Charging battery bank with woodgas

Greetings all.
I am working towards making my very first powerwall project. Things are progressing bit slowly at this point with only one opus charger. Now i have time to think about how to charge my powerwall when it's up and running. I am going to invest in solar later on but at the moment there is many trees shading my yard and rooftop.
Our home heats with fire places, and we have our own forest (backyard) from where i get as much firewood i need. I am thinking of utilizing the debris from the trees to produce electricity with wood gasifier.
Does anyone have any good ideas how to make this work? What kind of charger would be ok? Maybe a 5kw generator? Wood gasifer+genny would be running every day after work about 5-6 hrs. and would produce electricity to the house and surplus would charge battery banks.
I would still be grid tied because i live in a cold and wet country up north so if something happens i don't want to freeze
Haven't started anything yet more than braking a few laptop batteries and tested some cells. Budget to this project as low as possible but if it works, maybe can invest a few solar panels worth of money

Just thinking aloud here...

I imagine running an engine on wood gas would clog the inside of the motor up after some time. You would have to filter it somehow. If I personally were going to try this, I would use an old side valve engine, so it was easy to remove the head and clean the soot out.

It would be very interesting to see how you go with this. It certainly would (wood?) be achievable. Many people have used gasifiers to run engines.

Geek said:

Just thinking aloud here...

I imagine running an engine on wood gas would clog the inside of the motor up after some time. You would have to filter it somehow. If I personally were going to try this, I would use an old side valve engine, so it was easy to remove the head and clean the soot out.

It would be very interesting to see how you go with this. It certainly would (wood?) be achievable. Many people have used gasifiers to run engines.

Click to expand...

It will be interesting to see how the engine will run, and how long, as i'm having some doubts for the same issue. Have been googling for a while now for different gasifier solutions and have found the one most interesting one. It's the ben petersons model that is the most promising version of the low budjet ones. As my profession as a chimney sweeper, i can see why people like the peterson model above others. Wood must be as dry as possible, but the clogging issue shouldn't be much worse than with fossile fuels.

I imagine you could get the engine to run just fine. Wood gas can be very explosive. Google 'flash over'

As for soot buildup it would probably be dependenton the type of wood used. Pine and wood that is kiln dried tend to have lots of tannin left. If you get a good piece of hardwood that has air dried and weathered for a few years, it produces very little soot.

The topic caught my interest and while googling I stumbled across this website

Any ideas about what kind of inverter/charger setup would work with generator? Propably would use about 5kw generator with the gasifier. So little information about charging batteries with backup genny...
The type of wood actually shouldn't matter, as long as it's dry and good quality. The burning process matters the most. Heat is the key in soot buildup. Of course gas filtering also. In my line of work there is a strong belief that some trees burn "cleaner" than others. The problems with tar/impurities inside chimney/fireplace are always result from not enough heat in the burning process. (not enough air/ too much moisture/not enough fuel).

Would love to see this up and running. Something I have thought about in the past and on the very end of the to do wish list....

The leafs contain more sulfur than the rest of the tree.

Pass the gas through a cold section (<20C coil in a pond/water) to condense the tars out, which will provide you with some good quality wood preserver and also some of the condensates. This will help draw down some of the thicker contaminants that will stop the engine very quick. Pass the gas into a bag after that (away from the house) and this will then provide a buffer storage that is relatively safe from flashover risks. Pipe the engine into the gas bag and then you have your setup...

Higher the temperature some of the water is also split and creates a higher energy content in the gas, but the main risk is from carbon monoxide poisoning as wood gas tends to be high CO if there is not enough temperature or not enough Hydrogen available.

If you get the gas high enough quality and stable enough (no oxygen) then you could always compress it into some old LPG cylinders at 110psi and this could then provide a reserve for a few kWh of output as an emergency. Very very big warning is that if you compress oxygen in then you have a serious issue...

Any gasoline engine should run ok. Charger, depends on your pack voltage and generator output. I am using old cisco catalyst power supplies (2800W and 4200W) as they provide 50V and 12V output at very high Amps and can be picked up very cheap. Add in a few buck or boost units and you have a very cheap very high power charger.

Look up "flash arrestors" as you will need them...
Like the old ol mine lamp theory, separate the flame path and prevent the flash over from going a little more than just a flash over.
Put the arrestors in the gas lines before and after the bag.

Separate note... I used to play around (about age of 12) with filling large bags with gas from the stove, taking them outside, adding a bit of air and then from a distance throwing matches on them. The distance was I was uncertain of the mix if it was going to be a slow burn or take all the hairs off my face...

Finnlogger said:

Greetings all.
I am working towards making my very first powerwall project. Things are progressing bit slowly at this point with only one opus charger. Now i have time to think about how to charge my powerwall when it's up and running. I am going to invest in solar later on but at the moment there is many trees shading my yard and rooftop.
Our home heats with fire places, and we have our own forest (backyard) from where i get as much firewood i need. I am thinking of utilizing the debris from the trees to produce electricity with wood gasifier.
Does anyone have any good ideas how to make this work? What kind of charger would be ok? Maybe a 5kw generator? Wood gasifer+genny would be running every day after work about 5-6 hrs. and would produce electricity to the house and surplus would charge battery banks.
I would still be grid tied because i live in a cold and wet country up north so if something happens i don't want to freeze
Haven't started anything yet more than braking a few laptop batteries and tested some cells. Budget to this project as low as possible but if it works, maybe can invest a few solar panels worth of money

Click to expand...

Hi Finnloger, I'm doing the same. Buy Ben Petersons book if you want to make the build easy. A gas generator from 4 to 22kW can be used with his design. If you can find a genny that is set up for propane or natural gas you will not have to modify it to run on woodgas. I'm in Canada so I get why you want a backup to charge your batteries. I have 24 solar panels but my December power production is very low per day. Keep in touch if you decide to build the gassifier as I am just starting mine now. (I have acquired all the parts) THe flashback issue that some are mentioning does not exist with bens design if you follow his plans. The whole lid of the gassifier is a spring loaded safety valve and once started the gassifier runs oxygen restricted for the pyrolysis to produce the wood gas. His system also cools and filters the gas so that tars and soot are removed. Dry hardwood chunks are recommended to further reduce tars. If your supply of wood is pine or fir it may require additional measures to protect the engine. Keep posting and good luck.