Homemade 7/10 KW Genset.


Old 02-09-08, 02:34 PM
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Homemade 7/10 KW Genset.

Hi All,

Because of my engineering background, I am writing you this brilliant idea :) .

I want to build a 7-10 KW Generator on DIY basis, as we know every generator has two parts i.e. Engine and Alternator. I have seen many generic 20 HP Diesel Single or dual piston engines with 7-10 KW Alternators but they create too much noise (cant sleep), therefore, I want to use a Car Petrol Engine 1500 CC OHC EFI/Non EFI for same with Chinese Single phase Alternator.

I feel this will work better then ever, as Car Engines are fuel efficient and also run on Natural gas or LPG (Dual Fuel System) and create very low noise as well, plus all other benefits of car i.e. engine starting, charging, engine cooling, maintenance and troubleshooting of various issues. At later stage you can add ATS panel as well.

I am also worried, how engine will maintain its RPM as load varies because Non EFI Petrol engine does not comes with Electronics/Manual Governor and EFI engines are little complex to understand due to ECU/ECM interconnect.

This will be very cost effective as well as compared with regular 7-10 GENSET available in the market.

I appreciate your contribution on this idea and discuss technical aspect of this project.

Kind Regards,

Abdul Rauf.
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Old 02-09-08, 03:34 PM
Join Date: Oct 2005
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Originally Posted by abdulr76 View Post
, I want to use a Car Petrol Engine 1500 CC OHC EFI/Non EFI for same with Chinese Single phase Alternator.
That's quite a large engine for just a 20HP load. About 100HP rated I think?? Is the alternator 1800 or 3600rpm?

Quieter? Yes, note however you will be dealing with strong fan noise thru the radiator. Cars are quiet also, due to large size of exhaust equipment.
Efficient? Not in my mind. Much bigger than required gas motor loafing is not efficient, injected or not. If you want efficient GAS, run a small engine hard, near WOT. (look at what a hybrid car does).
If you are going to run this a lot, go for the chinese diesel, 1800, a big muffler (could even run the output in water), a sound shield. Quiet AND efficient. Like amost 2x more fuel efficient.
Old 02-10-08, 02:52 AM
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Alternator RPM & Chinese Diesel-(needs more participation)

telecom guy,

Thanks for posting your reply, at this stage I have not finalized Alternator RPM because I can easy produce 1500 to 3500 RPM with 1500 CC Engine or less engine size.

As far as chinese Engines, they create too much noise, I am building this for my home, therefore, diesel transportation and storage at home is another administrative overhead and Natural Gas is already provided to residential areas and cheep as well.

The price of new 20 HP Chinese Engine (locally manufactured) without warranty and 1300 - 1500 CC good condition engine is almost equal.

I appreciate if you could put some light on low and high RPM alternators for this project.

Abdul Rauf.
Old 08-21-08, 09:12 AM
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Generator Idea.....

....Abdul, How's this:

Get a Briggs & Stratton Opposed I/C Twin (18-20Hp range) engine (either horiz. or vert. shaft), a really BIG alternator (24V), a few batteries and a pair of Xantrex SW-series sinewave inverters. Bring them all together, and you would have a really good setup. I like the older opposed I/C Twins & Twin IIs because they are inherently balanced and produce very smooth power. I did a smaller vertical shaft B&S tied to a delco 140A alternator, 300Ah of battery storage, powering a Xantrex Pro-Sine 1800 inverter. While this is only 1800W, the concept is certainly scaleable. 20Hp driving a 8-10kW alternator (like Military-surplus out of a HMMWV) should do fine for the low-voltage DC section. The SW inverters can be tied together to produce the 120/240VAC split-phase power made by most gen-sets over 3.6kW.

The beauty of it here is that engine speed can be lowered under light loads to conserve fuel.

Just my $0.02 worth. Comments, please. Thanks

Old 08-21-08, 09:49 AM
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Are you sure a residential gas meter has the pressure and cf/sec to run a large engine? I seem to recall you may need a separate gas meter but I may be wrong.

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