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Does anybody know right off hand how much wattage the magneto produces on a 21 hp Intek Briggs? This would be on a lawnmower without a power take off.

Reason I ask is I'm going to build me a shade cover for my Husquvarna. It already has mounting holes for one, but I'm going to make my own out of some threaded rod and fiberglass.

I would love to mount some sort of fan underneath the cover to blow air on top of me to keep me cooler.

Some B&S engines like push mowers do not even have a magneto.

My Husquvarna does not have a power take off which to me anyway is not really the correct terminology. I always thought a power take off was a driveshaft on a tractor (or small lawn tractor) that runs an implement. Where a power take off on a riding mower is an electromagnet clutch which engages the blades when you pull a knob out instead of using a lever.

I've heard if you blow the engine on a lawnmower with a power take off, if you use a donor engine from another mower, your supposed to use the magneto from the blown engine or find an engine that produces enough current to operate the clutch. Otherwise it will discharge the battery and eventually the blades won't engage. I find it hard to believe an electromagnet clutch would pull that much current. So it must not be that much.

Turbo I think you have your terms mixed up. Almost every small engine has a magneto (CDI COIL) to provide spark. You can’t run anything else off a magneto. I think you are talking about a charging system (stator and voltage regulator) which are used to keep the battery charged and provide power fo4 accessories, such as lights, PTO, etc. Briggs has six different sizes depending on the engine size. They are rated in amperage, not wattage.

You are correct. The magneto is the ignition system not the charging system.

I think this is what I would need but i'd first need to check to see if it fits my engine.

https://www.ebay.com/itm/Briggs-Str...054?_trksid=p2349526.m4383.l4275.c10#viTabs_0

I guess I could wire in a shunt wire and ammeter guage from the current charging system going to the starter and hook the fan up to the battery and see if the needle on the guage goes into the discharge range. That would tell me if fan would pull more current than the charging system could provide.

The easiest thing would be to test how many amps the fan would pull and compare that to known data. So far I have not turned up anything about the current alternator's capacity.

Briggs alternators are all coded by the shape & colour of the plug and the wires that go into them from the engine
You should find most of them here.
Briggs fitted different alternators to the customers requirements.
It is one of the things that the code part of the model number refers to.
But you need the parts book then check the alternator section and you will see which numbers had what alternators.

Maybe these charts will help you, but from a post you made about last winter I doubt you trust my info.

https://docs.google.com/open?id=0B6NaqjIxWV1yYURBWDhWUUNyZ1U

https://docs.google.com/open?id=0B6NaqjIxWV1yLXF2bHppdFBPLTQ

https://docs.google.com/open?id=0B6NaqjIxWV1yYURBWDhWUUNyZ1U

Rivets said:

Maybe these charts will help you, but from a post you made about last winter I doubt you trust my info.

https://docs.google.com/open?id=0B6NaqjIxWV1yYURBWDhWUUNyZ1U

https://docs.google.com/open?id=0B6NaqjIxWV1yLXF2bHppdFBPLTQ

https://docs.google.com/open?id=0B6NaqjIxWV1yYURBWDhWUUNyZ1U

Click to expand...

Well I don't know what I said to you but I apologize. I appreciate the links.

This is exactly like my mower. Even the same engine. Looks like it has a dual circuit system. 3 amp unregulated voltage to recharge the battery and 14 volts regulated for the lights.

https://www.youtube.com/watch?v=zuKZSXdwMqc

The AC to the lights is not regulated either,
This is the most common system because it is cheap and very durable.
It uses the battery as a voltage regulator and that takes a toll from the battery.
IT also makes it difficult to fit accessories as the supply from the diode goes from 0 V DC to 14 V DC then back down to 0 again followed by nothing for same time then back 0 to 14 & back to 0 .
Some will cope quite fine while others will not, all depend upon how they are wired inside.
So in a nutshell you have 3 x 12 = 36 watts to play with without running down your battery, however you will not be recharging it either so when you have finished mowing it will need to go on a battery charger.
You get 50 to 100 starts from a battery depending upon how easy the mower starts and the condition of the battery.
You can change the stator to upgrade the system .

I used to have a "pith" helmet, I think that is what it was called...bought it at sharper image and it had a fan pointing at my face made into the brim... had a solar cell on top to run it... it made me look like quite the dufus ... but I never cared since it really worked to keep me cooler in the sun.

bertsmobile1 said:

The AC to the lights is not regulated either,
This is the most common system because it is cheap and very durable.
It uses the battery as a voltage regulator and that takes a toll from the battery.
IT also makes it difficult to fit accessories as the supply from the diode goes from 0 V DC to 14 V DC then back down to 0 again followed by nothing for same time then back 0 to 14 & back to 0 .
Some will cope quite fine while others will not, all depend upon how they are wired inside.
So in a nutshell you have 3 x 12 = 36 watts to play with without running down your battery, however you will not be recharging it either so when you have finished mowing it will need to go on a battery charger.
You get 50 to 100 starts from a battery depending upon how easy the mower starts and the condition of the battery.
You can change the stator to upgrade the system .

Click to expand...

I can connect the fan I have in mind using to the battery and measure the current draw and do the math and see if it exceeds the charging capacity.

I'll check with a guy I work with who has a sideline lawnmower repair business and see if he has any used staters that came off a lawnmower with a power take off. That might be enough to run my fan. I still can't imagine an electromagnet clutch would need a larger charging capacity to avoid discharging the battery.

txzrider2 said:

I used to have a "pith" helmet, I think that is what it was called...bought it at sharper image and it had a fan pointing at my face made into the brim... had a solar cell on top to run it... it made me look like quite the dufus ... but I never cared since it really worked to keep me cooler in the sun.

Click to expand...

I actually have a large solar cell I could mount on top of my cover to boost the charging capacity but most solar cells produce allot of voltage but not allot of current. They seem to be ideal for recharging batteries, not running smaller motors.

For now I'm just going to make a hard top cab cover, no sides like this one:



This one is too tall. I'd have to remove this thing just to get it out of my yard barn!

BTW, not to get off the subject but I've heard putting knobby tires or chains on a mower with a hydro-static transmission will wreck the transmission.

TurboFiat124,

Fret not, I have the remedy for your malady. I use this on my Hustler Raptor SD60. Just clip it to two horizontal pins of 1/8" rod suspended by two angle brackets on the foot panel. It will blow your hat off on high. On high it will run about 4 hours on a fully charged battery. Great for when the power goes off in the hot part of the year as well.

Have fun explaining this to your friends.

Max

https://www.homedepot.com/p/Ryobi-18-Volt-ONE-Hybrid-Portable-Fan-Tool-Only-P3320/205022215

turbofiat124 said:

I can connect the fan I have in mind using to the battery and measure the current draw and do the math and see if it exceeds the charging capacity.

I'll check with a guy I work with who has a sideline lawnmower repair business and see if he has any used staters that came off a lawnmower with a power take off. That might be enough to run my fan. I still can't imagine an electromagnet clutch would need a larger charging capacity to avoid discharging the battery.

Click to expand...

The clutch draws around 2 to 5 Amps depending upon the model.
Mowers with electric clutched usually have a 9 or 15 A fully rectified & regulated charging system
If you read the books you would have seen that the same stator will produce 3 A or 5 A depending upon the size of the magnets in the flywheel.
Be careful you do not end up making a solar oven
Side should be made out of shade cloth not clear plastic and prefferably the light coloured cloth at 80% shade.

mhavanti said:

TurboFiat124,

Fret not, I have the remedy for your malady. I use this on my Hustler Raptor SD60. Just clip it to two horizontal pins of 1/8" rod suspended by two angle brackets on the foot panel. It will blow your hat off on high. On high it will run about 4 hours on a fully charged battery. Great for when the power goes off in the hot part of the year as well.

Have fun explaining this to your friends.

Max

https://www.homedepot.com/p/Ryobi-18-Volt-ONE-Hybrid-Portable-Fan-Tool-Only-P3320/205022215

Click to expand...

That's exactly what I need!

bertsmobile1 said:

The clutch draws around 2 to 5 Amps depending upon the model.
Mowers with electric clutched usually have a 9 or 15 A fully rectified & regulated charging system
If you read the books you would have seen that the same stator will produce 3 A or 5 A depending upon the size of the magnets in the flywheel.
Be careful you do not end up making a solar oven
Side should be made out of shade cloth not clear plastic and prefferably the light coloured cloth at 80% shade.

Click to expand...

I did read the books but I figured I was going to have to pull the flywheel to inspect the stator to see what size magnets it had on it before I did anything. Unless you can go by the wiring harness coming off the stator past the shroud and judge it that way. If that's the case then this engine probably has the lowest capacity charging system that was installed. My guess is since my mower doesn't have an electromagnetic clutch and the low watt headlight bulbs it uses the 2 to 5 amp stator.

Thanks for the tip on the side shades. I was thinking just an awning of some sort like what's on my Father's 76 John Deere tractor to go over my head and a fan would be sufficient. The other day it was 95/30C and it's quite humid where I live so the heat index was closer to 100F/38C. While mowing, I was thinking it would be nice to have some shade. Or mount some brighter LED bulbs that pull less amps in place of those incandescents and mow after dark! I bet my neighbors would appreciate that.

I can usually tolerate this kind of weather, even driving around in some of my non air conditioned cars as long as I am moving.

It's when I start doing some major activity like dragging tree limbs and brush around I start sweating liters. But by the time I got done (4 hours) just riding around the yard, I didn't even bother running the weed wacker it was so hot. I just blew my driveway off and called it done. My wife won't even get out of the house this time of the year unless it's straight to the car.

I personally hate cold weather. I'd rather sweat that shiver.

On the flip side, the vinyl side shades might come in handy this fall when the temperature drops (actually create a solar oven). Providing it's not cloudy.

I'd like to get a jump start when it comes time to mulch leaves because it takes me longer in the fall to mulch than it does to mow in the summer. But it's a bit frigid at 9 am hopping on the mower in the fall. By the time it's warmed up to 50F/10C it's noon.

And since it get's dark around 6 pm I'm fighting the clock to get as much done as possible.

Another idea I came up with was to mount a vent I had left over from an auto air conditioning project in the panel below the steering wheel to channel heated air off the engine. I might have to run a duct and make a scoop below the cylinder fins to channel air. Like the heating system on my Trabant 601 and Citroen 2CV.

Once again, turbofiat124, I shall fail ye not. Do as I did and use this kit to give you a nice "heated seat". Install and extra battery and run in parallel so that you have plenty of reserve amperage. Once your butt is toasty, switch that sucker off. You can also place one hand below your butt to warm the hand, then switch and continue mulching.

https://www.ebay.com/itm/12V-5-Leve...18832855?epid=22016028518&hash=item3d4f0686d7