my ideas for a electric generation

[phillbus914]

I put it to a real test about a month ago and after about 2 hours of running everything in my bus it overheated. With a few minor tweaks I think it would work as well as a store bought generator. I'm thinking it could use a bigger pulley on the motor so the motor isn't working as hard, and maybe one of those squirrel cage fans blowing on it. I still use it from time to time if I need to charge a battery, or jump start a car. It's cool jump starting a car off a lawnarator.

Just today I found a good deal on a generator that I'm going to use for my primary power source. I haven't given up on the lawarator, I just came upon a deal I couldn't pass up on a generator.

[the_experience03]

Ok...pictures of my mowernator tomorrow...

I used it at Country Fest last weekend and it did remarkably well although now I get the feeling it is not putting out power anymore. I need to meter it to check it out, but lifetime warranties rock. Alternators do not like spending a lot of time near rated output. They ESPECIALLY don't like when the cooling fan is turning backwards. I notice you have a 12SI, Phill which should handle the heat better than my 10SI.

Anyone have a source for reverse rotation alternator fans? I'm thinking maybe marine application, but I am yet to stumble across a good source. A fan off an SI or CS series GM alternator that has a smooth serpentine pulley would also work as this dictates that the alternator spin backwards. I've heard of such a beast, but I'm yet to come across one.

[the_experience03]

As promised...pictures of my mowernator...or rather tractornator

The specs:

12 hp Briggs I/C (iron sleeved), 28 ci, model 287017
Old Crapsman tractor
GM "1-wire" 10SI alternator, BBB/Lester p/n 7127-1W
~70 amps output @ 1200 RPM motor speed, fuel consumption of about .5 gl/hr


This project started out as an old Crapsman lawn tractor. My father had acquired it secondhand to mow at his office for $200 about 15 years ago. 10 years ago I got it for free when they upgraded. I mowed with it at the house for probably 2 years. Then the deck just plain wore out and it wasn't cost effective to replace all the parts. I removed the deck and used it as a pseudo go-kart for the summer. In the winter I turned it into a halftrack. I built track frames using wood (I was young...welding wasn't an option yet) and made tracks using old carpet strips cleated with riveted wood strips and bolts for studs. It worked amazingly well. But all good things come to an end. The Peerless transaxle gave up the ghost and wasn't worth the replacement cost. The tractor sat for several years with a great motor. I couldn't get rid of it, but what do you do with a 12 horsepower vertical shaft motor?

Now I have my bus and the need has arisen for generating power for longer term boondocking. I do not like running the bus engine because a 6.6 liter diesel DOES suck some fuel down plus I don't want to damage a mission critical component like the bus' alternator in the middle of nowhere.

What's a guy to do? Well...I had an old lawn tractor, a 63 amp 10SI 3-wire alternator, and a queen size bedframe worth of angle iron. It was time to get to work and I ended up with what you see here. The original alternator I had a bad front bearing that turned on the shaft so replacing the $2 bearing wasn't an option. The regulator also had a diode that was malfunctioning in that it was drawing power even with the unit supposedly deenergized. I ended up putting on the alternator listed above and reconfiguring for 1-wire operation. I think I have since then toasted that alternator due to heat but lifetime warranties are great. The replacement will be a 7127-1W105 which is the 105 amp version of the alternator and is actually cheaper ($41) but was not on the shelf when I was doing this. I will put the correct reverse rotation cooling fan on it and may even put an aux. 12 volt fan on driven off the stator output of the Briggs.

So here it is. The rack on top holds a 6 gallon boat style tank which lasts a surprisingly long time. The chassis is the forward half of the tractor. I welded the draglink to the tierod to lock the steering and recycled the old deck lift handle as the carrying handle.



These are the controls. The throttle is the original from the tractor. All the way up is choke. I typically run this thing right around 1200 RPM or just above idle. It smooths out the performance but keeps the volume and fuel consumption as a surprisingly reasonable level. With my pulley ratio (using the original deck drive pulley) the alternator is spinning well above 4500 RPM at that engine speed so it is at full rated power. Anything above that and you hit diminishing returns.

The red switch grounds the ignition coil of the tractor. It will be interesting to see how long it lasts. Even in the open position the light will illuminate. This means that the spark energy is jumping the gap to ground. This has no ill-effects on engine performance, but the arcing can't be good for the switch. Still, it gives me an indicator light when the engine is running. I guess that's good if I ever lose my hearing.

The push button switch is for the electric starter. The tractor had no provisions for manual pull starting and converting wasn't feasible. This means you must have a battery with a decent charge remaining to start the rig. This never turned out to be a problem since it takes so little to kick over a Briggs. A person also could start it off a car and haul it over to the bus if they wanted.

You can also see the Ford solenoid in the picture. This serves as a common terminal as well as the solenoid to start the engine. The hot feed from the alternator attaches here as well as the cable going to the battery. This is also my take-off for the starter switch. All the wiring is 4 gauge with crimped and soldered connections.



Underneath you can see just how simple it is. There is an F-shaped bracket welded to the chassis that serves as the mount for the alternator. It pivots on this point so that the turnbuckle seen can be used to properly set belt tension. I mocked it up using a 15345 automotive belt (fan belt for a 22re ) so I figured a 35 inch A-belt would be about the right length. When I replace it I will go with a 34 inch to allow more adjustment if the need arises. The A-belt is a perfect fit on the tractor pulley and works ok on the alternator. It is far more robust than an automotive V-belt and was only like $5.




So how do you operate this beast? It's actually pretty simple. Obviously you need to put the fuel tank on and squeeze the bulb to get a prime to the carb. There is no fuel pump so this is important. You then hook up the ground and hot "jumper cables" to their appropriate places. This will backfeed to start it. A few revolutions on the choke followed by a few on a lower throttle position and it jumps to life. The switch light illuminates and the "jumper cables" now feed power to the battery as the alternator self energizes.

What are my overall thoughts? This thing is BIG and HEAVY. It is a pain to lug around. But with that comes reliability. All my parts are common and the 12 horsepower has no issues turning the alternator over at all. It is hardly even working which is nice. The stock muffler has also turned out to be surprisingly quiet. The best part is the fuel pinching nature of the 28 cubic inch Briggs single. I expected to put a lot of fuel through this thing for very little return in electrical energy, but that wasn't the case. Sure, I could turn a WAY bigger alternator which would alleviate some of my heat concerns, but for $41 I can't go wrong with the alternator I'm using. The engine also has another pulley on it. I've considered using this to turn an old power steering pump. With some quick connects this could serve to feed a log splitter or any other number of implements.

[paul iossi]

experience, you should add another alternayor or three. I remember using a startall on a service truck, it was a 12 hp with 4. 70 amp delcotrons and 2 sets of cables. it could be switched 12 or 24v, it would start anything down to about -30f,
anyhow more alternators = more power, truck alternators are built to withstand more abuse, but the heat is what kills the diodes, the real answer is monster diodes on an efficient external heatsink.
the fan is refered to by Delco as an air cleaner and is ment to draw air thru from the backside and sling debris away from the front of the alternator

[the_experience03]

I had considered adding another alternator, but I was concerned that the charging would be inconsistent at best. My fear was that they would sense the voltage of each other and that would throw them off if that makes sense. I am also still considering monster diodes moved to the outside of the alternator on a fan cooled efficient heat sink. We'll see where I take it. For the time being the project was a 95% success.

Still no luck with the fan though. The fan blade design is VERY inefficient at pushing air through the alternator instead of pulling it as you described. I can't help but think that the better fan like Phill's 12SI has is even worse.

[phillbus914]

I don't know how well my fan works, but I can tell ya that even after an hour of running it, the alternator case warm to the touch - not hot.

I was looking at the pictures I have posted on here of my lawnmower engine, and I noticed I have heat fins on the bottom of my motor. I bet with the blade on there it'd move a lot of air over the bottom of the motor, that may have something to do with it overheating.

Nice job on your lawnarator though, yours is like the Cadillac of lawnarators.

[the_experience03]

Ironic you should say it's a Cadillac as that is what the original 3 wire 10SI came off of.

[Joe Monstermaker]

I've done a lot of playing around with contraptions and alternators, so here's what I can add.
My favorite cheap plentiful junkyard alternator is the GM CS130. It's a 105-amp unit that still makes about 50 amps at idle, unlike the SI type that drop way down to about 15 or maybe 20 at idle. They're found on late '80s - early '90s small GM front drive cars and they're superior to the old SI type in every way. Wrecking yards are full of the cars they came on.
They're 3-wire, not one-wire, but there's no reason to be afraid of that. There are four terminals on the alternator's plug: S, F, L, and P. Two aren't needed. "S" is the one that monitors the voltage and adjusts the regulator; all you have to do is connect that wire straight to the big + ouput lug on the back of the alternator. The only other one you need is the "L". That one goes to the "alt" idiot light. You just have to connect it to a small indicator light bulb, and the other end of the bulb to ground. The light will turn on if the alternator fails. And it does need to be hooked up. You can use a resistor instead of a lamp if you want.
I've found that more than one can be connected in parallel to increase output and/or decrease the load on each.

You can remove the serpentine belt style pulley it will have on it and replace with an older v-belt style, they will go right on.

[the_experience03]

I like the CS series as well. You are correct that they put out a lot of power and they are EVERYWHERE. Heck, even the remanufactured ones are pretty darn cheap, typically only a few bucks more than a reman 10 or 12SI. I've also noticed that they carry residual magnetism better than any other internally regulated alternator I've seen meaning that most of the time they are able to self excite like a 1 wire alternator...very cool. The only issue I have with them is the failure rate I've seen from overheating. The CS case is much smaller than the SI amd the internals are much more cramped in there so they don't deal with heat real well. These are the alternators everyone is talking about when they say that you will burn up your alternator if you jump a car and let it charge that way.

I'd still like to find another 27SI off a Cadillac or other big vehicle like that. A CS alternator will burst output more than a 27SI, but you could have that big ol' alternator running at max output for hours on end and the case would remain cool to the touch.

[paul iossi]

has anyone tried wiring up an external diode pack on a heatsink like the ambulance people do?

[Jarlaxle]

Ressurecting this thread, sorry...

one more idea i think would work very well but have not yet tried is adding a 2nd alternator to the bus engine that only runs the house system.

I have done it...my bus spins two alternators. One is the factory alternator, charging the starting battery & powering lights, heat, etc. The other is a standard Delco 12SI (factory application is a mid-80's cop/taxi Caprice, it's about a 90 amp) hooked to the "house" batteries. The systems are separate (though both ground through the engine & chassis), a failure of one alternator won't affect the other. The 12SI can be connected to provide "chassis" power (both are wired with the same connectors).

[Joe Monstermaker]

I did that too, with two GM CS130 alternators, on my "Land Yacht". I also installed cables and a switch to allow both batteries to be connected in parallel, for self jump starting or charging in case of failure of either alternator.
The alternators are effectively connected directly together when I hit the switch. I experimented with it and found that they work together just fine and share the load.

[the_experience03]

Originally Posted by paul iossi

has anyone tried wiring up an external diode pack on a heatsink like the ambulance people do?

That's not a bad idea. A person could even take the diode pack out of the alternator (rather than get the bigger aftermarket ones) and put it on a heatsink with a cheap computer fan.

[lapeer20m]

Originally Posted by Joe Monstermaker

I did that too, with two GM CS130 alternators, on my "Land Yacht". I also installed cables and a switch to allow both batteries to be connected in parallel, for self jump starting or charging in case of failure of either alternator.
The alternators are effectively connected directly together when I hit the switch. I experimented with it and found that they work together just fine and share the load.

that's interesting. I was curious before about how trucks that come from the factory, like older ford plow trucks, were able to have dual alternators.

i am also a big fan of having dual separate alternators on a bus. On my last bus, the aux alternator was 24 volts. The advantage is that at that voltage it only takes half the current to run high amperage loads, like a 3K watt inverter.

i plan to repeat that setup on my next bus.

they were both gm 1 wire alternators, and oddly enough they were identical housings.