Stock alternator output

I'm considering putting heated grips on my bike. Does the stock alternator put out enough juice to run the grips and all the lights?

My service manual for 1982 XS650HJ says 14V - 16A @ 5000rpm

I would Like some heated grips also, it was a bit chilly days ride yesterday. Maybe loose all the regular bulbs and go LED I think that may do it.
I have little electrical understanding in my head but I looked at these grips
http://www.hotgrips.com/store.php?crn=203&rn=121&action=show_detail
they have ribs to help keep the heat out of the handle bars so less amps I think.

Says they need Approx 3amps

So I think its do-able maybe - Anyone?

Those are the grips I would be using. I've had them on my other bike, a Suzuki Bandit, for about a year and a half now. They're not kidding when they call them "Hot Grips". The only time I can continuously keep them on "High" is when it's below 40 degrees F. Even then, my hands are seriously toasty. I've never had a problem with the power draw on the Bandit, but that's 20 years newer and a totally different bike.

By the way, if you're going to install them, it's best to install them through a relay. This will save your battery if you accidentally leave the grips on when you park the bike.

http://www.canyonchasers.net/shop/generic/relay.php

I use a 40 watt electric vest on my 1981 xs650... no problem.

These are best case numbers that do not include turn signals or brake light and 11 amps from the alternator @2,000 RPM.

Headlight, low beam = 40 W
Tail Light = 8 W
Ins. Lights 3 X 3.4 W = 10 W

Total lights = 58 W/14.5 V = 4 Amps
Ign. Coils (points) 14.5 / 4.5 = 3.2 * 50% = 1.6 Amps
Regulator 14.5/5 = 2.9 Amps (current decreases as the rotor heats up)
Reserve to charge battery 2 Amps

Total Amps = 10.5 Amps

Net available Amps @ 2,000 RPM = 11 - 10.5 = 0.5 Amps (7.25 Watts)
Net Available Amps @ 5,000 RPM = 16 - 10.5 = 5.5 Amps (79 Watts)

Notes:
1. Brake light 27 W / 14.5 = 1.8 Amps
2. Above assumes a factory new charging system with battery < 1 yr. old.
3. Replace brake light with an LED for city riding (.1 Amp vs 1.8 Amp)
4. Suggest installing a neutral switch relay to turn off the headlight when stopped at a light.
5. Regulator current will be less as the rotor heats up. Actual resistance of rotor and brushes is higher than nominal 5 Ohms, which reduces the current consumption, but also lessens the available current. It's likely that the net available current @ 2,000 RPM could be negative.
6. Application of brake light and / or turn signals will result in a negative net available current at or below 2,000 RPM.
7. Switch contacts are available to turn off the instrument lights with the headlight switch to save 10 W during daylight. (10 W = .6 A)
8. Once the battery has regained its full charge, the reserve 2 Amps is available for other loads, such as the High beam headlight.

Conclusion: Adequate power available for heated clothing at speeds above 2,000 RPM. Less than adequate power available at low speeds or when stopped.

^^ He's an XS genius

In other words its not gonna work

It sounds like it'll work as long as I'm not in traffic. I don't ride in the city and rarely sit in traffic. In my experience, the grips are most necessary when on the freeway with 70-mph winds moving over your hands. When stopped, the grips can be turned off.

The neutral switch relay Pete uses to turn the headlight off when in neutral could also be used to turn the heated grips off.

Yeah, I don't shift to neutral at red lights, though.

I suppose if you really wanted more power you could do the permanent magnet mod to your charging system. Get a higher wattage output ?
On page 2 there are some numbers as in amps and watts.
http://xs650temp.proboards.com/index.cgi?board=Charging&action=display&thread=11096&page=2

Change some of your lights to LED's and you should have enough power

xstwin said:

In other words its not gonna work

Click to expand...

No that's not what it means. What it means is that if there isn't enough capacity from the charging system, you'll be running from the battery. There's enough capacity if you're running along over 3k.