charging batteries w/generator

RussellJ
RussellJ Registered Users Posts: 15 ✭✭
in Solar Beginners Corner #1
what is the best way to charge my batteries with a generator. I have 600 PV watts feeding into 2 bluesky charge controllers charging four 6v trojan's wired up for 12 volts. Most of the year they do just fine but now that it is cold out and the days are short and cloudy the batteries aren't always getting a full charge. A couple times this winter the suresine 300 has cut out due to low voltage. There are 2 setting for cut off and I'm using the higher setting but still I hate to let them sit in that condition waiting for a good sunny day. What is the best way to charge 'em back up? I have grid power I could use but I also have a Honda 2000i that I would love to use for doing that. I need to do it with the genny anyway so I know how to do it if the grid power goes out.

Thanks for the help
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: charging batteries w/generator

    It's simple, really: the generator provides 120 VAC into which you plug a 12 Volt battery charger like one of these Iotas: http://www.solar-electric.com/bach1.html

    Not perfect charging, but good enough to keep it up to where sulphation won't be an issue.
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  • RussellJ
    RussellJ Registered Users Posts: 15 ✭✭
    #3
    Re: charging batteries w/generator

    That can't be right, sounds too easy. After a quick first look through the list of 'em, I like this one http://www.solar-electric.com/dls-45.html Says it has a max draw of 11 amps at 108v ac so my 2000 watt Honda shouldn't have any trouble running it, should give a reasonable charge time and all my wiring is set up for that amount of power anyway. I still have a few questions though. Is the output current smooth enough that it won't mess up the Trimetric? Should it be tied in upstream or downstream from the Trimetric? Will it make the charge controllers act funny to have current coming up from the batteries? Would it hurt to leave the Morningstar inverter hooked up while charging the batteries with a separate charger?
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #4
    Re: charging batteries w/generator
    RussellJ wrote: »
    That can't be right, sounds too easy. After a quick first look through the list of 'em, I like this one http://www.solar-electric.com/dls-45.html Says it has a max draw of 11 amps at 108v ac so my 2000 watt Honda shouldn't have any trouble running it, should give a reasonable charge time and all my wiring is set up for that amount of power anyway.

    There is a problem... sort of... the Iota has a low power factor. That means the generator needs to have a rating that is much higher than the wattage draw of the battery charger. The Iota also has a huge inrush current. Neither of these is a problem when you are charging from the grid, but both of these have been problems for folks using small generators such as the eu2000.

    That said, the Iota you are looking at is small enough that I think your generator can handle it. You may find that you need to start the Iota with the generator's eco throttle turned off. You may also find that it uses up most of the capacity of your generator. There are good power factor corrected power supplies available, but you will be hard pressed to find one as rugged and cheap as the Iota.
    RussellJ wrote: »
    I still have a few questions though. Is the output current smooth enough that it won't mess up the Trimetric? Should it be tied in upstream or downstream from the Trimetric? Will it make the charge controllers act funny to have current coming up from the batteries? Would it hurt to leave the Morningstar inverter hooked up while charging the batteries with a separate charger?

    To wire this up, you should have a bus bar for the battery (+) and a bus bar for the battery (-). You can hook up as many charge controllers, inverters, battery chargers, etc as you want. EVERYTHING connected to the (+) bus bar needs to be connected through a fuse or circuit breaker.

    The battery should be in a box, and the cables (which may be unfused if they are in conduit) to the battery bus bars should be in conduit. If you are not protecting the battery cables with conduit, you should have a "catastrophe" fuse attached to the (+) terminal to the battery.

    The trimetric works by reading the tiny voltage across the shunt. The shunt should be between the battery (-) terminal and the (-) battery bus bar. This way, any current returning to the battery must pass through the shunt. Make sure you put the shunt in the (-) circuit, not the (+) circuit.

    Midnite solar sells some very nice DC wiring boxes. You can buy one with the bus bars and shunt, and room for a few circuit breakers.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • RussellJ
    RussellJ Registered Users Posts: 15 ✭✭
    #5
    Re: charging batteries w/generator

    thanks vtMaps, nice to know it really is that simple :-)

    btw, nice Porcupine, I'm a big fan.
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  • Joe94
    Joe94 Solar Expert Posts: 42 ✭
    #6
    Re: charging batteries w/generator

    I'm looking to add a charger to my system as well. How would you size the charger to the battery bank? I have a 450ah 12v bank. I'm also planning to charge with a 2000 watt inverter generator.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #7
    Re: charging batteries w/generator
    Joe94 wrote: »
    I'm looking to add a charger to my system as well. How would you size the charger to the battery bank? I have a 450ah 12v bank. I'm also planning to charge with a 2000 watt inverter generator.
    In this case the Factor is not the battery bank, but the size of your generator. One has to assume it's a Honda or Yamaha 2000 W that is really a 1,600 watt. The best overall performance on the comes at about 800 watt output ( sound, gas consumption, stress ) There two chargers that will fit the bill, The IOTA DLS-45 or DLS-55.

    The IOTA's have been rock solid on the rated output and a good buy for the price. You want to buy the STANDARD model and buy the IQ-4 as a separate plug in Module option( $15 ). The Standard one will give you options to change the output voltage so you can Equalize your batteries if needed. The plug in Module will give automatic 4 stage charging.

    Plug in Module

    http://www.solar-electric.com/smarcharconi.html

    Chargers

    http://www.solar-electric.com/dls-45.html

    http://www.solar-electric.com/ioten55amp12.html
    .
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