Simple 2.5kw power station for boats or home, with solar charger

[markdansie]

I have one dumb question.
What advantages does your system have over using a solid state inverter?
I am not trying to be synical
kind Regards
Mark

[Tommey Reed]

Most inverter runs of 12v dc, so we can start there.



If I pull 1000 watts from my 36v dc generator I know that (1000/36)=27.8 amps with 3 batteries in series

If you do the same at 12v inverter you will pull (1000/12)=83.3 amps in 3 batteries in parallel.

It sound the same, but they are different.

As we all know inverter have a problem, its heat. The higher the temperature the less efficiency in electronics.
Also battery amps is the cause of short life too, by pulling less amps out of batteries you get greater efficiency and life out of it.
This is another reason why EV go with higher voltage.

Tom

[DreamThinkBuild]

Hi Tommey,

My design uses a diametric magnet. The magnet is attached directly to the shaft of the DC motor. I attached a closer shot of the motor and magnet. 3 coils pickup the AC.

I also attached a picture of it's bigger brother. This is using an electric snow blower motor belt driving the alternator (Has high speed and torque). Couldn't find RPM rating on motor(Toro s-210) but says shovels 200lbs a minute of snow. The Kill-o-watt meter shows it drawing 110vac 632watts 6.42amps. Now the Wind Blue is hooked through a bridge for DC output.

http://www.windbluepower.com/Permanent_Magnet_Alternator_Wind_Blue_Low_Wind_p/dc-540.htm

It shows an output of 248vdc @ 15amps = 3.7kw

Hello Marksdansie,

It is a good question, you can spend $800 or more on a pure sine inverter. Also most inverters have a no load/idle power draw(loss) of about 1amp. Running through the coils you get a pure sine wave out with only the cost of the coils ($40). If I fry the inverter I'm out $800+ fry a coil I can pop in a new one for less than $10. DC motors are also quite in-expensive.

The challenge is try to create a small portable turbo generator that can run off batteries or solar directly. Someone suggested I look at RC car motors they go up 35,000 rpm. I was originally using a Dremel tool @ 20,000 rpm but the motor is not built to run very long.

Now the pictures.
Pic's 1 and 2 show the closeup of the motor and magnet. You can also see one of the removed fish pump coil in the first shot.

Pic 3 shows the snow blower motor and wind blue setup. Small wire shelving also makes for fast prototyping and it's portable too.

Pic 4 shows it running showing the snowblower motor drawing 578watts and the wind blue putting out 248vdc.

[Tommey Reed]

When we talk about power, are you pulling any load when testing voltage and amps? Your set up show only volts, or is there something I missing?

120v ac brush type blower motor will run on dc 120v, I understand the higher rpm,s at no load.

But when a load is added, it will slow down the motor too.

your alternator have no regulator in it, or does it?
So at 13.5v @ 70a = 945 watts or 1.27 hp at what rpm's does this make that current?

a 13.5 @150a could product  2025 watts, but you will need 2.7 hp of motor power.
My generator has a 3.5 hp dc motor to run 2.5 kw generator.
The basic pull at no load to get to the 3600 rpm is (36v x 8A)=288watts.
That is my lost to get enough rpm's to start generating electricity at 60hz
In other words, as soon as I add 60w pull my amps increase by about 1 amp.

I have worked on high speed motors, but they have much lower torque to convert into energy...They also new more energy to produce higher rpm's.

My thought are 746 watts, will take one horse power of ac or dc motor power to make.
Just my understanding in energy....

Tom...

[DreamThinkBuild]

Hi Tommey,

You are right, the alternator is running unloaded so that is the higher reading. The alternator has no regulator, it puts out three phase AC which is rectified through the external bridge. I'll unhook the bridge and put an AC load on to give you a better reading with a measurable load. Thanks again for your experience, time and interest.