New 24v deka 255ah forklift battery

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oil pan 4
oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
in Off Grid Solar & Battery Systems #1
The LRS squadron on the local air force base bought the wrong battery for their forklift or warehouse tug.
So what do they do with it?
Throw it away of course.
Their stupidity, my gain.

So now $160 later I have a 560lb forklift or warehouse tug battery in my garage.

I'm new to 24v stuff so all I have besides that battery is a 120vac powered 7amp, 24v floor scrubber battery charger, that I bought from the same scrap yard for $3 last year.

The plan is to use it for backup power for now.
But I have literally never looked at 24v stuff, I always figured that my next system would be 48v.
I'm not buying another one of these batteries and making an inverter, already looked it up, one of these is about $1,000.
What would the guys recommend for a 24v inverter?
I'm thinking a small 120/240 pure sine wave unit, does not have to have a built in charger.
Or should I just do 120v only?

Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #2
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    What 240v loads do you have?
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
    #3
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    Back feed the whole house and run some lights and refrigerator, turn off all the 240v breakers.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #4
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    Hmmm... others with better AC experience may want to weigh in, but IMHO if there might be any 120v branch circuits using a shared neutral it could be a problem running both legs from a single 120v source. Any such circuits could potentially overload the shared with 2x rated current.

    I run 120v to both legs, but have no shared neutrals. My one 240v load (pump) runs off an autotransformer.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
    #5
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    I'm not going to try to run a 240v only inverter line to line that would be stupid.
    I would only try to use one that uses 2 hots, a neutral and ground, such that it would mimics the single phase center tapped neutral transformer power already coming into the house.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #6
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    I was thinking using a 120v only inverter feeding both sides of the panel, as I think a small 120vac 24vdc inverter is likely to be cheaper and easier to find.

    The problem with this might be if you have any circuits which rely on branch "hots" being 180° out of phase to share a neutral. I don't, so it works fine.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
    #7
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    The only problem with that is most if not all 120v inverters use a floating neutral.
    So it's like two 60v hots.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

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  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
    #8
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    I have been poking around as I have had time today and it looks like 120/240 volt 3 wire inverters are not really an option.
    So I will probably get a 1,500 watt pure sine wave 120v inverter.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,447 admin
    edited September 2018 #9
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    PSW & TSW (pure and true sine wave) inverters generally have a floating / isolated output and you can ground bond one leg for a neutral leg.

    MSW (modified sine / square wave) inverters are generally referenced to the DC battery bus. If you ground one AC leg (and ground reference the battery bus) you will short out the inverter

    As always, read the manual. There are exceptions to the above rules.

    Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
    #10
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    I think I found it.
    A samlex 2,000w 120v output 24v pure sine inverter. Doesn't have a built in charger.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

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  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
    #11
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    Brought my forklift battery up to 29v while drawing 19 amps with my transformer based 120v powered tig welder.
    So it least it should be charged up most of the way.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #12
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    You may have reached Absorb voltage, but you need to have it dwell for several hours there till the amps drop substantially.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
    #13
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    It says 13 amps are recommended for finishing.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

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  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
    #14
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    I have decided to make this my well pump battery.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

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