IGNITION - POWER CONSUMPTION

barbagris · Jul 20, 2015

Ok - This is a genuine question. If not then I'll have to try and find a way to measure it.

Has anybody measured how many Amps or watts their 3 coils are drawing from the electrical circuit?

It might seem a redundant question - but you don't get the sparks for free.
There used to be an Industry Rule Of Thumb - which iirc was 30-40 watts PER coil.
Depends on number of plugs, rpms and whether there a wasted spark.

Why does it matter? - well if you have (for example) a 400watt alternator - need 100 for the engine than you only have 300 left for lights, heated gear, power commanders etc. If it's 150 watts then you only have 250 to play with.

My gut says there are about 240-250 free from the way the voltmeter operates.

Joesmoe · Jul 20, 2015

What is the output of the R3 alternator ?

barbagris · Jul 20, 2015

tbh not 100% sure - I've seen 37amps at 2000rpm and 41 amps at 6000rpm quoted. Sure would mean I'd measured it.

But then again Triumph say it should be between 13.5 and 15V at 2000rpm - that's a potential 10% difference in available voltage which impacts wattage for the same amps. From experience the rectifier will lose some of that too. I'd say REAL WORLD 400-430 ish watts tops.But it's a bit of a guesstimate.

Just headlights will take 10Amps approx (5 on T) - add Fogs another 10amps-ish.

Going above about 3200rpm on steady motorway I've seen the voltmeter start to register lower volts - i.e. Demand barely meeting supply. The more sparks per second you discharge the more you have to put back into the coils.

If I dropped speed or switched something off - all fine. All I had back then was OEM H/lights and fogs. But that's only 220 Watts guys. And no heated gear etc.
It's what started me on LED lights - Could see no point in having extra lights if I could not power the ruddy things at speed.
I have no issues at all now - but ........................ We do not have bloody great bug 60amp upwards alternators

TURBO200R4 · Jul 20, 2015

how much does the cooling fan draw. if you measure the resistance of the coils and the fan blower we would know how much they draw.
on my classic there is not to much to worry about. and i am like you always curious but not curious enough to start measuring the bike.

rash_powder · Jul 20, 2015

I have a wattmeter for R/C use. If I ever find enough free time to look at my R3T I could hook it up, if possible, and measure the total watt draw.

http://hobbyking.com/hobbyking/store/__10786__HobbyKing_HK_010_Wattmeter_Voltage_Analyzer.html

Joesmoe · Jul 20, 2015

Would love to see that, if you find the time.

And would be interesting to know all the power consumers you have installed and operating.

Bedifferent · Jul 20, 2015

Joesmoe said:
What is the output of the R3 alternator ?

The old manual from previous posts says.....for the R3T:

37amps/min @ 2000 rpm
41amps/min @ 6000 rpm

For simplicity, you are working with roughly 450 watts at 12 volts.

Joesmoe · Jul 20, 2015

Don't alternators used in 12V systems really put out closer to 14V ?
And with voltage drops, isn't the charging circuit closer to 13V ?

And I thought a fully charged battery is supposed to be around 12.8V ?

Here again, oh to have that tachometer on the Touring.

Let's see:

1) headlight (single) on low: 90W
2) driving lights: off
3) heated vest & gloves (@100W) x 2 x 50%: 100W [note this is variable -- rarely, even in the coldest weather can I stand to turn this up past 50%]
4) engine coils: ???
5) cooling fan: I discount this, placing it in the same category as starting -- it'll come on when stopped, and the alternator is at lowest output, then when moving, airflow takes over, and battery is topped off
6) navigator: 1W
7) heated grips: ???
8) McCruise control: 5W
9) fuel pump: ???
___________________
Dunno

At night, add in driving lights - 40W x 2: 80W
Some high beam: +40W
___________________
Dunno + another 120W

Bedifferent · Jul 20, 2015

Joesmoe said:
Don't alternators used in 12V systems really put out closer to 14V ?
And with voltage drops, isn't the charging circuit closer to 13V ?

And I thought a fully charged battery is supposed to be around 12.8V ?

Here again, oh to have that tachometer on the Touring.

Let's see:

1) headlight (single) on low: 90W
2) driving lights: off
3) heated vest & gloves (@100W) x 2 x 50%: 100W [note this is variable -- rarely, even in the coldest weather can I stand to turn this up past 50%]
4) engine coils: ???
5) cooling fan: I discount this, placing it in the same category as starting -- it'll come on when stopped, and the alternator is at lowest output, then when moving, airflow takes over, and battery is topped off
6) navigator: 1W
7) heated grips: ???
___________________
Dunno

At night, add in driving lights - 40W x 2: 80W
Some high beam: +40W
___________________
Dunno + another 120W

Sounds like you got that baby loaded up. You forgot the fuel pump and your cruise control.

Joesmoe · Jul 20, 2015

Curious . . . when Honda produced the ST1100, a common complaint during its 10-year run, was insufficient alternator. When the ST1300 came out, it had a larger alternator.

One would think . . . no, maybe not. Producing a Roadster and Touring on the same production line . . . too hard to have a different alternator.

I think Goldwings have big alternators . . .

IGNITION - POWER CONSUMPTION

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