What is the max wattage for add-on electrical components?

[triumphvkk]

I'm thinking of adding heated gloves, a heated jacket liner, GPS, and a cell phone charger to the bike. This seems like a lot. Has anyone measured the wattage difference between the alternator output and the electrical power draw of the bike? I don't have any electrical tools anymore.

[MacBandit]

The bike has an alternator output of 400 watts. I would find it hard to believe if the bike used more than 200 watts including the lights. We use to add 2 55watt PIAAs, heated grips, heated vests and more to the old BMW K models which had a 400 watt alternator and never had a charging problem.

I'm putting heated grips on my R and I checked their draw the other day so I could buy a different switch for them. They drew a max of 2.6amps. That's 31.2 watts. I will also be adding power connector for a GPS. My GPS has a max draw of about .25amps which is 3 watts. A cellphone charger would be about the same or less. Heated jackets typically draw around 60-80watts on high. So you have a total draw of about 120watts on the high end. That leaves 280watts for the bike which should be way more than enough.

[Diego]

Of course, bear in mind that the 400 watt figure is the maximum output. Under a great many riding conditions, the alternator will not actually be able to achieve that level. Leave yourself an ample safety margin, or you may find yourself working the battery hard enough at low RPMs that its life expectancy may suffer.

[MacBandit]

Originally Posted by Diego

Of course, bear in mind that the 400 watt figure is the maximum output. Under a great many riding conditions, the alternator will not actually be able to achieve that level. Leave yourself an ample safety margin, or you may find yourself working the battery hard enough at low RPMs that its life expectancy may suffer.

This is true. I haven't checked to see what RPM the bike achieves max voltage at. Also Triumph rated the 400 watts at 12volts and most modern bikes and charging systems are rated at 13.6volts. So if that were true that would mean the peak charge rate would actually be 453 watts.

[sams675]

Hi

How can I check this. As my bike is having starting difficulties and I cannot use my hot grips as they simply switch off due to insufficient power?

thanks

sam

[MacBandit]

Originally Posted by sams675

Hi

How can I check this. As my bike is having starting difficulties and I cannot use my hot grips as they simply switch off due to insufficient power?

thanks

sam

I would do two simple things. Load test the battery. You can get a battery load tester for about $20. If you don't want to buy one you can connect a volt meter to the battery read the voltage then turn on the key and watch the voltage drop. The standing voltage on the battery should be around 12.5-12.8. When you turn the key on it should drop to around 11.8 and hold if it continues to drop fairly quickly say it reaches 11 volts within the next 10 secs you have a battery that is either under charged or bad. The next thing I would do is start the bike and check the voltage at idle at the battery and then rev the bike up to at least 5k and check it again. At idle you should see the battery recovering and start returning to it's unloaded voltage. When you rev it you should see the charging voltage at 13.6-14. If not you either have a charging problem or a bad battery that has a short or is drawing so much charge the bike can't over come it.