12 volt 1 wire alternater

How do I know if my alternater is working?

If you measure the voltage you should be about 13.8 or so if working 

Thanks to the guys also for the help

for a quick test on any car/ truck/ tractor , I just measure the voltage across the battery terminals with motor off.... should be about 12 - 12.6 volts .... then start the truck and  again measure the battery voltage... should be 13.8 - 14.6 volts.

For a starting battery with with full charge specific gravity of 1280 the full charged voltage is 14.200 volts at 68 degrees F. Pushing a greater voltage like 14.6 guarantees overcharge and loss of water from the electrolyte. The charging voltage can rise a little from 14.2 for higher and lower temperatures. That is at the battery posts. If you use a voltmeter somewhere else in the wiring the voltage will be higher because of voltage drop in the charging wiring.

The best indicator is the ammeter. After starting the charging current will be maximum, and if the voltage is regulated properly will taper to zero as the battery gets fully charged. The ammeter must be wired so that the charging current goes through it and also all equipment loads like lights, ignition, fans, etc that are discharging currents go through in the opposite direction. For negative ground the negative post on the ammeter goes to the positive battery post. The alternator and all loads but the starter are connected to the positive post on the ammeter.

Sometimes you can see the effect of the alternator charging on the brightness of the lamps but that can be subtle.

Gerald J.

MACK wrote: Touch the back of rear bearing with knife blade. If it is a magnet it is working.       MACK

Jay is right to a certain extent.  Here's what you need to know. Pretty simple. With a Voltmeter installed the normal charging rate is 13.9-14.5 Volts. 14.2 being ideal. If the needle is in that range, your good and everything is normal. If you make a habit of monitoring the Voltmeter, and its showing a charging rate of below 13.9, its undercharging. This will bring to your attention that the charging rate is down and the Battery and the system is not getting charged correctly. If its above 14.5 its overcharging, and there's something going on to cause that. Pretty simple. No guesswork involved. You don't have to be an electrical engineer or master mechanic to understand that.  Now, if there is a short (load) on the system, the Voltmeter will show a very high charge rate telling you something is going on and it needs to be looked at ASAP before smoke and flames appear. Now here is where Jay is correct. With an Ammeter down stream of an Alternator, if there is a short, the Ammeter will let you know theres a problem even quicker than a Voltmeter because its already burning and on fire in the instrument panel that's located between your legs. So yup, the Ammeter will actually show you more than a Voltmeter would. No doubt about it.....
Steve@B&B

Another way to check for charging is to pull on your headlights and see if they brighten even a bit when you throttle up from tick over speed.  Granted, this method is more qualitative then quantitative.  And works way better when it's dark out.

Your thought process is correct. A three wire Alternator wiring system is always better than a one wire setup.  With a three wire unit, you monitor the system with the voltage sense circuit. The Voltage regulator does its job in keeping the system (and the Battery) fully charged because it adjusts the Alternators output through the voltage sense circuit.
A much more accurate and effective system in keeping all functions operating the way they should, at the same time keeping the Battery happy.  A happy system is a reliable system.
Steve@B&B

I've used the CS-130 series of alternators, configured as 'one wire' and never had a problem( knock on wooden head..) HOWEVER I also used brand new wiring during the conversion. Have to think the IsquaredR losses can't be too much for 4' of wire.
hmm.. I need an 'excuse' to buy some $2 voltmeters, be interesting to see how well they work.
Jay

jaybmiller wrote: I've used the CS-130 series of alternators, configured as 'one wire' and never had a problem( knock on wooden head..) HOWEVER I also used brand new wiring during the conversion. Have to think the IsquaredR losses can't be too much for 4' of wire. hmm.. I need an 'excuse' to buy some $2 voltmeters, be interesting to see how well they work. Jay

Gerald J. wrote: The multiwire alternators can easily be wired so the internal voltage regulator works off the voltage at the battery or near the battery so that voltage drop in the wiring is compensated for to get better battery charging and starts charging with the engine at idle as soon as the engine is running and power is applied to the alternator start terminal. A one wire alternator samples the voltage at the alternator output terminal and so doesn't compensate for voltage drop between the alternator and the battery and the one wire alternator doesn't start charging until it is spun up. One spun up it charges down to idle, but on my gas 4020 with the smallest available alternator pulley and something like a 7" crankshaft pulley it takes about 1650 engine RPM which may be over 5000 alternator RPM before it starts charging. That need for goosing the engine doesn't always make the simple wiring profitable. Gerald J.

You need to get one of the good 1 wire alternators off ebay for $60,I have 8 on
tractors and every one will start to charge as soon as the engine fires up no matter
how slow the throttle is set.Fired up the AC 185 today to see how'd it'd start after sitting for over 3 weeks fired right up and starting charging with the throttle slightly cracked
up from idle.Battery didn't run down either in 3+ weeks(anther 1 wire myth).

Most old tractors have very little current draw almost none if its a diesel unless the lights are used and if they are replacing a generator then any alternator is going to supply way more power than any generator ever did.When I started the 185 today it charged a lot for maybe a minute then the needle dropped back after it had charged the battery back up.So it must be 'monitoring' what needs current.
An Old  tractor ain't a fully loaded 2017 SUV so you don't need the same electrical
capabilities.

Gerald J. wrote: The battery sets the charging current providing the generator or alternator voltage is regulated at 14.2 volts. As the battery charges the current decreases to zero when the battery is fully charged. The alternator regulator just controls the voltage for that to happen. A three wire alternator can be wired so the regulator senses the voltage near the battery so that wiring voltage drop isn't a factor. Gerald J.

So if you think the 3 wire is so good why haven't you put one on the 4020?

Go on ebay and get a one wire one from DB Electrical think you'll find that to be
better,definitely will not have to rev your engine up to anything close to 1650 RPM