Micro 12v Generator Project

[mattnj]

Stu:

What's the noise rating for your SDMO? I googled them and found 71db, a lot louder than(say) the EU10i at 52db.

Mattnj: Keep at it. it's interesting to read, even if you end up scrapping the thing. It's a great thing to do and the very least you will do is learn loads. Thanks for posting this.

yep 70db at 7m....LOUD!

Scrap it! you must be joking, its working well already, there is just a few things i am working on at the moment that need a touch of improving....


1) The current 55amp alternator seems to be too large and bogs down and stalls the engine on lower throttles (<50% throttle) but only when the batteries are badly discharged.

I have a 40amp alternator coming which will fix this high power requirement at low engine speeds (hopefully!)

2) Raw water cooled exhaust system is brilliant, very cool and quiet...but, need to have it auto start/stop with the engine. (not the alternator) working on a bit of electroincs for this at the moment (unless anyone has any easier ways i have missed)

I have ordered a larger 50amp ammeter which should be here soon, then i can start doing some decent performance testing and update the results here with some more videos soon.

 

[nimbusgb]

http://jiugaofeng.en.alibaba.com/product/311575371-210105560/Engine.html

small two stroke diesel engine $100 price FOB china.

As to the water pump challenge, either drive it from the generated 12v or rig a mechanically driven water pump from the other end of the motor. Something like this ? http://www.toolshopdirect.co.uk/item.php/site/froogle/sn/868760 a bargain at under a fiver!

 

[mattnj]

Update

Succesfully charging batteries at over 20amps...!!! (meter doesnt go higher than that and starts gettting noisy!)

The new alternator arrived and has been fitted, the smaller output unit (40amp vs 55amp) is better, less bogging of the engine at the lower speeds.

It actually works fully now and fairly well.....but i think i will carry on and sort out a custom alternator regulator and some sort of controler for the other bits and bobs, water pump, overheat etc...

The problem now (not a massive problem, but needs addressing) is that when the charger is started, it charges at say 20amps....40% throttle (ish) but as the amps drop off over time, the engine speed increases, so it gets quicker and quicker over time which needs adjustment on the throttle.

I am going to attempt to make an alternator controller, PIC based, that holds an engine speed....so you start the engine and it has a single throttle position, say 33% throttle (ish) the controller then sets the charge rate as high as it can without dropping the engine speed (outside of a set value) as it detects the engine speed drop off, the charge rate is dropped....maybe i should go for a servo at the same time....

 

[Blueboatman]

Generating praise

I think you are in excellent danger of resurrecting the true pioneering spirit of Denny Dessouter when he started PBO all those years ago.

Brilliant stuff !

Great that so many others are usefully participating their knowledge and 'sources' for parts, well done.
Alas I can contribute no'but praise !

 

[nyx2k]

Alas I can contribute no'but praise !

same here. im not at all technical but do live to here of people experimenting and just doing things for them selves

 

[Heckler]

Stu:

What's the noise rating for your SDMO? I googled them and found 71db, a lot louder than(say) the EU10i at 52db.

Mattnj: Keep at it. it's interesting to read, even if you end up scrapping the thing. It's a great thing to do and the very least you will do is learn loads. Thanks for posting this.

A
I put it on the sugar scoop on a rubber mat, I then let it run with the tele on, boat battery charger on, (its a 20amp Dolphin, it would run a 40 amper if i wanted it to) 60 watt lamp on and it copes admirably, I can hear the tele ok, the genny is just a background noise, am sure I saw 65 dbs, its not intrusive, much of the noise is vibration drumming rather than noise. Could do more insulation but hardly worth it, the biggest plus is that SWMBO can have toast with marmalade in the morning! Our toaster is 750 watts and it runs it great.
It is almost a third of the price of a Honda!
Stu

 

[mattnj]

Sorry to be a damp squib, you can already buy a unit such as he is talking about (see the other post for a pic) £690 ish. All ready to go, auto throttle, regulated etc. Proper, professional job. OK so he is trying to do it cheaper, hmm, £299 is the cheapest I have seen a new pump, plus how much for an alternator and and then designing and building a regulator and exhaust system? So it will probably cost as much or more to build one.
One of the arguments for doing it is that it could be a goer as a commercial project, well I would say why re invent the wheel? to do it commercially will cost as much as the existing one!
So the rationale for doing it is really that he likes fiddling with things, good on him, but to dress it up as a potential commercial project, to argue that it would be better practical proposition than a commercially bought one? Nah I dont buy that, and basically my entrenched position comes from the fact that I originally offered constructive criticism and was rudely (IMHO) re buffed. It strikes me that, as another person said, he is grandstanding and doesnt like constructive criticism!
Stu

I am fine with "constructive criticism" and have no interest in "grandstanding".

I am posting as i know that load of people are interested in the project, it is the second highest viewed thread on the forum so that says enough.

This is "practical boat owner" so i think the project fits well with that, but dont really care either way, i will continue to update with my findings on this project that is interesting to me, as i have said before i have no commercial interest at all, hopefully others will enjoy reading the development, even if it ends up in the bin and not working, thats fine with me, i have made it from things i have kicking about, cost so far is about £35

If you want to continue on about how pointless the project is is and how your SMDO thing is the best thing ever then go ahead.

I have spent a load of time "playing" around on this in the last few weeks and fairly confident that i can get it working as i want, which will be, all being well and water cooled, boxed, super quiet genny at about 8.5kg capable of between 15-35amps, output adjustable, depending on how noisy you want it to run.

Hope the rest of you are enjoying reading, if you all think i am just blowing my own trumpet, just let me know and i wont waste my time updating the post any further.

 

[Dockhead]

I am fine with "constructive criticism" and have no interest in "grandstanding".

I am posting as i know that load of people are interested in the project, it is the second highest viewed thread on the forum so that says enough.

This is "practical boat owner" so i think the project fits well with that, but dont really care either way, i will continue to update with my findings on this project that is interesting to me, as i have said before i have no commercial interest at all, hopefully others will enjoy reading the development, even if it ends up in the bin and not working, thats fine with me, i have made it from things i have kicking about, cost so far is about £35

If you want to continue on about how pointless the project is is and how your SMDO thing is the best thing ever then go ahead.

I have spent a load of time "playing" around on this in the last few weeks and fairly confident that i can get it working as i want, which will be, all being well and water cooled, boxed, super quiet genny at about 8.5kg capable of between 15-35amps, output adjustable, depending on how noisy you want it to run.

Hope the rest of you are enjoying reading, if you all think i am just blowing my own trumpet, just let me know and i wont waste my time updating the post any further.

Don't be so sensitive. The statistics speak for themselves. Even if the project is pointless, in the narrowest practical sense, it is still fun and interesting, both for you, and for us as voyeurs. Sailing itself if pointless, in the narrowest practical sense. Even the "damp squibs" can't resist posting over and over; that should tell you something. Bravo and carry on.

 

[mattnj]

Development

thought i should post a sensible project update....

I managed to blow up the built in alternator regulator yesterday by burning out the shunt on the ammeter and ending up with the alternator disconnected from the battery....ooops!

This left me with attempting to make up a regulator of some sort, as i had an LM338 circuit already made up (that is a 1.2v - 13v adjustable at 5amps max) i connected that up to the field yesterday and gave it a try, and it works ok, a simple turn of a POT gives control of the alternator output.

The circuit needs a bit of a tweak with a second regulator, to stop it hunting on the engine speed at the moment, but that is hopefully easy enough to do, will try that later on, this "may" end up being a better solution than a conventional regulator that holds voltage as at least the engine load is constant as the field voltage is constant. It may get rid of the issue where a conventional regulator can put as much load on the engine as the batteries demand and then stall the engine.

So, the next challenge is (once my new ammeter shunt arrives!) is to manully map out the best current outputs that the engine can manage at the given engine rpms, so 2000 = 10amps, 3000 = 15amps etc make a note of the associated field voltages needed, then i will work on mapping the engine speed to the field voltage, i already have the engine speed being output as voltage with the LM2917 circuit i use on my other project,

It would end up with a much more simple circuit than the full PIC controller i was thinking i may need. This way you will just be able to set the throttle manually on the lever, and the circuit will give the alterantor field a pre-determined voltage, and hence load. It will of course need overvoltage protection, my test battery has already seen 16v yesterday for a while...

will let you know.

 

[mattnj]

Don't be so sensitive. The statistics speak for themselves. Even if the project is pointless, in the narrowest practical sense, it is still fun and interesting, both for you, and for us as voyeurs. Sailing itself if pointless, in the narrowest practical sense. Even the "damp squibs" can't resist posting over and over; that should tell you something. Bravo and carry on.

lets all try and resist posting anything other than helpful technical info or help on this project from now on....anyway off to the garage from some more tinkering, more determined than ever to get it right now!

 

[Heckler]

thought i should post a sensible project update....

I managed to blow up the built in alternator regulator yesterday by burning out the shunt on the ammeter and ending up with the alternator disconnected from the battery....ooops!

This left me with attempting to make up a regulator of some sort, as i had an LM338 circuit already made up (that is a 1.2v - 13v adjustable at 5amps max) i connected that up to the field yesterday and gave it a try, and it works ok, a simple turn of a POT gives control of the alternator output.

The circuit needs a bit of a tweak with a second regulator, to stop it hunting on the engine speed at the moment, but that is hopefully easy enough to do, will try that later on, this "may" end up being a better solution than a conventional regulator that holds voltage as at least the engine load is constant as the field voltage is constant. It may get rid of the issue where a conventional regulator can put as much load on the engine as the batteries demand and then stall the engine.

So, the next challenge is (once my new ammeter shunt arrives!) is to manully map out the best current outputs that the engine can manage at the given engine rpms, so 2000 = 10amps, 3000 = 15amps etc make a note of the associated field voltages needed, then i will work on mapping the engine speed to the field voltage, i already have the engine speed being output as voltage with the LM2917 circuit i use on my other project,

It would end up with a much more simple circuit than the full PIC controller i was thinking i may need. This way you will just be able to set the throttle manually on the lever, and the circuit will give the alterantor field a pre-determined voltage, and hence load. It will of course need overvoltage protection, my test battery has already seen 16v yesterday for a while...

will let you know.

Ok
I know you dont like me BUT that is what I have been telling you to do over the last week or so! Control it from the excitation circuit! Ive worked in Africa and the Middle East most of my life in maintenance and when the camp gennies blew their controllers, that is what I used to do, so I do know what I am talking about, contrary to some of the put down remarks you have made about me!
Stu

 

[mattnj]

Ok
I know you dont like me BUT that is what I have been telling you to do over the last week or so! Control it from the excitation circuit! Ive worked in Africa and the Middle East most of my life in maintenance and when the camp gennies blew their controllers, that is what I used to do, so I do know what I am talking about, contrary to some of the put down remarks you have made about me!
Stu

you couldnt resist huh? I like you, i like everyone who sails...honestly i never met someone in sailing i dont like, you are just being very irritating on this thread
Good old bit of "i told you so" very helpful, thanks, if i listened to you, it would all be in the bin by now have a good day skipper stu, go wind up someone else...

 

[Playtime]

thought i should post a sensible project update....

So, the next challenge is (once my new ammeter shunt arrives!) is to manully map out the best current outputs that the engine can manage at the given engine rpms, so 2000 = 10amps, 3000 = 15amps etc make a note of the associated field voltages needed, then i will work on mapping the engine speed to the field voltage, i already have the engine speed being output as voltage with the LM2917 circuit i use on my other project,

It would end up with a much more simple circuit than the full PIC controller i was thinking i may need. This way you will just be able to set the throttle manually on the lever, and the circuit will give the alterantor field a pre-determined voltage, and hence load. It will of course need overvoltage protection, my test battery has already seen 16v yesterday for a while...

will let you know.

I'm new to this thread (I've been away for a while) and haven't managed to read all 100+ posts (you've certainly generated (pun!) a lot of interest!), so excuse me if I've missed anything vital.

Re the above, surely you need to regulate the output current to avoid stalling the engine. Fixing the field voltage will fix the open circuit output voltage but not the output current/load (which depends on the internal resistance of the battery/state of charge)).

Could you not sense the regulator from the voltage across the ammeter shunt and hence control against output current?

 

[wotayottie]

Hope the rest of you are enjoying reading, if you all think i am just blowing my own trumpet, just let me know and i wont waste my time updating the post any further.

One of the sad differences between here and the US is the attitude to the sort of project you are running. In the US it would be encouraged and supported - maybe even turned into a money making business. Here there are always people who are negative. Lacking imagination themselves they resent people who give the ball a kick.

Ignore them . Good luck with the project. It may yet fail but equally you may be the next James Dyson which is a bit more attractive than being the next Skipper Stu. Not that Skipper Stu isnt a thoroughly nice fellow.

 

[mattnj]

I'm new to this thread (I've been away for a while) and haven't managed to read all 100+ posts (you've certainly generated (pun!) a lot of interest!), so excuse me if I've missed anything vital.

Re the above, surely you need to regulate the output current to avoid stalling the engine. Fixing the field voltage will fix the open circuit output voltage but not the output current/load (which depends on the internal resistance of the battery/state of charge)).

Could you not sense the regulator from the voltage across the ammeter shunt and hence control against output current?

Yes, im sure you are right, but it needs to be linked to engine rpm too, so as the speed is increased the output increases.

Just experimenting at the moment, so i have a better idea of how it works, a "hands on" approach this one. The shunt idea is good, will look into that too.

It could be set to "ramp" up the field voltage until the engine speed drops i guess then hold field voltage to keep it at max output.

A lot of it depends on the simplicity of the ciruict i need to make, and my skills, i have no doubt that a full alternator fixed current regulator is the best, but may be a big challenge for me compared to a simple PIC "monitor RPM and ramp up a voltage until rpm drops" bit of code (which would take a few minutes)

I bet a wizard in power electronics would say, dont be silly a PIC is far too complicated an op amp and transistor is much easier!

thinking outload, is there NMEA sentances for Engine RPM, Volts, Current? My PIC setup here has serial output so would be an extra few lines of code to output the values via serial in NMEA if i could work out the NMEA syntax.

 

[VicS]

I managed to blow up the built in alternator regulator yesterday by burning out the shunt on the ammeter and ending up with the alternator disconnected from the battery....ooops

Ooops as you say
It's interesting because I had always been under the impression that disconnecting the load blew the rectifier diodes but I'd often wondered about the regulator.

Has your rectifier escaped unscathed do you know, or do you still have to test it fully?

 

[mattnj]

Ooops as you say
It's interesting because I had always been under the impression that disconnecting the load blew the rectifier diodes but I'd often wondered about the regulator.

Has your rectifier escaped unscathed do you know, or do you still have to test it fully?

Not tested it really, once it had "blown" then it stalls the engine even at full throttle and the output was going (briefly) over 15v before stalling, so i assumed the regulator has gone bang.

Not sure of an easy way to test the recifier, cant really get to the diodes without a full stip down, maybe the ocsilloscope on the output will show me something, worth a quick look.

 

[Col]

Yes, im sure you are right, but it needs to be linked to engine rpm too, so as the speed is increased the output increases...................................................................


It could be set to "ramp" up the field voltage until the engine speed drops i guess then hold field voltage to keep it at max output.

Could you not use a throttle govenor as used on old suffolk mowers?
The engine cooling fan blows agaist a spring loaded "vane" The more RPM >more air> vane moves>vane closes throttle RPM drops>vane pulled back by spring which opens throttle again

 

[davidfox]

I think you are in excellent danger of resurrecting the true pioneering spirit of Denny Dessouter when he started PBO all those years ago.


Brilliant stuff !

Great that so many others are usefully participating their knowledge and 'sources' for parts, well done.
Alas I can contribute no'but praise !

Same here, but I am learning a bit about generators even if i dont understand much of it!!

 

[mattnj]

Could you not use a throttle govenor as used on old suffolk mowers?
The engine cooling fan blows agaist a spring loaded "vane" The more RPM >more air> vane moves>vane closes throttle RPM drops>vane pulled back by spring which opens throttle again

way to difficult to make, rig up and adjust, ok for massive volumes not for a 1off