Calculating Surplus Wattage

[GLantern]

I am trying to figure out how much extra wattage i have available on my 1098 for accessories this is the piece straight from the manual detailing how much each electrical piece is using.  The 1098 forums has been little help and i know you guys are really knowledgeable.

The main components of the electrical system are:
headlight:
bulb type: 2 x H11 (12 V-55 W).
side light:
bulb type: 2 x H16W (12 V-6 W).
Electrical controls on handlebars:
turn indicators:
Front: LED.
Rear: bulb type: R10W (12 V-10 W)-orange.
Horn.
Stop light switches.
Battery, 12 V-10 Ah.
Alternator 12 V-480 W.
Electronic voltage regulator (rectifier), protected by a 30 A
fuse near the battery.
Starter motor, 12 V-0.7 kW
Tail light and brake light:
LED.
Number plate light:
bulb type: W5W (12 V-5 W).

I had done the math from the manual guessing on my own and it states the alternator puts out 450watts. And between the lights etc its using around 140watts so that would leave 310 watts available?  Am i correct in my assumptions?

[Speeddog]

Headlight + taillight + brakelight + plate light + instrument lights + ignition system +horn
140 Watts is a reasonable guess.

Keep in mind that the alternator isn't *always* making 450 watts, at idle and lower rpm it can't do it.
I don't know what it makes at idle.

Depends on what kind of load you're considering.
Electric clothing?

[GLantern]

Its about 125watts of electric clothing, gloves and jacket linerm and eventually a 15watt GPS.

[Speeddog]

You should be fine with that, there's folks here who run a good bit of heated gear, perhaps they'll chime in.

You could rig up a temporary voltmeter just to be sure.
Also, Aerostich sells some pretty nice permanent voltmeters.

[GLantern]

You should be fine with that, there's folks here who run a good bit of heated gear, perhaps they'll chime in.

You could rig up a temporary voltmeter just to be sure.
Also, Aerostich sells some pretty nice permanent voltmeters.

Awesome thanks for the info this question was on the 1098 forums since last week with no worthwhile reply, DMF 4 life! 

[Capo]

This is a little closer estimate. The load column is what could be drawn, the real column is a realistic draw during normal operation.

                               Load        Real
Headlight Main Beam   60           55
Side Light                    5              5
Number Plate              5              5
Rear Lamp                  5              5
Brake Lamp               21              0
Indicators (2)             20              0
Instrument Panel        2                2
Fuel Pump                60              60
ECU                         48              48
Fans                        60                0
Horn                        60                0
Total                      346             180

[Raux]

dont forget high beam and lo beam run at the same time right?

[Capo]

dont forget high beam and lo beam run at the same time right?

No

[Raux]

No

sorry idiot me. i was thinking 696. it has seperate lights for high/low

[NAKID]

This is a little closer estimate. The load column is what could be drawn, the real column is a realistic draw during normal operation.

                               Load        Real
Headlight Main Beam   60           55
Side Light                    5              5
Number Plate              5              5
Rear Lamp                  5              5
Brake Lamp               21              0
Indicators (2)             20              0
Instrument Panel        2                2
Fuel Pump                60              60
ECU                         48              48
Fans                        60                0
Horn                        60                0
Total                      346             180

Why would your real numbers for brake lights and fans be zero? Also, what do you think would happen if you had to use the horn with all the gear on?

[Capo]

Why would your real numbers for brake lights and fans be zero? Also, what do you think would happen if you had to use the horn with all the gear on?

Well because they are not on all the time, whereas the others are.
How often do your fans come on? How often are you on the brakes (as a percentage of running time), how often and for how long do you use your indicators?
What the OP is after is what output from the alternator would be available to power other devices. What has not been considered here is the demand of the battery charge requirement on the alternator.

[NAKID]

Well, I agree that they are not on all the time, or even on all that often, but they are significant. You can't discount them because they are on at times. The fans and brake light, for instance, are on at the most important time, when the rpms are lower and the bike is not making full electrical power. If he is using heated gear, that will be on at the same time as the brake lights, the fans, headlight, all of the high draw items...

[GLantern]

Well, I agree that they are not on all the time, or even on all that often, but they are significant. You can't discount them because they are on at times. The fans and brake light, for instance, are on at the most important time, when the rpms are lower and the bike is not making full electrical power. If he is using heated gear, that will be on at the same time as the brake lights, the fans, headlight, all of the high draw items...

Well i figure if im just sitting there i wont have the gear on it really would only be when im moving.

[Langanobob]

Also, what do you think would happen if you had to use the horn with all the gear on?

That's what batteries are for.  If there's a brief load that's higher than the alternator output, the battery provides the needed juice for a short time and gets slightly discharged.   Soon as the horn is off or speed picks up the alternator regains the load and recharges the slightly discharged battery. It's sort of the same principle as when you start your bike; the alternator is  not charging and the battery gets slightly discharged but the alternator kicks in on it starts, catches up and recharges it.     Only time there might be a problem is if someone rode around very slowly for a long time with the horn blaring continuously, brakes, bacon warmer and turning indicator on.

[Capo]

That's what batteries are for, in addition to starting non-kickstart bikes.  If there's a brief load that's higher than the alternator output, the battery provides the needed juice for a short time and gets slightly discharged. Soon as the horn is off or speed picks up the alternator regains the load and recharges the slightly discharged battery.   Only time there might be a problem is if someone rode around very slowly for a long time with the horn blaring continuously, brakes, bacon warmer and turning indicator on.

Thank you for clarifying my point.
In real terms, the CONSTANT load should not exceed 90% of the alternator output. Cyclic and infrequent loads will be supplied from the alternator surplus and the battery.

I have NEVER seen my rad fans operate during normal operation and that includes some tests of the radiator capacity involving reducing the effective radiator width by 100mm.
I would think that giving the climatic conditions that would cause the use of grip heaters, there would be even less likelyhood of the radiator fans operating.