Push button starter switch search ??

[Demaris]

My specific problem right now is with my Cletrac HG with the Hercules IXB3 engine. But this relates to any tractor with a 6 volt system.  In the winter, I often disconnect the charging system and put in a 12 volt battery so it will start. It is too sluggish on 6 volts in cold weather and just barely adequate in warm weather.

Here is my confusion. I found out after some voltage-drop testing that most of the problem is loss in the push-button starter switch.  I bought a new one and have the SAME problem. Now -after some research - seems every push-button switch I can find is only rated at 100 amps and that is ridiculous. It will work when hooked with 12 volts but not HD enough for 6 volts that needs twice the amperage. Not even close.  My 6 volt Delco starter is rated for 60 amps no-load and 500 amps fully loaded.  Probably should draw around 200-250 amps during normal cranking @ 4.5 to 5 volts.  Yet - I cannot find a push-button switch anywhere rated more then 100 amps.  Is nobody making them anymore?  100 amp rated switches sold for a 6 volt system are a rip-off, in my opinion. If that is all there is - no wonder so many convert to 8 or 12 volt systems.  If anyone knows where a true HD 6 volt switch is available, please post the info.  Even with electric-solenoids for 6 volt systems - so far I'm only finding ones rated for 200 amps max, but at least that's better then the mechanical push-button at 100 amps.

[hotratz]

When I restored my OC-46 I went to the local NAPA and was shown at least 3 different configurations of switches so they might have what you're looking for.

How much voltage drop are you getting? Are you measuring across the switch contacts or are you measuring across the battery?
The newer switches should work just fine. Case in point, I'm still using my original 6 volt starter and delivering twice as much voltage (12v) so the starting current is now almost twice as much as it was with a 6 volt battery. It starts very quickly. I tend to think your issue is not with the switch. The amp rating on the contacts is for continuous load. A switch rated at 100 amps continuous will easily carry twice that for intermittent load.

[Demaris]

Case in point, I'm still using my original 6 volt starter and delivering twice as much voltage (12v) so the starting current is now almost twice as much as it was with a 6 volt battery.

You have your understanding of electrical theory backward.  Twice the voltage means half the amps.   The OEM starter on a Cletrac HG or Oliver OC3 can draw up to 500 amps when hooked to a 6 volt battery.  If hooked to a 12 volt battery it can only draw 250 amps. Every push-button starter-switch NAPA sells is only rated for 100 amps @ 6 volts which is way less then needed.

When working correctly with 6 volts, the starter on my HG should drop no lower then 4.5 volts AT the starter when cranking.  That when battery voltage (at the battery) drops to 5 volts.  I.e, a 1/2 volt drop is tolerable in the wiring.  In this case - voltage at the input of the push-button switch is 5 volts, and at the output it is 4 volts.  A full 1 volt drop under load.  I did not even need to do a test since it gets very hot, very fast -so obviously battery power is wasted making heat instead of cranking my engine.

[oliverchris]

The keyed ignition switch on my 6v. OC-46 seems to work pretty well in Winter. You could try that instead of the push button?

[hotratz]

Case in point, I'm still using my original 6 volt starter and delivering twice as much voltage (12v) so the starting current is now almost twice as much as it was with a 6 volt battery.

You have your understanding of electrical theory backward.  Twice the voltage means half the amps.  

With over 45 years as an industrial electrician I doubt my theory is wrong. What you are missing is the circuit impedance of a 6 volt starter (windings) is half that of the windings on a 12 volt starter. You won't get half the circuit current unless you have a 12 volt starter also to limit current. If you do not change the circuits resistance to current flow (inductive impedance or resistance) the current will be proportional to the voltage applied. Think about what happens to a 6 volt light bulb if you apply 12 volts to it. It gets brighter and burns out because you increased the voltage without changing the bulbs resistance. Same thing with any 6 volt components on a 12 volt battery, Over current! Ohms Law: Current=Voltage/Resistance, works every time.

[Demaris]

With over 45 years as an industrial electrician I doubt my theory is wrong. What you are missing is the circuit impedance of a 6 volt starter (windings) is half that of the windings on a 12 volt starter. You won't get half the circuit current unless you have a 12 volt starter also to limit current. If you do not change the circuits resistance to current flow (inductive impedance or resistance) the current will be proportional to the voltage applied. Think about what happens to a 6 volt light bulb if you apply 12 volts to it. It gets brighter and burns out because you increased the voltage without changing the bulbs resistance. Same thing with any 6 volt components on a 12 volt battery, Over current! Ohms Law: Current=Voltage/Resistance, works every time.

My years working as an electrician are equal to your's.  Type of work I did compared to you  is likely different. I guess we will have to agree to disagree.  As I see it, it is a matter of what actually happens in real-world use.   Same starter button with a 12 volt battery has virtually no drop across it, no obvious heat, and the starter spins over like crazy.   Switch the battery to a 6 volt (same size/capacity as the 12 volt) and I get substantial voltage drop across the same push-button switch along with a lot of heat.   Also note that the OEM Delco starter on the HG and OC3 is rated at 500 amps @ 4.7 volts at max draw (2350 watts).  The push-button switch I got is rated for 100 amps at 6 volts (600 watts).  My statement/claim about "twice voltage/half current" was not meant to be 100% accurate. Obviously, if a starter turns over faster on 12 volts then when on 6 volts, more work is being done (not accounting for the heat waste when 6 volt is used).  If I was bored - I guess I could stick an inductive amp meter on the cable and get a reading, but can't say I really care. I already know the push-button suffers from excessive loss when used with 6 volts and does not when used with 12 volts.

One update.  After having three push-button 100 amp rated switchs not work, I went to a local Carquest store. I looked through their electrical catalog and found a push-button switch sold for an American LaFrance firetruck with a 6 volt system. No amp rating given but made for a bigger engine then my HG has. Oddly, they had one on the shelf that may have been sitting there for 30 years. Made in the USA.  Obviously better quality then anything else I'd tried but oddly was not physically any bigger then the others.  Still had 5/16" studs.  Put it in and it WORKS GREAT.  WAY better then the others. Maybe better, more conductive material in the internal contacts.