Micro 12v Generator Project

Fantastic! I Love it. It's really beginning to sound fully sorted. I particularly like the idea of the auto start when battery voltage drops too low - that's really cool.

Not sure the bought ones do that, unless you pay huge bucks!

The only thing I've been thinking about until now (and sorry if I've missed it somewhere) is, why rely on air cooling the motor when you've already sorted water cooling for the exhaust?

I haven't seen a close up of the cylinder head, but how hard would it be to wrap / curl some microbore copper pipe around the cylinder head and use the existing water flow to cool the head as well as the exhaust? When you come to put the assembly in a soundproof box in a corner of the boat, the airflow and cooling would no longer be a worry.

You'll still need to let it breathe of course, but it should make it a lot quieter..
 
I have to say I have been following this project and have loved it all the way from an engineering point of view.

I cannot add any pointers on the way forward but I did at one of the boatshows mention to the boss man on a generator stand why don't you make a small 12v genny small enough to be moved around or even fitted in an engine compartment, surely there must be a market for it. The reply was yes we know there is a market for one but we cannot source a small but man enough diesel to run it. I did come away thinking I bet I could find one.

Anyway keep up the good work and please keep us all informed on the progress.
 
Trundlebug said:
Fantastic! I Love it. It's really beginning to sound fully sorted. I particularly like the idea of the auto start when battery voltage drops too low - that's really cool.

Not sure the bought ones do that, unless you pay huge bucks!

The only thing I've been thinking about until now (and sorry if I've missed it somewhere) is, why rely on air cooling the motor when you've already sorted water cooling for the exhaust?

I haven't seen a close up of the cylinder head, but how hard would it be to wrap / curl some microbore copper pipe around the cylinder head and use the existing water flow to cool the head as well as the exhaust? When you come to put the assembly in a soundproof box in a corner of the boat, the airflow and cooling would no longer be a worry.

You'll still need to let it breathe of course, but it should make it a lot quieter..
Click to expand...

good idea, the microbore that is, i was thinking of something like that, but you can only get to 3 of the 4 sides of the cylinder due to the pushrods, or drive chain/belt, whatever it is, hard to see without a strip down.

I was also looking into a system to bolt 2 pieces of flat copper plate (that i have already have) on the outside of the cooling fins (the casting may need machining down flat) to take a load of the heat away, whatever i do (once all the other gubbins is done) it will be a hybrid water/air cooling system, so much of the heat is going out already down the exhaust it may not need a huge amount of cooling, we shall see....

Trundlebug said:
It's really beginning to sound fully sorted.
Click to expand...
it is actually at the stage where its all in bits and looks (visually) bad, but getting close to bolting it all together and take some running videos/pictures.


hang one....let me guess the SDMO genny is aircooled and water cooling is a waste of time, im just re-inventing the wheel....
 
Peanuts said:
I have to say I have been following this project and have loved it all the way from an engineering point of view.

I cannot add any pointers on the way forward but I did at one of the boatshows mention to the boss man on a generator stand why don't you make a small 12v genny small enough to be moved around or even fitted in an engine compartment, surely there must be a market for it. The reply was yes we know there is a market for one but we cannot source a small but man enough diesel to run it. I did come away thinking I bet I could find one.

Anyway keep up the good work and please keep us all informed on the progress.
Click to expand...

Please do find one....smallest i can find is a yanmar L40 at 22kg thats the non-electric start one. This whole unit is under 9kg at the moment.
 
mattnj said:
hang one....let me guess the SDMO genny is aircooled and water cooling is a waste of time, im just re-inventing the wheel....
Click to expand...

...It's also bigger, heavier, and far more expensive than your solution, (and I'm not sure it'll auto start on a low voltage trigger..) but for some reason that still makes it pointless using anything else.

Forget the flat earth luddites - I'm with you on this one. I've never been a fan of 240v when all you need is 12v or 24v, and I'm certainly no fan of noisy gennies that disturb the peace for other boaters. I'm also no fan of spending several hundred quid on something when I've already got most of the bits in the garage and all they need is a bit of time, wit and imagineering to put together!
 
Trundlebug said:
...It's also bigger, heavier, and far more expensive than your solution, (and I'm not sure it'll auto start on a low voltage trigger..) but for some reason that still makes it pointless using anything else.

Forget the flat earth luddites - I'm with you on this one. I've never been a fan of 240v when all you need is 12v or 24v, and I'm certainly no fan of noisy gennies that disturb the peace for other boaters. I'm also no fan of spending several hundred quid on something when I've already got most of the bits in the garage and all they need is a bit of time, wit and imagineering to put together!
Click to expand...

he will get cross again, Mr Know it All....just you wait....anyway the SDMO is so quiet that people rafted alongside "cant" hear it running dont you know, its "only" 75db after all ?!??! It is the perfect genny solution you must understand that....or he will be off again...
 
mattnj said:
....anyway the SDMO is so quiet that people rafted alongside "cant" hear it running dont you know, its "only" 75db after all ?!??!
Click to expand...

In fairness, the SDMO iNEO 1000 is rated at 70dBA @ 7m, not 75dBA. I'm assuming, charitably, that this is a full load noise level. However, this is still quite loud - the similar Honda model is only 59dBA at full load.

As you probably know, an increase of 10dB is perceived by the human ear as a doubling of the volume, so the SDMO is more than twice as loud as the Honda! And it's a bit of a raucous noise too (listen to this video).

I wouldn't want the boat next to me to run the SDMO for any length of time!
 
Yes, 10dB is an approximate doubling in perceived loudness (and a 10-fold increase in power).

Anyway, have you looked at water-cooled glowplug engines for model boat use? I guess they probably have higher RPM than you are using so might need reduction drive. Once you water cool the exhaust, I would have thought you'd get them pretty quite. Available in a wide range of power ratings, so I'm sure you could find one that would suit.

Perhaps not exactly diesel, but tick most of the boxes.

By the way, did you look for the "diesel-electric" model train I referrred to in an early post?
 
mattnj said:
Please do find one....smallest i can find is a yanmar L40 at 22kg thats the non-electric start one. This whole unit is under 9kg at the moment.
Click to expand...

I think for a genny in a sound-deadened box, you really need a little water-cooled diesel. Kubota's EB200 is quite neat, 4hp, electric start, but weighs 35kg, which would make the final unit weigh in at around 50kg.
 
Trundlebug said:
...It's also bigger, heavier, and far more expensive than your solution, (and I'm not sure it'll auto start on a low voltage trigger..) but for some reason that still makes it pointless using anything else.

Forget the flat earth luddites - I'm with you on this one. I've never been a fan of 240v when all you need is 12v or 24v, and I'm certainly no fan of noisy gennies that disturb the peace for other boaters. I'm also no fan of spending several hundred quid on something when I've already got most of the bits in the garage and all they need is a bit of time, wit and imagineering to put together!
Click to expand...
Again weve come full circle to the point that Dan steps in, read all the other posts and threads to see all the debate.
Stu
PS
I will say this one more time, the SDMO cost me £239 new, the Honda equiv is twice that, the pro Ozzie version of Matts jobbie is £699 new.
 
sarabande said:
I've just found that Peugeot make a 50cc water-cooled engine :)

http://www.pjme.co.uk/acatalog/Peugeot_Speedfight_50_LC_Engine_Parts_Top_End_.html
Click to expand...
Tim
lots of bikes have 50cc 2 stroke engines, quite a lot liquid cooled, where is this leading? I think if we were to really consider this seriously then a diesel is the only way to go, saves all the faff with differing fuels and also gives a robustness to the thing, thats why all the Farrymans etc go this way.. Dont forget they use watercooling of the genny bit because the soundproofing prevents a good flow of air to cool it.
Stu
This looks good http://www.youtube.com/watch?v=pm4WfH6v004
 
Last edited:
Oh, ye of little faith!
Click to expand...
I see. I think.
So if you had two similar sound sources, S-S kicking out 70 db and his twin brother similarly kicking out 70db that would double the sound pressure to 73 db.
Two more siblings each producing 70db would double it again to 76db. then another four would double it again making 79 db but the human hearing would still perceive that to be less than double the volume of just S_S on his own.

Is that right?

I reckon it would be intolerable :D

Never had to think about how the human hearing registered these noise levels although I used to have to measure noise levels in an industrial environment at one time.
Interesting.
 
VicS said:
I see. I think.
So if you had two similar sound sources, S-S kicking out 70 db and his twin brother similarly kicking out 70db that would double the sound pressure to 73 db.
Two more siblings each producing 70db would double it again to 76db. then another four would double it again making 79 db but the human hearing would still perceive that to be less than double the volume of just S_S on his own.

Is that right?
Click to expand...

Yes, that's about the gist of it.
Reality is slightly more complicated as the different sound sources, not being synchronised, don't quite add like that. But it's close enough.
 
VicS said:
I see. I think.
So if you had two similar sound sources, S-S kicking out 70 db and his twin brother similarly kicking out 70db that would double the sound pressure to 73 db.
Two more siblings each producing 70db would double it again to 76db. then another four would double it again making 79 db but the human hearing would still perceive that to be less than double the volume of just S_S on his own.
Click to expand...

That's how it works for noise nuisance calculations, for example multiple wind turbines to determine noise levels at surrounding properties.
 
You must log in or register to reply here.

Share this page

Top