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Author Topic: Solar: If you had to chose...more batteries OR more panels?  (Read 3029 times)

gruzzy47

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Would you rather have 400 watts of panels and two deep cycle batteries (225 amp hours) OR 200 watts of panels and four deep cycle batteries (450 amp hours). 

I've got space on the roof for the panels, no problem, but I'd have to do some serious rearranging to add two more batteries.  I'm leaning more towards 400 watts of panels. 

My thought is that 200 watts of panels runs the risk of not keeping all four batteries charged enough.   

Paul & Ann

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Re: Solar: If you had to chose...more batteries OR more panels?
« Reply #1 on: July 22, 2015, 01:09:59 PM »
My thought is that if I had a generator, I would go with more batteries, but if no generator, I would go with more panels, but the second option would limit your power available.
Paul & Ann  Iowa
2005 Winnebago Voyage 38J
http://stoughrvadventure.blogspot.com/

Kevin Means

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Re: Solar: If you had to chose...more batteries OR more panels?
« Reply #2 on: July 22, 2015, 11:31:50 PM »
The unknown factor here is your normal power consumption. Without knowing that we're just guessing at what would be most helpful. If you find that you're often running your house-batteries down overnight, more battery capacity would probably be more beneficial than adding more panels. If your batteries normally have a healthy charge in the morning, you're probably fine as you are.

Adding additional solar panels can be wasteful if your battery-bank doesn't have enough AH capacity to store all the energy generated by the panels. It's a three way balancing act - AH capacity, charging capacity and consumption. You really have to look at all three. We're big fans of solar, because we do a fair amount of boondocking, but solar is oftentimes hit or miss - depending on the weather and camping environment. In most cases, I think RVers could benefit most by installing more batteries.

Kev
2011 Winnebago Tour 42QD
Towing a Jeep Rubicon Unlimited LJ or an Acura MDX
RVI Brake 2, Minder TM-66 TPMS, 970 watts of solar
(Can't wait to spend more time RVing)
Lakeside, California

Mopar1973Man

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Re: Solar: If you had to chose...more batteries OR more panels?
« Reply #3 on: July 23, 2015, 05:10:45 AM »
Give you a feel.

My stick and bricks is powered on 400w of solar, 4000w inverter and 820amp/hours of batteries. I've been this way for over 20 years.

As for the RV I'm a mere 45w solar, 1,200 watts inverter, and 2 standard 12V deep cycle batteries. My power requirements are fairly basic for the RV.
Mopar1973Man (AKA: Michael Nelson) located out in the state of Idaho with...
2002 Dodge Ram 2500 5.9L Cummins Turbo Diesel
2000 Jayco Eagle FBS 296
2013 BigTex 70TV Utility Trailer

Gary RV_Wizard

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Re: Solar: If you had to chose...more batteries OR more panels?
« Reply #4 on: July 23, 2015, 08:08:50 AM »
The keys to the choice are your daily power consumption and the typical amount (hours) of sunlight where you are. The solar panels aren't really a direct power source - think if them as battery chargers. You need enough batteries to supply your daily power consumption needs, including some reserve for rainy days. One small panel will charge a huge battery bank if it gets enough hours of direct sunlight. More panels will gather more solar energy per hour, of course, but if there are 7-10 hours of good sun most every day, you probably don't need a lot of panels (watts) to get a full charge.

In general, then, more battery amp-hours is more useful than more panels. At the extreme, lots of panels and little or no battery is all but useless: you generate lots of power but have no way to store it, so the excess power is wasted. Conversely, a large battery can store lots of energy, even if charging is relatively slow.  The right balance between the extremes is the combination that stores at least as much power as you use every day, and replaces that same amount on a typical day of solar charging.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

Moonstruck

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Re: Solar: If you had to chose...more batteries OR more panels?
« Reply #5 on: July 23, 2015, 02:32:34 PM »
Keep in mind that discharging batteries below 50% state of charge can result in significantly shorter battery life.  So, a 120 amp hr battery would be good for 60 amp hrs on a consistent basis.
Don and Lou--Don Posting
Airstream Safari LS 25
'97 Chev Suburban 2500 Diesel
Tennessee/greenest state in the land of the free
"America is not a place;it is a road."  Mark Twain

Willie1971

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Re: Solar: If you had to chose...more batteries OR more panels?
« Reply #6 on: July 26, 2015, 12:13:45 PM »
I would do both in this order.

Matched set of batteries.
Add solar panels as you have the budget.

A 100 watt panel is about 110 bucks on amazon if you have prime.

That being said I would go for the batteries first.


TonyDtorch

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Re: Solar: If you had to chose...more batteries OR more panels?
« Reply #7 on: September 22, 2015, 08:35:59 PM »
The "Achilles heel" of all solar systems is sun light.

Put several cloudy and stormy days with a long winters night and you may wish you spent the solar panel money on more batteries and a wind generator.

I live in California and they keep telling us that it may even rain here !

More batteries is what I want, I'm going to convert one of my storage compartments to a second battery compartment.
« Last Edit: September 22, 2015, 08:43:48 PM by TonyDtorch »

JiminDenver

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Re: Solar: If you had to chose...more batteries OR more panels?
« Reply #8 on: September 22, 2015, 10:00:35 PM »
A lot of info is needed before making choices for a system. What do you have now, what does it do or doesn't do, what kind of conditions do you face are all things to consider.

Extra panel is great for not so perfect conditions if your batteries last long enough for you now. It takes a lot of extra solar to provide for your needs when it is overcast. Extra battery holds you over in bad weather longer but without enough solar, it's easy to fall behind on a big bank.

Look for what you need for the answer.

legrandnormand

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Re: Solar: If you had to chose...more batteries OR more panels?
« Reply #9 on: September 22, 2015, 10:30:59 PM »
More batteries like Gary mentioned; the more batteries installed, the more watts you'll need to charge them.
p.s. for sure, we are talking about an installation on a motorhome.
« Last Edit: September 22, 2015, 10:32:32 PM by legrandnormand »
Normand
Trois-Rivieres, QC, Canada
2010 Gulfstream Independance, model 8367
2009 Smart Cabriolet

JDOnTheGo

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Re: Solar: If you had to chose...more batteries OR more panels?
« Reply #10 on: November 02, 2015, 10:50:36 AM »
Would you rather have 400 watts of panels and two deep cycle batteries (225 amp hours) OR 200 watts of panels and four deep cycle batteries (450 amp hours).

As already stated by others, I would calculate my average overnight power usage (worst case) and how much power I expect from my solar panels on a less than optimal day and go from there.  I prefer to have enough stored power to last a couple of days and created a battery bank to achieve that.  Charging that bank from solar is highly dependent on the "sunshine" that is "available" to you.  I spend most of my time in the southwest so there isn't a shortage of power available. If I were somewhere else, it might be advantageous to have an unusually large PV array to capture as much power as possible (in the low light/short day scenario that is common).

I would also go with 6V batteries and not 12V "deep cycle" batteries.
JD - Full timer out west
1998 MCI 102 EL3 Revolution | 2010 Wrangler (daJeep) | 650 Watts Solar
My Adventures

 

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