alternator outpput 1200 GSA

[Bruce H]

how much does an alternator on a 2007 GSA put out and how much does the bike need? My qusetion pertains to added lights. I have factory heated grips and a heated vest (wiider, I'd guess 5 amps) and have added two 100 watt lights. Is there anything left? Am I on the edge?

 

Thanks, Bruce

[ExGMan]

Bruce - I think the 2007 R1200GS-A has an alternator output of something over 720 watts (which is what the R1200RT has). I went looking for the reference, but could not find the exact number, but I think it's 750 watts, and may be as much as 800 watts. I sure wish I could find where I'd read those numbers but am pretty sure about the 750-watt figure.

[TestPilot]

The current GSA alternator puts out 720 watts (per the spec sheet on the BMW Motorcycle web site). I suspect your bike is the same.

[Bruce H]

Thanks for the response. At 750 watts do I have enough to run whatever the bike needs plus the grips, heated vest and the extra lights? Or, do need to turn something off? Don't want to find out I killed the battery.

[johnlt]

Yes, you're not even close. I'm not sure I've even known of anyone to exceed the GSA alternator output. I've run two aux lights at 110W each AND two aux lights at 55W each AND, heated jacket, gloves, grips and seats. No problems

[Bruce H]

Thanks, that is what I wanted to know... Don't ride that often after dark but these do light 'er up.

[Hall Vince]

On this subject, I installed two FF50 spot lights to suppliment the high beam on my 2007 RT.

I also had two 100w H7 bulbs which I initially placed in the FF50's.

However on start up and testing the install I could hear the engine labour a little (drain on altenator) and increased noise from the altenator belt.

Belt should be less than 8000 miles as the front cover was replaced at 7k and I'm on 15k.

It was such that I removed the 100w bulbs and refitted the 55w and noise was pretty much gone.

 

I sure it was mostly belt noise, but my concern was excessive wear on the belt.

To be fair the spot lights only come on on high beam so not a lot of hours running in that state, I'm tempted to refit the 100w bulbs and run them for a bit.

 

I'd like to know if those of you who have fitted lights that draw an extra 200w total (or more)that...

1. have you also noticed the noise?

2. any problems with belt wear/slippage?

 

Info appreciated and apologies for butting in on the Bruces thread. But the info may be useful to him as well.

\v/

[krussell]

The really useful information that BMW should specify is the available power. I think it's great that my bike has a 720W generator. But what I really want to see in the spec sheet and/or manual is the budget I can use for accessories.

[johnlt]

I had two PIAA 910 with 110W bulbs on my 1150 along with a pair of PIAA 1100s with 55W bulbs. Even with everything on, I never noticed any additional noise. Ran them like that for ~30K until I sold the bike.

[Rich06FJR1300]

good luck on that one (bmw supplying available power for accessories)..someone on here posted something about this. But you can do the math yourself...power = amps x watts, add up each accessory you add on (example: lights...110 watts/12 volts = 9.17 amps (you have convert you alternator output to amps so 750 watts/12 volts = 62.5 amps), you need something like 25% to run the bike without any accessories so something like 15 amps are needed and you have 62 - 15.5 = 47.50 amps left to run accessories...you used 9 for the lights so that's fine.

[krussell]

good luck on that one (bmw supplying available power for accessories)..

 

One can dream!

 

 

But you can do the math yourself...power = amps x watts, add up each accessory you add on (example: lights...110 watts/12 volts = 9.17 amps (you have convert you alternator output to amps so 750 watts/12 volts = 62.5 amps), you need something like 25% to run the bike without any accessories so something like 15 amps are needed and you have 62 - 15.5 = 47.50 amps left to run accessories...you used 9 for the lights so that's fine.

 

Yes, computing your intended accessory load is trivial, but how does one arrive at the 25% to run the bike without any accessories number? Guess? That's where we could use manufacturer help, even though there is slim chance of getting it.

 

[Rich06FJR1300]

do you really need an exact number? bmw's have an alternator made for a car so there's plenty of juice for accessories. You can also put on a voltmeter to see the charge with all the accessories on, as long as its 14+ volts you are good to go.

[T__]

how much does an alternator on a 2007 GSA put out and how much does the bike need? My qusetion pertains to added lights. I have factory heated grips and a heated vest (wiider, I'd guess 5 amps) and have added two 100 watt lights. Is there anything left? Am I on the edge?

 

Thanks, Bruce

 

Bruce, the latest spec I show on the GS adventure (from the BMW service RepRom shows 660 watts (unless the manual is a misprint) but keep in mind that is at 4000 rpm’s.. It is only making 192 watts at low idle (1000 RPM’s)..

 

In any case unless you keep the engine running at high RPM’s you have limited alternator output of less than the 660 watts so a lot of idling can allow the battery to deplete if a high sustained electrical load at low engine RPM’s..

 

At idle those (2) 100 watt added lights + headlights + fuel pump + brake lights + computers & fuel injectors + 4 ign coils + other running electrical accessories are probably drawing a fair amount more than the alternator can make so you are operating off the battery at idle.. The later 1200RT’s (not sure on the GSA or early 1200 RT’s) have a voltage monitor algorithm in the fueling computer to boost the idle speed slightly when there is a high electrical load on the system but even that won’t go very high..

 

 

Still shouldn’t be a big deal as those BMW’s have a lot electrical capacity but it isn’t unlimited..

 

Adding a voltmeter to your system could be your friend here if you are regularly running a lot of added electrical accessories.. If you run a GPS powered from your bike’s electrical system some of those have the ability to monitor the system voltage,, my Zumo 550 does if you know how to access it (it’s in one of the secret test screens)..

 

Twisty

 

[krussell]

do you really need an exact number?

 

Need no. Want yes. Do I have issues with details? yes. :-)

 

I just wish BMW didn't keep us in the dark on this.

 

 

[JayW]

...some of those have the ability to monitor the system voltage,, my Zumo 550 does if you know how to access it (it’s in one of the secret test screens)...

 

Ooooo...please, do tell!

 

Jay

[krussell]

 

Bruce, the latest spec I show on the GS adventure (from the BMW service RepRom shows 660 watts (unless the manual is a misprint) but keep in mind that is at 4000 rpm’s.. It is only making 192 watts at low idle (1000 RPM’s)..

 

 

I didn't think to look at the DVD. For the 09 it shows 720w @ 4k, 336w @ 1k. I don't understand the exact point where the alternator change was made, there seems to be some overlap in the 06/07 model years. The other number I found interesting was "alternator speed for state of charge", which was 1200rpm.

 

Do RT-Ps run the stock alternator? I know they have a second battery.

 

On my 09, if I'm running low beam + oem aux lights (110w) + heated liner I can easily see the heated gear power cycle dim my headlights when idling.

 

And if I have high beams on and roll off to idle for a turn the loss in terms of light output is startling. I don't remember having the issue on my 08 RT.

 

I think for the GS a higher capacity battery would help with some of this.

 

Adding a voltmeter to your system could be your friend here if you are regularly running a lot of added electrical accessories.

 

You can get a nice LED that gives a good indication of what's going on for about $20-$30. Twisted Throttle sells one that MCN reviewed here:

 

http://electricalconnection.com/meters_indicators/MCN-bm.htm

 

And another company, Signal Dynamics sells a similar model.

 

Someday maybe we'll get one via the OBC?

[Hall Vince]

I had two PIAA 910 with 110W bulbs on my 1150 along with a pair of PIAA 1100s with 55W bulbs. Even with everything on, I never noticed any additional noise. Ran them like that for ~30K until I sold the bike.

 

Curious.

Even on cars I've had where I have fitted high draw lights there is usually some extra noise from the belt when the altenator is under higher load to supply the extras. It might be because I was in the garage that the noise seems amplified off the walls

 

I think I'll buy a spare belt and then stick the 100w bulbs back in and see if the output is any better than the 55w. They are very good now. If only I could get them to swivel when I lean into the corners ;-)

\v/

[johnlt]

Keep in mind that scene brightness is not linear with power. If you double the power of the bulb, you do no "double" the brightness of the scene. It will probably just be a small step up improvement.

[Hall Vince]

I see (no pun intended, well maybe a little)

 

I wonder what the increase would, Spose I should just try it.

I do recall from running high wattage spot lights on cars that they tale a little longer to come up to full brightness, just a small delay, but noticable from what I recall.

Also of course the small size of the reflector in the FF50 may not realise the full use of 100w bulbs.

 

I suppose I should try them and see (Oh look I did it again!)

\v/

 

[Jim VonBaden]

Up until 08, only the Adventurein the GS range had 720 watts. The standard GS was at 600 watts. In 09 all went to the720 watt alternator.

 

Jim

[Bruce H]

johnlt

 

"Keep in mind that scene brightness is not linear with power. If you double the power of the bulb, you do no "double" the brightness of the scene. It will probably just be a small step up improvement."

 

If the light would be about the same I'd put 55 watt bulbs in, I only got the 100's because they were offered. I do notice an increased pull on the alternator if I turn on the lights at idle. I make an effort not to do that. these are in place of the high beam light on the bike which I don't use because I can't aim it separately from the low beam. this belt has 30K on it, guess it should be replaced.