2014 R1200GS Electrical Load

[cjmckay]

I'm helping out a fellow LD (IBA) rider set up auxiliary lights on his 2014 R1200GS. Does anyone know what the additional load limit is on this bike? (in Amperes or Watts)
His initial plan is around another 112W of lights which I suspect will be ok but figured that someone here would know what is possible and what may not be possible before the stator/alternator gives up the ghost.

 

[Vlad]

There is a lot of conjecture around this out there, but for what it’s worth.
The alternator output is I believe 720 watts, 20 odd amps at idle rising to 35 at 6000 rpm. The conjecture starts when talking head room. Some say as much as 380 watts.
I have a 2013 model, it does have a different alternator to the one in question but I suspect not much diff in spec.
I run 4 36 watt pull driving lights , the electric grips , heated gloves and liner, gps with no problem, things get tricky when I plug in another heated liner. Make of that what you will.
If you connect everything straight to battery terminals they will get hot, read melt the top of the battery.
Much better to mount a fuse block in the tray under the seat and connect that with heavy gauge leads to the battery.

 

[Giggles]

I thought I'd put my 2 cents worth in on this.

Electrical systems are all about supply and demand (duh). It is relatively easy to work out what's what by looking at the bikes documentation and doing some calculations.

I found this and am assuming our model is identical to the South African model -> https://www.motorcyclespecs.co.za/model/bmw/bmw-r1200gs-14.html

This tells me that the bike has a 12V battery (which is odd as they are generally about 13.2V) and the alternator can supply 620W. Ohms Law tells us that by dividing 620W by 12V you can have a current draw of just over 50 Amps. Checking the fuses in the bike it shows that the main fuse is indeed 50 Amps. Sweet.

The problem we do have is measuring what actual current is being drawn at any one instant in time. You can use an ammeter that you place in series and that'll show you. However, what most people do is add up what the various bits are on the bike and go from there. Using Vlad's example, the four driving lights will use 144W on top of the 240W (12V x 20A) at idle which means he's using 384W already. Given you only have 620W to start with, you now only have about 240W left. Out of that you have to send some power into the battery to maintain its charge or it will start providing more current that it can get from the alternator (Fatman and LTP ran into that problem on their Lap of Australia ride). All those other add ons are going to quickly use that spare power so you might get into the process of using some stuff and not others.

Vlads suggestion of using a fuse block is wise. It further separates each add on into its own circuit and that is a good thing.

What I did with my Super Tenere was to install a voltmeter and a Clearwater battery monitor (which I can't find on their site). As your battery usage goes up, the voltage at the battery terminals will drop (on mine from 14.2 down to 13.4 if my spotties and heated vest are on). The battery monitor will show a flashing green colour when there is more current going into the battery than is leaving it (this is good) and will show red if it is the other way around (this is bad, very bad, and you are heading for a flat battery if you let it go on for too long).

One thing that might be useful is a OBD2 reader if the bike in question has that port. My Ford Ranger does and some parameters it does provide is voltage, current and wattage values. I have no idea whether it would work on a bike but you never know.

Good luck.

 

[cjmckay]

@Vlad - thanks for the feedback. I asked because I understand there is some conjecture and I figured the good people here probably have a better handle on it than most. I've read that the alternator may only be ~540watts (or even 510W depending on where you read) (although I believe it may have gone up around 2014-2015, possibly to 620W, ). I've also read that there were some issues with the 2013-2014 model stator - so I don't want to be too close to the limit.

Interesting comments re: mounting to the battery directly - the opposite should be the case or otherwise no worse.

We'll keep plodding on and see how we go. I think we'll be ok but just wanted to be careful...

 

[cjmckay]

I thought I'd put my 2 cents worth in on this.

Electrical systems are all about supply and demand (duh). It is relatively easy to work out what's what by looking at the bikes documentation and doing some calculations.

I found this and am assuming our model is identical to the South African model -> https://www.motorcyclespecs.co.za/model/bmw/bmw-r1200gs-14.html

This tells me that the bike has a 12V battery (which is odd as they are generally about 13.2V) and the alternator can supply 620W. Ohms Law tells us that by dividing 620W by 12V you can have a current draw of just over 50 Amps. Checking the fuses in the bike it shows that the main fuse is indeed 50 Amps. Sweet.

The problem we do have is measuring what actual current is being drawn at any one instant in time. You can use an ammeter that you place in series and that'll show you. However, what most people do is add up what the various bits are on the bike and go from there. Using Vlad's example, the four driving lights will use 144W on top of the 240W (12V x 20A) at idle which means he's using 384W already. Given you only have 620W to start with, you now only have about 240W left. Out of that you have to send some power into the battery to maintain its charge or it will start providing more current that it can get from the alternator (Fatman and LTP ran into that problem on their Lap of Australia ride). All those other add ons are going to quickly use that spare power so you might get into the process of using some stuff and not others.

Vlads suggestion of using a fuse block is wise. It further separates each add on into its own circuit and that is a good thing.

What I did with my Super Tenere was to install a voltmeter and a Clearwater battery monitor (which I can't find on their site). As your battery usage goes up, the voltage at the battery terminals will drop (on mine from 14.2 down to 13.4 if my spotties and heated vest are on). The battery monitor will show a flashing green colour when there is more current going into the battery than is leaving it (this is good) and will show red if it is the other way around (this is bad, very bad, and you are heading for a flat battery if you let it go on for too long).

One thing that might be useful is a OBD2 reader if the bike in question has that port. My Ford Ranger does and some parameters it does provide is voltage, current and wattage values. I have no idea whether it would work on a bike but you never know.

Good luck.

Actually @Giggles - it isn't that simple (hence the questions - I'm an electrical and electronics engineer professionally so this stuff isn't foreign). Firstly the alternator doesn't produce its rated output @ 12VDC and nowhere is it specified as such. Typically, charging(running) voltage is around 14VDC and therefore this reduced the available current for a given alternator Wattage. Also - the main fuse being 50A only tells us that 50A of draw is permissible. The specifications you referenced also state that the alternator is 510W not 620W(actually the specifications are in self-conflict). Also, nowhere does there appear to be any documentation of what the 'base configuration' load is - from which spare capacity + headroom can be determined. Unfortunately, the clearwater battery monitor (voltage sentry) does not measure current (or its directionality) - it is a (not-so-) simple voltage measuring device.

Yes - I fully agree with separating off the accessories onto separate fuses - I always do this - especially where CANBus bikes are involved.

Thanks for the advice.

Cameron

 

[cjmckay]

...and sticking a DC ammeter into the circuit isn't exactly easy as it needs to deal with the near 100A of cranking current when the bike is being started (not impossible but not your 'off the shelf' DC ammeter either...) and even then it won't tell you the whole story.

 

[LeMaitre]

When calculating current draw it is easy to forget the amount of power consumed by the ignition system and if equipped fuel pump. At higher rpms bike will consume more power than at idle.

-Mark

 

[Fatman]

Cameron, as Giggles correctly indicated, LTP and I ran out of power at Eden on our "Around the big paddock ride". It was a cold morning and we both had our full (top to bottom) warm and safe heated gear on. I also run 4x Clearwater Ericas LED lights. Afterwards I did a bit of a guess at the current draw we were using, see below. These are my best estimations at the current draw my bike uses.

Our 2011 R1200RT has a 720W alternator. I since also put on a digital Volt meter to keep an eye on the battery. I am not sure what size alternator the GS's use, Vlad is most likely on the money there.

Don't forget these figures for the Warm and Safe are for 2 sets (both LTP and I) of elec heated gear, half it if riding solo.

Warm and Safe heated gear .. Jacket liner x 2 @90W ea = 180W. Pants liner x2 @ 40W ea = 80W. Socks x 4 @ 9W ea = 36W. Gloves x 4 @ 9W ea = 36W. TOTAL = 332Watts approx 26amps @ 12.8Volts

Other Current Draw.. Headlights x 3 (incl. 2 lo & 1 hi beam) @ 55W ea = 165W. Ericas x 4 @ 60W ea = 240W. Tail light x 2 @ 5W ea = 10W. Fuel Injection I'm guessing = 60W?. Radio = 10W?
TOTAL = 485Watts approx 38amps @12.8Volts

I don't use the grips or seat warmer much at all now due to the Warm and Safe gear. Grip Warmers = 60W?Seat Warmer @ 60W ea = 120W.
TOTAL = 180Watts approx 14Amps @ 12.8Volts

Since the Eden no start incident If we both have full elec heated gear turned on I turn off 1x set of Ericas, saving 120W.

I also dont run the 1x high beam headlight saving 55W.

I also don't run the 2 x front park lights, saving 10W (not included in my figures above).

So my best estimate is 485W - 55W (Hi beam draw) = 430W. Minus 1x set of ericas that I turn off = -120W = 310W plus the current draw from the Warm and Safe gear 332W. that we are drawing around 642W approx 50Amps @12.8Volts.

We have never run short of power since, if riding with our full Warm and Safe elec gear turned on and turning off 1x set of Ericas.

I hope that may help a bit.

 

[cjmckay]

Thanks for the advice.