A 20A voltage regulator upgrade for a 16HP Briggs & Stratton engine

[mountainman]

Yesterday I did the winter prep work on my Max II. In addition I installed a high-power 20 amp voltage regulator because I've been through two standard regulators in four years. I drive my ATV a lot (720+ hours so far), usually with the headlights on, and I think the standard regulator just isn't designed for the constant 8 amp current flow. The standard regulator starts to switch on and off either providing no power or a very high current implying a very high voltage. Either way is not good for battery.

The high-power regulator has thicker wires and a heat sink. It can't fit flat on the engine like the standard regulator so I used some stand-offs to make a gap between the engine and the regulator. Hopefully this will help keep the regulator cool.

I was pleased to discover that a high-power regulator existed. My original plan was to wire up two standard regulators in parallel.

I uploaded some pictures to the gallery.

[micmac]

Hey mountain man,

sounds like a great mod. How about posting some parts # etc for thr archives.

[mountainman]

The part I put in is Briggs and Stratton number 808297 but apparently it's been replaced with part 691573. B&S sells it direct for $100.

[Uncle Vin]

I have a Vanguard Bandolero Engine. Is it possible to install the 20 amp Alternator to up the juice? Your regulator upgrade just beefs-up the regulator, it does not produce more juice, does it? Uncle Vin

[jerseybigfoot]

My friend Lori installed a Performance V-Twin in her Max 2. I had Al Hodges install the 20 amp stator and regulator when he built the engine. Maybe check with Al at Performance to see what the parts are. He may have the parts to do the conversion.

[Model Citizen]

My friend Lori installed a Performance V-Twin in her Max 2.

Well, ALL RIGHT. What did she get? How many horses?

Bridget

[jerseybigfoot]

lets just say it's enough. Check her out on the Busco drag strip. She didn't want to run it full throttle without a helmet.

[Model Citizen]

Check her out on the Busco drag strip. She didn't want to run it full throttle without a helmet.

I saw that video. I didn't know she had a new motor in it. Smart lady not to run it full throttle without a helmet. Took me a while before I felt comfortable to run mine full throttle and I've got suspension. Next time, get her a helmet there, Marc.

Bridget

[Uncle Vin]

My friend Lori installed a Performance V-Twin in her Max 2. I had Al Hodges install the 20 amp stator and regulator when he built the engine. Maybe check with Al at Performance to see what the parts are. He may have the parts to do the conversion.

I looked at the B&S website and they sell the stator for a little less than $50. The only question left is whether the factory wiring on a Max IV can handle the increased current. Anyone know the answer? I like this upgrade. Uncle Vin

[mountainman]

Here's the conservative maximum ampacity of different sizes of copper wire:

18ga: 10A
16ga: 13A
14ga: 17A
12ga: 23A
10ga: 33A

I don't know but I've been told that the 16HP B&S V-Twin in my Max II had a 16 amp regulator. This implies that the wiring is 14ga. If you install a 20 amp stator and regulator, and you plan to use all that current, then you should probably make sure the wiring is 12ga.

[Uncle Vin]

Here's the conservative maximum ampacity of different sizes of copper wire:

18ga: 10A
16ga: 13A
14ga: 17A
12ga: 23A
10ga: 33A

I don't know but I've been told that the 16HP B&S V-Twin in my Max II had a 16 amp regulator. This implies that the wiring is 14ga. If you install a 20 amp stator and regulator, and you plan to use all that current, then you should probably make sure the wiring is 12ga.

I was looking at the shop manual after I posted. It's not just as simple a changing the stator and regulator. In addition, the flywheel must be changed as well, because the generation of current is a function of the stator [I]and[I] the number of magnets on the flywheel. The manual specifically says this. To sum up, in order to upgrade to 20 amp, you must: a) change the stator; b) change the flywheel; c) change the regulator; and d) rewire the machine. Any other comments would be helpful. Uncle Vin

[6X6]

Hi:
Well, if I understand the initial post, the Idea is the 20A Regulator/Rectifier will not burn out under sustained load as easily as the original. Replacing the Stator coil to a heavier unit would also be more durable but the magnets are also needed to make the 20A available. Without it the other parts will not be able to put out a full 20A. Rewiring the machine is necessary only from the Regulator to hot (+), the ground will be plenty beefy enough because of the starter. Any other rewiring would only be if you are changing/adding something. (Higher power headlight, Beef up headlight wires (Including hot to switch and ground) etc... (This is ASSUMING the 20A Regulator is the same plug as the stock)

[Roger S]

Great research on the subject. I suspected the flywheel was different. For a 4 amp increase, it sounds like a waste of time and $. I wonder why the original poster had regulator problems in the first place.

Now, if you could adapt a 23hp 20-50 amp system to the earlier blocks, that might help justify the cost. I think the engine block is different where the stator bolts on. Well, just buy a bare block for a couple hundred and put all the 18 hp parts on it with a set of intek 44 pistons for flat tops. Oh the 16 hp? crank, it would need a long rod and I don't know what piston, it would be like a 16 with a huge overbore. Oh, just buy the bigger crank for $150

On a more serious note, maybe see if the stator could be adapted to the earlier blocks. I have a small alternantor from a '70's datsun I would hang on some where. Otherwise, I'd live with the 16 amp system that's worked fiine for a decade. I guess it helps to have somewhat of a real battery size in the argo instead of a lawn and garden battery.

About the magnets in the flywheel, reminds me of the old GM alternators. The only difference in them was the size of the rotor windings (magnet). The stator, diodes, and regulator were all the same.

[Uncle Vin]

Great research on the subject. I suspected the flywheel was different. For a 4 amp increase, it sounds like a waste of time and $. I wonder why the original poster had regulator problems in the first place.

Now, if you could adapt a 23hp 20-50 amp system to the earlier blocks, that might help justify the cost. I think the engine block is different where the stator bolts on. Well, just buy a bare block for a couple hundred and put all the 18 hp parts on it with a set of intek 44 pistons for flat tops. Oh the 16 hp? crank, it would need a long rod and I don't know what piston, it would be like a 16 with a huge overbore. Oh, just buy the bigger crank for $150

On a more serious note, maybe see if the staor could be adapted to the earlier blocks. I have a small alternantor from a '70's datsun I would hang on some where. Otherwise, I'd live with the 16 amp system that's worked fiine for a decade. I guess it helps to have somewhat of a real battery size in the argo instead of a lawn and garden battery.

I know that some members had installed an alternator onto their machines, but I have never seen one installed on a Max IV with a Vanguard. I would like to. Once an alternator is installed, heating the cab becomes easy, as well as running all sorts of power-draining accessories. I wish someone would post a how-to on this subject [hint]. Uncle Vin

[jerseybigfoot]

Here is a Max4 with a 18 opposed and alternator. You would need the flywheel PTO, pulley and belt for the Vanguard.