Solar upgrade on a 2014 E21

[John in Santa Cruz]

so my E21 has the 2014 vintage 160 watt solar panel on the roof.

I'd like to replace that with the highest capacity panel I can put on the original rails, maybe a little bit larger to use up more of the space behind the A/C...



hoping I can stick with the factory solar wiring... anyone know what the largest panel I can fit back there is?. the existing panel is 27" x 58" or so, and I think I could go as big as 44 x 66, maybe adding a couple more mounting points in front of the existing aluminum railings. hmm, looking at sizes of random panels, maybe I can run 3 20x44" 100W panels to get to my 300W target and stay in a reasonable size foot print without having to mount panels on the forward part of the trailer...

I also want to get LFP's to replace my GC2's, as I'm getting a compressor fridge, so I'll be replacing my power converter and existing dumb PWM solar charge controller with Lithium compatible units. PD4655L will do the power converter, but I dunno much about solar converters other than the basics. I'd as soon avoid fly-by-night chinese stuff in favor of more reliable and supported brands... I started looking at GoPower, only to see they are now Dometic, ARRRRRRRGH.

[davidmurphy02]

Originally Posted by John in Santa Cruz

I also want to get LFP's to replace my GC2's, as I'm getting a compressor fridge, so I'll be replacing my power converter and existing dumb PWM solar charge controller with Lithium compatible units. PD4655L will do the power converter, but I dunno much about solar converters other than the basics. I'd as soon avoid fly-by-night chinese stuff in favor of more reliable and supported brands... I started looking at GoPower, only to see they are now Dometic, ARRRRRRRGH.

If Dometic bought them they'll probably change the name to NoPower

[Centex]

Originally Posted by John in Santa Cruz

... I think I could go as big as 44 x 66, maybe adding a couple more mounting points in front of the existing aluminum railings. hmm, looking at sizes of random panels, maybe I can run 3 20x44" 100W panels to get to my 300W target and stay in a reasonable size foot print without having to mount panels on the forward part of the trailer...

You might take a look at some of the 'bare panel' offerings AM Solar lists, several of the Zamp 100-115W panels (in a multi-panel array) seem to be within your footprint and output goals though some innovative framing might be required.

Much of what they offer is available through other sources but given AM Solar's reputation a listing by them might be taken as a positive indicator of a component's quality / suitability for our applications.

BUT, we must note that as of May 26, 2021, Zamp is also now under Dometic's less-than-reassuring umbrella. Perhaps they've not yet had time to screw-up the products, and you're willing to take a chance on never needing long-term support?

I must mention that it strikes me a pair of the Grape Solar 200W panels as offered by AMS might be an ultimately easier and more cost-effective install even though that does mean placing one forward of the MaxxFan. AFAIK Grape Solar has no affiliation with Dometic (yet ).

All just for your consideration, Have Fun!

[dfandrews]

John,
How about a solar panel on a post, that can be aimed. I'm thinking about a rear bumper mount version of Ron in BC's scheme.

https://www.escapeforum.org/forums/f...ount-4951.html


maybe even one front, one rear.

[John in Santa Cruz]

Originally Posted by dfandrews

John,
How about a solar panel on a post, that can be aimed. I'm thinking about a rear bumper mount version of Ron in BC's scheme.

https://www.escapeforum.org/forums/f...ount-4951.html


maybe even one front, one rear.

I want my solar fixed and always working. I *am* toying with a tip-up roof mount, but it would likely require a ladder to raise and lock in place. I like to camp with the hitch facing due north when I'm boondocking, that way the morning sun is on the curb side, and the afternoon sun is on the street side, so my mount would only have to tip up and towards the back (south)

BUT, we must note that as of May 26, 2021, Zamp is also now under Dometic's less-than-reassuring umbrella. Perhaps they've not yet had time to screw-up the products, and you're willing to take a chance on never needing long-term support?

arrrgh. coming soon, Thor buys Dometic, or Dometic buys Thor, same difference, the whole RV market is doomed.

[Rossue]

Large solar panels are costly to ship, however Platt Electric is not too far from you and has LG & Panasonic panels in the 350- 400 watt range. One 375 watt LG panel is 67 x 40".

I was going to use one on a van, yet decided to go with 2 Eco Worthy 195 watt panels instead as they ship for free on Amazon and are easier to put on a high roof van.

[Centex]

Originally Posted by John in Santa Cruz

I want my solar fixed and always working.

Originally Posted by John in Santa Cruz

I *am* toying with a tip-up roof mount, but it would likely require a ladder to raise and lock in place.

I was really enamored with this notion, but finally reality checked-in and I acknowledged I'd want to mess with adjusting panel tilt (and then re-adjusting for travel) about as often as I'd want a root canal ....

... decided my money was better spent on a combination of 'excess' PV capacity (for when angle / harvest yield is less than optimal) and extending the capacity / duration of my storage. Don't know about you but the older I get the less I like ladders of any type or height.

Originally Posted by John in Santa Cruz

arrrgh. coming soon, Thor buys Dometic, or Dometic buys Thor, same difference, the whole RV market is doomed.

funny, if it weren't so sad

[John in Santa Cruz]

Originally Posted by Rossue

Large solar panels are costly to ship, however Platt Electric is not too far from you and has LG & Panasonic panels in the 350- 400 watt range. One 375 watt LG panel is 67 x 40".
....

those large panels are a higher voltage, tho, aren't they? I guess they'll work with a MPPT

[alanmalk]

Originally Posted by John in Santa Cruz

those large panels are a higher voltage, tho, aren't they? I guess they'll work with a MPPT

The higher voltage panels will work quite nicely with MPPT. One advantage is that the current (amps) between the panel and the controller will not increase significantly, but the voltage will - resulting in no increase of voltage drop power loss. Plus those large commercial panels are now approaching 500 watts in a single panel.

[John in Santa Cruz]

so whats a good brand of MPPT suitable for lithium ? ideally switchable between flooded and LiFePO4 ?

[rubicon327]

Originally Posted by John in Santa Cruz

so whats a good brand of MPPT suitable for lithium ? ideally switchable between flooded and LiFePO4 ?

John you might like this video

https://m.youtube.com/watch?v=kF_cVEYxj3E

[Perry Butler]

Are you planning on just replacing your 160 watt or adding another panel?

It looks like you have plenty of room in back for a 400 watt panel. Our 5.0 does not have the room your 21 has in back. For a panel that large I'd probably use rails at the ends of the panel (sides of the camper), but definitely use a few glued brackets to keep the middle of the panel nice and flat.

Solar panels have changed in the last few years. This spring, in a conversation with Northern Arizona Wind & Sun, one reason solar farms are exchanging their panels is because today's panels are much better at harvesting sun early in the morning and late in the afternoon, one of the traditional major reasons for wiring in series. Before talking to NAW&S I was going to add another set of wires to the roof for 300 additional watts. Mixing our existing 170 watt panel with three 100 watt panels in series gave a loss of 65 watts, but in parallel only a 5 watt loss, giving us 465 watts on the roof. No way was an additional loss of 60 watts going to make up for the theoretical gain from series in our case.

Our 10 awg wire can handle up to 25-30 amps. Since our panels are flat on the roof, and nothing is perfect, our realistic goal is to provide 15 amps down the wires at under 4% wire loss. Our 465 watts on a sunny day easily meet that requirement. The most I've seen is 22 amps, at high noon, the end of June, for a 10 awg wire loss of 5.6% (for jollies, I flipped the panel breakers off the previous night and on again at 12:30 daylight time) That extra loss means nothing to us, since the batteries will be full by noon under those conditions anyway.

We wanted Victron components, because they can work together with each other. Our Victron BMV-712 battery monitor, works with our Victron 100/30 for our roof panels, and our Victron 100/20 for our portable. Victron SCC's are also configurable for either lead acid, lithium or most other batteries. There's easily more Internet help on configuring a Victron controller than any other brand.

Buy quality panels/SCC's/cabling! Don't scrimp! Plan wisely!

Enjoy,

Perry

[Vermilye]

If you want to stick with the original mounts, I've been told by GoPower the their 190 watt panel is exactly the same dimensions as the 160 watt panel. Anything larger is going to require adapting the current mounting hardware. I did a modest search for a panel larger than 190 watts that would fit in the 160 watt mounts and did not find any. While panels are getting more efficient (ie smaller for the same wattage), the GoPower panel was the smallest 190 watt I found.

As to solar controllers, I've been pleased with a Victron 100/30, and when I went to a larger portable panel, the Victron 100/50. One point - if you expect to use the Bluetooth connection to your phone from the tow vehicle, with the 100/50 you may need to add a VE Direct Dongle. The Bluetooth signal from the 100/50 was not strong enough to reach the truck. With the dongle, it works fine. I also have the Victron 712 Smart battery monitor, which is useful for determining an accurate state of charge of the batteries.

[Perry Butler]

Originally Posted by rubicon327

John you might like this video

We have a Victron 100/20 for our portable solar panel and a Victron 100/30 for our rooftop. As Will found out the wire bus for the 100/20 is a joke. However, the wire bus for the 100/30 is much more robust and not a problem. Sometimes Will's video's leave a little to be desired. While I watch Wills videos and belong to his DIY Solar Power Forum, I prefer Explorist.Life for advice and wiring.

Another Victron plus is a bluetooth connection so we can watch our three Victron products while driving down the road or sitting outside. I want to know where we're at in case there's a problem. One time a wire came loose on our GoPower controller going down the road, so we had no charging that day. With our AGM's and only a 170 watt panel on top we slept that night with the furnace turned down to the thermostat's minimum 45 F. The GoPower SCC was replaced with our Victron 100/30 last February.

Last month, heading north we observed 12 amps going up hill and 10 amps going downhill. OK, it's fun to watch, but meaningless in the true scheme of things.

Enjoy,

Perry

[Centex]

An interesting video by Mr Powers but I never caught where he mentioned the amp/volt output ratings of his test panels? The array output ratings have a significant bearing on selecting an appropriate and cost-effective SCC, IMO.

FYI Victron offers an Excel-based 'MPPT calculator', IMO a nifty and informative tool which can be loaded with parameters for whatever brand PV panels you might be considering and see output performance with a range of Victron SCCs and system / operating configurations.

Once you've loaded various other-than-Victron panel parameters in the "Modules" tab, it's easy to play with different array configurations to see results, but the tool is limited to arrays with all panels (modules) being the same (e.g. it can't handle arrays of different panels feeding one controller, not sure that's a desirable situation anyway). The info could probably be correlated to other-than-Victron SCC's having similar characteristics.

Scroll to the bottom of this webpage to download Victron's "MPPT Calculator Excel sheet".

Have Fun!

[Brian B-P]

Originally Posted by John in Santa Cruz

those large panels are a higher voltage, tho, aren't they? I guess they'll work with a MPPT

Yes, as long as the maximum open-circuit voltage of the panel is within the allowed input voltage of the controller. For an example, Victron's smallest MPPT solar charge controllers are identified by the maximum input voltage and charging current, so a "75/15" allows up to 75 V from the panel and up to 15 amps to the battery. Common panels for residential use in the 300 watt to 400 watt range have 60 or 72 cells in series, so their open-circuit voltage is about 33 or 40 volts... you could even put two of them in series (if they're suitably matched in size) and into one of these controllers.

There are higher-voltage panels and different controllers could have lower input voltage ranges, so definitely check the panel and controller specs.

[John in Santa Cruz]

ill probably consult with my fiberglass marine repair guy on the mounting, but right now, a single 350-400W panel sounds perfect, i can probably flip my old 160W and GP PWM controller.

I like the idea of the Victron, I have their SmartShunt now (like the 712 but phone only, no display)

[oldwave]

Originally Posted by John in Santa Cruz

so whats a good brand of MPPT suitable for lithium ? ideally switchable between flooded and LiFePO4 ?

Victron

[fudge_brownie]

Be aware that if you are installing a panel in the 350-400 watt range it will be a 24 volt panel. This is good, as they are more efficent than the 12 volt you have now. What you need to be aware of is; the need to have a solar controller that will handle 24 volt. Not sure of implications of mixing 12 and 24 volt.

[John in Santa Cruz]

Originally Posted by fudge_brownie

Be aware that if you are installing a panel in the 350-400 watt range it will be a 24 volt panel. This is good, as they are more efficent than the 12 volt you have now. What you need to be aware of is; the need to have a solar controller that will handle 24 volt. Not sure of implications of mixing 12 and 24 volt.

the 350 and 400W home panels I've looked at have an even higher DC voltage, like 40-50 volts. You can't use these with PWM, but MPPT controllers handle this easily, for example the Victron 100/30 or /50 handle up to 100V open circuit voltage... The 100/50 will handle up to 700W of solar panels, and can be configured for 12V LFP.