Ben Peterson gasifier or diffetent?

Hi I am standing in choosing to which gasifier i want to build
I would like to make gas for LPG aggergate (tar free as best as possible?) to charge baterries ,produce electricity
My question is:
Does Ben Peterson project is suitable for this kind of thin or should I look into another project??
To be honest i am totally green about gasifier but eager to learn and do what’s necessary,considering region i come from…
My LPG/gas aggregate is 5.5kw ks7000eg
Any advice would be great:)
Thank you :slight_smile:


Wober38: Welcome to the forum!
If you already have a small generator, do you run it on LPG (we call it “Propane”)?
Or is it Diesel, or “petrol / Benzine / Gasoline”?
What I am saying is mostly, you need a spark ignition engine. There are possibilities of converting a diesel, but that gets complicated. To answer your question, a Ben Peterson gasifier is good for a 5KW +/- generator set. Depending on your fuel supply, a charcoal gasifier can be a much simpler build. Raw wood is good if you have it. Charcoal can work better for small engines (Less than 500cc). I am no expert, there are many threads to look at in this forum and the library. Again, others will reply, there are usually multiple approaches to explore. :cowboy_hat_face:


Welcome to the DOW site. It sounds like you want to run a small generator to charge batteries. If so and you do not want to mess with tar then a wood charcoal gasifier would be the way to go. It is a lot easier to build. I would go with a updraft for my first build to get started. Down drafts you will need to build more into the gasifier to get it running.
Making the charcoal is easy as a 55 gallon barrel open top tilted to at a 45% angle and built a fire of dry wood in it.


Hello Mr Wojciech? Mr Wober?
You ask about the Ben Peterson Book Built system gasifier.
Per that book you need to use an IC engine of at least 500cc’s. At 50hertz a 500cc sized engine driven electrical generator will be at least 10,000-12,000kW.
Plus a PV solar battery charger does not continual work load an IC engine generator system. You’d have to work load fill in with live electrical loading too like stored water pumping. Electric clothes drying. Etc.
Gasifier system loading is critical because that is what gnerates enough heat to make the various reactions take place thorurally and completely.
Do not downsized built up, and then underloaded use a B.P. book based system. It will under-perform.

You show as only yet reading here on the DOW for less than an hour.
Up in the top page tool bar click open the stacked papers tool icon.
This will give you discussion and projects group categories.
You have a small engine systems.
Please do at least skim over the Small Engine topics.
Your answers will be in there for what others have done.

Steve unruh


It’s a mix propane/petroleum generator…I have Access to raw wood ,not hardwood,thank you for the reply.I have very limited knowledge about gassifiera.Stumbled?proper Word? By accident.Here where i live solar and wind technology is quite expensive ,and i want to make something sturdy,easy to fix/patch which will work…Thank you i will try to look for something ,but ,to be honest would like to get best ideas ,from users whom know the subject,and be able to select based on pros and cons of those projects…


Thank you for quick reply:)
Yes i would like to charge 120Ah batteries or something bigger,maybe charge batteries and supply power for Basic stuff in house??
To be honest it’s a prepper thing,and i would like to make it once and permament ,so IT won’t break…but i won’t have to pay for parts 2000-3000$…
Is there any topić or project you can Direct me for such thing…
I am considering every option ,because of the situation on our borders…and timewise is essential for me very much,that’s why i am Asking also for help from mu h more advanced users:)
My girl supply is wood from forest,mostly moisture ,no dry wood to be honest


Thank you ,have the book ,looked into IT,and was a bit confused,i can buy digital files,but i am hesitating because every dime matters for me.Yes i read very rarely but not od my ignorancję,but lack of Time ,(trying to rebuilt some stuff at house,and other stuff ,and i am overwhlmed to be honest…


Good clarifying statements you have put up now.
My advices.
You have been and will be strongly advised to go with a pre-made charcoal fueled system.
You say you do not have access to hardwoods. BEFORE you commit to a charcoal gasifier system which can fuel your smaller engine-generator system . . . make the charcoal from the woods you do have. Learn if your made charcoal can be size down; broken down; and sorted; then stored without disintegrating into char-dust.
That will be your possibilities qualifier. Most of the vehicle driving woodghasifier guys soon go away from not-hardwoods; not-conifer woods to only using true hard hardwoods.

The Ben Peterson Book system was designed to operate on conifer woods too. But it does take a larger engine generator system. Takes more gasifier-filter systems soots cleaning on conifer woods to keep operating.
Get your other big projects settles before you distract yourself with woodgas system building; and operating.
Yeah. I know. Still having to buy out LPG.

Please, where are you in general, located?

Steve Unruh


What types of wood are available to you for free in the forest. Is there any fruit tree orchards near by where you live.
What Steve said, I agree.
Are you in a climate where you can dry your wood to 18% dry.
Small tree branches make excellent Charcoal, you do not need big trees. Even brush can be used.
Look around on the site many people here run small generators to charge up battery systems, by using wood Charcoal gasifiers.
Hopes this helps.


Yeah man build a charcoal system, you will be running your engine instead of fixing it. For your application, reliabibility should be a primary concern. In that aspect charcoal is king. Besides in a SHTF senario you will need hot water and heat? Well use your charcoaling method for that. Now you are making more usable energy than you would with a wood fuel system. Wood fuel systems have thier place but its not on a small engine.

Making charcoal is very easy and its not wastful in many cases you can use feed stocks that would not otherwise be useful for wood fueled gasification.

Here is the most stupid simplest and most effective way to make charcoal.

Plenty of us here working on developing charcoaling methods for energy use as well. These system will be true CHP systems that are practical and usable eventually.


hello Wojciech, greetings from another newbie ))

i do charge off grid batteries by running 500cc engine on raw wood,
however it is well dried firewood, mostly birch.

i run the generator since February, the engine has some 100…150 hours of running time on wood gas.
so far i haven’t noticed problems with that engine.

here is link to thread about fabrication of the gasifier, may be you will find something useful there
First post, looking for advice


Welcome Wojciech.

You have many demands on your time but spending any of it messing with a build that will not work would be foolish. Gasifiers like a Ben Peterson or a Wayne Keith are labor intensive and time consuming and not without expense. They require considerable fabrication skills. Getting into any kind of gasification takes considerable commitment and trial and error. Study what actual full time users, like the people here are doing , and avoid much of the stuff you see on Youtube. That’s a crap shoot at best. Start out with something like a easily assembled Simple Fire or one of Matt Ryders basic builds as found on the Thrive off Grid thread. Everybody here wants you to succeed.


I try to do everything as possible to my abilities.
I have LPG generator
Just trying do everything asap ,because of situation on the east
So Basic stuff is doing charcoal ,right? And go with charcoal gassifier?
How large generator engines for Ben Peterson project?
Can you advice Please any project which can full fill my reqirements?? Or there is an option to downsize Ben Peterson project…
I have found a welder and i can purchase parts for Ben Peterson project.Time now is my Main factor to be honest…


That’s why i can aqquire files from Ben Peterson website,and Ask somebody do it…
Thank you for kind Words:)
Just trying to find best solutions in narrow Time …


Thank you:)) will look at it more later


Just some speculation from experience, but even if you had a CNC plasma table to cut out the parts and you had the materials on hand, it would still take probably 60 to a 100 man hours to build a functional BP. Start with something like in these videos and get a functioning power supply up and running in days. I could build a functioning simple fire in a few hours with junk I have laying around. I wouldn’t be a work of art but it would gas an engine. Even so there is still a learning curve to keep it functioning. You really should look through Matt’s Thrive off Grid thread. I don’t remember if his Ammo box gasifiers are in that thread or not but like the simple fire, another quick to build design. No gassifier I’m aware of is fill it and walk away like you would do with gasoline. You pretty much have to climb in bed with them and rub the right spots. Simple Fire videos.


Thanks for the location reference Wojciech.
My last family name of Unruh originated in the Baltic Sea north area of the world there.

So practicalities. You will be want then 50 Herz AC electrical power.
This is good. Means smaller electrical generators will need to be spun at 3000 or 1500 RPM.
3000 IC engine RPM is much better in the combustion speed of woodgas/charcoal gas than our North American needed 3600 RPM for 60 hertz AC.

Which system you would go with really comes down to your available actual wood supply in wood types and quantities.

Again you part of the world is favorable because much applicable work has been done in Poland/baltic countries/Finland on quick growing hard woods for home sized furnace heaters.

The Ben Pertesson books evolved into three published sequential versions. The 1st addition said only use engine generators of at least 1000cc’s. With added hearth external insulations then he was able to reduce the engine-loading power minimum to engines of 500cc’s.
I/we in his development shops did years and years working with smaller engine systems and and smaller woodgasifier systems.
It can be done. But you will have to baby-sit it nearly constantly. Many, many reasons for this. And clearly on YouTube you can find hundreds who do claim success on smaller systems with lot and lots of added complex embellishments. They lie that theirs are good. They never put up proofs of hundreds of hours of hands free operation. What you will need on an annual basis to be outside supplied fuel free.

Using your woods in-my-opinion you begin with space heating. Then house hot water heating. These will teach you wood harvesting, preparing, and annual use needs.
And later then add in wood for electrical generation.
You can force this learning by getting again a spark ignition IC engine electrical gnerator of at least engine sized 500cc. Fuel it on LPG. Then work to not have to buy the LPG. The then need driving the learning process.

To reverse this learning, yes do first go with pre-made charcoal fueled gasifier systems for electrical generators.
In that FIRST make the qualities of wood charcoal you project needing. Other wise your actual DIY power system will just be a fairy-project.
Me NOT HAVING Hardwoods available to me, my charcoal gasification is very limited.
Others here you are directed to now do have these experiences.

On a time-driven-needs here USA we are coming onto a national election where the radical Left and radical Right are already practicing taking out the power Grids if the election does not go thier way. And this will be happening next cold winter December and on.
I just monthly keep buying another and another mini-electrical generator for close family and close neighbors friends. Out of time now to help them with alternative DIY fuels.
The needs must first force convert them to drastically downsizing their power needs and demands.

Any one of these can be pre-made charcoal gas powered. They will have to long-term be willing to sacrifice in-yard shade and fruit trees. Not the abundant areas free growing conifer trees.

My $2,000+ USD; 9500/7250 watts; 459CC inverter-generator unit is what is needed to load drive a Ben Peterson book system using conifer woods.
With an even larger electrical generator like this V-Twin system better:

Steve unruh


I just did this tutorial on how to build a charcoal producer that is very efficient. Plus it can be used for a shop heater and possibly hot water production. Be aware you do not have the losses you might think. A wood gasifier also has losses just in different places. Instead of losses in fuel process the gasifiers reactor will use 30% in its process. A charcoal gasifier with water injection is putting BTU’s back in process. Plus producing charcoal is much faster especially in colder climates. Small wood fueled system require fuel that is dry as possible and this is much easier said that done.


Transmission belt made from tires on woodgas small engine - Small Engines - Drive On Wood!
hello wojciech, wellcome in the forum…on this topic i have built a easy gasifier from propane tanks, material what is simple to get…
under my profile you can also find a topic for making charcoal from twigs in a bath tub…this coal is automatically right sized for motor fuel…


That is sweet. Thank you. :slight_smile:

It looks like yours is simpler and MUCH cheaper then the allpowerlabs solution. :slight_smile: