Micro CoGen.

QuoteUsually the current limiting is done on the load on the inverter, not the supply to it. Can you tell more about what your trying to do?

This class of small Chinese inverters are notorious for drawing unlimited amperage and burning up.
Their input is determined by the size of the PV array feeding it.
As an example:
The inverter can accept 20 - 38 vdc and is rated at 1000 watts.
A 35 volt 900 watt solar PV array puts out a MAX of 30 amps and 900 watts when under load and pulled down to 30 volts.
There is zero chance of killing the inverter because the panels can never produce enough to overpower it.

However if you connect the inverter to a 24 vdc, 400 amp battery bank, the inverter runs right up to full input amps and runs so hot that it cooks the Mosfets. If the battery bank output (inverter supply) was limited to 800 watts just like a PV array, the unit would last longer.
That's what I'm trying to achieve.

Can anyone help me with a recommendation for a device that can limit DC current from a battery bank to a device?
In this case the 24 volt battery bank is connected to a 1000 watt grid tie inverter.
When connected, the inverter immediately draws the full 1000 rated watts and runs at it's maximum capacity (and heat) with no restrictions for longer life or safety.
My goal is to restrict the supply current to 800 watts (33.3 amps) by installing some device between the battery and the inverter.
For low wattage circuits a light bulb can sometimes suffice, but for 800 watts, I have no idea what would work.

If a big resistor is a possible solution, I need some help sizing it.

Any recommendations or instruction ?

Thanks

Very nice system this fellow built.
https://www.youtube.com/watch?v=PekTV2PQVQg

BobG, one of these outside your Tiny House (R175 engine) would do the job, and nobody would know it exists.

Wow! I remember him. Very knowledgeable fellow for solar and electrical stuff.
He posted a lot here and on the LEF.

Update on those little PM generators from "the east".
From what I can find, they only produce 1/8th of their rated performance.

https://www.youtube.com/watch?v=59FNmua4ZyE

This fellow revs a 300 watt unit up to the rated 550 rpm and gets 49 watts from it. 

Buyer beware.

Quote from: keith71 on September 15, 2023, 04:53:13 PMHere is another about the same size and they are claiming 600 watts. And they throw in a rectifier as well..

https://www.amazon.com/Permanent-Generator-Alternator-Generators-Rectifier/dp/B0BJVTNM1W/ref=psdc_3754021_t1_B0BG47RMGV?th=

Interesting little units.
What do you think is the efficiency of these.
Would it be in the 50% range like a car alternator? or maybe near 90% like an AC generator?

Ok, I posted on the LEF also.

I think HenryW has almost every manual known to man also 

I lost my paper manual for the R175 diesel.
Does anyone have a PDF version for the R175 or R180 engines?

Cheers,
Veggie

Here's a way to produce 36 volts from a 12 volt automotive alternator.
https://www.youtube.com/watch?v=ETN3lW-c6fY

Would the higher voltage also make the alternator more efficient ?

Thanks Keith,

The idea is similar to yours. Feed 70 to 130 VDC into an inverter.
I suspect it may be best to add capacitance to the pulsed DC after rectification.
One benefit of this setup is that the generator is no longer bound to making perfect 60hz power.
RPM fluctuations either side of the target RPM are ok.
My 3600 rpm gen head does have a low voltage drop-out, so I think the minimum I can produce is about 95 volts.
However !! I do have a 3KW ST type head that may be able to produce AC power all the way down to 36 volts.

Does anyone here have experience running ST heads at low rpm for a rectified DC output ?



 

What's the most efficient way to convert 1000 watts, 120VAC to 120 VDC ?
(I have a 1kw DC device which can accept 90V to 150V)

My 120VAC generator will be providing the AC power.

Good catch Henry, the arrow is incorrect.
Rotation is counter clockwise facing the flywheel.

My guess is that mark #1 is TDC and mark #2 is 18 degrees before.

I will confirm by removing the injector someday.

Keith, thanks for the pics and explanation.

Tom, my engine is a Direct Injection, so removing the injector to find TDC may be the answer.
Also, your suggestion of moving the piston to TDC and finding the spot where both valves clearances "rock" between before/after TDC is useful.

cheers

Anyone ?? 

Does anyone speak (or read) Manderin?
The flywheel on my Changfa 195 has 3 markings.
I would like to know what the markings mean so that I can confirm the injector timing.
The manual says to rotate the engine on the compression cycle until the "mark"  (does not say which mark) lines with the notch in the water hopper and that will equal the required 18 deg. BTC.

Well ... mine has 3 marks, and mine does not have a hopper cooler, it has a factory radiator with no notches or markings. 

I have attached these pictures in case anyone can help identify the rotational degree values of these symbols.

<Click on the pictures to enlarge>