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Barry M

Solar battery charger

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I looked at it and actually own the 1.8W unit to keep a work truck battery in tip-top shape . The charge rate for the 5W panel is only about 1/2 amp per hour in full sun. It's useful for keeping a battery topped off in storage, but it will not even begn to compensate for normal usage. For comparison, my 1.8W unit will not even power my RV monoxide alarm.

Before investing in solar, think about your usage. If you use 10-15A (normal for a shurflo) for 4 hours a day you consume 40-60 amp/hours. To compensate for that (and charging losses, you will need to accumulate 60-80 amp/hrs per day. Assuming 12 hours of full sun every day (unlikely), you'll need to provide 6.67 amps during that entire period. That means an 80 watt or better panel (the one you listed is 5W). And given that sun profiles are far less than 12 full hours/day, I'd plan on buying at least 150W+ panel. That'll set you back $8-900 and require about 60"x30" of real estate...

Bottom line, these are storage maintainers, not battery chargers. For that reason, a charge controller is not neccessary for panels under 12W. If you need more info, search RV forums like RV.net. This is a HOT topic for travel trailers owners who camp in areas w/o power.

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If you have a question involving complex applied mathematics, Philip seems to be the guy.:)

I usually don't even bother to check him anymore.

Now, if he could just write a useful dissertation on the mpemba effect. I can't get my father to even read what has been written, and I generally rely on him for answers to these sorts of questions.

OK, I know I'm :topic: , but I wanted to aknowledge Philip as the Math:yoda:.

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Something you may want to look into is a battery minder that charges your batteries off of your vehicles charging system while you drive. It's more powerful than the solar panel, and I believe it's cheaper. Look in the Northern catalog, I believe I saw something in there. If I find it, I'll post a link.

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Got that right about Philip. The first time I met him, he was very happy to help me out of a PW pinch with a quick physics 101 on expanding hose ends.

He explained what happened to my unit. I said "uh-huh alot , like I knew exactly what he was talking about and boom..... 2 seconds later I was up and running again.

I'm still waiting for my copy of "How to pressure Wash" book and guidelines.

I can't hardly wait. He knows his stuff.

When I chat with him on the phone I usually walk away with a new set of information. I don't know how many notebooks I have filled up chatting with him. He's like a Stephan Hawking of PW biz.

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:lgtear: Had to burst my bubble didn't you.

Really though, thank you that's some good info.

What type wiring connector does your trailer have? I have a 7-pin, so it is already wired for aux. power. I simply ran that line back under the trailer to where I have my shurflo battery mounted, and wired it up through the floor of the trailer and connected it directly to the battery. That way, while I'm driving, the battery is getting charged. I wouldn't do it this way if I were drawing a LOT of power, but my shurflo draws 7 amps, and rarely runs more than an hour at a time.

If you're not already setup with a 7pin, it wouldn't be that hard to rewire it.

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I never thought of that Mike, great idea.

I have the north side roofs of 12 different office buildings to wash, totaling 32,000 ft. They are all on the same property and can only be done on weekends, when they are not occupied. So I'll be putting in some long Saturdays and Sundays and I need enough battery to run the shurflo constantly. I would hate to run it off the truck battery and have the truck running with gas this expensive. Is there an alternative? How long will a 1.8 shurflo run on a typical marine battery?

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Before hooking your PW'er to your vehicle power system, install a "battery isolator" It allows the vehicle to charge the PW'er, but does not allow the PW'er to draw from the vehicle Battery. This keeps you from getting stranded is the PW gen 12v gen dies quietly. It will also not allow charging the trailer battery unless the vehicle battery is good.

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I never thought of that Mike, great idea.

I have the north side roofs of 12 different office buildings to wash, totaling 32,000 ft. They are all on the same property and can only be done on weekends, when they are not occupied. So I'll be putting in some long Saturdays and Sundays and I need enough battery to run the shurflo constantly. I would hate to run it off the truck battery and have the truck running with gas this expensive. Is there an alternative? How long will a 1.8 shurflo run on a typical marine battery?

My group 31 battery is 800Ah. That means 400Ah is useable. My deckster (pumptec = similar to shurflo) draws 15 A. 400/15 = 26 hours.

I have personally run my shurflow for 3 hours off a lawn and garden battery. Granted, it killed the batter after 3-4x times but it was an SLI and not a deep cycle.

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If you have a question involving complex applied mathematics, Philip seems to be the guy.:)

I usually don't even bother to check him anymore.

Now, if he could just write a useful dissertation on the mpemba effect. I can't get my father to even read what has been written, and I generally rely on him for answers to these sorts of questions.

OK, I know I'm :topic: , but I wanted to aknowledge Philip as the Math:yoda:.

Shucks, you guys are much to kind. Well, I guess all those years at GaTech had to be good for something... :) But please do check, otherwise I'll start believing my own BS sooner or later...

WAY OT: mpemba effect - I'll give you my theory in two phrases. Double Pane Windows and Crystal Formation. Think about why double pane windows decrease energy waste.

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