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Earl1

Battery Charging Question

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We occasionally dry camp for three or four nights and use minimal electricity...a couple lights in the evening, water pump and once in a while, the furnace for a few minutes in the morning. I have a battery charger that has 2 and 10 amp output with 2 amp input. I would like to buy a small, lightweight generator just to run the battery charger. My idiot lights on the trailer go down approximately 1/4 or 1/3 in a day. How long would it take to charge my one Deep Cycle RV battery back to full power?  Would a cheap, small generator do the trick for very occasional use?  Thanks

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13 minutes ago, Earl1 said:

We occasionally dry camp for three or four nights and use minimal electricity...a couple lights in the evening, water pump and once in a while, the furnace for a few minutes in the morning. I have a battery charger that has 2 and 10 amp output with 2 amp input. I would like to buy a small, lightweight generator just to run the battery charger. My idiot lights on the trailer go down approximately 1/4 or 1/3 in a day. How long would it take to charge my one Deep Cycle RV battery back to full power?  Would a cheap, small generator do the trick for very occasional use?  Thanks

Sure, the very smallest of generators will put out much more than the 2 amps your charger needs. How long it takes depends on your battery capacity and the depth of discharge, plus if you're trying to bring it back to 100% SOC, topping it off after bulk charging will take a couple more hours. Figure 5 hours minimum for a 10 amp charger to bring a group 31 battery up from half to near full. All depends on your setup. Jay

Edited by Jaydrvr

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An alternative could be a small 100w solar charging system. We do our best to dry camp when it's sunny. Would you recommend  solar  or generator?

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11 minutes ago, Jaydrvr said:

Sure, the very smallest of generators will put out much more than the 2 amps your charger needs. How long it takes depends on your battery capacity and the depth of discharge, plus if you're trying to bring it back to 100% SOC, topping it off after bulk charging will take a couple more hours. Figure 5 hours minimum for a 10 amp charger to bring a group 31 battery up from half to near full. All depends on your setup. Jay

Thanks. That's what I need to know.

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7 minutes ago, Earl1 said:

An alternative could be a small 100w solar charging system. We do our best to dry camp when it's sunny. Would you recommend  solar  or generator?

I would strongly prefer the solar. A hundred amp panel would probably be plenty, as it could be always on, but be sure to use a quality charge controller to protect your battery. Solar is certainly quieter than any generator. Jay

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1 minute ago, Jaydrvr said:

A hundred amp panel would probably be plenty,

I believe that Jay means a 100-watt panel.

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Also, for best results, it's important to know exactly what your SOC is at all times. Otherwise, you're just guessing. Cheapies are available for as little as $20-30 on Amazon, up to a couple hundred for higher quality ones. Jay

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4 minutes ago, Kirk W said:

I believe that Jay means a 100-watt panel.

Lol... Yeah, little difference there!!

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Your trailer should have a built in converter/charger. You can plug your shore power cord into a generator and charge your battery. I use a 1000 watt Yamaha generator that works well. Make sure to switch your fridge from auto to LP and don't try to use any appliances that draw a lot of current while charging.

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16 hours ago, Earl1 said:

How long would it take to charge my one Deep Cycle RV battery back to full power?  Would a cheap, small generator do the trick for very occasional use?  Thanks

The answer to that question is: It depends on the battery,,,,,,,,,,,,,,,,,,,,,, and how much its been discharged,,,,,,,,,,,,,,,,,,,,,and the battery chargers ability and capacity.

  For example if it were discharged lets just say 20 Amp Hours below full charge, a two amp charger running for 10 hours equals 20 Amp Hours HOWEVER charging lead acid batteries isnt near such a 100% efficiency factor IE it would take a lot over 10 hours. Similar a 10 amp charger is 2 hours PLUSSSSSSSSSS or a 20 amp charger 1 hour PLUSSSSSSSSSSS due to charging characteristics and inefficiency.

 Most RV;s have a built in Converter/Charger and many are at least 10 amps up to 50 or 60 or more on high end units. Plugging the RV into a Genset will charge your batteries or use a charger of your own

YES a small generator will do the trick

ALTERNATIVES  a 100 Watt Solar panel subject to sun and angle and a charge controller could deliver say 5+ charging amps into your battery and 5 amps x four hours (if sun provides at x angle and brightness) = 20 Amp Hours input, but again it would take much longer for a full true 100% SOC charge

A cheap n easy method is a 100+ watt suitcase style set out solar panel but if its real shady or rainy or overcast 200 watts is better. If all you use is say 10 to 20 Amp Hours per day Id go with solar, 100 to 200 watts versus a Generator

 John T

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Thanks for the comments and ideas. Being I won't use it all that much I think I'll try a small mid priced solar. I wont have the noise or upkeep of a generator.

 

 

 

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Here's an 'all in one' kit from Zamp. Permanent mounted 170W panel for the roof, 3 stage controller, wiring, and mounting brackets. Spec's say a bit over 9A, figure 7A for planning purposes. 3-4 hours of good sun, would yield you 21-28A back into your battery back. I usually plan for 5 hours of good strong sunshine, so perhaps as low as 35A to as high as 45A in that peak time. The hours before and after peak, should yield you another 20-30A too, so possibly to see 65-75A range very easily. If you find you want to increase your power consumption, and say add a battery, this kit has enough up side capacity to handle two batteries, say Grp 31 again, and you can add other panels to bump up watts of sun harvesting. 

 

I just added this link, as an example. Whatever way you go, I'd recommend leaving some extra headroom capacity on any controller you might add. Small extra cost now, and it's amazing how many people I know have started with XX solar watts, and ended up with XXXX solar watts:)!

 

On Amazon, you or google Zamp, you can also see they have some suit case portable units, which was also a suggestion from the above input. It has the benefit of being portable, so you can angle it, and change the angle during the day, to obtain higher Amps out of the the Watts available.

 

No right or wrong, just choices:)!

Best of luck to you,

Smitty

 

https://www.amazon.com/ZAMP-SOLAR-KIT1005-Deluxe-Solar/dp/B07GNLQ9PM/ref=sr_1_4?crid=IF24HCHLM7OK&keywords=zamp+solar&qid=1554990274&s=gateway&sprefix=amp%2Caps%2C211&sr=8-4

 

 

 

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Earl, If for whatever reason ??? you went with a permanent roof mount solar panel, I buy 235 Watt panels locally that measure 39 x 64 for around seventy cents per watt. Match that with say a 20 amp charge controller and a bit of wire and fuses/breakers you will come in cheaper then many factory "kits"

BUT ALL THATS YOUR CHOICE DUE TO BUDGET AND INSTALLATION HEADACHES. An advantage of a portable suitcase set out panels is the ability to move them around plus tilt towards the sun as the day goes on to increase energy harvest versus if they were permanent flat and not portable.

Based on your minimal energy requirements a small set out panel in the 100 to 200 watt range should get you by (subject to sun and angle) easy peasey even if not as cost effective as a roof panel and NO CUMBERSOME MOUNTING REQUIRED...……. 

 

John T

 

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Thanks for the replies. I'm going to go with a small portable unit. The roof top system is going to be overkill and more work than I want  to go to.  For the few times I need it I hope it will work out. Thanks again for the suggestions.

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https://campaddict.com/portable-solar-panels/

 

I recalled reading this review when a neighbor with a Class B was looking for a little added juice to his coach. He actually ended up going with a combo panel and lithium battery. (Said he could use it around the home in case of power outages, so though more expensive, he felt the double duty and emergency prep justified the cost (Or he told his wife that:)!).

He went with a Yeti solution Go Zero.

https://www.goalzero.com/product-features/portable-power-stations/?gclid=Cj0KCQjw7sDlBRC9ARIsAD-pDFoPjkBUR9c71v2C0oiPUe4Hvcg1oyBr1rFpGX2auoiXxNcKnJXUMtkaAgfOEALw_wcB#

Travel safe, and have some fun,

Smitty

 

 

 

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