Amp gauge

[Bamacub]

Can a bad amp gauge not let the battery charge. I just put a new one wire delco alternator on and already 12 volt tractor. It's wired the same as other tractors with the same alternator. It's a friend's tractor and he said it showed no charge before.

[Glen]

Hi,
I think they have said on here that a burned out ammeter will not register, and power won't go through it.
See if the ammeter registers anything when you turn on the lights, it should show discharge.

TM Tractor has ammeters that look like the original styles, if you want that, but with a 12 volt alternator, you probably need an ammeter made for more power.
The original style IH ammeters at TM Tractor go to 20 amps.

[Bamacub]

This is the delco mini one wire alternator, any chance it could need a diode to excite it to charge. My post said this was the same alternator I had used before, this is my first with the mini.

[tst]

alternators the gauge may read backwards from if it was converted from a generator, check it with a meter for charging

[Bamacub]

I have checked with a volt meter at the battery with tractor running not charging. Both terminals on amp gauge reads the same as battery.

[Glen]

Does the ammeter pointer move when you turn the ignition switch to on, if the Cub has a Battery Ignition unit, the pointer won't move if it has a magneto.
Or does the pointer move when you turn the lights on.

[Bamacub]

Pointer does not move lights are not connected. It's a battery ignition 12 volt changed from a generator to alternator. One wire from alternator to plus side of amp gauge.

[staninlowerAL]

This is the delco mini one wire alternator, any chance it could need a diode to excite it to charge. My post said this was the same alternator I had used before, this is my first with the mini.

Some alternators are self exciting and some require a current flow to start charging. The RPM of the engine is critical also, depends on the alternator that you have. Maybe you can check with the seller for the specs.

[ntrenn]

My mini denso doesn’t tickle the ammeter, but it does show 14.5v or so at the battery terminals when running. The only problem I have had is battery terminal corrosion...when it gets a bit, the volts are there but the battery does not charge. Starting third season, I think...

[Gary Dotson]

Check the continuity through the amp meter with a multimeter, should show basically zero ohms. The meter movement can malfunction but as long as it shows full continuity it won't prevent charging. It seems that all Mini Denso's are not created equal, some I've installed self excited perfectly while others have required the diode. I'd go ahead and add the diode, it can't hurt anything.

[Bamacub]

wiring diagram shows diode 1n4001. where would a good source to get one. i did a search for napa and oreilly no luck

[Gary Dotson]

If you have any sort of electronics store in your area, they can fix you up. It doesn't have to be that exact diode, about any in the 2 - 6 amp range will work. I ordered some off e-bay, for a couple bucks, I have a supply, they cost almost nothing.

[tomstractor]

My amp, gauge shows a small discharge with the lights on and when I start it shows 20+ for a short time then goes down to a small charge with
the lights on and the tractor running. No diode and a Denso.

[fiddler]

The ammeter is in series with the charging circuit on the battery. If it opens up you will not charge the battery. There is practically zero ohms resistance across the ammeter. You could easily disconnect the positive battery cable from the battery and ohm the cable to the charge wire on the alternator. If it is open the only thing in line is the ammeter so that would be your culprit.

[Bamacub]

Zero ohms across the ammeter zero ohms positive battery cable to charge wire on the alternator. I plan to go with a diode. I will let you guys know how it goes. Thanks for your input