd love to see it and compare the setup - if there's something I could improve I'd be game to try it.

Side note: I'd actually be concerned if the panel will output max stated wattage since wiring, controller, etc should be spec'ed for max output + 20% and unless you're in a perfectly ideal scenario that would indicate to me that your panel could end up generating *more* power than expected, which could be a fire hazard if your wiring is only spec'ed to handle the stated power.

 

[mep1811]

Like with anything, there is no perfect solution.
Anything left in the hot sun will get hot. Solar panels will have limitations like not working at night.

 

[FrazzledHunter]

I found this review on Expedition Portal. Have a look at the Merlin.
Portable Solar Panel Testing- Results

 

[NYC570]

Here's a video where 4 panels are being compared. They all produce between 70% to 80% of their claimed wattage. My cheap Paxcess foldable panel has achieved 90% of the claimed wattage and my rigid rich solar panel has achieved close to %100. So this has been my experience. Unless it's overcast, my panels produce more than 50% their stated wattage.

 

[linuxgod]

I found this review on Expedition Portal. Have a look at the Merlin.
Portable Solar Panel Testing- Results

I'd be concerned with a 160W panel that outputs 176W - not in the output itself (that's great) but you can burn out your charge controller or melt the insulation in your wiring if you are dumping more amperage down the wire than anticipated.

Here's a video where 4 panels are being compared. They all produce between 70% to 80% of their claimed wattage. My cheap Paxcess foldable panel has achieved 90% of the claimed wattage and my rigid rich solar panel has achieved close to %100. So this has been my experience. Unless it's overcast, my panels produce more than 50% their stated wattage.

Not sure where/when this is filmed but he's getting 75-81%, slightly tilted and with more space underneath for airflow than on a trailer (or vehicle) roof. Assuming for a moment that a real life flat-mount on a roof with minimal air gap like that would be about 65% (give or take). To his point I'm not shocked the Newpowa panel in that video is higher output since it's physically larger.

MPPT controllers should be able to get above 95% efficiency as well (I've calculated mine at 98%, assuming you trust the input and output data that Renogy displays) but there's certainly a final output hit there as well.

It's possible to get 100% output if the manufacturer is stating numbers which are either (a) not under ideal testing circumstances, or (b) simply stated lower than actual output in order to appear to perform "better". So the cheap foldable panel might be capable of producing 120W give its size but the mfr states 100W so that you won't be disappointed when you only see 90W. I don't recall the watts-per-inch calculation but there's a limit to solar cell efficiency (about 25%, and that's pushing it) and at some point you cannot get more power without a bigger panel.

In my case I haven't tried testing the wattage for my panel at the panel before the charge controller like he does though, but offhand 175W x .65% panel output x .98% MPPT efficiency = 111W, which isn't far off from the 210W or so I've seen from the pair of panels I have. Given my 175W panel is identical dimensions to the Renogy 160W panel again I'm not surprised to ultimately see 100-110W from a panel that size.

 

[mep1811]

I heard back from Cascadia 4X4 and they said this panel fits the 200 Series up to 2015.
If it's up to 2015 our 85w panel will work.

Toyota Tacoma 3rd Gen (2016-present) VSS System™ - 85 Watt Hood Solar Panel | Out of Stock - Pre-Order for VSS System 2.0 - Shipping Summer 2024

The Cascadia 4x4 VSS System™ 85 Watt solar panel system for the 2016+ 3rd gen Toyota Tacoma is a vehicle specific hood-mounted solar panel system. The Cascadia 4x4 VSS System™ mounts to the hood of your 3rd gen Tacoma and provides a constant flow of clean solar energy to your primary or...

www.cascadia4x4.com

SPECIFICATIONS

Power	85W
Voc	20.06V
Vmp	17V
Isc	5.5A
Imp	5A

 

[Desert Yeti]

You can do it very easily yourself. Lots of FJ Cruiser guys do it. The method they use is attach vinyl sticker material for wrapping a car to the hood in a design that looks nice and then use 3M molding tape to hold it down. I've had mine on for at least 2 years now.

As far as building up heat, The heat from under the hood is irrelevant since the time you need the charging from the panel is when the car is off...

My ARB runs 24/7 in my 200 in the AZ sun with this 55W panel on the hood.

I got it and the charge controller on Amazon for under $200.

Make sure you put some door edge guard on the Windward side of the panel to prevent delamination.

 

[mep1811]

@desertrush has been running one of these for a while. Based on his Instagram he seems to like it .

 

[FloodHopper]

You can do it very easily yourself. Lots of FJ Cruiser guys do it. The method they use is attach vinyl sticker material for wrapping a car to the hood in a design that looks nice and then use 3M molding tape to hold it down. I've had mine on for at least 2 years now.

As far as building up heat, The heat from under the hood is irrelevant since the time you need the charging from the panel is when the car is off...

My ARB runs 24/7 in my 200 in the AZ sun with this 55W panel on the hood.

I got it and the charge controller on Amazon for under $200.

Make sure you put some door edge guard on the Windward side of the panel to prevent delamination.

View attachment 2457937

Mind I ask which solar blanket this is and where you got it from? I’m looking to do a similar setup to feed in yo my redarc 1225.

 

[Taco2Cruiser]

If I still had paint, I would never put a solar panel on my hood. I barely like to put a panel on my hood now because of how hot they can get.

Goes back to that no airflow under the panel comments. But my concern is the paint itself, after I saw a 4Runners paint from that same situation.

 

[tampacruiser95]

You can do it very easily yourself. Lots of FJ Cruiser guys do it. The method they use is attach vinyl sticker material for wrapping a car to the hood in a design that looks nice and then use 3M molding tape to hold it down. I've had mine on for at least 2 years now.

As far as building up heat, The heat from under the hood is irrelevant since the time you need the charging from the panel is when the car is off...

My ARB runs 24/7 in my 200 in the AZ sun with this 55W panel on the hood.

I got it and the charge controller on Amazon for under $200.

Make sure you put some door edge guard on the Windward side of the panel to prevent delamination.

View attachment 2457937

How do you keep the inside of your vehicle cool while parked outside during the day? If anything at all? Getting ready to move to Arizona and trying to prepare.

 

[RET2]

How do you keep the inside of your vehicle cool while parked outside during the day? If anything at all? Getting ready to move to Arizona and trying to prepare.

Apparently one must only learn the following mantra "But it's a dry heat"

 

[tampacruiser95]

Apparently one must only learn the following mantra "But it's a dry heat"

I've always thought that's ridiculous. People said the same thing overseas. 100 degrees is a 100 degrees everywhere lol.

 

[greynolds]

I've always thought that's ridiculous. People said the same thing overseas. 100 degrees is a 100 degrees everywhere lol.

Yes, it’s still hot, but it’s a lot more uncomfortable when it’s also really humid. I prefer 100 and dry to 85 and humid any day.

 

[mep1811]

How do you keep the inside of your vehicle cool while parked outside during the day? If anything at all? Getting ready to move to Arizona and trying to prepare.

Tinted windows help

 

[Markuson]

How do you keep the inside of your vehicle cool while parked outside during the day? If anything at all? Getting ready to move to Arizona and trying to prepare.

One thing that massively improved my interior heat—even with my heat absorbing dark grey LC snd even darker roof?

LIMOUSINE dark tint from the second row and rearward…. Slightly lighter front row.

The difference was stunning heat reduction when parked, and I live where if can get 110 occasionally. Also goes a long way to protecting interior on my 15 year old 200 (built in 2007, and never in garage).

Also worth noting—I can still see out in daylight, even tho its impossible to see in.

 

[radman]

Stupid solar question of the day: does solar charging the primary rig battery while driving interfere/confuse our "smart alternators"?

I'm about to mount one of these to feed my house LiFePO4 bank, but i'm also considering branching off to the primary battery. If i do this, the alternator will see the additional voltage.

 

[linuxgod]

Stupid solar question of the day: does solar charging the primary rig battery while driving interfere/confuse our "smart alternators"?

I'm about to mount one of these to feed my house LiFePO4 bank, but i'm also considering branching off to the primary battery. If i do this, the alternator will see the additional voltage.

It should not, though I probably wouldn’t do it. The solar charger and the alternator should both back off from “bulk” charge mode to “float” once the battery gets to about 80-90%. That’s a natural battery effect, where the charger wants to switch from constant current to constant voltage. What you’ll likely find is the alternator backs off but the solar CC will continue charging, and that’s where you could have issues. The LFP internal resistance will be lower than the lead acid battery so once the wet cell is full the solar CC should basically only charge the LFP, but I’m not 100% sure the starting battery won’t still get a higher charging load than is optimal.

The big risk you would have here is if the solar CC stays in constant current (bulk) mode for a long time you could push the lead acid battery too hard and (essentially) boil it, particularly if it’s able to push amperage greater than the C/5 bulk or C/20 float values for an extended period of time.

Ultimately it’s a question of whether your LFP and starting batteries have drastically different bulk-to-float voltage switchover points. If they don’t then assuming your starting battery is a wet cell and not an AGM I think it’ll be fine. But if the are drastically different you may find the charger keeps trying to apply high current well past the point the starting battery can absorb it. LFP internal resistance is lower so that should still absorb the excess current but if it doesn’t then it will boil the starting battery.

In reality I can’t see why you’d need to do this. The alternator will charge the starting battery just fine, there’s no need to apply a float to the battery unless the vehicle is sitting for weeks at a time unused. If it is then yes you can do this and so long as the LFP is fully charged to start with then no it won’t hurt the starting battery.

 

[rlynch356]

I am pretty interested in these, has anyone used one of the ones from Lenssunsolar? they make versions for both of the 200 series hoods..
I am wondering about longevity really, the hood while a great place to mount it is less so from a heat perspective for both the mounting VHT and the panel.
But parked in the sun I can see it is use.