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How much juice does your bike draw when parked?


Emoto

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Hi folks,

 

Over the 3 years of owning my R1200GS, I have had the battery go flat on me more than once due to inactivity. This means that the bike draws from the battery when parked. That is understandable what with the clock and the CPU and all.

 

What I am trying to collect is a good sample of how much the average hexhead draws while parked, so I can get an idea of what normal is. The higher the drain, the faster a battery will go dead unless put on charge. Be advised that some accessories can draw a lot of power, even when turned off.

 

Ok, using this meter set to measure amps http://www.radioshack.com/product/index....rentPage=search I made some measurements with the circuit to the battery broken, and the meter in between closing the circuit. Digital meters are hard to read for ranges, but I tried to notice the high and low.

 

Public Service Announcement: Don't forget that after disconnecting and reconnecting your battery, you need to reset your system by turning on the ignition, letting the self-check run, and then slowly rolling open the throttle to full open 2x.

 

The bike itself (1st release 2005 R1200GS) with no accessories:

 

5.1 - 6.7 mA.

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ShovelStrokeEd

I have to make a couple of assumptions here as I was unable to find any useful information.

 

Assumption 1: Battery voltage will drop in proportion to battery capacity remaining.

 

Assuption 2: 11.6 volts is probably the useful minimum battery voltage before problems occur either in starting or with the ABS system.

 

Either or both of these could be wrong but I gotta start somewhere.

 

Typical battery in BMW motorcycle is rated at 20 ampere-hour capacity.

Typical charged voltage is 12.6 volts based on 100% charge of 6 2.1 volt cells.

 

Let's call the load 6.0 mA. 20/0.006=3,333 hours to completely drain the battery.

 

11.6/12.6=.9204 Multiply that by the 3,333 hours and you get 3068, subtract from the original and you have around 264 hours or 11 days.

 

I think I might be a little wonky there as I have gone on trips lasting up to a month and my Blackbird, which draws about the same and has the same sized battery has never failed to start for me. There are, of course, other factors. Temperature at which the battery is stored, percent of full charge attained prior to shut down, age of the battery and the type of use it has received.

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I was told by my dealer to always remove the key from my 05 RT when not in use because they were having problems with the battery going dead on some when the keys were left in the ignition..Don't know what causes it but that's what he told me..

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I was told by my dealer to always remove the key from my 05 RT when not in use because they were having problems with the battery going dead on some when the keys were left in the ignition..Don't know what causes it but that's what he told me..

 

The key has a coded chip in it. The black ring around the ignition is the antenna for the coded chip. The antenna is actively listening for the chip. This "listening" doesn't really doesn't draw much power. However, once the chip is within range (key in the ignition), the EWS's "anti-drive-away" system (a form of anti-theft, i.e. bike can't be started without the chipped key) is disabled, which does require additional current. As long as the key is within range of the antenna ring, this higher current draw will be taking place.

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I was told by my dealer to always remove the key from my 05 RT when not in use because they were having problems with the battery going dead on some when the keys were left in the ignition..Don't know what causes it but that's what he told me..

 

The key has a coded chip in it. The black ring around the ignition is the antenna for the coded chip. The antenna is actively listening for the chip. This "listening" doesn't really doesn't draw much power. However, once the chip is within range (key in the ignition), the EWS's "anti-drive-away" system (a form of anti-theft, i.e. bike can't be started without the chipped key) is disabled, which does require additional current. As long as the key is within range of the antenna ring, this higher current draw will be taking place.

 

Wow........I just learned something. thumbsup.gif

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5.1 - 6.7 mA.
That's about right. I had the issue on our 12GS with the ZFE module not always shutting down. When it was in that state it would measure a drain of 300 mA. When shut down correctly, 7 mA.
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Thanks, Ken. I appreciate it. thumbsup.gif

 

It would be great if other folks would measure the draw on their bikes and post it here. How about it guys? We could get a pretty decent sample.

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Here's my report:

2005 R1200ST with all current software upgrades installed.

Voltages and current measured with a Fluke 189.

 

Battery voltage during the test: 12.57 volts

 

Current draw without key: 2.146 to 2.386 milliamps

 

Current draw with key in: Same as key out. No difference detected. This is curious in light of FB's comment above. I put the Fluke on maximum sensitivity and still couldn't detect any difference. Tried both of my keys - no change.

 

Just a note - if folks are going to post current readings, it might be useful if they included the battery voltage too.

 

Tim

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Public Service Announcement: Don't forget that after disconnecting and reconnecting your battery, you need to reset your system by turning on the ignition, letting the self-check run, and then slowly rolling open the throttle to full open 2x.

 

Huh? Really? What if I didn't do that when I installed my Centech? Can I do those steps anytime I start the ignition or do I need to disconnect the battery first?

 

thanks,

Steve

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Don_Eilenberger
Here's my report:

2005 R1200ST with all current software upgrades installed.

Voltages and current measured with a Fluke 189.

 

Battery voltage during the test: 12.57 volts

 

Current draw without key: 2.146 to 2.386 milliamps

 

Current draw with key in: Same as key out. No difference detected. This is curious in light of FB's comment above. I put the Fluke on maximum sensitivity and still couldn't detect any difference. Tried both of my keys - no change.

Not a surprise to me actually - despite what FB said. (FB - where did you get this info from?) The EWS (which BMW has had on their cars for decades) isn't actively listening for a signal until the ignition is turned on. Doing it otherwise wouldn't make any sense at all.. Plus - it's a binary function. Draws as much power as a 1 as a 0..

Just a note - if folks are going to post current readings, it might be useful if they included the battery voltage too.

 

Tim

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Don_Eilenberger

Public Service Announcement: Don't forget that after disconnecting and reconnecting your battery, you need to reset your system by turning on the ignition, letting the self-check run, and then slowly rolling open the throttle to full open 2x.

 

Huh? Really? What if I didn't do that when I installed my Centech? Can I do those steps anytime I start the ignition or do I need to disconnect the battery first?

 

thanks,

Steve

This was true on the R1150 Motronic equipped bikes where it had to relearn the TPS.. Is this still true on the R1200/hexheads? I believe the later ECUs are capable of retaining that information with power removed.
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Huh? Really? What if I didn't do that when I installed my Centech? Can I do those steps anytime I start the ignition or do I need to disconnect the battery first?
Yes. What you are doing is training the BMS-K module of the entire throttle range, the entire TPS voltage range. You can do it at any time. Turn the key on with the bike ready to start, stands up, kill switch on, etc. but don't start it. Now rotate the throttle through its entire range twice. Then start the bike.

 

The bike will learn the entire range over time anyway, especially if you do a WOT run once in a while, so not doing this isn't the end of the world, just a short cut.

 

BTW, it's in your owners manual. wink.gif

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The EWS (which BMW has had on their cars for decades) isn't actively listening for a signal until the ignition is turned on. Doing it otherwise wouldn't make any sense at all.. Plus - it's a binary function. Draws as much power as a 1 as a 0..

 

Having it check on power up, as part of the system initializing makes a lot more sense. One time I left the key in my ignition for several weeks, and it didn't drain the battery.

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Don_Eilenberger
What you are doing is training the BMS-K module of the entire throttle range, the entire TPS voltage range. You can do it at any time. Turn the key on with the bike ready to start, stands up, kill switch on, etc. but don't start it. Now rotate the throttle through its entire range twice. Then start the bike.

 

The bike will learn the entire range over time anyway, especially if you do a WOT run once in a while, so not doing this isn't the end of the world, just a short cut.

 

BTW, it's in your owners manual. wink.gif

Ken, I went and RTFM, and damn if I can find it. It's not under the battery charging/removal/replacement section (they do mention resetting the clock..) Do you have any hint as to what section it might be found in?

 

Thanks!

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<snip>

Assumption 1: Battery voltage will drop in proportion to battery capacity remaining.

 

Assuption 2: 11.6 volts is probably the useful minimum battery voltage before problems occur either in starting or with the ABS system.

</snip>

 

I disagree. 90% of the battery's energy will be dissipated when the voltage is 11.5VDC. Voltage does not drop linearly with a decrease in energy.

 

With a 6mA discharge rate and a duration of 4.1 months, a 20A-H capacity battery will have a terminal voltage of 11.5VDC and 10% of its energy left over. (best case).

 

(20A-H/6mA) * 0.90 = 3,000Hr = 125 days = 4.1 months

 

Ed

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ShovelStrokeEd

OK, that makes more sense than my assumptions and fits more with my experience. Certainly explains why I can let a bike sit, in moderate temperatures with a healthy battery for a couple of months and it will still start up, albeit a little reluctantly.

 

Thanks for the clarification. thumbsup.gif

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Ken, I went and RTFM, and damn if I can find it. It's not under the battery charging/removal/replacement section (they do mention resetting the clock..) Do you have any hint as to what section it might be found in?

 

Thanks!

 

It's under Installing Battery. Ch.7, Pg. 133.

 

"Switch on ignition. Without starting engine, open throttle twist-grip once or twice for at least one second so the control unit of engine management system can register throttle-valve settings. Switch off ignition."

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Don_Eilenberger
It's under Installing Battery. Ch.7, Pg. 133.

 

"Switch on ignition. Without starting engine, open throttle twist-grip once or twice for at least one second so the control unit of engine management system can register throttle-valve settings. Switch off ignition."

No mention of it at all in the Roadster Riders Manual.. page on Installing Battery is Chapter 7, Page 118-119:

 

  • =========================
    Install positive cable
    Push on protective cap (1)
    Install negative cable (2)
    Installing seat (see 55)
    Setting clock (see 47)
    =========================

That's all that's there...

 

Wonder what changed?

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