I've googled for small generators and found the smallest to be about 750
watts. I'm wondering if such exists < 100w? The application being to
charge batteries from AAA, cell phones, to car or device batteries in the
bush. How about running on a small butane, propane or gasoline? How about
the thing weighing in at 5 pounds or less? It seems there would be a good
market. I wonder if I could rig-up an RC gas engine with a bicycle
generator. I hate it when my electric fishing reel line stripper dies and
have to do it by hand.
I'd suggest a storage battery and a small solar panel to keep it
charged. I rigged a panel on top of my "Yankee Flipper" squirrel
flinging bird feeder about five years ago to keep the nicad batteries
which power it charged and it's worked "slicker than snot" since then.
Years ago at a formerly local power equipment place, I saw a Honda
generator that I thought was a model at first. The thing was about the
size of a tissue box and was actually a real functional generator rated
at something like 200W. I've never seen it since and it isn't in Honda's
For small jobs like charging phones and small batteries, the solar
chargers seem to be about it these days. You might consider a
thermocouple based unit if you had to make a fuel powered one. That way
you don't have a lot of moving parts or noise, same concept as the heat
powered fans they sell for use on wood stoves.
There certainly are RC engines that can deliver 100 watts (0.134 HP).
Check Tower hobbies. (You didn't mention budgetary constraints.)
You'll want an 0.9 or larger engine.
An RC engine will cost more and may not run as long as a weedwhacker
engine, but it will be smaller and lighter weight.
A DCPM (permanent magnet) motor will produce DC. Look for a motor
that is rated at 12 volts or so, 8 amps continuous, and a speed
compatible with your choice of engine. It will probably be about the
size of the motor in a cordless drill -- about half the size of a can
of frozen orange juice. In fact, it might be a whole lot like the
motor in a 12-volt drill if you can match up the speeds. They won't
be far apart, both somewhere between 5000 and 15000 RPM.
I'd start with cheap 12V to 18V cordless drills from HF, or even
better, drills found with dead batteries at garage sales or flea
markets. Ignore the rated speed, the speed you're after is the motor
speed before all the gear reduction inside the drill.
A bicycle generator won't do it because 100 watts of steady output for
any sustained period would tax a cyclist in good condition.
A weedwhacker or small chainsaw engine could do this while loafing
well below max speed, which should make speed matching real easy.
You didn't mention anything about noise, right?
100 watts of solar cells will be quite large, and probably a bit
fragile, and of course it only works when the sun is shining.
You'd probably want some sort of voltage and current regulation elex.
I can help with that if you can build simple electronic circuits.
PS, Tom, the guys I shoot with liked my XD .40 trigger job so well I
didn't get to shoot my XD for the first 45 minutes at the range.
I'll bet there are guys in MN tonight disassembling their XD's in
paper bags -- you know why they're doing it in a paper bag.
Get a PM DC motor. Turn the shaft.
If you want a good one - try hobby shop - those under glass - for Gliders.
Cobalt magnets - with or without gear reduction.
Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot"s Medal.
NRA Second Amendment Task Force Charter Founder
IHMSA and NRA Metallic Silhouette maker & member.
Why not a 4 stroke model engine driving a dc motor. They are quiet and
use very little fuel. Better still might be a small diesel model engine.
The fuel is mostly kerosene with some oil and ether mixed in. These have
been made to run so lean that 6 ounces of fuel can last for 3 hours..
no glow plug. Belt drive the dc perm mag and viola.. Google up P.A.W
I think I'm gona try this since I have a few laying around in boxes
Miracle of miracles, I found the motor I once took out of a $1.50
fleamarket 14.4 volt drill -- with very dead battery.
This motor is about 1.5" dia, 2.5" long, weighs 8.2 oz. Stall
current with 1.8 volts applied is 10 amps, which makes the armature
resistance 0.18 ohms. This implies a 12-volt stall current of 67
amps, which would certainly smoke it -- but the point is that while
drawing (or delivering) 8 amps (96 watts at 12 volts) it'd be
dissipating only about 11.5 watts. It could probably do that for
quite a while without overheating.
Don't know what the 12-volt speed is, but I suppose it wouldn't be too
hard to kludge up a way to measure it. It's fast, probably quite
compatible with a small RC or weedwhacker engine.
14.4 volts is pretty close to what you'd need to charge a 12 volt
lead-acid battery. So, it seems that a 14.4 to 18 volt drill motor
might do ya just fine -- and you'd still have over 4 lb for the
engine and whatever mounting and packaging means you might devise.
***Don't they have a trained bandsaw?***
The trigger gets better and better as it wears in and you get more and more
used to it.
I think one necessary feature would be the ability to charge a car battery
even if it takes a number of hours. (don't ask) I imagine charging a
laptop enough to play a DVD and wet cells to power a big flouresent lantern
while out fishing. Even the smallest genny I've found is too big and heavy
for fly-ins. On those trips, gasoline would be the most plentiful fuel.
I'll bet we haul in ten pounds of spare batteries for everything especially
the sonar units, they EAT batteries. The weight payback is there. I like
the idea of a RC engine but how long can they run? I can always handle
noise one way or another. Budget wise, all those batteries are expensive
and how do you put a price on MP3s and DVDs in the bush, not to mention
plenty of light?
The RC model engines that I'm familiar with run on nitromethane fuel,
basically methanol (it is a blue, water soluble liquid that smells just
like denatured alcohol, if a little less potent) and use glow plugs to
start. They shouldn't be too hard to hook to a small motor for
Another idea, if you could get the gearing/speed issue worked out,
would be a medium sized Stirling engine. That could be powered off of
a regular camp/cook stove or other burner. They would have to be
geared. I'd bet you could even use a model steam engine. Just heat
the water and away you go.
Tom Gardner (nospam) wrote:
If this is for fishing trips on running water, then hydro-power is the
only reasonable way to go . I'm thinking about something like those
SE Asian river launches with a 12 foot long prop shaft attached to a
gimballed engine on the stern of the boat. Since the shaft would be in
tension it could be quite slender, perhaps even aircraft cable, in which
case it would be much like a taffrail log. Of course a cordless drill
motor wouldn't be a good speed match for such a rig, but the right slo-
syn motor might do.
Check out ebay item 230067379458. I have no knowledge of it beyond
what I read in the auction, or affiliation with the seller. So take it
as buyer beware etc.
That's a stirling engine that turns its rotor at 1,000 rpm, if we are
to believe the seller. That's quite suitable for attaching a pulley
driven DC motor generator. Converting its output to clean DC for
battery charging is not very complicated.
Probably produces a few watts of power. Enough to charge little
A doctrine fostered by a delusional, illogical liberal minority and
rabidly promoted by an unscrupulous mainstream media,
which holds forth the proposition that it is entirely possible
to pick up a turd by the clean end.
I wound up with a brand new 12vt DC prop spinner for RC aircraft. Hook
it to a battery and it spin starts your RC motor. About the size of a
small air die grinder.
I would assume that could generate something, if externally spun, if
anyone wants it.
>Martin H. Eastburn
>@ home at Lions' Lair with our computer lionslair at consolidated dot net
>TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot"s Medal.
>NRA Second Amendment Task Force Charter Founder
>IHMSA and NRA Metallic Silhouette maker & member.
>Tom Gardner wrote:
>> I've googled for small generators and found the smallest to be about 750
>> watts. I'm wondering if such exists < 100w? The application being to
>> charge batteries from AAA, cell phones, to car or device batteries in the
>> bush. How about running on a small butane, propane or gasoline? How about
>> the thing weighing in at 5 pounds or less? It seems there would be a good
>> market. I wonder if I could rig-up an RC gas engine with a bicycle
>> generator. I hate it when my electric fishing reel line stripper dies and
>> have to do it by hand.
Personally, I go up country to get away from all that crap. Have you
ever considered that you don't have to have man made noise 24/7 to have
a good time?
You might be able to handle the noise OK but I hope you don't have any
neighbours. I can think of few things worse than someone running a high
revving chainsaw motor, RC motor, weed wacker etc in a campsite within
my hearing. If you're in a private camp in the middle of the boonies,
FWIW my people built such a device but IIRC it was a bit more than 5
lbs. It was used to charge batteries etc on a sub-Antarctic island. In
essence it was a PM generator ratted out of a motorbike coupled to a
Honda powerhead a la weed wacker. It worked but the noise made it
There are some pretty neat fuel cell powered devices available. And
Model engines will run just fine on alcohol and oil mix. The nitro does
boost output but in some parts of the world it is not allowed. The
diesels only use a kerosene oil and ether mix and no glow plugs.
There are simple kits to convert glow engines to spark ignition.