Mikee Minute #12 - Ammeters

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Mikee Minute #12 - Ammeters

Post #1 by mikenixon » Fri Sep 13, 2013 9:08 pm

Image

This is a picture of an ammeter installed in a customer's Gold Wing. I am a huge fan of ammeters on motorcycles. I believe the last one put in by a factory stock, on a motorcycle, was on Kawasaki's Z1R. But they were once quite popular. And I believe for good reasons.

The ammeter is a compensation monitor.  If at any point the meter reads a loss without showing an immediate compensation, there is something wrong with the electrical system.  Engine rpm, the battery's charge state, and vehicle electrical load all influence the ammeter's reading.  Thus the needle normally moves around all the time as the engine is throttled and you change gears.  

As the bike is ridden, the back-and-forth swing of the needle will gradually decrease, until after some time the swing from low amps to high amps will be small, in fact minimal, indicating that the load pulling on the battery is equal to the push coming out of the battery due to the bike through riding having refreshened the battery's charge.  At its least active point the ammeter's needle will hover almost but not quite motionless around a point on the meter slightly above 0, say between 0 and 1.  I.e., half an amp.  However, at a stop light the needle will again dip below 0, and accelerating from the light, the needle will swing an equal amount above 0, and as the vehicle moves this swing will repeat, gradually lessening, i.e. narrowing, until again it is minimal, quivering around the slightly above 0 point again.  So, widest with little positive charge on the battery, narrower as the battery is recharged. But always swinging back and forth, even if just perceptibly, and always centered slightly above 0.  

This is a scenario that many find unintuitive, even difficult to understand, and it is probably why ammeters fell out of favor some years ago.  The way to think of it is when in science class in school the teacher moved a magnet near a piece of wire tied to a -- guess what, an ammeter!  Each time the teacher moved the magnet left, the ammeter's needle moved one way, and each time the teacher moved the magnet right the ammeter needle moved in the oppostie direction. This same thing happens on your bike.  Once you have spent some time observing it, you will intuitively find the ammeter faithfully represents the interplay between battery and alternator, offering a moment-by-moment picture of the health of the charging system. You will probably be surprised that the battery loses so much charge upon starting the vehicle, and equally amazed that the bike replenishes that lost energy so quickly as it is ridden.  Each load, as it is introduced and then removed, will display on the meter.  The turnsignals, for example, will cause the ammeter needle to wiggle in time with the flashes.  The brake light will show as a slight dip of the ammeter's needle.  And as already mentioned, the starter's maximum downward dip will be compensated for with an equally strong upward swing.  The lower the ammeter needle's dip downward, the higher its resulting swing upward again.  Consequently, very small dips are followed by very small upward compensations.  

I believe this offers a more realistic picture of battery and charging system health than does a voltmeter. Ammeters are actually more available today than they have been in decades thanks to the huge vintage parts industry. Though a little tricky to install, it is well worth it.
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Re: Mikee Minute #12 - Ammeters

Post #2 by sunnbobb » Fri Sep 13, 2013 11:41 pm

Thanks Mike. Where does the ammeter install or how is it connected to the Wing electrical system?

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Re: Mikee Minute #12 - Ammeters

Post #3 by mikenixon » Sat Sep 14, 2013 11:00 pm

Here you go....


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Re: Mikee Minute #12 - Ammeters

Post #4 by sunnbobb » Sun Sep 15, 2013 1:04 am

thanks!

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Re: Mikee Minute #12 - Ammeters

Post #5 by mikenixon » Sun Sep 15, 2013 5:01 pm

Couple of articles for you to check on, below. Take care to very carefully route the wiring to and from the ammeter. It will be live, unfused wire, so it must never be in danger of chafing or being pinched. And it should be large gauge, I have used 14 wire gauge.

http://www.motorcycleproject.com/motorc ... meter.html
http://www.motorcycleproject.com/motorc ... ethic.html
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Re: Mikee Minute #12 - Ammeters

Post #6 by Recycled Roadkill » Fri Sep 27, 2013 12:00 am

I've wondered from the time I first got my '77 why there was no ammeter on it and why, when I got the '78 there was a voltmeter instead of an ammeter.

I'm still wondering about both my bikes. Your article has encouraged me to buy ammeters for both bikes. As for the '77 I really don't feel much need for a fuel gauge anyhow as I tend to rely more on the trip odometer for when I'll need to refill the tank.

Thanks for those wiring diagrams, Mike!! action1

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Re: Mikee Minute #12 - Ammeters

Post #7 by CYBORG » Tue Oct 08, 2013 10:17 am

anyone who knows me and my bikes, knows i love gauges. and i grew up with amp meters in cars as stock equipment. they then went to volt meters as an upgrade, and later idiot lights.. kind of a go/no go circuit. an amp meter monitors the condition of your charging system. very useful. but for me, a volt meter, tells me that, and more. if my charging system fails, my volt meter drops to battery voltage, and as i continue to draw from the battery, it tells me how fast it is losing the ability to get me someplace for repairs.
Also a volt meter only monitors the battery. an amp meter has to be in line with the entire electrical system. if an amp meter fails, the bike is dead in the water. if a volt meter fails, the rest of the system still works. the amp meter requires heavier gauge wire, because it is carrying the entire load of the bike. volt meter only monitors the system.
Mike, your info on the amp meter is great, and very helpful. put i will stay with a quality, full sweep volt meter, which i feel gives me more information, and is safer

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Re: Mikee Minute #12 - Ammeters

Post #8 by mikenixon » Fri Oct 25, 2013 1:33 pm

That's cool.
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Re: Mikee Minute #12 - Ammeters

Post #9 by Toehead » Fri Nov 29, 2013 10:59 am

Just adding on:


There are also ammeters that use a shunt of known resistance, and are perhaps easier to install.

You place the shunt in the charging circuit, and the ammeter monitors the voltage drop across the shunt. From this it can calculate current.

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Re: Mikee Minute #12 - Ammeters

Post #10 by Sidecar Bob » Fri Aug 01, 2014 12:36 pm

Where did you find an 8/0/8 ammeter? The lowest I have been able to find is 30/0/30 and since it was made for a tractor it doesn't have a light.

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Re: Mikee Minute #12 - Ammeters

Post #11 by mikenixon » Wed Aug 27, 2014 8:41 pm

Sidecar Bob wrote:Where did you find an 8/0/8 ammeter? The lowest I have been able to find is 30/0/30 and since it was made for a tractor it doesn't have a light.


There are dozens of them on the Internet, most of them out of England and made for restoring pushrod Brit bikes. You don't want anything larger scale as it won't be very readable in that case. And no, none of them are backlit, unfortunately. But neither were those in Triumphs. They're also kind of small, and again, this is because the ones that came in Triumph headlight shells were too.

Incidentally, the ammeter in my article is a Japanese-made unit once sold by Tucker-Rocky and a very nice unit. In the 1980s I installed these in many customers' Hondas. Unfortunately they are long discontinued, but the somewhat more expensive Brit jobs are plentiful.
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Re: Mikee Minute #12 - Ammeters

Post #12 by Sidecar Bob » Wed Aug 27, 2014 9:27 pm

D'oh!! Now why didn't I think of using something made for a vintage Brit bike (or a modern version of one).

I'd bet this one would be perfect http://www.ebay.com/itm/261072999938 There are no numbers on the dial but the listing says it is 8V. The bulb is 6V but that's easy to change.

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Re: Mikee Minute #12 - Ammeters

Post #13 by salukispeed » Thu Aug 28, 2014 12:01 pm

Ammeters can definitely have there place and once you get used to how they respond they can be a good tool. In a perfect world the best solution would be both volt and amp meters. It would give you all the information but who has room for that. One thing to remember is that the amp meter can only be connected in the red/red-white smaller wiring and not include the starter cable to the solenoid as the starter draws more than 100 amps to start.

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Re: Mikee Minute #12 - Ammeters

Post #14 by mikenixon » Fri Aug 29, 2014 5:39 pm

Sidecar Bob wrote:D'oh!! Now why didn't I think of using something made for a vintage Brit bike (or a modern version of one).

I'd bet this one would be perfect http://www.ebay.com/itm/261072999938 There are no numbers on the dial but the listing says it is 8V. The bulb is 6V but that's easy to change.


Wow, even backlighted. From India. Hmm.
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Re: Mikee Minute #12 - Ammeters

Post #15 by Sidecar Bob » Sat Aug 30, 2014 10:05 am

Sidecar Bob wrote:There are no numbers on the dial but the listing says it is 8V.

Oops. I meant to say that the listing says it is 8A

Royal Enfield have improved a lot of their parts over the last decade or so. I think it may have a lot to do with customer expectations in the North American & European markets. I bought a couple of pairs of handlebar switches from that same seller last year and installed them on my Hondas. They may not last quite as long as the original ones on my bikes did, but they are probably as good as what modern Hondas come with and I'm sure will last as long as I will need them to :)


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