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Discussion Starter · #1 ·
I have a 20 GS with a rated 510W alternator. I am currently running a set of Clearwater lights (An Erica, and a Krista combo) that is rated to draw 96 watts at full power (only when I have the high beams on or flash to pass do they go that high.. Normally 20% at night and 40% during the day.

I plan on using my heated gear (Warm and safe heated gloves and jacket liner) that will draw a rated 124Watts at full power. ( I dont think I have ever ran the jacket past 60% but I want to be on the safe side here)

With these add ones alone I am using 220W of the alternator (albeit that is PEAK) I am also running a high-speed phone charger (45w rated) and a have the Garmin nav 6 (???? current draw)

With these accessories I am now at a listed 280ish Watts

Does anyone know what the bike needs to power itself with high beams, brakes, and a turn signal on (I would guess this to be max load on the electrical system, unless the ESA starts adjusting preload which I am sure is a pretty big electrical load!)

I would like to know if I still have enough left over in the alternator to charge the battery enough to replenish a single start after a 30minute ride.

Thanks in advance.
 

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You should be ok if riding.
Only once it had happened....we had parked on a ride...bike was idling with a pair of Baja Designs XL80, a pair of Baja designs S1, the headlight on high, Nav 6, Ram wireless charger and the heated seat at full and my bike flashed Low voltage or something to that effect.
But once moving all was ok.
 

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You should be ok if riding.
Only once it had happened....we had parked on a ride...bike was idling with a pair of Baja Designs XL80, a pair of Baja designs S1, the headlight on high, Nav 6, Ram wireless charger and the heated seat at full and my bike flashed Low voltage or something to that effect.
But once moving all was ok.
Correct....The 510W alternator isn't putting out 510W at idle. I don't know what the idle output is, but it is more likely in 200-300W range. You can last for a short time under such situations as the excess draw will be taken from the battery, but eventually, that will be a problem.

IIRC, the bike will shut down non-essential elements (such as the heated seat) under a low voltage situation. But, it can't shut down independent accessories that it doesn't really know about or have control over....heated gear, aux lights, etc. If you find yourself at a long stoppage, either turn the lights off and/or the heated gear off (or way down) or rev up the engine a bit to keep from drawing the battery down too much.

I'm new the the GS, but I've seen the same on my K1600 but primarily when riding 2-up with 2 sets of heated gear (tops and bottoms) and heated seats/grips on.

The phone charger is unlikely to be pulling 45 watts unless your phone was discharged when you put it on the bike. It is more likely to be drawing around 5 watts steady state, and only if the screen is on and it is doing something.
 

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Discussion Starter · #5 ·
You could power your accessories through a load manager which will de-energize each accessory in sequence based on battery voltage and restore them when voltage increases. Load Managers
interesting concept, but I do not think that would work in this scenario. If I had my heated gear connected via a load manager, the gear would disconnect when the battery voltage reaches its drop out voltage (normally 11.7VDC) when the gear is disconnected the battery voltage would increase as there is now enough overhead for the alternator to supply charging voltage to the battery (13-14VDC) the relay would then re-energize and will cause an large in rush current to be placed on the charging circuit (electronics do not like large in rush currents, and may blow fuses) I think the relay would just chatter between states.

Load managers are designed to hold a circuit on until the voltage drops to a set disconnect point after the vehicle is turned off to prevent the load from killing the battery. We use these at work to isolate loads that have a parasitic drain on the batteries for police vehicles.

If you know of a load manager that works smarter than this, maybe a current sensing one, please let me know.
 

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Discussion Starter · #7 ·
The load managers I linked to will do exactly what you need without the issues you mention. I have been using them for years on emergency vehicles. Anyway just thought I would offer a suggestion. Good luck.
I will check into them deeper. Thank you very much for the link.

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Most of the load manager turns OFF and ON at a different tension to prevent theses issues. Generaly, they will turn OFF between 11.7 to 12 v and will only turn back on when the tension reach 12.7 to 13. Some are ajustables.
 

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Discussion Starter · #11 ·
I'm new the the GS, but I've seen the same on my K1600 but primarily when riding 2-up with 2 sets of heated gear (tops and bottoms) and heated seats/grips on.

The phone charger is unlikely to be pulling 45 watts unless your phone was discharged when you put it on the bike. It is more likely to be drawing around 5 watts steady state, and only if the screen is on and it is doing something.
I also have a K1600GTL and I noticed that even that bike, which has a larger alternator, has a RPM "surge" when my gear is on at idle.. not a lot of surge, but it sort of feels like a "miss" and you can see it on the tach. Turn off the jacket an the "miss" goes away. The controller of the warm and safe is Pulse Width Modulation (PWM) which would explain the "surge" as the current draw is not continuous.

Do you notice that as well?

I am sure you are correct about the phone chargers as well. I also do not use the PD charger all that much and normally use the 18w (ish) QC3 charger. When I get a chance I will build a ground extension wire that I can then connect a clamp DC amp meter to and see what the bike draws with the accessories off. and then with them at full power. I will report back here when I do.
 

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I also have a K1600GTL and I noticed that even that bike, which has a larger alternator, has a RPM "surge" when my gear is on at idle.. not a lot of surge, but it sort of feels like a "miss" and you can see it on the tach. Turn off the jacket an the "miss" goes away. The controller of the warm and safe is Pulse Width Modulation (PWM) which would explain the "surge" as the current draw is not continuous.

Do you notice that as well?

I am sure you are correct about the phone chargers as well. I also do not use the PD charger all that much and normally use the 18w (ish) QC3 charger. When I get a chance I will build a ground extension wire that I can then connect a clamp DC amp meter to and see what the bike draws with the accessories off. and then with them at full power. I will report back here when I do.
Absolutely, I have noticed that on my K1600 and on others. I agree with what you say is the cause...a low frequency PWM changing the load on the alternator every every second or do. The computers that control the engine speed take a moment to adapt in order to keep the engine at the target minimum RPMs. As you turn up/down the heated gear level, the effect shifts.
 

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None of the things you mention will actually draw the rated power on average. Not even close. For example, your phone battery only holds about 8Wh total, roughly. If it really drew 45W from your motorcycle battery, it would fully charge your battery in ten minutes from complete empty. So you can almost ignore this load for all intends and purposes, on average. Also, for heated gear, my vest has been on a setting of three on the coldest days, out of And finally the lights, you wrote yourself that most of the time these will run between 20% and 40%. I don’t think you have anything to worry about with this set of very common add-ons.
 

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Discussion Starter · #14 ·
None of the things you mention will actually draw the rated power on average. Not even close. For example, your phone battery only holds about 8Wh total, roughly. If it really drew 45W from your motorcycle battery, it would fully charge your battery in ten minutes from complete empty. So you can almost ignore this load for all intends and purposes, on average. Also, for heated gear, my vest has been on a setting of three on the coldest days, out of And finally the lights, you wrote yourself that most of the time these will run between 20% and 40%. I don’t think you have anything to worry about with this set of very common add-ons.
The S22 I use has a 5Ah battery that when using the 45w charger will charge a dead phone to full in about 1.25 hours at 14vdc that is very close to the listed 45watts (3.3 amps)

I do appreciate your insight into this but the concern is not just how much current is being drawn, it is how much of the available charging capacity can actually RECHARGE the battery after starting the bike with all of this on? If I am using 450w to run the bike and accessories, that leaves only 60w to charge the battery. If the battery is depleted 1ah (cranking 200amps for 2 seconds) by starting the bike, that would take me over a 1/2 hour to recharge the lost battery capacity. Driving to and from work in stop and go traffic for 1/2 hour each way will keep me from charging the battery at all and after a few of those trips the battery might be 2-3 amps low on a 12Ah battery (new and at 80 degrees) which might be enough to prevent a start. Even worse case would be that I am running 600W and now I am depleting the battery at a rate of 90w or 1amp every 22 minutes of riding at full alternator capacity.

I know I can put a charger on it to re peak it up as needed. my question is will this be required.
 

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Only one way to find out! If it drains then a battery tender is your solution. If it doesnt...well then youre good. Plus we dont have all the accessories running all the time all throughout the year.
We can endlessly discuss theory but the only true test would be in real time.
 

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The S22 I use has a 5Ah battery that when using the 45w charger will charge a dead phone to full in about 1.25 hours at 14vdc that is very close to the listed 45watts (3.3 amps)

I do appreciate your insight into this but the concern is not just how much current is being drawn, it is how much of the available charging capacity can actually RECHARGE the battery after starting the bike with all of this on? If I am using 450w to run the bike and accessories, that leaves only 60w to charge the battery. If the battery is depleted 1ah (cranking 200amps for 2 seconds) by starting the bike, that would take me over a 1/2 hour to recharge the lost battery capacity. Driving to and from work in stop and go traffic for 1/2 hour each way will keep me from charging the battery at all and after a few of those trips the battery might be 2-3 amps low on a 12Ah battery (new and at 80 degrees) which might be enough to prevent a start. Even worse case would be that I am running 600W and now I am depleting the battery at a rate of 90w or 1amp every 22 minutes of riding at full alternator capacity.

I know I can put a charger on it to re peak it up as needed. my question is will this be required.
Isn’t that 0.11Ah to start the bike? 200A/60min/30?
And again, I don’t think you will actually see either a full 200A consumed by the starter at normal temperatures, nor for a full two seconds. If you worst case scenario everything you may come to the conclusion that there is a problem when in fact there is none.
 

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Discussion Starter · #18 ·
Isn’t that 0.11Ah to start the bike? 200A/60min/30?
And again, I don’t think you will actually see either a full 200A consumed by the starter at normal temperatures, nor for a full two seconds. If you worst case scenario everything you may come to the conclusion that there is a problem when in fact there is none.
Yep,you are correct,I must have missed a zero on the calculation I made. Refcat's and you are both probably correct. That I am
1) over thinking this
2) can just check the current draw and watch the bike meter.

Thanks guys.

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