Author Topic: Battery voltage reads higher than Charging voltage  (Read 6517 times)

rcb78

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Battery voltage reads higher than Charging voltage
« on: December 19, 2019, 12:36:30 AM »
I just noticed today that my battery voltage is reading higher than the charging voltage, see pic below.  I replaced my battery and regulator over the summer and when I did, I wired the regulator output directly to the battery instead of re-using the original connection.  Is it possible that the charging voltage is now reading low because it's after the battery, headlights, etc,, where before it would have been before these in the circuit?  Thanks in advance.

https://drive.google.com/file/d/1_x9ZY2GL-dkYmXlTsFYRocXkpWOn_I5t/view?usp=sharing

Alexm1

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Re: Battery voltage reads higher than Charging voltage
« Reply #1 on: December 20, 2019, 09:50:10 AM »
I guess anything is possible. Why not put the wiring back to the way it was designed and see what happens?
Alex

rcb78

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Re: Battery voltage reads higher than Charging voltage
« Reply #2 on: December 20, 2019, 06:47:57 PM »
I did and no change.  Then I went back through a few logs I made before I replaced the battery and R/R and it shows exactly the same thing.  Additionally, someone on the ADV Rider forum posted on image of one of their data logs and show's the exact same thing I'm seeing.  So now I'm wondering exactly where the GS-911 is getting data for the charging system and if it's accurate.  I'm going to pull the ZFE sometime over the Holidays and double check all the connections and grounds to rule out bad contacts.

Alexm1

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Re: Battery voltage reads higher than Charging voltage
« Reply #3 on: December 20, 2019, 11:58:39 PM »
Have you checked it with a meter? I have never used the gs911 to check charging, I just put my meter on it, battery can sit static at up to 12.3v, with charge 13.5 - 14v. Easy way to check. Good luck.
Alex

rcb78

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Re: Battery voltage reads higher than Charging voltage
« Reply #4 on: December 21, 2019, 12:17:07 AM »
I have, voltage at the battery read with a meter matches GS-911 values.  Voltage at the accessory port (DIN plug) matches the lower value reported as the charging voltage.  Since that port is controlled by the ZFE, that leads me to believe there is more to investigate.

Alexm1

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Re: Battery voltage reads higher than Charging voltage
« Reply #5 on: December 21, 2019, 12:29:21 AM »
What if you just leave the meter on the battery, check it static, then with the motor running? The green graph is showing a normal charging voltage, I have no idea where the higher voltage could be coming from. If the meter shows normal then unless you have a problem I would forget it.
« Last Edit: December 21, 2019, 12:32:44 AM by Alexm1 »
Alex

WayneC

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Re: Battery voltage reads higher than Charging voltage
« Reply #6 on: December 21, 2019, 02:12:36 AM »
The precise model of the bike needs to be specified to know which of 2 different methods the diagnostics system is using to report voltages

rcb78

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Re: Battery voltage reads higher than Charging voltage
« Reply #7 on: December 21, 2019, 06:30:50 AM »
What if you just leave the meter on the battery, check it static, then with the motor running? The green graph is showing a normal charging voltage, I have no idea where the higher voltage could be coming from. If the meter shows normal then unless you have a problem I would forget it.

Multimeter at the battery, voltage static is 13.7, bike turned off after sitting overnight.  With the engine running it mirrors the yellow line (14.3-14.4), but that's expected since the R/R runs directly to the battery.  Reading taken at the accessory port is about .1 lower than GS-911 reports the charging voltage, so 13.8-14.0.


The precise model of the bike needs to be specified to know which of 2 different methods the diagnostics system is using to report voltages

Well there are only two choices for F800GS in the program, "F800GS K72 (2007+)" and F800GS Adventure K75(2013+).   I've tried both and they both give the exact same numbers.

Alexm1

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Re: Battery voltage reads higher than Charging voltage
« Reply #8 on: December 21, 2019, 06:34:49 AM »
So based on the meter readings all is well.
Perhaps there are bad connections in the gs911 plug or wiring?
Alex

WayneC

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Re: Battery voltage reads higher than Charging voltage
« Reply #9 on: December 21, 2019, 07:33:06 AM »

Well there are only two choices for F800GS in the program, "F800GS K72 (2007+)" and F800GS Adventure K75(2013+).   I've tried both and they both give the exact same numbers.

You did not answer the question directly re model, only what you were selecting in the GS911 menu & both are K-Line BMS-K models

The bike model & year, the type of GS911 & the software version being used are all important pieces of information needed to provide answers as there are 2 different diagnostics protocols on different pins used plus different Engine ECU's (BMS-K, BMS-X, BMS-M) in different year models

The later BMS-X, BMS-M models are CAN Diags & the ECU's are interogated to provide the voltage information as the diagnostics socket only has V-Batt whereas the earlier BMS-K models are K-Line protocol & have both V-Batt & V-Ignition wired to the diagnostics socket so the voltages can be read directly

It sounds like you are using a Yellow GS911 & older PC App software as GS911 WiFi has 6 models for F800 Series listed as does the latest PC App plus your bike is one of the older year models with BMS-K, can you confirm that ?

rcb78

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Re: Battery voltage reads higher than Charging voltage
« Reply #10 on: December 21, 2019, 08:51:53 AM »
Using a the newer GS-911 wifi (mfg date 6/27/18 - sticker on back) on the mobile app, all software is current and checked for updates each time I plug it in.  Bike is a 2013 F800GS (not adventure).

WayneC

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Re: Battery voltage reads higher than Charging voltage
« Reply #11 on: December 21, 2019, 09:27:34 AM »
Using a the newer GS-911 wifi (mfg date 6/27/18 - sticker on back) on the mobile app, all software is current and checked for updates each time I plug it in.  Bike is a 2013 F800GS (not adventure).

OK, understood so it is a BMS-K ECU model, the the WiFi firmware for Web Interface should be 0.254-0.175-0.152 & the PC App 1912.1

How up to date is the iLevel in the bike ?, autoscan will tell you, the latest I have seen for the K024's is K024-18-07-500

rcb78

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Re: Battery voltage reads higher than Charging voltage
« Reply #12 on: December 21, 2019, 07:24:44 PM »
Doesn't look like it's been touched since the bike was built Autoscan Report

Aside from maybe an incorrectly reported value, is there any reason I should spend the money to have my dealer update this?  Benefits?
« Last Edit: December 21, 2019, 07:27:08 PM by rcb78 »

WayneC

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Re: Battery voltage reads higher than Charging voltage
« Reply #13 on: December 22, 2019, 04:17:09 AM »
The voltages aspect is likely that the voltages are derived by interrogating the ECU's rather than directly reading from the socket, others may be able to confirm that & I would not be concerned by it

Re firmware in ECU's, BMW are not always forthcoming to Dealers on what firmware updates are actually doing but they can be improvements & bug fixes to program code or market specific data, coding & diagnostics capability etc, see the OSV, FSV, MCV,  values in the autoscan

History has shown an update can transform a bike with better starting hot or cold & improve engine response at different rpm's etc. Too often Dealers were told dont update unless the owner complains re a specific problem so in general terms updating is worthwhile, it looks like on BMS-KP there are a couple of updates for your K72 model, I cant comment on the other ECU's
« Last Edit: December 22, 2019, 04:22:54 AM by WayneC »

rcb78

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Re: Battery voltage reads higher than Charging voltage
« Reply #14 on: December 22, 2019, 09:08:12 AM »
Thanks for the info.