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Help me purchase a solar system for my class c.

Droptop351
Explorer
Explorer
So let me preface by saying im knowledgeable enough to be dangerous.
heres my plans and what I understand I need.
Id like to put enough panels on rv to avoid having to use generator as much as possible, its right below the master bed and i cant possibly sleep with it running to power the ac.

id like to wire up a 30 amp receptacle from the inverter near my generator so I can just plug in the shore power cord here ( understand that id have to turn off breaker on the power box to avoid charging the batteries while drainging them heh)

Also id like to be able to boondock and use as little gas as possible running the generator. ( have an onan4000 now, also have a champion 3500 that was given to me by previous owner who said it was alot better on gas so this is option as well). Having said that id like to be able to have the ac run during the summer in the day by pulling from batteries and relying on solar to charge them up. This would also be nice for driving down the road in the summer and keeping the ac unit on in the god awful summer heat we get in nc with the humidity. As a side note im not opposed to upgrading the alternator on the v10 to a beefier one to help keep the batteries up while driving and ac running. I could plug the 30 amp in to the inverter outlet and let the house ac run off of it.

I know these may seem strange but i just want to take advantage of free sun, and avoid using gas so that I can be out as long as possible, also not worry about generator noise restriction in places I may go. Am I crazy?

I have a little boy who does like to watch tv going down the road but we use the rv to get us to destinations where we can either go out and tent camp, or go hunting, or fishing adventures and having a comfortable place to come back to. When weather is bad its a fall back place, or when hes tired of fishing and im not him and mommy can go watch tv ๐Ÿ™‚

So devices that would be using power
a. AC 15,000 btu coleman mach unit, I want to go out on a hike in summer and come back and rv be cool because the ac was running while I was gone.
b. fridge (but im thinking to save power might be beneficial to just run off gas, enlighten me)
c. 19" tv with dvd player for my boy ( he drained the 2 batteries i had in about 6-8 hours of watching tv) - ive considered getting an led version that might use less power than the lcd version. Really i am trying to avoid spending alot of time in the rv more out and about
d. charge my son's ipad, we can do this from 12v or 110 either way so that is not a big concern

1) Solar Panels (how many to be determined)
Im considering either the TYN or Amerisolar panels on this page Click Here
What are the differences between these? One better than the other?
Im thinking either 2 or 4 of these since the price is good. What would align with my needs?
Given the charge controllers ive looked at below I could wire these up in 48v and run smaller wire down to the charge controller.

Next question then becomes mounting them, im somewhat crafty and have considered building a modular system to store the panels inside and just put them up when we stop, but im not opposed to permanent mount on top of the rv either.

Thoughts/recommendations/previous examples welcome here also.

2) Solar Charge Controller (mppt, beyond that I have no idea)
Looking at Tri Star mppt
Would I be better served to get the 60 or just stick to 45?

3) inverter (pure sine wave im assuming)
Educate me on what would be best - im thinking 2000-3000w here
do I need pure sinewave? or will i be ok using modified?

4) Upgade Batteries
I currently have 2 of these (put in by previous owner) I believe they are 100ah roughly but dont know that they are "deep cycle"
NAPA 7236 Batteries
Are these batteries viable, if so get 2 more for a total of 4? Or should I dump them and goto golf cart style batteries? 4 total and wire in series banks parallel?
Battery recommendations are most welcome?

5) wiring - going to mount the inverter as close to the batteries as possible but still use 4/0 between batteries and to the inverter is my thoughts. Then what about from the inverter to the receptacle near the current outlet for the generator/shorepower cable?

Wife has given me the go ahead on this and budget isnt unlimited but im not opposed to future proofing either.

4 panels = $600
4 batteries = $6-800ish
Controller = 3-500ish
Inverter = ???

Thanks in advance for all the help
46 REPLIES 46

time2roll
Nomad
Nomad
7345 is not great for ANY battery. Mostly just a 12v power supply for the house.

westend
Explorer
Explorer
I'd bet a doughnut that a Parallax 7345 won't be a good fit with 6V AGM or FLA batteries. The output will not be right to keep them charged correctly or quickly.
A new programmable solar controller will do everything right with your batteries and you could keep the Parallax for those seldom times a 120V charger is needed.

Also, in a previous post, you have stated Amp Hour capacity in 6V batteries as below 200 AH. I believe that is incorrect. All 6v GC2 batteries I've seen have more than 200 AH capacity. Series mating two 6V batteries maintains the original capacity of amp hours but outputs 12V. I'd suggest to buy 6V FLA batteries from Costco, Sam's Club, or Trojans at a golf cart supplier. The Trojans will be the best but the others will be less expensive and work. AGM's will be expensive, period.
'03 F-250 4x4 CC
'71 Starcraft Wanderstar -- The Cowboy/Hilton

pianotuna
Nomad II
Nomad II
Hi Droptop,

It may be necessary to email duracell to find out what they recommend as the maximum charging voltage. Then look at the specifications on the existing parallax unit.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

Droptop351
Explorer
Explorer
Agm duracell
Looking at the battery above...
Another question for those more knowledgeable than me, if I were to upgrade to agm batteries do they require a special charger or does the parallax 7345 be fine for that? A local Trojan dealer told me I need a special agm charger

Any thought on above battery as well? Open to other suggestions also

grizzzman
Explorer
Explorer
pianotuna wrote:
And you need to count the cells in each string of the panel. Or look at the specs.

grizzzman wrote:
pianotuna wrote:
Each cell on a solar panel produces about 0.5 volts. 250 watt panels may not have a greater cell count than 150 watt panels, so the output voltage would be the same. The amps on the 250 watt panel would be greater.


You need to do you're homework. This shows that you don't understand the difference between panels.


Looks like "I" need to do my homework. I apologize
2019 Ford F150 EcoBoost SuperCrew
2016 Rockwood Mini Lite 2504S. TM2030 SC2030
640 Watts Solar. Costco CG2 208 AH and Lifepo4 3P4S 150 AH Hybrid. ElectroDacus. Renolagy DC to DC charger. 2000 Watt Inverter.
Boondocking is my Deal

Almot
Explorer III
Explorer III
Easy, grizz. If there is a dozen people here who do understand, maestro is one of them.

pianotuna
Nomad II
Nomad II
And you need to count the cells in each string of the panel. Or look at the specs.

grizzzman wrote:
pianotuna wrote:
Each cell on a solar panel produces about 0.5 volts. 250 watt panels may not have a greater cell count than 150 watt panels, so the output voltage would be the same. The amps on the 250 watt panel would be greater.


You need to do you're homework. This shows that you don't understand the difference between panels.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

grizzzman
Explorer
Explorer
pianotuna wrote:
Each cell on a solar panel produces about 0.5 volts. 250 watt panels may not have a greater cell count than 150 watt panels, so the output voltage would be the same. The amps on the 250 watt panel would be greater.


You need to do you're homework. This shows that you don't understand the difference between panels.
2019 Ford F150 EcoBoost SuperCrew
2016 Rockwood Mini Lite 2504S. TM2030 SC2030
640 Watts Solar. Costco CG2 208 AH and Lifepo4 3P4S 150 AH Hybrid. ElectroDacus. Renolagy DC to DC charger. 2000 Watt Inverter.
Boondocking is my Deal

time2roll
Nomad
Nomad
Both the panels you stated have 60 cells and are 24 nominal panels. Will work fine with the MS MPPT controller.

A few 24v panels have 72 cells and the higher voltage will dictate more parallel than series. You can get controllers up to at least 600 volts if you really want to do it all in series. There is a modest loss of controller efficiency as the conversion grows wider.

Almot
Explorer III
Explorer III
Don, you've lost me with 150 vs 250W.
All 150W I've seen were ~20 Voc. All 250W are +30 Voc, this particular one is 38 Voc.

If number of cells was the same, and in the same strings, then yes, 150 and 200W would have same voltage but 250W would have have higher amps.

time2roll
Nomad
Nomad
Droptop351 wrote:
When you guys say 150v controller where do you get that number from and what does it mean?
It is in the manual. I recommend any controller you should fully read the manual before you click and buy.

Use the string calculator to verify panel and configuration compatibility with controller.
http://string-calculator.morningstarcorp.com/

pianotuna
Nomad II
Nomad II
Each cell on a solar panel produces about 0.5 volts. 250 watt panels may not have a greater cell count than 150 watt panels, so the output voltage would be the same. The amps on the 250 watt panel would be greater.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

CA_Traveler
Explorer III
Explorer III
Droptop351 wrote:
Does that mean the total amount of volts it's capable of? So 4@24 would be 96 volts even though I wire them up in series/parallel to get 48v feed to controller?
No per above it's the panel Voc. 4x series/parallel would be about 60V.
2009 Holiday Rambler 42' Scepter with ISL 400 Cummins
750 Watts Solar Morningstar MPPT 60 Controller
2014 Grand Cherokee Overland

Bob

Almot
Explorer III
Explorer III
Droptop351 wrote:
Does that mean the total amount of volts it's capable of? So 4@24 would be 96 volts

Please read the specs.
Nominal 24V panel makes over 30V. 250W panels are usually 36-38V.
Besides, as CA noted, specs are for 77F and on a cold sunny day you can get a bit more than 36V.