Solar Mounted On Truck Cap?

RZRBUG

There have been numerous discussions about using solar power with the T@B.  Some have bought portable panels and some have installed flexible panels on the roof.  Both have their advantages/disadvantages.

I have been thinking about mounting flexible panels on the roof of my truck cap.  They would be low profile and hardly ever seen.  Also, I would not need to worry about hauling panels around and setting them up, and I could move the truck into position to catch the sun without moving the trailer.

My question is what is the maximum length of cord I can use with solar panels?

Nomad

Don't have an answer but I now wish I'd taken a picture of this mini van in a campground I was at - the guy had solar panels duc-taped to the hood and roof.

Verna

Larry, I've thought about putting two 100 watt solar panels on my kayak rack on my truck shell. 

As far as how long of a cable, I know the Zamp 80 watt solar panel I have has about a 20' cable on it.  I'm still waiting for my Zamp 200 watt solar panels to come off of backorder, so I don't know how long its cable is.

jkjenn

I picked up a flexible 50 watt Renogy panel that I plan on securing on my roof rack while driving to add a little boost to my TV charge and then using with my other solar when I set up camp. I am using Goal Zero cables and charger, so I picked up a 30‘ GZ extension cord. I will post photos when I take off in September.

RZRBUG

I've been thinking about the pros and cons of this setup and it occurred to me that I would be limited to keeping the truck in camp.  If I decided to do any motoring around the area, I'd be taking the panels with me, right?  So there would be no charging while I was gone.  Just another thing to consider.

I have a 10W GZ maintainer, but that is the only experience I have with solar.  I also have no experience with boondocking (unless you count one night in a Walmart parking lot), but I'm thinking more and more about doing so and will need a power source.

Verna

I used the 80 watt solar panel with a 100 ah battery last winter while boondocking some.  I ran out of power during one rainy, absolutely no sunshine weekend with very little solar gain. 

The other time I ran out of battery power was when I blew the fuse on the solar panel, somehow.  I was in a hurry and didn't troubleshoot well, so I just unplugged every thing from the battery for the night.  I found the blown fuse first thing in the am, only lost 2 degrees overnight on the ARB and as soon as I replaced the fuse, the solar panel started charging the battery. 

This winter, I will have 200 watts of solar panels with 264 ah of batteries.  Even with the phantom battery draws, I do believe I will be fine with power.  I can be very frugal in my battery usage, and have no problem pulling fuses for the TV, sound system and the fridge if I run low on power.

120 watts of solar power is the recommended amount for a T@B, by the way.

And, one thing you do need to remember is that you should never run your battery under 50%, but that is not 6 volts......it is 12.06 volts. 

Verna

Here's the chart for the voltage and percentage use of the battery:

jkjenn

RZRBUG said:

I've been thinking about the pros and cons of this setup and it occurred to me that I would be limited to keeping the truck in camp.  If I decided to do any motoring around the area, I'd be taking the panels with me, right?  So there would be no charging while I was gone.  Just another thing to consider.

I have a 10W GZ maintainer, but that is the only experience I have with solar.  I also have no experience with boondocking (unless you count one night in a Walmart parking lot), but I'm thinking more and more about doing so and will need a power source.

Larry, yes, that's the con of a vehicle mount solar set up, that's why my main set-up will not be mounted to my Jeep. This set up should allow for quick and easy access to install and remove, utilizing the grommet and some reusable ties. In addition to the TV boost, I am thinking it will at least provide a little bit lf a charge if I stop somewhere or before or after I am done driving for the day, if there is light, when I am just overnight parking while traveling. The panel also easily hangs via suction cups to the T@b to augment my existing 120w solar set-up, bringing the total to 170w.

I will let you know what I think after my bigger trip at the end lf September since this is mostly untested theory right now.

Nomad

My 120w has a 20' also.
RZRBUG - I'm frugal in my battery use (mainly just fridge, Alde as needed, a reading light at night) and only have a 24 battery and as long as I have sun I do just fine and I boondock a lot - most of the time in fact. Only had hookups 3-4 times all summer. I do have a generator for the rainy/overcast days or if I need to keep the computer charged for long periods while photo editing. The only two things I wish I had were the 200w panels (didn't have them last fall) and a 27 battery.
I suppose if I was going out in the woods for extended periods with marginal sun a dual battery setup might be handy but I'm not so it's overkill.

Edit Add: When I hit a wooded area (or campground) I make sure I find a site where I have some sun so I can deploy the panels. I don't spend much time in forests. I like vistas :-)

T@Buhura

RZRBUG said:

...

My question is what is the maximum length of cord I can use with solar panels?

Direct Current (DC) like comes out from solar and batteries does not do distance well and is why AC (Alternating Current) is what's prevalent for distances - think transmission lines from power stations to substations to homes. 

Anyway as as to what's the max distance depends on the voltage (think of it as a measure of strength to propel the current through the wires) and the conductive quality of the wires, quality of your power source (your panels and quality of light hitting them to generate power), etc. and will depend for your installation. The best way to determine is you could get a multimeter and measure the output voltage using the standard length to confirm how much your panels are generating from the sun and more importantly the current (measured in series to your battery). Then add an extension to see how much loss there is at the end of the extension (compare the current with and without). This will give you an idea of how much power your extension is robbing from your set up. 

Remember, Power = Voltage * Current and when you take your two measurements it'll give you an idea of how much of your rated panel's power is actually delivered. 

Nomad

Thanks - That was informative.

RZRBUG

Appreciate it, T@Buhura.  I realized later that the question was really too open-ended and depends on a lot of factors.  Kinda like asking how many marbles you can put in a jar without knowing the size of the marbles or the jar.  Your explanation is a great starting point.

ChanW

RZR, 
If you use the proper gauge wire you can extend the distance quite a ways. There's a 'wire size calculator' for solar, available here. But with 12v solar panels, it looks like that wire might have to be pretty heavy gauge to keep the losses down. 

Tabuhura, DC doesn't have any more trouble with distance than AC does, unless you're trying to 'transform' it. Solar panels output nominal 12v (I think), so no need to change the voltage. Look here for interesting stuff.

Lisa33

I recently returned from 9 days of camping in partial to full shade.  Some days involved driving, but half did not.  In each case, my batteries were fully charged before noon.  I don't worry about getting the panels in the sun despite pretty liberal use of battery power.  I had the low-amp Fantastic Fan running 24/7 along with two refrigerators ( Norcold in the trailer and ARB in the tow vehicle).  

Yes, you certainly could install the panels on the top of your truck.  The only concern I'd have is that if you go off for the day with your truck to hike, bike, sightsee, etc, then the solar panels won't be with your trailer to do their job.  I wouldn't want to feel tied to the campsite.  

Frankonsand

RZR, use the largest gauge wire possible and minimize the length of wire but most importantly place the charge controller as "close" to the target battery as possible. Most turnkey systems lose efficiency as the CC is closer to the panel than it is to the target battery- I've been cogitating on this idea as well, thanks for starting this discussion!

RZRBUG

Frankonsand, thanks for the suggestion about placing the controller as close to the battery as possible.

I just can't decide whether to place panels on the truck cap or on the T@B itself like mash2 has on his.  They would work better there for sure, but I was thinking more of the looks.  Not that they are ugly, but for my personal taste, the T@B just looks better without them.

BTW, mash2 mentioned in another thread that he got his panels on sale for cheap because the company that made them had gone out of business.  Other companies have started making them, but they are very expensive.  May have to think about this for a while.

Nomad

RZRBUG - I think Zamp announced flexible panels - no clue as to the cost. I think if I was going to do it, I'd mount them on the T@B like mash2. Probably never will as the suitcase I have does me just fine.

mash2

I actually keep two mounted on the T@B permanently and have an additional one that can be plugged in if I feel I want additional capacity (and this one can be located wherever I want, including on the T@B). RZBUG, I did get a great deal on them (less than $200 spent on 200 watts worth).  

I try to not proseletize about mounting on the T@B (the opinions seem strong on both sides of the debate).  As I've said before, I never deal with them, they are just always there.  When the T@B is parked, they're keeping the batteries charged.

While the angle of the permanent panels isn't perfect, it's not a bad approximation.  I just try to generally orient the T@B to to where the sun is and they function fairly well.

Since unisolar's 68's are back up to $200 per panel, I'm not sure whether I would go that route at this point.  There are some other flexible panels out there (look like they're about 175-200 for 100w).   

I think lisa has a similar system to mine and her experience sounds like mine as well.  Since I moved the batteries inside, the distances of the charger, are minor.  I used 00 gauge wire to hook up components of the system to minimize resistance and kept the distances as short as I could.  

If you use the truck during the day, it will limit the value of the panels -- unless you don't plan on using the vehicle.  If I didn't install permanently, I would not have gone to the vehicle.  I love leaving in the morning and returning to a full battery set after a long day of going places....

On the panels, keep an eye on ebay... I've seen some better deals than are there today.  I think I've seen other flexibles at about $150 for 100 watt panels.  

Since you're thinking about it for a while, just keep your eyes open for deals, particularly on EBAY.    
   

KyBawpaw

This is a great site for solar power questions.  I linked you to the wire size calculator area. Go here: http://www.freesunpower.com/wire_calc.php

Bill_in_Tulsa

Verna said:

Larry, I've thought about putting two 100 watt solar panels on my kayak rack on my truck shell. 

As far as how long of a cable, I know the Zamp 80 watt solar panel I have has about a 20' cable on it.  I'm still waiting for my Zamp 200 watt solar panels to come off of backorder, so I don't know how long its cable is.

They recommend about 30 feet total...

Bill_in_Tulsa

I just purchased the Zamp 200w portable and it is awesome...

RZRBUG

The truck mount would probably be OK for someone camped in one spot for a long time, but I rarely do that.  I have decided for my personal situation, something portable would be more practical, if I ever go solar.  Or, the permanent mount on the trailer would probably be even better.

Nomad

The Zamp 120w cable is 20ft also. I made a 20ft extension for those rare times I can't get out of the shade. Only used it once so far and really didn't notice a change in readings.
RZRBUG - Portable works best for me - Like you, not in one spot very long and in all kinds of sites - Need to put everything where it needs to be for best output.

Saw a guy in a small NV site that had his van covered in cells. Roof and his hood. Looked kind of strange.

jkjenn

jkjenn said:

RZRBUG said:

I've been thinking about the pros and cons of this setup and it occurred to me that I would be limited to keeping the truck in camp.  If I decided to do any motoring around the area, I'd be taking the panels with me, right?  So there would be no charging while I was gone.  Just another thing to consider.

I have a 10W GZ maintainer, but that is the only experience I have with solar.  I also have no experience with boondocking (unless you count one night in a Walmart parking lot), but I'm thinking more and more about doing so and will need a power source.

Larry, yes, that's the con of a vehicle mount solar set up, that's why my main set-up will not be mounted to my Jeep. This set up should allow for quick and easy access to install and remove, utilizing the grommet and some reusable ties. In addition to the TV boost, I am thinking it will at least provide a little bit lf a charge if I stop somewhere or before or after I am done driving for the day, if there is light, when I am just overnight parking while traveling. The panel also easily hangs via suction cups to the T@b to augment my existing 120w solar set-up, bringing the total to 170w.

I will let you know what I think after my bigger trip at the end lf September since this is mostly untested theory right now.

As a follow-up, I was very happy with how this turned out. The little 50-watt did a nice job charging when I would unplug while stopped for lunch, to dump my tanks, grocery shop, or other stops over 10 minutes. The best part was for the nights where I didn't unhook and overnight parked at Walmart. The panel charged until it was actually dark (only stopped before dark once) and before I took off in the morning.

Nomad

Jenn - As we've discussed before, our Jeeps must have different alternators/batteries. On the road, my Jeep tends to handle the fridge and keep the T@B battery charged. I rarely even unhook when I'm shopping or dining. Have left it that way for over an hour with no problem since the T@B battery is charged and not drawing much from the TV - I have shut the fridge off though as it seems to seal and hold the cold in well.