Wood Fueled Battery Charger

[sunsurfer]

I've been working on a design for months now. Anyone interested in helping me design a test build?

Goals
1 - Simplest possible (few moving parts) power from wood source while also heating water.
2 - Keep cost down
3 - Use off the shelf parts
4 - Automated
5 - reliable hours of use and easy rebuild

Options and problems
1 - Steam = to much tending/dangerous/regulations/ lots of moving parts
2 - Piston engine Gen. via wood gas = Generators wear out fast / lots of moving parts

I live 100% off grid. I've ran many types of generators. They are just not cheap no matter how you slice it. Best option I have found is a lister CS(cold start) clone from India but the builds are just not as good as the originals and they are very hard to find and $$$. I have an 8/1 clone but they still require an outside fuel source.

Keeping the mechanics simple and being able to use a fuel source most of us have in our own yards is the dream of anyone off grid. I love my solar but how can I get the last mile covered for those cloudy days?

After much deep thinking, I think I may have found a solution. I started a thread at this site but there is not many people there interested in "electricity" if you know what I mean; https://donkey32.proboards.com/thread/3945/power-wood

I think the solution might be an automotive turbo charger based gas turbine.

Here is some of the challenges;

- Unknown output / efficiency (5%??) ...but, there is the potential for up to 5KW+ (based on Garrett eTurbo 48v model used by Mercedes) I have some white papers on this.
- Noisy.
- Regulating output / preventing run away.
- Corrosive gas stream
- Precision mounting needed for mounting gen head to compressor

Some of the benefits are;

- Super simple, only 1 moving part for generator not counting the oil system.
- Lots of heat for winter time
- Local fuel source
- Turbos are plentiful and easy to rebuild. I have done a few.
- Turbos new are cheap on ebay
- Could use RC brushless DC motors for Gen head sent to a MPPT SCC (cheap off ebay)
- variable output (few hundred watts to KWatts adjustable)

If I could get my hands on a Garrett eTurbo with the brushless DC motor integrated that would be awesome but i bet they are $5,000 from Mercedes. I think a classic T3/T4 hybrid from ebay for a test build would work fine($100). Nose mount the RC motor to the compressor wheel. It would double as a starting motor.

 

[toms]

Keen to follow your progress. Where i live sun is plentiful so generator use is not a significant issue.

 

[Leeds]

Have you considered a sterling engine geared up to spin an alternator?

 

[CoolWill]

Wood gas is great. The secret that all the YouTube videos either miss or obscure so they can sell a book, is heat exchange. Effective wood gas tar cracking occurs when you get the reactor temperature above 800 degrees C. That happens by preheating the incoming air with the output gas. The hotter the incoming air, and the cooler the outgoing gas, the better.

 

[BiduleOhm]

Peltier modules would fit the bill:

1 - Simplest possible (few moving parts) power from wood source while also heating water. --> solid state so no moving parts, excepted a fan or two if needed.
2 - Keep cost down --> super cheap on ebay or aliexpress (a few $ each, especially if you buy 5 or 10 at a time)
3 - Use off the shelf parts --> OTS and ultra standard (typical models are 12706 and 12712 for example; the last two digits give the max current they can handle)
4 - Automated --> not sure what you mean but there's no starting or whatever needed like with engines so I gues it's 100 % automated by default.
5 - reliable hours of use and easy rebuild --> dozens to hundreds of thousands of runtime hours shouldn't be a problem, first thing to fail will be the fans if present.

The only downside is the efficiency which is not great... but the other advantages are maybe worth enough to counter balance that for you, I'm just throwing the idea if it can be useful

 

[sunsurfer]

Have you considered a sterling engine geared up to spin an alternator?

to many moving parts. Turbo has one part.

 

[Charleswgibbs]

What about oil for the turbo?

 

[sunsurfer]

Peltier modules would fit the bill:

1 - Simplest possible (few moving parts) power from wood source while also heating water. --> solid state so no moving parts, excepted a fan or two if needed.
2 - Keep cost down --> super cheap on ebay or aliexpress (a few $ each, especially if you buy 5 or 10 at a time)
3 - Use off the shelf parts --> OTS and ultra standard (typical models are 12706 and 12712 for example; the last two digits give the max current they can handle)
4 - Automated --> not sure what you mean but there's no starting or whatever needed like with engines so I gues it's 100 % automated by default.
5 - reliable hours of use and easy rebuild --> dozens to hundreds of thousands of runtime hours shouldn't be a problem, first thing to fail will be the fans if present.

The only downside is the efficiency which is not great... but the other advantages are maybe worth enough to counter balance that for you, I'm just throwing the idea if it can be useful

Oh yes, I forgot to list Peltier as an option. There are problems still. Otherwise you would see them everywhere. Here is something I wrote from the link above on the other forum;

Thermo electric would be nice but I figure I would need between 50-100 modules. Decent modules would be about $30-$60 each plus all the heat sinks etc. I figure it would be between $3,000-$5,000 to build a large one. Also, they need to be matched to a loads resistance to work right. If they get too hot, they can be damaged. I have researched them many times over the years. The modules are getting better but the good ones are still to pricey for the number of modules needed.

Those cheap modules can barely power a small LED, It could take 1,000 of them to get to say 20 amps. Some good modules here that make decent power but they are $$$ - tecteg.com

 

[sunsurfer]

What about oil for the turbo?

Electric oil pump for sure, though I am working on a gravity feed setup.

 

[sunsurfer]

Wood gas is great. The secret that all the YouTube videos either miss or obscure so they can sell a book, is heat exchange. Effective wood gas tar cracking occurs when you get the reactor temperature above 800 degrees C. That happens by preheating the incoming air with the output gas. The hotter the incoming air, and the cooler the outgoing gas, the better.

I do plan on playing with wood liquid fuel at some point vs the gas. Perhaps even methanol or wood oil. Still, the motor has lots of parts that wear out. Rings, bearings, valves, etc...all need work frequently when ran 4+ hours a day. 8 hours a day for a year is like 200,000 miles on a motor going 60 miles per hour continuesly.

A turbo would have similar rebuild window but they are so simple to rebuild.

 

[740GLE]

Seems like another system that adds to the complexity.

Also how fast are you expecting this turbo to spin? Combustion pressure of a wood stove and back pressure of a combustion engine are two mighty different things even if you are using gasification of the wood smoke.

 

[CoolWill]

One idea I've pondered over is a modification of the thermosiphoning water heater. A coiled tube is connected to the bottom of an elevated water tank. The tube fills with water under the action of gravity and the open end of the tube is above the water level (otherwise the water would flow out!). A heat source gently heats the coil and the hot water rises and spills out the end of the tube...

But if you put enough heat on the coil, the water turns to steam. Quite forcefully. Ask me how I know. I always figured someday I would hook a turbine up and see how much energy I could extract. It's simple and there's no chance of a steam explosion because there are no closed vessels.

 

[sunsurfer]

Seems like another system that adds to the complexity.

Also how fast are you expecting this turbo to spin? Combustion pressure of a wood stove and back pressure of a combustion engine are two mighty different things even if you are using gasification of the wood smoke.

20-30k RPM. Youtubers over drive turbos for fun on wood. Runaway is an issue.

 

[Nobodybusiness]

I've been working on a design for months now. Anyone interested in helping me design a test build?

Goals
1 - Simplest possible (few moving parts) power from wood source while also heating water.
2 - Keep cost down
3 - Use off the shelf parts
4 - Automated
5 - reliable hours of use and easy rebuild

Options and problems
1 - Steam = to much tending/dangerous/regulations/ lots of moving parts
2 - Piston engine Gen. via wood gas = Generators wear out fast / lots of moving parts

I live 100% off grid. I've ran many types of generators. They are just not cheap no matter how you slice it. Best option I have found is a lister CS(cold start) clone from India but the builds are just not as good as the originals and they are very hard to find and $$$. I have an 8/1 clone but they still require an outside fuel source.

Keeping the mechanics simple and being able to use a fuel source most of us have in our own yards is the dream of anyone off grid. I love my solar but how can I get the last mile covered for those cloudy days?

After much deep thinking, I think I may have found a solution. I started a thread at this site but there is not many people there interested in "electricity" if you know what I mean; https://donkey32.proboards.com/thread/3945/power-wood

I think the solution might be an automotive turbo charger based gas turbine.

Here is some of the challenges;

- Unknown output / efficiency (5%??) ...but, there is the potential for up to 5KW+ (based on Garrett eTurbo 48v model used by Mercedes) I have some white papers on this.
- Noisy.
- Regulating output / preventing run away.
- Corrosive gas stream
- Precision mounting needed for mounting gen head to compressor

Some of the benefits are;

- Super simple, only 1 moving part for generator not counting the oil system.
- Lots of heat for winter time
- Local fuel source
- Turbos are plentiful and easy to rebuild. I have done a few.
- Turbos new are cheap on ebay
- Could use RC brushless DC motors for Gen head sent to a MPPT SCC (cheap off ebay)
- variable output (few hundred watts to KWatts adjustable)

If I could get my hands on a Garrett eTurbo with the brushless DC motor integrated that would be awesome but i bet they are $5,000 from Mercedes. I think a classic T3/T4 hybrid from ebay for a test build would work fine($100). Nose mount the RC motor to the compressor wheel. It would double as a starting motor.

Why not just use an Imbert Downdraft and a small Generator? Proven design.

 

[740GLE]

20-30k RPM. Youtubers over drive turbos for fun on wood. Runaway is an issue.

So how many hours a day do you expect the turbo to run at peak output?

I can’t say eBay turbos are designed for constant peak load for hours on end.

 

[BartHenry]

you just need to get a sh*t ton of the biolites
biolite

 

[svfalkor]

I know you said "from wood" but I am wondering if bio gas wouldn't be easier? You could just use an ordinary gasoline generator with a methane kit? The bio gas (methane) should be fairly easy to produce from waste material?

 

[BiduleOhm]

Oh yes, I forgot to list Peltier as an option. There are problems still. Otherwise you would see them everywhere. Here is something I wrote from the link above on the other forum;

Thermo electric would be nice but I figure I would need between 50-100 modules. Decent modules would be about $30-$60 each plus all the heat sinks etc. I figure it would be between $3,000-$5,000 to build a large one. Also, they need to be matched to a loads resistance to work right. If they get too hot, they can be damaged. I have researched them many times over the years. The modules are getting better but the good ones are still to pricey for the number of modules needed.

Those cheap modules can barely power a small LED, It could take 1,000 of them to get to say 20 amps. Some good modules here that make decent power but they are $$$ - tecteg.com

It all depends on how you define small LED but you can get pretty decent power out of the cheap modules. Altho I forgot to ask how much power you want to generate and that's probably the main problem, they're not ideal at large scale. But anyway, sorry it didn't help, it was worth the try

 

[Maitake]

Those turbos scream at a particular frequency most likely to induce a murderous rage.
Add hearing protection and body armor to your required equipment list.

 

[sunsurfer]

I know you said "from wood" but I am wondering if bio gas wouldn't be easier? You could just use an ordinary gasoline generator with a methane kit? The bio gas (methane) should be fairly easy to produce from waste material?

Yes, you are right but one of the main goals is to get away from complex mechanical parts that wear out pistons, rings, valves, etc...