17 replies to this topic

[Bradders]

Check out these two You Tube videos which talk about connecting solar panels together. You may need to cut and paste as I'm not sure that the hyperlinks work.

 

  - DIY solar power with Will Browse 

 

 - Explorists Life - DIY campers

 

Will Prowse is excellent and is worth subscribing to as he does a lot of reviews on lithium batteries, etc.

 

What they basically say is that Parallel connected panels need to be the same voltage and series connected panels need to be the same amperage.

 

If you are going to use the splitter in the Amazon link above, you will need to get a panel which produces the same voltage as the one that is already on the roof as the splitter is wired in parallel.

 

Now with regards to the inputs on the back of the camper and on the roof, (and hopefully somebody will correct me if I'm wrong here) they must be wired in parallel otherwise there would be an open circuit when one of the outputs wasn't being used. In which case any panel that you connect to the rear input must be the same voltage as the panel on the roof.

[GflGdog]

As a newbie to solar, it seems from my studies that one complication is the high voltage of the overland 160w panel that FWC installs on the roof. Voc is 32.8v, where most of the portable panels are around 18 or 19v. 

[JohnathanAcevedo]

Congratulations on your new Grandby model! It's awesome that you're considering adding a second solar panel. Generally, if your camper is prewired for solar, the installation process for an additional panel should be relatively straightforward. However, it's essential to ensure that the existing wiring can accommodate the extra load. Consulting with a professional or reaching out to forums for advice from experienced campers might provide valuable insights.
Additionally, exploring solar panels cork could offer helpful information tailored to your specific needs and setup. Best of luck with the upgrade, and happy camping!

Edited by JohnathanAcevedo, 21 February 2024 - 12:45 PM.

[SCHawk]

I mounted the portable solar panel that we got with our 2015 Hawk on the roof to the rear of the factory panel. I just plugged it into the provided receptacle on the back camper wall. I figured that since the camper was set up to handle both panels anyway that this was the simplest way to go. I haven't seen any posts about anyone else doing this.

[superduty]

I recommend that you think about the following:

 

First figure out how much power you use and need for the type and seasons of camping you will be doing.  Remember to factor in consecutive days of low Sun, clouds, rain, etc. if appropriate to your type of use (boonie camping no shore power, occasional shore power, etc).

Size your Solar and battery storage needs to accommodate the power needs you have already figured out (above)

Think about roof weight and if you are going to need to replace your solar controller to accommodate the added solar panel(s)

Consider buying the largest single panel that will fit on your roof.  It will be cheaper and lighter in total weight than any combination of two or more solar panels.  Yes, I know you already have one panel but the additional cost of one large panel may not be much more than another smaller panel.  I bought a 360 watt LG residential panel for $310 in May 2021.  I did have to upgrade my solar controller with a new one to accommodate the new panel.  I previously had two 100 W panels and the single new 360 W panel is less than the combined weight of the two 100 W panels. Only one set of wires too.

If you do decide to add a second panel to your existing system, assuming you are using industry standard MC4 connectors, you can buy a Y cable, to connect to panels together in serial or parallel, on Amazon.

I hope this information is helpful

 

 

Craig

 

Do you have a write up on the residential solar panel you added? 

 

  What are the dimensions of it?  How much does it weigh?  Some of those residential panels weigh a lot (for camper use)?  How did you mount it?

Edited by superduty, 13 April 2024 - 10:15 AM.

[ckent323]

superduty, et. al.,

I had two 100 watt panels and started looking at what it would take to get 300 or more watts of solar on our camper.  The combined weight of the two 100 W panels with cables and mounts was about 40 pounds.

 

I looked at a number of 100, 120 and 200 watt crystalline cell solar panels.  I also looked a a number of 350 - 400 watt crystalline cell solar panels.  In all cases, any combination of those 100 W - 200 W panels resulting in 300 W or more will be heavier than a single 350 - 400 watt crystalline cell panel.  

Besides the panels there is the extra weight of the cables to connect two panels as well as two mounts instead of one.

The cost of 350 - 400 watt residential panel vs a 100 or 200 watt panel was slightly more.   When I checked 100 W panels were $115 to $175, 160 W - 200 W panels were $220 - $300 and 350 W - 400 W panels were $330 to $450 (all prices depending on manufacturer).

100 W panels weigh about 15 lbs, 160 W & 170 W panels weigh about 20 lbs, 200 w panels weigh about 25 lbs and 350 - 400 W panels weigh about 40 lbs.  None of these weights include mounting brackets or cables.  Keep in mind then that there is an additional cable set required when adding a second pane as well as additional mounting.  Once the additional weight of those items are included the total weight for a single panel is roughly 5 or more pounds less (including cables and mount) and the cost is almost the same since you don't have to buy another set of cables and you may not need to buy another mount (your original mount may need modification though).

Importantly one must look at the dimensions of the various panels to be sure they will fit.  The vent location(s) will dictate what the maximum size will fit on a particular camper.  Vent locations and numbers vary widely depending on camper model , configuration and model year so each person must measure the available space on their camper roof.  Our camper is a FWC Keystone and the panel mounts between the two roof vents.   All the panels that I looked at from 320 W to 380 W were 67" x 40" x 1.57" thick. Once the panels get over about 380 W the length and width can get a bit larger.  Roof widths are 75" for the Swift and Fleet models to 80" for the rest of the models.  The determining factor is if there is a clear 40" wide location on the roof for the panel (assuming it is placed with the long dimension across the width of the camper roof.

Prices may have undoubtedly changed since I did this comparison in early 2021.

When I though about lifting the top with the 40 pounds of existing solar panels I decided it was already as much as I wanted to deal with. I wound up selecting an LG 360 W panel and replacing the two 100 W panels with it.  I got 150 additional watts (1.75 times the original 200 W or 75% more power) with no added weight.   I was able to use the two 100 W panels on a boat but I could have sold them and recovered some of their cost.  I paid $310 for the 360 W LG panel.

<Edit: My LG panel is 360 W not 350 W - change made above>

I hope this is helpful,

 

Craig
 

Edited by ckent323, 13 April 2024 - 11:28 PM.

[superduty]

Great info. Thank you. On a previous truck build I put a 380w panel on a shell. Worked great.

How did you mount the panel?

Fwiw - Craigslist is a great place to find the residential panels for a fraction of the price of new. I think contractors have a panel or two left over from a job and they sell them.

[ckent323]

Original 200 W panel mounting

https://www.wanderth...n-fwc-keystone/

I used two of the four Aluminum square tubes attached to the Yakima tracks with T-bolts to mount the 360 W panel between the two roof vents.