Output of alternator

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If you have a volt meter then have the bike running and check what volts are going into your battery, should be no more than 14.5 volts when revs are up a bit and if its under 13 volts then something is wrong.

Ashley
 
Since some will run after starting and then disconnecting the battery, you do mean to test with the battery connected? (I guess I could just try it, but thought I'd ask)
 
At 2500 + RPM you should be able to measure system voltage between 13.8 and 14.2, a bit more is OK, a bit less is not. Check with no accessories on then check with high beams on. If you run with the lights on and you're doing local back roads watch your revs as you may find that you are loosing battery resources, at 3000+ RPM you should be OK, if your charging system is in good health. One of the big advantages of higher capacity charging systems is that they put out more power with less RPM; IIRC 2500 is considered the "basement" charging systems to come alive.
 
Yes with the battery connected the volt meter will tell you how much volts are going into your battery when running, its not only the altenator that can be at fault if not charging.
 
The warning light assimilator on my new to me 74 850 died over the weekend. I wasn't sure if I had a charging problem or a bad assimilator, checked the voltage across the battery and it was the assimilator. After 40+ years it died. Ordered an electronic one fro improvingclassicmotorcycles.com for under $30 shipping included. I have one on another one of my Norton's and it works great.

John in Texas
 
an ammeter is a good addition to a norton electrical system. It tells you everything you need to know at a glance. It shows whether your charging system is working. It shows where your rpm's spin fast enough to charge your battery. It shows if your zener diode is working properly. It even shows if you forget to turn your directional off, by the pointer pulsing back and forth as the blinker flashes.


I put mine in my headlight shell facing backward at me. I'm used to looking at it showing slightly positive charge when I'm moving along, and slightly negative when I am sitting at a stop light idling. Eventually, you become accustomed to knowing what it should show given your bike's rpms, and it's reassuring to look down and see what you expect to see which tells you everything is working. I supose the warning light assimilator tells you if your charging system is broken, but does it tell you if your zener diode goes bad??


Output of alternator
 
My '74 came with a voltmeter...
The turn signal flash cadence is good & swift at 3000 rpm, slows down at idle, after a long bit of city traffic, ( all with the 45W halogen lamp on... ALWAYS) it eventually burns steady at idle, not enough voltage to flash.
Checked & compared with a voltmeter, equals 13.6, 12.8, 11.8 respectively

And, I used to be an "ammeter" enthusiast, but have come to realize a voltmeter tells all that & more
 
I like the voltmeter idea, but never found one small enough to fit the ammeter hole in the headlight shell. Anybody know where we cd purchase a voltmeter in that same size?
The body is about 1.61" (41mm) diameter and the bezel is 1.77" (45mm).

Did the Norton Tech Digest warn us off actually hooking up the ammeter for some reason?
 
Hi,

be sure your battery is fully charged before measuring the voltage. you wont get 14.2 V with decharged battery, because power will be sucked.

i guess an ammeter isnt very attractive, because using a ammeter means all electrical power has to go through the ammeter. You need an extra line to and back to the ammeter.

there are LEDs availabel, fitting in the headlamps controllight gaps, which change colour according to the voltage. nice thing. Already discussed here.

eg: http://www.ebay.de/itm/12v-24v-LED-...lternator-charge-warning-lamp-J-/201285036531
 
This has some good information, although for airheads. Much of the science is useful.
http://bmwmotorcycletech.info/amp&voltmeters.htm

I found that article to be ambivelant and biased. The author says stuff like:

"A voltmeter will give some indication of the state of charge of the battery & system performance. An Ammeter will give a bit more information, mostly unnecessary."

.... then later he says:

"If you have a voltmeter, especially a highly accurate one (although the stock expanded meter IS accurate enough)....it will tell you if the battery voltage is high enough for you to assume it is charged; or not. An ammeter will tell you if current is flowing into, or out of the battery, but will not indicate more."

... that's rediculous. The author will infer that his battery is charging from it's voltage, but he wont infer it from an ammeter which shows direction of current flow in series with the battery. This article is pretty hyperbolic. I would be more swayed by some of the simpler arguments than this guy's "chicken little the sky is falling because of ammeters" hyperbolie.

I feel like I could use either meter, and there is no doubt that a voltmeter can be safer since it's just another parallel circuit on the wiring harness, rather than a series connection on the main battery circuit like an ammeter. If I had to wire my bike again maybe I would go voltmeter the next time, but my ammeter works flawlessly as I said previously. It doesn't bounce unless my blinker is on, and it's very informative although I DO infer that things are working because I know where the pointer should be when my bike is running. I have none of the issues the author warns about or claims has poor accuracy. My wiring harness is a combination of '70 wiring and later model directionals added, with a dip beam and a deleted kill switch circuit. (I turn the key to kill it)

I absolutely acknowledge that a voltmeter is as good as an ammeter, and probably safer to have installed on a bike. BOTH instruments tell you something different about the state of your circuitry, and BOTH require you to INFER the health of your components based on what you see on the instrument. I'm used to having an ammeter, so I know where the needle should be pointing at all times. If it's not, I know there's a problem. The other day my ammeter seemed to be charging a little high on the scale. I pulled the zener blade connection then cleaned it and reinstalled it. the ammeter needle moved back where it normally belongs....
 
The other day my ammeter seemed to be charging a little high on the scale. I pulled the zener blade connection then cleaned it and reinstalled it. the ammeter needle moved back where it normally belongs....

I sprayed a bit of red grease in the female connector (as I do every auto/moto connection) as I assembled it and it looks/functions as new, 5 years/32,000 miles.
JMWO:D
 
I found that article to be ambivelant and biased. The author says stuff like:

"A voltmeter will give some indication of the state of charge of the battery & system performance. An Ammeter will give a bit more information, mostly unnecessary."

.... then later he says:

"If you have a voltmeter, especially a highly accurate one (although the stock expanded meter IS accurate enough)....it will tell you if the battery voltage is high enough for you to assume it is charged; or not. An ammeter will tell you if current is flowing into, or out of the battery, but will not indicate more."

... that's rediculous. The author will infer that his battery is charging from it's voltage, but he wont infer it from an ammeter which shows direction of current flow in series with the battery. This article is pretty hyperbolic. I would be more swayed by some of the simpler arguments than this guy's "chicken little the sky is falling because of ammeters" hyperbolie.

I feel like I could use either meter, and there is no doubt that a voltmeter can be safer since it's just another parallel circuit on the wiring harness, rather than a series connection on the main battery circuit like an ammeter. If I had to wire my bike again maybe I would go voltmeter the next time, but my ammeter works flawlessly as I said previously. It doesn't bounce unless my blinker is on, and it's very informative although I DO infer that things are working because I know where the pointer should be when my bike is running. I have none of the issues the author warns about or claims has poor accuracy. My wiring harness is a combination of '70 wiring and later model directionals added, with a dip beam and a deleted kill switch circuit. (I turn the key to kill it)

I absolutely acknowledge that a voltmeter is as good as an ammeter, and probably safer to have installed on a bike. BOTH instruments tell you something different about the state of your circuitry, and BOTH require you to INFER the health of your components based on what you see on the instrument. I'm used to having an ammeter, so I know where the needle should be pointing at all times. If it's not, I know there's a problem. The other day my ammeter seemed to be charging a little high on the scale. I pulled the zener blade connection then cleaned it and reinstalled it. the ammeter needle moved back where it normally belongs....


I won't defend the author. I just thought some basic electrical facts practically applied to vintage motos may help some folks who are not masters of the electron (they say: "electrickery"). I kind of thought he more explained "pros & cons".
 
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