Home made welder by day, DC generator by night

oil pan 4
oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
edited January 2018 in Off Grid Solar & Battery Systems #1
It turns out I have already built 90% of a DC battery charger and it works.
I took a Honda GC200 v belted it to an AC Delco DR44G alternator that I had upgraded to a much heavier "250 amp stator", external rectification provided by some used MRI machine parts and externally powered field excitation.
All I use it for is a welder. With the little GC200 engine it makes about 95 welding amps at 24vdc and makes a maximum of 87vdc open current voltage with 12v of field power wide open and 20v at idle. The alternator is over driven 1:2.
The crazy thing is it works really well, its one of the better DC machines I have ever used. I think because it's rectifying 1,000Hz 3 phase AC to DC.
Only problem is I would like to have more in the neighborhood of 120 to 130 welding amps for a lot of things and really 150 to 160 amps would pretty much do everything I would want a portable machine to do.

All I would need to do is add a voltage regulator to it and a bigger engine. I'm thinking about a 13hp engine.
If I were to go off grid I would most likely use a forklift traction battery, two 24v batteries in serries. At least 1,000 to 1,200AH, or as big as I can afford and still be able to move around.
I'm thinking it should be able to make 50 to 80 amps at 55v with out any issue and with out running it wide open.

Would as little as 50 amps help any for a pre morning bulk charge?
Because in the winter I normally get up 1 to 2 hours before sun rise and I could fire up the generator for a bit with a little fuel and leave it to run its self out of gas if I suspected the battery was real low or wasn't going to get a full charge off sun power.
Or should I go wide open, burn a lot more fuel and try to get close to 70 to 100 amps?
I think best fuel economy on these engins is some where around 2,200 to 2,500 rpm.

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 ✭✭✭✭✭
    #2
    You really don't want to plan on a generator running out of gas.    When charging batteries, you are pushing hard and heat soaking everything, engine is hot and loaded, alternator is hot....  If you loose gas, and it shuts off, all that built up heat starts cooking insulation, loosening glue and varnish on the insulation and to suddenly loose all cooling, stuff is going to cook.   And it's not good for the engine either.  Like driving on the interstate for 4 hours, you overheat when you pull into the gas station and switch the engine off.
    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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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #3
    Any morning amps would help make up for the short winter days. Whether it would be enough obviously depends on the size of the deficit. 55v might be on the low side if the bank is cool/cold, but shouldn't matter much for early bulk stage.
    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 ✭✭✭✭
    #4
    I was going to use a 167 amp although that's been up graded to 250 amps at well under 100 amps or less to prevent cooking on shutdown.
    I can check it with my flir i7 to check the temperatureof the stator.
    If I'm going to run it wide open, at 150 or more amps not going to let it run out of gas.

    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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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    edited January 2018 #5
    @oil pan 4  Was doing some research on welding and came across this page, thought it may be of interest to you.

    http://diy-welder.com/buildit.shtml
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
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