MaineDad 85 #1 Posted February 4, 2011 Guys, The ammeter on the C-120 has always been bouncing. The terminals are clean and there is no corrosion. Where's the best place to buy a new ammeter? Share this post Link to post Share on other sites
rmaynard 15,936 #2 Posted February 5, 2011 The ammeter on my first B-100 bounces all over the place, but it still charges fine. I figure as long as the battery is charging, I will let it go. Keep your eye on eBay. I see them there quite often. Also, they are still available new from online Toro parts dealers for about $26.00. Share this post Link to post Share on other sites
iicap 1 #3 Posted February 5, 2011 Micah, if you have a DVOM, do a little investigating. Put meter to proper voltage range and with the engine warmed up some, running about 3/4 throttle, no accessories on, test the voltage at the battery and see if it is holding steady, not varying around. I'd say it should read 14.20 to around 14.50 volts and hold steady. If it is varing/jumping around something is going on with the charge system. Don't just go buy another ammeter without trying to find why this one is bouncing. good luck Share this post Link to post Share on other sites
rmaynard 15,936 #4 Posted February 5, 2011 Just to add to my last post, even though my ammeter is bouncing back and forth, I have a steady 14+ volts at the battery. Share this post Link to post Share on other sites
WheelHorse_of_course 99 #5 Posted February 5, 2011 Micah, I would not buy a new one. I have seen the same thing on several tractor with electronic regulators. The only one I have seen that did not bounce had a starter /generator and mechanical regulator. My educated guess is the electronic regulators use "pulse width modulation" (PWM). Lets say it has a 10 amp system and the battery is low, it will bounce less. But most of the time the battery needs less, lets say 5 amps. With PWM it will give 10 amps 50% of the time and 0 amps 50% of the time. After a while it may only need 1 amp. So then it gives 10 amps 10% of the time and 0 amps 90% of the time. You may have noticed this is how microwave ovens adjust their "power". If you look carefully you should be able to see that most of the time it bounces more to the right than the left, but when the lights are on it bounces less to the right than usual. If you do decide to replace it, try to find one with a relatively short needle. The less mass the less over shoot. My Charger did not have one so I added one. I finally ended up with one that says IH since it had the shortest needle I could find. Stil bounces..... cheers :thumbs: Share this post Link to post Share on other sites
1961551 2 #6 Posted February 8, 2011 my 312-8 amp meter bounces to the point, u cant read it unless the pto is engaged. its charging 13.9v. dont know why pto egagement matters? maybe vibrations. i dont know. i dont worry about it. i know its charging. jimmy Share this post Link to post Share on other sites
