Hey Steve, could not agree more. dc charging and inverter ac conversion. After 18 months of futzing around with AC that just loves to fluctuate on woodgas I’m going ahead with my DC system. 6hp Briggs horizontal shaft turning a permanent magnet alternator I have kicking around. Small one but should be good for close to a KW; plenty for my battery bank. Still charcoal but I’ve started playing with exhaust recycling at last to reduce consumption and temp. Would love to do an all seperate system charging a secondary battery bank running a second inverter but that’s not in the cards for right now. Just plan on running it through a dump load controller for now since I have all the parts. Hope all is good there, David Baillie
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I agree, it makes sense to make DC and then convert it to AC, my only issue is I have no idea of “how much” I need to get what I want… so, if i want 5KW how big of an engine do I need, how big of an car generator. Any guide lines, or where to find the info would be appreciated… I don’t mind doing due diligence, just not sure where to start the looking part.
Hi Arvid
748 watts = 1 hp so 5000/748= 6.684 hp plus 25% load factor although for batt charging you probably don’t need the safety factor.
for the amps at 12 volts 5000/12 volts =416 amps for 14 volts =357
but that’s a really big full time load
I helped a friend do propane a back up for solar in colorado he used 2 100 amp alternators to charge his batt bank and it was an over kill for what he needed
Good luck
Tom
Good reply TomM.
I come up with a similar answer based, as yours, on real working systems. Don’t freak at my much higher base rated engine horsepower needed based on real obseved wood gas converted engines. A min 30% to as high as 50% penalty in loss of engine shaft power:
17.5 kWe/28 hp Generac V-Twin system; 6500 int/5500 continuous kWel/9 hp Briggs system; 1st generation Victory 5000 watt (el) sets.
ArvidO for a full 5000 watts electrical continuous able to use you would need SIX of those 75 amp nominal 12vdc auto alternators as shown on the “Czech 3.5 hp system” thread here being driven by a gasoline rated ~18 horsepower engine once it was being then woodgas fueled.
Helped a friend evolve to this for 5000 watt electrical woodgas fueled systems. He used TWO specially made 200 amp X 12.5 volt late model Ford internal fan pattern alternators for his nominal 5000 watts system output. He uses a three cylinder Methane rated ~18 horsepower engine. I pointed out an approximate 5-10% conversion loss in the DC to AC inverter and cabling to flow this high of amperage. Engine had its own 40 amp X 12.5 vdc charging alternator so another 500 watts there could be counted as generated too.
I am now staying at home now for the last year and he has moved on to I think 32? or 48? vdc alternators for their ~20 and 30% higher conversion efficiency and to get the amps down to make cabling more reasonable. Amps should now be down to only ~136 and ~96 respectively. Ha! Ha! Higher rarer, Special alternator and inverter costs now though. The Less amps, the less heating and longer potential service life.
Standard 12 vdc alternator are no higher than ~50% shaft to electrical output conversion efficient.
Means at a 5000 watt system electrical load most common auto alternators WILL be kicking out and needing to shed 5000 watts of waste heat. 'Nother ~500 watts of waste heat coming off the inverter at this load (why they are so heavily finned and in larger sizes have their own cooling fans).
Past multiples of ~500-875 Watts made in any way and for the higher conversion efficiencies it gets really dollar expensive.
If you want to study up on all of this in plain English read here:
www.microcogen.info
Especially the Automotive alternators; Project systems; Propane, Methane and Producer Gas Engine, and Fuels boards. Good written articles now in the White Papers section too.
Me, DavidB, Gary Graham and a few others here are active members there learning from others actually living it and doing self/home power generating all over the world in many forms.
I always say now with woodgas fueling NO heats are a waste if it can be use them to effectively dry, and pre-heat condition fuel wood to an ideal reactor hearth delivered 10% moisture or less. Using this philosophy allows using cheaper more available engines and charging components simply oversized and ganging them up and harvest the waste heats for fuel conditioning wet picked up woods in my 9-10 month a year rainforest climate. Out fir trees do grow here year round converting solar to usable fuel even in the clouds and rain.
Regards
Steve Unruh
hey steve yes i was quoting propane hp although my friend had a big house and the ave load was way under 5000 watts
i think he ran about 3 or 4 hrshdaily to maintain his battery bank
tom
Anyone who has not should really take a look at www.microcogen.info but be prepared to be burried in a treasure trove of info. Also be prepared for some of the coolest solid working systems I have ever seen. Steve U has been gamely trying to marry the woodgas world with that hardcore battery charging and cogen world. It seems a natural fit.
Best regards, David
Thanks guys… I really wasn’t too far off in my thinking just i prefer to keep my mouth closed and have people thinking me dumb than to open my mouth and prove it to them… 
I’ve always used the 1kw = 2hp = 4lbs wood/hour to do my approximates… I also figured it would be far easier to gang generators on a larger engine.
Keep the faith.
Hi Arvid
yea overkill thats the best when indoubt
king knob coal used to run 10 alt on a v4 wisconsin to start dozers or weld with 1/2 all thread lol
good luck
tom
looks very very nice… I want one…
Hey old web foot Unrh. Glad to see you broke down an bought a good Gen/welder. With the rates your utility is charging for running a line from your house to the shop, I’d thumb my nose at them too and put in my own power plant. OK, here is the challange. Would you like a gasifier that can get your Miller generator running in less than 5 minutes? Would you like to build one that doesn’t need welded up? Would you like a gasifier that can be made from plumbing parts available at your local hardware store? If you want to take the easy route, build a charcoal gasifier. The Simple-Fire design should work well on your new aquisition although the air inlets and outlets should be sized up to 1 1/4" for your larger engine. You should be able to make this gasifier in a day if you have a 30 gallon drum and a 5 gallon pail (for the filter) The hardest part will be to make an adapter to the carburator. Yes, the big drawback is making the charcoal, but I find it easier to make and process than wood chunks. Guess it is all in your perspective.
You mentioned running your woodgas powered generator in the building to produce heat. I believe it was you who mentioned pulsing in a small engine carb. I have seen this where the engine is running full throttle and puffs of woodgas are pushed out the carb air intake. This means carbon monoxide will be pushed out into the shop. Will you put a hose over this air inlet to vent the CO?
If you are interested in this Simple-Fire, let me know. We can move the discussion over to the Simple-Fire section of the forum that Chris set up a month ago and continue.
until later,
Gary from PA (Made another batch of charcoal this evening! Love that stuff!)
sounds like you have your work cut out for you my friend
Has anybody tried to make a genset running off an outboard boat motor? They come in applicable power ranges (2-50hp) and are made to run at stable rpm ranges. Almost all are water cooled though…
Alrighty then… I just looked up the prices on such engines and never mind. One could easily buy an early 90’s 3-4 cyl car in decent shape for these prices! You’d even be able to sell the rest of the car for parts/scrap and recover some cash.
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Steve,
I started the Ranger wide open throttle by accident when it was stone cold. The timing chain was damaged by my mistake. Up until I did this, the engine ran fine. The design of these DOHC are very unforgiving and not worth the effort. I would never do another one unless it was an emergency and no other fuel was available.
I have been told that all the aftermarket replacement parts for any of these engines are low quality and original factory parts are not available. This adds to the risk of failure and not worth the time. I am embarrassed but I just don’t want people getting the wrong idea.
Hey BruceF
I did not mean to highlight, put you on the spot. Just wanted the Wonderer Why’ers to see the good valve/piston pictures Sean posted up.
I have that street racer DOHC Mitsubishi Turbo Coupe that snapped the balancer shaft drive belt, sewing machinelike feeding the broken end up under the T-belt causing it to jump timing on both cams breaking off the heads of every single valve burned into my memory and pocket book. I think I told you directly about that one didn’t I?
Regards from a friend who’s been there.
Steve Unruh
Hi Steve; You are a treasure trove of information. Although I sometimes have quite a time desiphoring exactly what you are saying, I keep reading until I at least think I get it. I really like your comment of 12-1-2012 posted just ahead of this one referring to cncmachiningisfun and screw the blue flare colors. Sounds like a mild rant I recently had on my youtube channel titled My thoughts on flare colors and disagreements. Thanks for all your time and info. Dan
Hi Steve,
This is the kind of car i want to have a gasifier for…
https://docs.google.com/file/d/0B4CL3bqit0osTDdZOGZ2SU9QUms/edit?usp=sharing
on the picture: Opel, 1200 cc engine, 4 cylinder, side valves…
This car here runs in Switzerland…
Here in Thailand they have pickups, max cc 3000, diesel engines, to be considered as small engines ?
I am in contact with Toyota here, i might ask them for a engine to rebuild and run on woodgas.
we could make something together out of it ? ( combining knowledge ?)
Steve,
You guys talking about pulsations effecting as far back as the char bed caught my attention. I’ve been baby-sitting a wood-gas powered ford six genset day-in, day-out for awhile now and the noise level is tremendous, right? But in the midst of the total noise package I hear extremely low frequency sounds that must be coming from the gas flow lines. Sounds that would drive an elephant bat-shit at fifty miles. Just glad we don’t have any zoo close by. Would hate to see a rogue bull elephant come storming in looking for that cute elephant gal making all those noises.
All kinds of different sized piping, different temps and velocities of gases, maybe like organ pipes? They even produce harmonics if you ever try sorting out all the different sounds. Interesting.
love this small engine corner, I haven’t seen a comment on it but I was load testing a dual 12volt charging system and realized that high charge rates into a battery produces hydrogen, when removing a battery load clip the spark ignited the hydrogen small explosion, no one got hurt but I learned to vent the batterys. just a word of caution
Yep.Yep. On the lead acid battery blow-up NathanS.
FIVE in my life time. This was in amongst a solid 16 years in the Auto Elecric industry with at least 30,000 FLA batteries tested, charged and handled. And twice that in jump/boost starting. Half deafened in one ear since 1986 from one these with some faint minor facial scaring from the shattered plastic case.
You can do everthing right and sooner or later the odds will catch up with you. It is the sneaky ones with an internal cell to cell cracked connector strap that are the real unavoidables. I’ve seen these blow when already hooked up and standing feet away and just switching on the remote battery charger. Seen one of these happen after a long hard cranking discharge; finnaly then engine started up and a 100 amp charging system trying to recharge THEN Ka-Boom. It is the battery internal current flow arc jumping the now heat expanded or contracted opened up cracked metal connector gap. Spark -> Ignition -> Pressure build up -> Boom.
So connecting; disconnecting; Heavy charging or even Heavy discharging keep faced away and REACH way back at one arms length. Have some dousing water always in hands reach. And a BIG box of baking soda on hands aways. Trash-can pitch-out or burn the clothes. Washed; they will fall apart unless wool, high % polyester or nylon.
Very glad you were just scared sh##less and not hurt.
S.U.