Use for M725 storage box!

[Panther]

Ever look at all your junk in your garage and start to thinking how to throw stuff together?

Had a craftsman lawn mower next to a york compressor and thought, "huh, this has a nice briggs and stratton, why not make on board air?" Then I see an alternator and figure "hey here's my generator."

What I wanted to do was fit it all in the outside storage box on the pass side. The space we are talking about is 19.5" long, 14" deep and 12" high, not a lot of room to work with.



The lawn mower had a pulley to power the rear wheels and was run by a 6.75, 190cc briggs. I built a wood base from scrap and cut the base of the mower. It was already raised for the pulley, I just noticed it in a couple spots for the belt to go to the alt and compressor. I also had to shorten the shaft from the motor to fit within the 12" height. Got flat stock to make 2 "U" brackets for the york and used some other misc stuff to mount the alt.



Went to Grainger and picked up some fittings, check valve and pressure switch. Had the rest of what I needed from another project, including a 8 gal air tank. I still have to mount that on the opposite side behind the drivers seat.



But there ya go. It works pretty good.
Copy the 5 tons and have your own air and power!

[Blitz]

thats`pretty durn kool Panther.

Do you have to energize the field on the alternator for it to start putting out 14+ volts?

I dont know how to do it. but you can modify that alternator and make a welder out of it.

I think it will put out 120 volts also , if someone walks ya through it.

ONAN? Who needs an ONAN? lol

You just saved yourself about 5k.

Impressive.

3600 rpm on the Briggs?
Will the alternator take that rpm, or does the pulley drop that down?

I dont know , just asking...

Impressive.

[Panther]

Good questions, I'm learning this stuff myself. All input is appreciated.

I needed the compressor so that was my first focus, I'm still working on the generator details.

The alternator is a 63 amp, internally regulated GM style. I have it wired right to the battery but haven't actually put an amp meter to see if I have 14 volts. I know what you mean by "tripping" the field, that's pretty simple, I think I heard the alt running though. There are "F" and "L" connections which I think are field and line? I many have to route these in some arrangement, I've seen it wired a few ways. 63 amp probably won't be enough to weld but I think you have to do something to the stator and or internal regulator. If I can find a way to get a higher output alt to act as both power and welder, heck why not? I do plan to run a small invertor off the battery, maybe something 600 watt.

I believe the pulley on the briggs and the alt are both 2.5" so it's a one to one ratio. The york is like 4/4.5 so it works harder to keep the compressor running. This is not something you want to run all day but yeah, have your own onan with junk in your garage! The briggs is just at idle whatever those rpms are, I have to find the throttle but haven't really thought of that. Don't want to ask to much from this little motor.

After I did this I saw several set ups on youtube, don't think there was a combo with air and power but lots of ideas. I'm just going to keep monkeying with it, the biggest challenge was getting it to fit!

Suppose most of us could build something similar for our trucks with stuff we already have. 5k for an onan? Think I have about $120 into it so far. Even just to have your own generator in an emergency. It also saves your truck motor from having an extra compressor or alt that you don't use that much.
I have to carry gas and diesel now but it's worth it.

[Blitz]

Yep 5 k for an ONAN that will "FIT" in a Motor Home external generator bay.

I totally understand the FIT was the hardest thing.. thats why its so impressive.

I "Think" that because you already have the alternator connected to the battery, you wont have to energize the field... but I'm not more than 50 % sure of that.

If You Do have to energize the field, you can do that with a 9 volt square "portable radio" battery.

It will pull down a lot harder when the field is energized, and you may have to bump the rpm's up a bit.

Its impressive.
I dig it.
I always wanted one, but never did it... and Never thought about doing AIR at the same time.

I would not worry too much about the ratios, and just run it... ( for the short times you will need it )
But there are formulas out there to figure that out... if you are going "off the grid" and need to depend on this full time.

I "think" again.... ( everyone duck )
that 200 amps are available in alternators for like Caddys's and big boat cars with lots of power seats, windows, etc... and air..
Now you are talking some bucks though... and would want to figure out the gear pulley ratios before you burned up a 300 dollar alternator...

Yep
I dig it.

On the inverter... If you put a dedicated deep cycle battery in the truck, ( called a house battery ) You will get a lot more run time and not kill your engine battery... ( starting battery) and you could pull 2000 watts + with out blinking.

Nice rig.
The price is even better

[jeeper]

Good questions, I'm learning this stuff myself. All input is appreciated.

There are "F" and "L" connections which I think are field and line?

I think F is "Field" but I think L is "Light". It closes the circuit on the warning lamp.

[Mikel]

Love it

[Panther]

Yeah the idea is to have this as a "house" battery charger, maybe add another but still separate from the engine, yet connected if need be.

Also to get it to "fit" I had to take much of the air cleaner off. I'm going to try and set something up that will use one filter for the briggs and the york.

So it's "R" for relay which is considered #1 and "F" for field for #2.
Guess I should look these things up but when you're doing you own application, just test til it works.

I think you're right about increasing rpms, the bands for this alt reaching 63 amps is probably really high. I'll have to find the throttle.

Forget where I found this but it's a basic diagram for generator (non automotive) set up.



A switch might be good to take the load off, certainly don't want to run the comp and alt at the same time.

Glad you guys like it, no one seems to get it around here.

[Blitz]

Yep... Make the house battery a deep cycle. You can connect it if need be to the starting system, but it will pull a load much better and longer than the starting batts.

I like the diagram...
I cant see any reason to not hook it up that way... including the switch.
You wont ever have to energize the field.

Quote " no one seems to get it around here. "

Lol... story of my life.

Most never think that the power can go out. Or think outside their comfort zone. Nor have HAD to.

It already did here 5 times since my last post. ( power went out )

Cleaned out the sump pumps twice from all the tree debris and made sure the genny had full fuel and a drop cord next to it.

When it rains around here... things flood. INSIDE. From the floor coming UP.

Screw the fridge, the lights and the freezer... I want my feet to be dry !

Think ahead and prevent problems.
" PPPPPPP "

I like the rig.
If I run across those pulley formulas I will send them to you.

HP is a factor also in relation to the alternator amps... but You should be OK under 100 amps.
I think it took 8 HP to run 100 amps if memory serves me still.

[jeeper]

I'm not an engineer but the general rule is 1 horsepower = ~746 watts.

To calculate watts the formula is VA or volts x amps.

If the alternator puts out 14.4 volts x 63 amps by my math that equals 907.2 watts. Thats about 1.2 horse power. I'd say your engine will have no problem running that alternator at full output.

[Panther]

Thanks guys good stuff.
When you research homemade generator so see all the "prepper" folks, which does influence my decisions. If stuff doesnt go down around here, I still have a sweet 4x4 camper, if it does I can be ready and help others. They think I got the idea from junkyard wars and complain about the noise.

The volts vs amps is helpful. Then the question is: at what rpm is the alt producing 63 amps? 4000? Have to test amps to see but can I get a tach to read a small engine like this? I think this is around 6 hp.

Sent from my SM-T217S using Tapatalk