Saturday, 11 February 2006


Wll I have been slaving away with my off grid setup and here are a couple of questions I have been asked and the answers to go with them.

1) How large is the power inverter - it looks very large - what is it rated at full output?

ANSWER: The inverter is a 5,000W (5KW) Constant 10,000W (10KW) Peak modified sine wave inverter rated @ 230VAC 43.5A Peak it an handle all loads in my house providing the shower is run at 4KW.

2) How large is your generator head - what is rating at full output?

ANSWER: The Generator Head(s) are a 80A 13.8VDC automotive van alternator & a Lister 110VDC 1500W generator not In use yet but that is for Phase 2 of the project!

3) How many HP and RPM is the Lister Running at? What is the generator head rated output?

ANSWER: This particular Lister is a four stroke single cylinder 3HP engine running at 600-650 RPM (low Engine)

4) Any issues with Battery Bank, Engine, Fuel - Fumes in basement - Any special ventilation Required?

ANSWER: My battery bank has no issues at all, I am running at 2,000AH 12VDC mostly made up of Hawker SBS60 gel cel's (60 AH Each)

5) What is your wind generator rated at - what voltage and amperage have you been getting?

ANSWER: Let me explain a little about the wind machine, I constructed it from a Brooke Crompton British made permenant magnet motor rated at 90VDC 1750RPM 3KW, it is connected to the battery bank via a large Lucas blocking diode. If I run the generator open circuit then it soars to 60-70 VDC with relative ease. Since the generator is connected via the batteries they regulate the voltage to around 13.5 - 13.8VDC, when the wind tries to accelerate the wind machine the result is converted into chargin current which sits around 4-15A in light to moderate winds, I have yet to see it working under a good wind speed but I would be confident in saying it will be capable of 30-50A output @ 13.8VDC which equates to around the 690 Watts mark. I will report on the max outputs I see as I see them, I intend to build a data logger to constantly log all the outputs of the entire site wide installation so I can see exactly what is being produced and when...

6) How long will your house run without power with this system?

ANSWER: That is the million dollar question! How long is a piece of string?
Honestly that all depends on the variables i.e. Wind, Time of year, intermittent load demands, children leaving lights on, amount of fuel for the generator etc etc.... In essence it will run indeffinately once complete....

7) What do you drive in your house in terms of power load?

ANSWER: Everything a normal domestic Yorkshire Working class family would have.

8) Is there any power/voltage loss in the system - from wind generator to battery bank, etc.

ANSWER: Well I have done my best to minimise ALL foreseeable losses throughout my setup, the wind machine has a 16 Meter run to get power back to the house but is fed in 16MM2 Copper Cabling which to some may sound like overkill but I want the losses to be minimal throughout my system and running at such low voltages BIG really is better!

The Lister engine has losses of course, mainly 2/3 of power produced is lost in the form of heat, 1/3 through the cooling system and 1/3 through the exhaust system, I have built 2 heat exchangers, one for the pre heat of fuel (More on the subject later) and one that heats the DCH of my house (With the option to heat 150 Litres of water for the new shower) both the flow and return pipes are lagged underground from the Generating shed to the house.

9) Do you create biodiesel/veggie fuel mix? Or just using diesel fuel?

ANSWER: Fuel, my system starts from cold on Dino Diesel until the exhaust and head are running at an ambient temptrature then I switch over the WVO (Waste Vegetable Oil) which is the primary fuel for the engine, just used veg oil from various free sources, filtered of course to a degree. Phase 2 of my project will see my setup running on 100% WVO with no Diesel to prime the system at all.

10) What are your expectations of what this system can provide in terms of driving your home energy needs?

ANSWER: My expectations are that the system will eventually provide 100% of both my heating and power needs for my home with redundancy built in along the way, I am keeping my Grid connection for backup purposes but fully intend to run off grid where possible, that is the whole purpose of my experiment, to prove that one can produce all the power you need from renewable, alternative energy sources.

11) Are you heating water with the heat exchanger on the lister exhaust?
ANSWER: Yes, DCH and a storage tank in the very near future.

Really clean and neat design? You did an excellent job building it.

How long did it take to build
so far? $$ Invested?
ANSWER: Hard to put a time scale on it, most of my spare time for 3 months and $$ TBC when I reverse engineer the project once complete.

HomebrewPower - Life After Fossil Fuels!

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