techy charging system

[puddlejumper 67]

well I ask the squirrels at the bird feeder about the charging system ona old techy.and they said something about soi university and redsquare members.

1st what I think I know :

1 engine at idle I have around 13volts ac across the two stator leads and 28 to30 at high rpm.

2 Manual says not to run engine without battery installed and not to run tractor more than 4 hours without removing 1 diode to prevent overcharge on battery(removing diode cuts charge rate in half) ENGINE HAS BEEN RUN WITHOUT BATTERY)

3 I only have 1 diode that when checked with a ohmeter (thinking of it as a check valve) I get a open circuit in one direction and a slight 1/2 ohm resistance in the other.

QUESTIONS

1 does all the above infomation sound correct

2 are there any more test I can perform and how

3 A few months back there was a thread about purchasing suitable replacement diodes from radio shack. If this is true could I get the pertinent info to do so.(all the lettering and numbers are unreadable on my diode)

[formariz 11,849]

Here it is.Hope it helps. If you PM your address I will send you a few correct original diodes

[puddlejumper 67]

Thanks for the info and the diodes will be appreciated.

[formariz 11,849]

No problem. Glad to be able to help.

[Save Old Iron 1,563]

puddlejumper,

all good info from Cas.

Manual says not to run engine without battery installed and not to run tractor more than 4 hours without removing 1 diode

looking at the specs from the Tecky manual, apparently this charging system can supply nearly 18 volts to the battery when the engine is running at 3600 RPM.

A fully charged lead cell battery sits at about 14.6 volts when connected to the charging system. Anything higher than 14.6 volts and you will start to burn off some of the electrolyte in the battery and "cook" the battery.

removing 1 diode to prevent overcharge on battery(removing diode cuts charge rate in half

This one I would have to check out personally. Removing 1 diode will in fact cut down the charge CURRENT but not the charge VOLTAGE. Your still supplying the battery with 18 volts charge but at a reduced current.

I'm not sure this really helps the overcharge condition all that much. Think of it as disconnecting a 3 amp battery charger from a battery and hooking up a 1 1/2 amp charger instead. The 1 1/2 amp charger will still overcharge the battery if it produces 18 volts BUT IT WILL IN FACT TAKE LONGER TO DO SO.

Again, not sure this really helps you out.

Manual says not to run engine without battery installed

True, the electronic ignition systems in the tractors can put out 200 - 300 volts spikes onto the +12 volt supply wire. Without the battery to absorb these spikes, damage can be inflicted on the diodes and stators in the charge system. That is why you see warning stickers on the newer tractors.

replacement diodes from radio shack

absolutely - and probably light years more reliable than the oldies. You loose the original "look" but pick up modern day reliability and low cost.

http://www.radioshack.com/product/index.js...oductId=2062579

Check out this website too - some really good info.

http://home.earthlink.net/~edstoller/id11.html

Just as a side note - If you would like to investigate the use of a home made regulator substitute for the original tractor circuit, I could whip up an SOI special reg circuit that will control the charge VOLTAGE to 14.6 and supply up to 3 amps charge CURRENT.

Very simple three terminal regulator IC's are available for about $2 - 3 dollars that can be made into a 3 amp regulator very easily. Self protecting from overheating and over current - pretty darn near indestructible.

Let me know.

[HankB 16]

http://www.radioshack.com/product/index.js...oductId=2062579

Or go to http://www.sciplus.com/search.cfm?utm_sour...x=0&btnHand.y=0

and get 15 for $3.

I got a bunch of extras and can't give them away.

:)

[Horse'n Around 22]

Quote :Manual says not to run engine without battery installed

"True, the electronic ignition systems in the tractors can put out 200 - 300 volts spikes onto the +12 volt supply wire. Without the battery to absorb these spikes, damage can be inflicted on the diodes and stators in the charge system. That is why you see warning stickers on the newer tractors"

SOI, Would this also be applicable if you were running the engine alone with no wiring ,only using the batt to run the starter but no other wiring is present or being used. I started my HH120 using this method but only let it for a couple of minutes. I rebuilt the carb yesterday and I was planning to start it and get it adjusted but I dont want to cause any damage. The wiring that goes to the rectifier is not attached to anything at this point.Basicly its just the enging sitting in the frame with the fuel line and the batt hooked to the starter and a switch just to run the engine . Will this damage the charging system ? If so I hope I didnt hurt anything when I started it . Now Im worried I wish there was a cringing smiley face with crossed fingers to display for times like this .

John

[Save Old Iron 1,563]

The wiring that goes to the rectifier is not attached to anything at this point.Basicly its just the enging sitting in the frame

John,

your probably OK here. I have to open up a Tecky wiring guide to see how its all hooked up.

But for Kohler points based systems, there is a definite voltage pulse feeding back thru the coil primary into the electrical system. The energy stored in the coil primary which is not transformed to secondary energy will generate a feedback pulse typically 60 volts and over - fed back into the +12 volt power line and absorbed by the battery.

Batteries make really great filtering capacitors by the way.

I'll see what type of diagram I can come up with to try to explain this a little better.

stay tuned.

and that look John - that squinty eyed fingers crossed look -

I call that the "face shields down" look.

[Horse'n Around 22]

The wiring

[puddlejumper 67]

Thanks to everybody for the Info.

SOI ,I will pass on the homemade reg at this time armed with above Knowledge and the parts I have think i am ok on that end of the system for a while. But there is another project on the way back burner that may call for a lesson in rewinding the stators under the flywheel. But no use getting into that now because I will forget it all before I get around to it.

And as far as highjacking threads its all worth reading. learn something everytime I get on here.

[Save Old Iron 1,563]

Puddlejumper,

on the stator winding,

I am actually trying to investigate rewinding the charge coil on a HH100 stator.

The charge coil was fried, and the SSI ignition module shows a burn mark on the epoxy seal on the back of the module.

I have unraveled the charge coil off the stator and purchased a coil of 26 awg magnet wire to attempt to rewind it. The whole stator was soaked in oil and I believe the enamel on the wire eventually breaks down fro exposure to the oil. The plastic "bobbin" the coil was wound on is old and fragile. It just cracked apart into fragments when touched. Makes life interesting. I can't claim victory on any stator rewinds yet. But there are other ways to supply the high voltage to the SSI units. Inexpensive AC inverters might be able to pump 120 volts into the SSI unit which is about what the charge coil does.

Let me know when your ready to rewind the stator. We will learn together on that one!

[wheelhorse656 20]

http://cgi.ebay.com/Diode-Rectifier-3-Amp-...=item2c50112ee9

here are some diods on ebay for a good deal.