AC Headlights / KGro 18HP

[BrianX128 107]

I have an old KGro with an 18hp opposed briggs / 42" deck, it's basically a re-branded craftsman. It was my grandfathers on my dad's side of the family, it only has 200 hours and the deck had rotted because it sat under a tarp basically in a puddle for a few years after he passed. It runs great, just never had a usable deck. I got one for it that had a rust hole in the front but I got it patched up and mows great. It's just an extra, but it has a mulcher / bagger that works nice for fall.

 

I realized trying to use it the other night that the headlights are AC powered as they dim a lot based on rpms but my voltage never actually changes on the battery. I have some LED's I could throw in but I'm guessing they aren't going to like AC voltage like normal bulbs would. On the other hand I could easily re-wire the headlights from the battery with a fuse to the same switch but I'm pretty sure this is a 5amp charging / 3amp AC to headlights system and I'm not sure what the best solution is here. The lights are useless, and since this is primarily a fall machine for me it would be nice to not have to stop just because it's dark early on a cloudy fall evening. The mower isn't exactly quiet either, and having to red line the engine to see to put it back in the upstairs of my garage by my neighbors house late in the evenings feels a little rude also. 

[ebinmaine 67,408]

Does that Briggs have a magneto that runs the spark and then a separate charging system? For recharging the battery I mean?

 

Or more to the point do you know what that first 5 amps is actually used for?

 

To be honest I think you'd be fine. Rewire some LED lamps into the existing sockets and connect those wires to a switch on the dash or maybe your accessory terminal in the ignition? and just stop using that AC headlamp system all together...

 

Those LED light bulbs for the most part draw so little. 

[BrianX128 107]

Yeah, I'm pretty sure the 5amps is for nothing but recharge it's a magneto spark system with the dual fire wasted spark setup. I remember reading that part when looking up info about the engine. I might have to wire up a cheapo parts store voltage meter somewhere, all the tractor has is an amp gauge. I'm guessing it's coming from the charging wire into the battery so I should still be able to make sure I'm not going negative. I guess it wouldn't hurt to do the re-wire first to the halogens to see what that gauge does before swapping the LED's in. 

 

I was kinda hoping led's would swap into ac voltage like regular bulbs can in this, but I am almost 100% sure they won't like that. 

[ebinmaine 67,408]

I'm not really sure who you can ask about that but I know the LEDs in general do have some variability on the voltage. But as far as going from say like 15 or 20 volts ac all the way up to 60 volts ac or whatever. I'm not sure I've seen any that have that capability.

 

Probably would be worth a phone call to somebody like grainger, mcmaster-carr, something like that.

 

On the one hand it would be nice not to need to rewire the tractor but on the other hand if you could get yourself a consistent 14-ish volts going to the bulbs that would be the same lumens all the time. 

[Achto 27,562]

You could place a diode inline on your AC circuit, this would change your AC power to DC power. Remaining problem would be that you're still relying on the RPMs of the engine to make the proper voltage. You will be much better off to install LED lights and wire them to the battery via a switch. This will give you constant reliable light and the low draw of LED's will allow your charging system to keep up without issue.   

Edited September 28, 2020 by Achto

[BrianX128 107]

So I had to try tossing 1 led in as it was since I have a bag full and surprisingly they work but surprisingly it's worse of a change from wide open to idle. They don't even work at idle ha.

 

I swapped everything over and used the existing switch and just changed where it was getting fed to be from the ignition instead of from the orange ac wire and it's happy and bright.

 

Thanks!

[D_Mac 8,607]

I had one of those awhile back. What I remember about it was the engine ran great, rest of it was kinda cheaply made. I had to repair the steering gear on it. One I had was a 16 hp.

[Achto 27,562]

4 hours ago, BrianX128 said:

So I had to try tossing 1 led in as it was since I have a bag full and surprisingly they work but surprisingly it's worse of a change from wide open to idle. They don't even work at idle ha.

 

As the RPMs drop so will the voltage output from the stator. An incandescent bulb will just dim when the voltage drops. A LED will just shut off when the voltage drops too low. Glad that you have the lights working well.

[BrianX128 107]

Yep that's it. This is mine but from a month ago before I found a cheap deck that didn't have a hole in it and make crunching noises..

 

 

 

Engine and trans seem tough but the deck and all of the trim pieces are super flimsy. The trans does let you shift while moving which is neat as long as you half press the clutch to where it's not hitting the brake yet and able to coast into the next gear when you want to go faster or hit the brake slightly to downshift. Best feature of the mower.

 

It is super loud also. Not sure if that's just the nature of the opposed briggs engines or what but it sounds like it's at 6k rpms and you can't hear yourself think while mowing.

[Handy Don 12,210]

Do your old age hearing a favor and get some ear protection to wear while using this beast!

 

[bds1984 1,429]

I don't think that is abnormally loud for an opposed Briggs of that era.  Soon that tractor will be an orphan brand as there are only about 35 Kmarts left in existence.  I'd like to have one as a conversation piece someday.  Michigan was the home of Kmart, but I don't ever recall seeing many of those being used or in sitting in the boneyard.  Your's is definitely a Craftsman clone for sure.