Sizing Solar System

[eXodus]

So my winter project will be - installing a solar system:

At the moment I've got
2x 225ah new 6V golf Cart batteries = 225ah
1x 110ah old 12V deep cycle = about 95 ah

Just guessing = 320ah usefull / 2(50%) = 160 ah * 12V = 1920wh -  nearly two kwh.

1x 800 amp cranking coach battery.

I did just install a residential refrigerator which draws about 1kwh a day plus inverter and charger losses I have to produce about 1,5kwh a day. Which would be optimal.
But I wouldn't mind running the genset and we are more the active kind of people so we will be driving ever other day.

If my old 12v deep cycle dies I will just switch in two more of these golf cart batteries. Would end up with 450ah.

I found some nice flexible solar panels which would have the perfect size for my roof:
http://solopower.com/products/solopower-sp1/

86x 15.5 inches with 80-95w.

I could probably fit up to 8 on my roof. But they are not really cheap - about $1.6-2.0 a watt.
How big should I go ? are 360w enough ? (4x 90w) $1.6 per watt

We are no big energy users. Most time outside with the horses.

[ClydesdaleKevin]

My advice with solar is to get the most you can afford.  The more the better.  Even at 705 watts flat mounted with a VERY good system, we still find that we are lacking once in a while (my wife is a power hog...lol!)

Kev

[eXodus]

efficency is so far as my knowledge with panels goes a problem of size. i had some CIS panels at my house they where not the best efficient but they didnt lost anything if there had been clouds on the sky. in fact they got better when they where cooler, so a cloudy day i got more amps in then on a bright hot day.


this are not not perfect modules but easy to mount.
mrmuse why is driving a problem with flexible modules ? they stick with the full side to the roof. i dont wanna loose them.

[pvoth1111]

Panels do loose their ability to create power at their rated power output when they get hot....they make water cooled ones that do much better in hot areas but they cost too much and are not practical for RV use....

[eXodus]

thanks for the responds !

This is my problem:
[smg id=6718]

My roof is cluttered like hell.  I do get to my calculation maybe 3 square panels on my roof.  But 8 of the long and skinny ones.

25% of 320ah is 80ah * 12V =  this means I need 960 watts of solar ? Sounds like very much. 
With this kind of setup I could recharge my battery bank with full sun in about 5-6 hours. We've got about 8-12h of full sun here in Florida.

Could it be that you are meaning 25% of the amp hours I will be drawing ?
Would I go from the 160ah which I will use most likely then 25% - = 40A which translates into 480 watts of solar.  Which sounds more realistic to me.
I got the Motorhome for driving and exploring the country.  If the solar setup is a little to small - the alternator will top up the rest. In a another post I was researching for installing a 250A Alternator. It is do-able, if we run out of energy we pack our stuff and go on the road for 2-3 hours.

We are running out of Hay and Water every 5-7 days so we have to move.

[Rickf1985]

One big problem I see is right there in that picture, shadows from all of the stuff up there. I have the same problem with mine but a lot of my stuff is low profile and the shadows are not an issue. I did a bunch of reading on solar and the flexible panels were not the best rated although the technology is improving. There are three different types of panel cell construction and they all differ in efficiency. I do not remember what they all were but read up on them first before jumping in. It is possible that the flexible ones have improved to the point that they are now worth it. One problem I can think of with the flexible ones is they are stick on aren't they? That would create problem with roof maintenance in the future since you will not be able to access the area under them and that area will be getting very hot. Maybe too hot for the rubber too handle. When you try to peel them up I guarantee the roof coating will come up with them and that will negate ever being able to stick them down again. Just some things to think about.

[ClydesdaleKevin]

I went with as much solar as I did so I could flat mount them and not worry about too many shadows...and as long as I park with the starboard side facing the south, there aren't any shadows at all.



I still have enough room up there to mount 2 more 100 watt Kyocera panels, and even a couple of smaller ones on the AC shrouds, which I eventually might do.  As long as I have enough room to walk one foot in front of the other between them, I'm all good...lol!  My Morningstar MPPT 60 amp charge controller can handle up to a 1000 watts easily. 



And my battery bay holds 6 6 volt Interstate golf cart batteries.



Its a good system for boondocking...although like a said I may add another couple hundred watts to offset Patti not being very good at power saving habits...lol!

Kev

[eXodus]

eXodus,
Don't laugh now, but I've seen people hang the smaller ones on the side of their MH, or even secure them to the roof rack to hang down the side.  You could store the panels away when driving while securing the wiring up top til you reach your destination, then plug in again.

you got me thinking - I will be towing a horse trailer most of the times. With a completely empty roof.
Thanks, I will explore this possibility. 

Maybe I just do two or three solids at my roof and can add much more cheap power at the trailer. Less wholes to worry about. Are there good quick connect connectors available ?

[ClydesdaleKevin]

gogreensolar.com has everything you'll need, including connectors.  And they have awesome prices.

Kev

[DaveVA78Chieftain]

Are there good quick connect connectors available

Simple answer is yes (Plow and wrecker plugs/connectors)

Concern may be length of cabling (voltage drop)

Dave

[pvoth1111]

There are many marine connectors available they are tough and water tight....made to take it.....this is how we power mega yachts here in south Fla. Those big boats eat power in large bites and its all done with cords just like our Rv's....just bigger.... lots bigger.

[eXodus]

here is what I see:

A lot of Air in between - a potential for ripping them off during driving or while a hurricane or storm her in Florida.

That's why I wanted sticking panels in the first place - we've could get some very heavy winds down here - and nobody has solar panels mounted with a air gap in between.

[ClydesdaleKevin]

That's why I put a wind fairing in front of the front solar panel...effectively protecting all the panels behind it from head winds.





Kev

[eXodus]

So I'am really thinking about the - use the trailer roof for Solar solution.

Since I've got lot of space in the trailer and weight is no concern, I was thinking about putting a couple of deep cycles in the trailer and reduce the cable length between batteries and Solar system.
In this case I would have a 12v system in the trailer (light and stuff) and 12v system in the coach.  So now how do I get the energy economic into my coach ?

Some kind of 12V/12V Charger/ Regulator ?
Or should I just trust the Trailer Battery charging wiring ? I will put maybe about 400watts of solar on the trailer. So it would be 34A, and with the batteries in the trailer (same size as coach) they should get an equal charge of 17A -  which would be well inside the limit of the hitch connector (30A)  Or even when I would run the onboard charger (rated with 45A but I'm guessing this it not charging) I would have 22.5A.

But I would have a awful long 12v cable from the trailer to the coach battery.

[eXodus]

I found some cheap panels  2x 200w could get them for $300, but they have 63V open Circuit voltage.

But for this Voltage - anything over 48v the Charge Controllers are getting expensive - about $200 for a 40A model. Only MPPT in this regions.

Or is 200 ok ? So I would still have a 400w system for about $500. Has anybody maybe a experience with a cheaper model ?