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Roof & Remote Solar


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#1 JWL

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Posted 01 August 2020 - 11:03 PM

I have looked up this topic and most here (that I found) are several years old, so looking for updates. 
I am in the final stages of planning my solar need for my Hawk Shell. It’s going to be light at first, probably 1 AGM battery, no fridge, only a furnace that will rarely get used, 2 fans that may get used at night and may not even use the camper lights that much. BUT I know that will change, I see a portable fridge in our future and will go to Lithium when the AGM is gone. So my question here is how to balance the solar/controller that will handle the “growth”. I know I want to instal a controller now that will handle future power, most likely Victron, so what size? 
I thought about going 2 100 watt panels on the roof but am now thinking I may not need that much and why carry all that weight around everyday (it will be my everyday driver) so would I be better off starting with say 150-170 watt and add more down the road when needed?
Which brings me to my real dilemma. Since we don’t always camp in full sun would I be better off going with less on the roof and remote solar. Less weight to carry around daily etc. Most of the suitcase type panels I have seen have a controller built in usually a PWM so I assume I would not run that through the one in the camper but would it be less efficient? And when I go Li would it work? And if I go with something that doesn’t have a controller I assume the rear solar input is set up to wire into the camper controller? AND, finally, if the roof top solar is not putting out that much and I put out the portable do I need a controller that could handle all of it, roof and portable, or would one that handles the rooftop suffice? 
I hope this makes sense, I have been researching this  all afternoon and my head hurts. Thanks!


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#2 Vic Harder

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Posted 02 August 2020 - 12:13 AM

Budget and space are important factors too.  And how long you plan to be "out" for between recharges.  Check out my More Power Scotty thread... link in my signature block


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#3 JWL

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Posted 02 August 2020 - 06:39 PM

Thanks Vic, for everything. I have read your post many times, usually gleaming for specific information, this time I read through all 28 pages. Man I hope there is not going to be a test! 
I was just curious though that since that is what, 3 rears old, if there has been any changes in the technology? Like Lithium batteries weren’t even mentioned until the end and I believe solar panels have gotten more efficient over time.

 

The things that I did not know and wonder if this is still the case is that you have to have a separate charge controller for separate PV panels? Like rooftop and remote. But I guess that even if the rooftop is putting out a little charge if they were separate you would still get the charge from both to the battery. So that makes sense, more expensive but more efficient. 

 

I’m still not sure about the “adding” panels thing though. In there it was stated that if you add a panel you have to add another Controller. But toward the end there was talk about adding panels to the roof and still being fine with the size controller they had.  So I am still wondering if I can start off with a smaller solar array on my roof and then add later? I imagine that since there is only the one connector on the roof it doesn’t make any difference as long as the controller can handle it but can you mix panels? Like start with 150 watt and then add a 100 watt later? Isn’t amps amps and watts watts? 
 

I also realized that I have been way over thinking the size of my controller based on what most are using. That will save some $$

 

Thanks again for all of this it has given me a much clearer understanding of it all. Believe or not :)

 

And any changes out there that anyone has seen or is doing on the remote panel front? I know toward the end there you said you didn’t know if it was worth it, has that changed. 


Edited by JWL, 02 August 2020 - 06:50 PM.

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#4 rubberlegs

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Posted 03 August 2020 - 05:40 AM

We’ve been ok with just 90W portable solar and one AGM battery. We have a 2 way fridge, water pump, lights, heat, one fan that’s rarely used, two iPads and two phones. Of course, that’s in sunny weather. Cloudy weather we can’t keep up.

I put the portable solar on the roof and lock it while out hiking.
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#5 craig333

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Posted 03 August 2020 - 04:18 PM

You can add panels up to the capacity of your controller. I find three hours of sunlight is usually enough so unless its completely shaded I'll usually get enough of a charge. I have a separate controller for my portable panel but I could have easily wired it into the trimetric controller. I just used the other controller because I had it and its a backup in the unlikely event I ever have an issue with the trimetric. 


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#6 JWL

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Posted 03 August 2020 - 09:28 PM

Thanks craig333!
 

I also jus realized a lot of my questions were answered in this post  

https://www.wanderth...ttage-mismatch/

 

And this too

https://www.wanderth...lar#entry214521

And here I thought I had really searched through everything! 
Thanks Y’all 


Edited by JWL, 03 August 2020 - 09:55 PM.

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#7 rando

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Posted 05 August 2020 - 04:40 PM

Your plan sounds solid.     

 

I also have 160W on the roof and a rarely used 120W foldable/portable panel.   

 

I plug in the portable in parallel with the roof panel through a Victron MPPT 100/20 charge controller.   The key thing here is that the 160W roof panel is sufficient to keep everything going in normal conditions, without any thought or effort.   It is only when the roof panel isn't providing enough power that I need the portable, so you don't really need to size the controller for the full rating of the roof panel and the portable at the same time.   An MPPT 75/15 or 100/20 would likely be sufficient for what you need.   

 


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#8 Stokeme

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Posted 06 August 2020 - 04:50 PM

X2 ... my $.02 here ... (have not read the above linked threads) ... I tend to overcompensate in case I want/need more later. The 100/20 should offer that, but, it all really depends on your eventual energy consumption. I highly recommend spending the extra $ for a Smart Victron controller, with Bluetooth, no matter what your controller size. Having all that ready info, plus having the capability to easily change settings, is of tremendous value. As you probably have read, you can grow your system by running batteries & panels in parallel. In that fashion you retain a 12V system. 12V allows an easy plug & play with a rear portable panel, if needed, using your one solar controller. You will not need a 2nd controller, with a 12V system, to access multiple external solar outlets, if your initial controller is adequate.

Edited by Stokeme, 06 August 2020 - 07:03 PM.

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#9 Vic Harder

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Posted 06 August 2020 - 05:54 PM

Another data point:  Just got back from a trip up to a lake outside of Prince George, BC.  We were camped in partial shade.  The 330W rooftop panel could NOT keep up with our demand (which includes a 1800W inverter cooktop) can can easily keep up when we are moving about and parked at sunny trailheads.  


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#10 craig333

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Posted 06 August 2020 - 06:52 PM

Not many of us are crazy enough to run an 1800w inverter cooktop! Whats your average cook time using that?


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