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270w solar world panels

sportzfann
Explorer
Explorer
I have a buddy that can get these panels for very cheap thru his home solar co. I wanted to know if these type panels are worth installing on my fifth wheel. I checked the internet and the voltage is rated high, compared to the ones I see advertised for RV installs.
Any comments/Advice from you solar folks? thanks, Brian ๐Ÿ™‚
37 REPLIES 37

JiminDenver
Explorer
Explorer
I plug the trailers shore cord into the big inverter. Two of our big panels keep the 8-D I use as a inverter bank charged up. A third panel keeps the trailers battery up unless we are running big loads, then it too is switched to the inverter bank. Those panels allow the bank to run much more than it can alone. Unfortunately I can not run big loads like that at night when I'm asleep. Luckily the TV/sat is about the only thing that is used late.
2011 GulfStream Amerilite 25BH
2003 Ford Expedition with 435w tilting portable/ TS-MPPT-45
750w solar , TS-MPPT-60 on the trailer
675 Ah bank, Trip-lite 1250fc inverter
Sportsman 2200w inverter generator

jrnymn7
Explorer
Explorer
Also keep in mind, you do not want to run your batteries down over 4 or 5 days. Sulfation will increase considerably. So, best to charge daily or every other day. And deeper discharges greatly decrease battery life. Also, continually doing less than a 100% full charge, over a week or two will cause increased sulfation. This is where solar really earns its keep. Many folks will charge with the genset in the am, and then let the solar do all the absorption and top charging to full, throughout the rest of the day and evening. But ultimately your daily useage will dictate your charging regimen.

jrnymn7
Explorer
Explorer
Brian, the problem with a smaller bank is it cannot handle heavy loads, such as a microwave, etc. The peukert effect especially effects 6 volters; although they do bounce back well, but it can set off the low voltage alarm on your inverter.

I will let someone else deal with your wiring set-up, as I built my own camper, and do not have distribution panels and such.

As for how long it takes to charge a pair of 6's. That depends on several things... Ah capacity, charger size, depth of discharge, voltage setting, etc. Roughly speaking, you can do a 50-90%, at 14.8v and a C/4 rate, in about 2 hours. Most people like to keep the rate (and voltage) lower, but there is no evidence I know of that suggests faster charging will hurt your batteries. And even if it does take a year or two off your batts, it saves so much in genertor run time and fuel, it's well worth it. Of course, going solar, you'll need the gennie much less. So you have to consider your needs, camping habits, budget, etc.

Just keep in mind, converters can be very slow at charging, because many drop down to 13.6v during the constant voltage / absorption stage. So just as the battery's acceptance is dropping, the converter's ability to "push" amps into the bank is significantly reduced at the lower voltage. 2-3 hours can turn into 6-9 hrs... not good when running the gennie.

I noticed you said 2-6's wired in parallel. No. You wire two in series for 12v. Two such "strings" can then be wired in parallel to double Ah's.

http://www.trojanbattery.com/Tech-Support/TechologyLibrary/ConnectionsDiagram.aspx

sportzfann
Explorer
Explorer
jrnymn7 wrote:
I'm all for the OP going with a 540w mppt system, if he plans to increase his boondocking, considerably. But then I'd also suggest a larger bank.


Now, I think if I went with four batterys I could stay out longer.
I want to run all the appliances for (limited time)seperatly except
the a/c unit.
I just need to find the space, and wire them in
(parallel 2-6v together) I want to know how you wire your appliances
to run off a inverter. does the inverter feed the panel while on solar
and then a transfer switch while on shore power?
Does someone have a schematic for something like this?
I will make sure size wise the panels will fit on the roof.
Sorry for all the questions, just getting started with solar.
Brian

jrnymn7
Explorer
Explorer
I'm all for the OP going with a 540w mppt system, if he plans to increase his boondocking, considerably. But then I'd also suggest a larger bank.

JiminDenver
Explorer
Explorer
$150 is a fine price, I would prefer polys but then again my 245s are mono's.

Recharge in one or two days? Just running the trailer even with lots of furnace use, we simply could not use the power from our 230w panel. Our grp 27 would be in float around 9 am and the panel would cover everything we did till night fall. Being in float all day left the battery well charged to handle another night of LED lights and running the furnace in freezing temps.

Now if you use a lot of power over night and take the battery down to 50%, you are going to need to replace the ah as well as what you use during the day. One panel would do it especially in a two day window. Two panels would have the power to push the bank around and get the voltage up faster when the sun is out. This is a thought if you need that kind of charging on shorter winter days when the sun is lower.

The panels you have listed on a cold day where I camp would push 20a each. My twin 245w panels each peak at 17a and playing with them has been a blast. We don't conserve, we look for ways to use the excess power. Making coffee, cooking, heating water all cut down on propane use. Add a third panel and we can run a small AC on the rare occasion we need it. We could stay out all summer without the generator but food and water limits us to two or three weeks.
2011 GulfStream Amerilite 25BH
2003 Ford Expedition with 435w tilting portable/ TS-MPPT-45
750w solar , TS-MPPT-60 on the trailer
675 Ah bank, Trip-lite 1250fc inverter
Sportsman 2200w inverter generator

CA_Traveler
Explorer III
Explorer III
sportzfann wrote:

I believe I can get the panels for about $150 ea.
I would like to be able to recharge my batterys in 1-2 days?
It looks like I will need to get the mppt controller.
How many watts/Amps/time is required to charge a pair of 6v batts?

Thanks, Brian ๐Ÿ™‚
That's a good price if they are poly. Check Solar Blvd for a comparison. They've had 250W for $160. Just recharging the batteries you don't need this size panel. Otherwise you need to determine your power consumption. Or buy what fits on the roof.
2009 Holiday Rambler 42' Scepter with ISL 400 Cummins
750 Watts Solar Morningstar MPPT 60 Controller
2014 Grand Cherokee Overland

Bob

sportzfann
Explorer
Explorer
JiminDenver wrote:
So how good of a price is a good price?


I believe I can get the panels for about $150 ea.
I would like to be able to recharge my batterys in 1-2 days?
It looks like I will need to get the mppt controller.
How many watts/Amps/time is required to charge a pair of 6v batts?

Thanks, Brian ๐Ÿ™‚

JiminDenver
Explorer
Explorer
I felt the same way when I found my big panels cheap. Well that was until I mated one with the Eco-worthy and found that just one of them flat easily covered our needs. Increasing panel just allows us to have more home like comforts.
2011 GulfStream Amerilite 25BH
2003 Ford Expedition with 435w tilting portable/ TS-MPPT-45
750w solar , TS-MPPT-60 on the trailer
675 Ah bank, Trip-lite 1250fc inverter
Sportsman 2200w inverter generator

westend
Explorer
Explorer
Solar sizing calculator
My suggestion would be to put as much module on the roof as you can afford, you'll find a use for any unused power and the large capacity will mean a quick recharge to the batteries.
Don't let the large module and MPPT haters deter you from using that choice. The larger modules have greater power density/area and the MPPT controllers not only harvest more power but have more functionality.
'03 F-250 4x4 CC
'71 Starcraft Wanderstar -- The Cowboy/Hilton

Shadow_Catcher
Explorer
Explorer
I made a mistake when I bought our 185W 66 cell high voltage panel to use on our teardrop trailer as it was intended for a grid tie system and puts out 70+V no load. This required an MPPT controller and the Morningstar would handle the voltage. The outcome is we get usable power from sun up to sun down and in shaded camp sites. I have seen it put out 36V in shade and 17V under a full moon.
A good discussion http://www.victronenergy.com/blog/2014/07/21/which-solar-charge-controller-pwm-or-mppt

TechWriter
Explorer
Explorer
sportzfann wrote:
I need to do a power assessment of how much wattage I need.

That's good place to start. However, unless you never park under a tree or cloudy sky or increase the wattage you need, plan for the biggest system you can put on your roof.

At the very least wire for that "biggest system" as rewiring can be a major PITA.
2004 - 2010 Part Timer (35โ€™ 2004 National RV Sea Breeze 8341 - Workhorse)
2010 - 2021 Full Timer (41โ€™ 2001 Newmar Mountain Aire 4095 DP - Cummins)
2021 - ??? Part Timer (31โ€™ 2001 National RV Sea View 8311 - Ford)
www.rvSeniorMoments.com
DISH TV for RVs

JiminDenver
Explorer
Explorer
well not a big one at least. ๐Ÿ˜‰
2011 GulfStream Amerilite 25BH
2003 Ford Expedition with 435w tilting portable/ TS-MPPT-45
750w solar , TS-MPPT-60 on the trailer
675 Ah bank, Trip-lite 1250fc inverter
Sportsman 2200w inverter generator

2oldman
Explorer
Explorer
sportzfann wrote:
I don't want to get a expensive inverter and run wire for a/c and microwave.
Nobody runs a/c on batteries. And you don't have to run wire either.
"If I'm wearing long pants, I'm too far north" - 2oldman