question for people running ammeters

I replaced my ammeter this week, which was broken and stopped moving to indicate charging and draining. The new ammeter shows a charge when I start the bike and rev the engine. It dips negaitively if I hit the high beam flasher or turn on the lights. It will bounce rythymically if I turn on one of the directionals... but once I am riding and the RPM's are up, the charge indicator goes to zero pretty quickly.

My assumption is that my battery is nearly at a state of full charge, so once I get going so the ammeter show zero charging because I quickly recharge the battery and reach a state of equilibrium where my battery is being charged by the rotor/stator but also has the ziener diode disapatting that excess charge.... So my net indicator of charge is zero.... Does that sound feasable?

Everything is working, I just wondered why it doesn't show a state of charge all the time. Perhaps it's the way I have it wired... that makes it work that way.... comments, please....

That sounds normal. Once the battery is up to the regulated voltage then there will be no more currant flowing into the battery. Jim

Thanks for the gut check Jim. Everything works normally on the bike but I just had to ask.... After reading the other ammeter thread, I thought about mounting a voltmeter in the ammeter's place, but I figured that once I get used to seeing either one of them regularly, I would learn to interpert them similarly regardless of whether it was showing charging amps or total state of charge.

The one thing I was concerned about was that someone said if your ammeter died that it would be like blowing a fuse and your entire electrical system would be disabled. That was not the case with my broken ammeter. It stopped indicating charging or draining, but my entire electrical system still operated fine. I liked the 3 color diode charge indicator too, but I already had a 1 5/8th's hole drilled into my headlight shell for the last 20 years so I decided to use the existing wiring and just put in a new ammeter...

I just went the other way. I programmed the gauge in my dash to reed voltage instead of amps. Looking at the gauge when I was cruising down the highway and seeing it at zero always made me wonder if the gauge was working.

Now it just sets on 14... Jim

comnoz said:

I just went the other way. I programmed the gauge in my dash to reed voltage instead of amps. Looking at the gauge when I was cruising down the highway and seeing it at zero always made me wonder if the gauge was working.

Now it just sets on 14... Jim

Click to expand...

From memory the test of the overall charging system in the factory manual was that you should get 1 Amp of charge at 3000 rpm with the headlight on. I would expect to see that. Was that test with the zenir disconnected? I can't remember.

Jim's perfectly right. Understanding the ammeter means you have to understand what it's reading. When the battery is fully charged it will not accept any more current (no + on the meter), when it needs charging and the charging circuit is up to it, the meter will indicate +. When you hit the lights, of course the battery will discharge and the meter will most likely will go into - because the charging circuit can't keep up with it unless you're revs are way up. A good battery will charge up pretty quickly and the meter will be sitting at 0 most of the time. Then there's the zener, it cuts in when voltage gets above about 13.8V. I see my ammeter jumping around + and - sometimes and the charging circuit and the zener are just trading around. A voltmeter will actually tell you the same thing, knowing what the voltages mean, anything below about 12.7 V is discharging or a bad battery. But the voltage reading is not instantaneous like the ammeter.

...... if your battery is fully charge and you are buzzing along at a decent speed your ammeter reads zero... which could mean one of two things, either the ammeter is indicating the full charge or it's broken so it's not indicating anything...

If you have a voltmeter, and it's indicating something over 12 volts, you know the voltmeter is working ok because if it was broken, it would read zero....

In the case of my own ammeter use, I can always distinguish between an ammeter that reads zero because it's broken and fully charged battery who's ammeter reads zero. Either I hit the directionals which make the ammeter needle pulse, or flash the high beam flasher which really makes the ammeter jump, so I am not too freaked out driving around with the ammeter reading zero.

My old ammeter read zero for a month of riding before I concluded that it was probably broken since it didn't seem to be moving. As soon as I hooked up the new ammeter, it was pretty apparent that the old one was broken by comparison to how much the new one reacted to turning on lights and blipping the throttle. I guess I had forgotten how much it moved when it worked...

Peel had 1.2 ah two cigarette pack size lead acid battery & 3 phase sparx. Early on numerous times before installing a LED Vom - bat volts got so low brake light draw blew analog boyah brains > fire went out. Low enough kicking would not restart. This usually happened in nasty night conditions deep in city or far out in woods. So why not have best of both worlds a cute quaint clock thats schizo to judge plus a distinct indicating Vom to tally time and rpm mostly green. Lucas system is cleaverly well balanced for cost and size of components matching current draws so close to pilots pensiveness. For extra fancy look try to figure out how to fill and hold glycerine, w/o a bubble.