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Author Topic: INEXPENSIVE GENERATOR TO CHARGE A 12V BATTERY  (Read 346 times)

Markowb

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INEXPENSIVE GENERATOR TO CHARGE A 12V BATTERY
« on: July 24, 2020, 10:11:44 AM »
I dry camp from time to time. What would inexpensive generator would you recommend that would charge my battery in about 4 hours. I only want this to charge my battery.
Thank you

Lou Schneider

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Re: INEXPENSIVE GENERATOR TO CHARGE A 12V BATTERY
« Reply #1 on: July 24, 2020, 10:30:32 AM »
The generator won't directly charge your battery, it sends 120 VAC to your converter which in turn charges the battery.

This means the generator size will be determined by the power draw of your converter and whatever else is turned on at the same time.

A 1000 watt inverter generator is marginal, it may or may not be able to supply the power you'll need.  Prices start at less than $200 for the Sportsman to $900 or more for a Honda or Yamaha.

A 1600-2000 watt inverter generator will definitely do what you want, again prices range from $400 for a Wen or Sportsman up to $1100 for a Honda or Yamaha.

Avoid the $99 specials.  Their 2 stroke engines sound like a chain saw running wide open.

The Harbor Freight 2000 watt Predator inverter-generator at $500 is a good compromise between price and durability.  It's often on sale or you can find a 20% off coupon.

All of the inverter generators at a given price point are about the same - as you go higher in price you gain in areas like durability and the availability of replacement parts. The Honda EU1000i generator I bought 20 years ago is still running fine. You want an enclosed inverter generator because they're much quieter than a conventional generator with an exposed engine.  Do a Google or Amazon search for the best prices.
« Last Edit: July 24, 2020, 10:47:25 AM by Lou Schneider »

donn

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Re: INEXPENSIVE GENERATOR TO CHARGE A 12V BATTERY
« Reply #2 on: July 24, 2020, 10:34:57 AM »
Be careful with cheap generators.  They tend to be noisy and not really neighbor friendly.  Harbor freight Preditor series does offer a couple that are kind of quiet as do other places.

Lynx0849

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Re: INEXPENSIVE GENERATOR TO CHARGE A 12V BATTERY
« Reply #3 on: July 24, 2020, 11:54:11 AM »
No reason he canít use a conventional battery charger plugged in to a small generator. It would have to support the 12v loads and charge the battery but not power the AC loads.

A 2000 watt class inverter should do it, be quiet enough and light enough to stow.
Rob & Deryl, Nettle & Tigger
Clyde, a 2015 RAM 3500 Cummins Longhorn SRW w/ARE cap
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Isaac-1

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Re: INEXPENSIVE GENERATOR TO CHARGE A 12V BATTERY
« Reply #4 on: July 24, 2020, 12:03:07 PM »
You don't say what size battery you have, regardless assuming you have a conventional lead acid battery, if it is significantly drained you are not going to fully charge it in 4 hours  due to the charge acceptance rate of a lead acid battery.  Simply put with a lead acid battery, the first 80% of the capacity can be charged fairly fast, but the last 20% gets slower and slower before eventually being fully charged.  Therefore you should expect with 4 hours per day of charging and running the battery down to 50-60% charge each night, to never get over 85-90% charge, which in the long run is bad for the battery.
2002 Safari Trek 2830

Lou Schneider

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Re: INEXPENSIVE GENERATOR TO CHARGE A 12V BATTERY
« Reply #5 on: July 24, 2020, 12:18:06 PM »
No reason he canít use a conventional battery charger plugged in to a small generator. It would have to support the 12v loads and charge the battery but not power the AC loads.

Most conventional battery chargers will only produce about 10 amps on a continuous basis.  Many will do up to 50 amps but that's only for a few minutes before they shut down until they cool off.

120 watts (12 volts x 10 amps) is hardly an efficient use of a 1000-2000 watt generator.
« Last Edit: July 24, 2020, 12:19:49 PM by Lou Schneider »

Isaac-1

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Re: INEXPENSIVE GENERATOR TO CHARGE A 12V BATTERY
« Reply #6 on: July 24, 2020, 03:03:13 PM »
I don't know about that, it depends on the generator, my Honda EU1000i on ecothrottle mode running at low engine speed only puts out about 250 watts before throttle up.  Still a larger charger would be good, which is where the onboard converter comes into play as it allows the battery to charge at a higher rate, plus provides power to the other DC systems in the RV while the generator is running, so perhaps a couple of hundred watts or so if lights etc. are  being used at the same time, more if you are running any AC appliances.
2002 Safari Trek 2830

NY_Dutch

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Re: INEXPENSIVE GENERATOR TO CHARGE A 12V BATTERY
« Reply #7 on: July 24, 2020, 07:18:22 PM »
Years ago I had a little 1.5 HP gas engine mounted on a board along with a belt driven single wire 12-volt alternator. I charged many batteries with it when a 120 VAC source was not available for my charger. As I recall, the only parts I bought for it were the belt and one pulley. The alternator came from a car i was parting out and the engine from a broken farm sprayer pump.
Dutch
2001 GBM Landau 34' Class A
F53 Chassis, Triton V10, TST TPMS
2011 Toyota RAV4 4WD/Remco pump
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Chakara

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Re: INEXPENSIVE GENERATOR TO CHARGE A 12V BATTERY
« Reply #8 on: July 24, 2020, 10:22:58 PM »
  For just charging a 1000W should be enough for most rigs.  You don't state what you have as to rig/battery/charging systems so I'm guessing here.

  If the above is true, I agree with the others and loo for an inverter generator.   You and your neighbors will like the quiet.

  Honda is the bee's knees in this space for quietness and reliability (I have a 13 year old one).   But Yamaha is a close second in the forums.  Below that I don't know......

Good luck!
-Chak
2018 Arctic Fox 27.5L
2015 Chevy 3500 Dually LTZ


Gary RV_Wizard

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Re: INEXPENSIVE GENERATOR TO CHARGE A 12V BATTERY
« Reply #10 on: July 25, 2020, 09:30:42 AM »
The issue here is expecting to charge in 4 hours. You can't fully charge even a modest size 12v battery (Group 24?) in 4 hours, but you can get to around 80%-90% level.  The typical 8-10A automotive charger would be hard-pressed to do it, but a 45-55 amp RV converter/charger probably would.  In any case, you only need about 600-800 watt generator to power the charger only. Problem is, there are usually at least a few other items that will try to use some 120vac power if allowed. If you want to charge with a minimal size generator, you are going to have to make sure some things are disabled from using 120v.

A better choice is a 1000-1200 watt generator to give you some cushion on the power demand. They aren't much larger or more expensive.
Gary
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Gary Brinck
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