General Category > GS-911

Why was the minimum voltage increased from 12.0 to 12.5V???

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Skim:
I'm no expert at this. Just wondering, considering the changes that can be made to displays and other settings on the newer bikes... I would assume it's of critical importance to maintain good voltage to ensure update coding is not interrupted/corrupted. Even on my 2010 parraffin model, maintaining correct voltage is a bit of a PITA but learned to live with it now.

botus:
as various elements of the bike's systems do stuff the volts jump about - bike batteries are pathetic low capacity things - BMW dealer tools have high current posh "power supply" devices that hold the voltage right up there - the ISTA stuff has a 15 Volt minimum threshold for programming - below that things don't behave and the tool isn't meant to even operate

the newer bikes really need high volts, for the suspension especially - I'm surprised a CTEK charger I'm using mostly manages to hold the bike at 14.2V...

if you are dropping below 12.5 V expect things to go wrong - I doubt Hex increased the volt demand for the tool to operate - but its perfectly reasonable, if the system needs it, their tool needs to respect it - the idea is to service the bike not to introduce software issues

karlh:
From your reply it appears the 12.5 volt requirement is driven by the complexity of the latest models.  My 2007 ST never had a problem with lower threshholds.  Hex should make the operating threshhold model-dependant.

WayneC:

--- Quote from: karlh on April 15, 2026, 12:20:52 AM ---From your reply it appears the 12.5 volt requirement is driven by the complexity of the latest models.  My 2007 ST never had a problem with lower threshholds.  Hex should make the operating threshhold model-dependant.

--- End quote ---

As I stated in  th OP's other thread, the minimum voltage can be set by BMW in the ECU firmware so it is best to ensure 14v  regardless of  the model, BMW specify 1v on the cars & 13.5v for the bikes in the Dealer System

botus:

--- Quote from: karlh on April 15, 2026, 12:20:52 AM ---From your reply it appears the 12.5 volt requirement is driven by the complexity of the latest models.  My 2007 ST never had a problem with lower threshholds.  Hex should make the operating threshhold model-dependant.

--- End quote ---

just because it appeared to work - doesn't make it a good idea - I have a 2007 R1200GS and I get twitchy if its dropping under 13v - if just scanning for codes - you'll just get more and slide in a spiral of annoyance - if trying to do any real work like coding a Tyre pressure sensor - get the volts up

I thought in the recent updates there's a toggle to change how it nags you ?  I'd leave it std and get the volts up either way

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