Micro 12v Generator Project

[sarabande]

agreed. I am full of admiration for the traditions of DIY PBO engineering which Matt is undertaking.

However, the body of existing technical knowledge re engines, alternators, and battery charging requirements is such that if this were a commercial project, all the questions of charge rates, required power curves from engine, cooling , heating, silencing, etc, would have been sorted out BEFORE a spanner was turned. Matt would have been saved many expensive hours of 'engineering by hacksaw', and would have saved himself a shedload of time and frustration.

That, however, is the world of technical project management, and we would have missed the narrative and visual drama (and verbal fireworks) of the last few days' development.

 

[Leonidas]

agreed. I am full of admiration for the traditions of DIY PBO engineering which Matt is undertaking.

However, the body of existing technical knowledge re engines, alternators, and battery charging requirements is such that if this were a commercial project, all the questions of charge rates, required power curves from engine, cooling , heating, silencing, etc, would have been sorted out BEFORE a spanner was turned. Matt would have been saved many expensive hours of 'engineering by hacksaw', and would have saved himself a shedload of time and frustration.

That, however, is the world of technical project management, and we would have missed the narrative and visual drama (and verbal fireworks) of the last few days' development.

As mentioned above this project is a true PBO star!
I am also impressed with the determination and effort to see this through and the water cooled exhaust solution.
Perhaps I should also mention that I read in one of the camper van magazines that the Australian Outback is served with a very similar product made by Christie Engineering ( www,christieengineering.com.au) who they also use a Honda GX100 to drive a 80A Bosch alternator. This firm also markets higher output 12 or 24v alternators driven by small air-cooled petrol or diesel engines . Apart from the need to adjust the throttle whenever the load increases or decreases, another of the problems mentioned is the need to modify the voltage regulator to trickle charge when dealing with deep cycle batteries .
May be a smart regulator will solve the problem??

 

[VicS]

I read in one of the camper van magazines that the Australian Outback is served with a very similar product made by Christie Engineering ( www,christieengineering.com.au)

And that looks the same to me as the one that was illustrated earlier in the topic on post #53
In fact Christie Engineering was one of the links given three post later

 

[mattnj]

agreed. I am full of admiration for the traditions of DIY PBO engineering which Matt is undertaking.

However, the body of existing technical knowledge re engines, alternators, and battery charging requirements is such that if this were a commercial project, all the questions of charge rates, required power curves from engine, cooling , heating, silencing, etc, would have been sorted out BEFORE a spanner was turned. Matt would have been saved many expensive hours of 'engineering by hacksaw', and would have saved himself a shedload of time and frustration.

That, however, is the world of technical project management, and we would have missed the narrative and visual drama (and verbal fireworks) of the last few days' development.

not completely sure about that theory....it is a case of making things fit/work together that already exist. You are unlikely to find an off the shelf alternator that will work with an off the shelf honda engine with a matched power curve, so hence the little bit of electronics to match up the loads, i could have spent all the time in the world working out the "theory" but no-one could really say what the efficiency and losses would be of a given alternator at a certain speed and temperature without actually trying it (and adjusting for it)

All the theory has been done "before a spanner was turned" it is now in the process of adjusting and debugging the system.

 

[sarabande]

you mistake the years you have spent tinkering with things for proper scientific / engineering knowledge. But that does not take away from the entertainment value and encouraging example of the work with which you are fiddling.

In the States, it's called "Shade Tree Mechanics" and is no less honorable for that appellation.

 

[mattnj]

er, if you say so, have a degree in machanical engineering with electronic systems used to run a machining business now have a software business and a small electronics company....mmmm think that is "proper knowledge"

 

[Stoshak]

In the UK it's called Development Engineering, the fix for when Right First Time isn't quite.

 

[sarabande]

If I have underestimated your skills and knowledge, I apologise, but it hasn't come over in the earlier part of the thread. But I still cannot see why you are developing this product in such a piecemeal, step by step fashion. There seems to be a lot of re-inventing the wheel; not finding what commercial products are already in the market, and seeing how they have already solved the issues which you are running into.

I remain convinced that you are right. A genny, portable by one hand, capable of quietly charging a set of batteries intelligently - people will bite your arm off !

 

[VicS]

There seems to be a lot of re-inventing the wheel; not finding what commercial products are already in the market, and seeing how they have already solved the issues which you are running into.

Hey dont you start. We heard all this from the Stewed-kipper.

 

[mattnj]

If I have underestimated your skills and knowledge, I apologise, but it hasn't come over in the earlier part of the thread. But I still cannot see why you are developing this product in such a piecemeal, step by step fashion. There seems to be a lot of re-inventing the wheel; not finding what commercial products are already in the market, and seeing how they have already solved the issues which you are running into.

I remain convinced that you are right. A genny, portable by one hand, capable of quietly charging a set of batteries intelligently - people will bite your arm off !

well, i am not sure why it is so piecemeal and not sure what i am re-inventing, but hey maybe i am just missing something...

If you can point me in the direction of any of these products that would be great and very helpful:-

1) small water cooled engine, diesel or petrol (under 4kg, a few hp ish)
2) digital programmable alternator controller (so i can interface it to a PIC/PC whatever)
3) digital engine control servo/govenor rpm holding type thing again programmable.

the reason i am developing it in a step by step fashion, which was mentioned at the start is because i have a honda wx10 water pump kicking about in garage, and a denso lightweight alternator also kicking about...so the project was born....

i also mentioned in the start of the thread, no interest in any commerical angles on this item....its just a 1 off for me, for fun, as a challenge, it may very well end up being a pile of junk...

sure if i didnt have those things and i was going to attempt to sell them, I may have gone down a completely different route....

 

[mattnj]

viks...did you see the much earlier thread on copper exhaust reacting with exhaust fumes and being poision....can you shed any light on that?

 

[VicS]

viks...did you see the much earlier thread on copper exhaust reacting with exhaust fumes and being poision....can you shed any light on that?

Yes I saw it.

Just a small point. Copper exhausts are illegal on road vehicles because of the reaction between the gasses and the copper producing some nasty by product. Cupric oxide or something like that....

Nothing to contribute I'm afraid which I why I did not comment at the time.

Copper oxide ?? perhaps you don't want it being blasted into the atmosphere but if it is produced then you'll be washing out an insignificant amount compared to what is released from antifouling paints!

Maybe if copper oxide is produced it's due to the hot copper reducing the carbon dioxide which may lead to an increased carbon monoxide level in the exhaust gas.

More info required from Bassplayer.

 

[daveyw]

Have you ever read Nevil Shute's book, "Trustee from the Toolroom"? A major element in it is a home-designed and home-built motor-generator set, with a 7cc 4-stroke petrol engine driving a governed generator at 3000 rpm. The overall size was 4" x 2" x 2½”.
I don’t know whether Shute ever made (or even had ever seen) such a device, but he was a good engineer. And the book is worth reading just for its sailing content.

Thanks Peter, as a result of your post I ordered this book from Amazon. Just finished it. A great read. 10/10.
Any more recommendations?

 

[pvb]

Copper oxide ?? perhaps you don't want it being blasted into the atmosphere but if it is produced then you'll be washing out an insignificant amount compared to what is released from antifouling paints!

Maybe if copper oxide is produced it's due to the hot copper reducing the carbon dioxide which may lead to an increased carbon monoxide level in the exhaust gas.

More info required from Bassplayer.

I think Bassplayer's fallen for an urban myth. The only restriction I'm aware of for copper in exhaust systems is in North America, where copper-based materials aren't allowed to be used in catalytic converters. The US authorities are concerned that, in the very high temperatures inside a catalytic converter, copper zeolite has the potential to catalyse dioxin formation.

 

[Heckler]

If I have underestimated your skills and knowledge, I apologise, but it hasn't come over in the earlier part of the thread. But I still cannot see why you are developing this product in such a piecemeal, step by step fashion. There seems to be a lot of re-inventing the wheel; not finding what commercial products are already in the market, and seeing how they have already solved the issues which you are running into.

I remain convinced that you are right. A genny, portable by one hand, capable of quietly charging a set of batteries intelligently - people will bite your arm off !

Tim
Weve gone full circle, the Ozzie one is available as a package to do just that, pix on earlier threads/posts, the water cooled exhaust could be bolted on although frankly I personally dont see the point, we run Ebers quite happily with dry exhausts on our boats. My SDMO does exactly the same thing as does any of the small suitcase Honda gennies with the advantage that we can utilise the 240 v if necessary. I could fix my genny inside the sugar scoop to quieten it even further with an Eber exhaust type fitting but I find it is light enough to sling around to do any charging etc as is. My fixed Dolphin mains boat charger runs quite happily on it and calculations suggest that if necessary I could upgrade my charger to deliver more amps if necessary.
The project is quite interesting, something that I like doing myself, I made that point through out my contributions, but from a commercial point of view, as I keep saying, why re invent the wheel?

Stu

 

[sarabande]

Stu - I concur. But it is rather like watching a potted history of the Industrial Revolution, with science overtaking technology. 5/5 to Matt for trying.

 

[Heckler]

Stu - I concur. But it is rather like watching a potted history of the Industrial Revolution, with science overtaking technology. 5/5 to Matt for trying.

I concur as well ref Matt, but the temptation to say I told you so was too great to resist!
Prob from my point of view as well, been there done that, Have several beat up gennies and engines (one courtesy Vyv Cox) that I messed around with before biting the bullet and buying the SDMO, the rational for the SDMO by the way is that it is half the price of a Honda and still built in the EU.
St

 

[mattnj]

pretending you are not still here, you are just not adding anything interesting, more "told you so" action, well done.

 

[mattnj]

the generator "ECU" is complete and working/tested

my re-invention of the wheel is almost complete, starting to really kick myself, why didnt i just buy one of these from Maplin, what have i done, silly boy!!


the ecu for the generator is now complete and all tested and working (other than some software tweaks needed)

for those that are interested, labels are:-

a) 5v power supply for the integrated circuits

b) 555 monostable to clean the incoming engine speed data into a nice clean pulse, the rpm is picked up by simply taping a thin wire to the outside of the HT lead.

c) relay, starts the water cooling pump when engine is running and stops it automatically if/when engine stalls/stops, also turns off the alternator regulator when engine is not running, there is also a second pole on the relay to fire the electric starter solenoid as needed.

d) lm338 linear voltage output, needed to adjust the flow from the electric water cooling pump, as head varies (depends on install height)

e) LM2917 - frequency to voltage converter, smooths and averages engine rpm into voltage, 1v per 1000rpm, 3000rpm = 3v output to send to PIC

f) PIC microcontroller, has various analogue inputs and outputs to measure/adjust things based on the software it is running.

g) engine target RPM led, comes on when engine is at the "target" rpm, goes out if rpm if is currently being "adjusted" by servo.

h) op amp, to reference battery voltage and alternator output charge rate, this is interfaced with the PIC giving a full variable and programmable alternator output.

the board is also connected to the larger power transistor for the alernator field control, not shown on this board, as it is on a remote heatsink.

The green connector at the top left has 9 connections:-

0v
12v
RPM pick up In
Battery Sense In
Servo 5v Out
Servo Control Out
Water Pump Out (on/off)
Output to Alternator Regulator Transistor
Output to electric starter solenoid

Took 8 hours to make that lot...but had a load of the circuits done already from other projects..

It now does anything that i ask it to do....any engine rpm it will hold regardless of load (within reason of course) and you can select any charge rate, that the engine speed will do. It will also auto start the engine at a certian low battery voltage if you want. There will be 2 modes to run it, automatic, where it runs a predetermined software program, or manual where you turn a pot which sets the engine speed to whatever you fancy and the alternator regulator adjusts the charge rate accordingly.

 

[nimbusgb]

Excellent!