The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: BooG on April 16, 2017, 05:24:14 AM

Title: Low battery voltage at ignition
Post by: BooG on April 16, 2017, 05:24:14 AM

Hi!
have just rebuilt starter motor with new bushes etc. When re installed, I have put the meter on the battery at startup, and when I turn the key to the on position, battery voltage drops to 8volts; this is before pressing the starter button. It was showing 12.7 prior to engagement of key. Naturally, this is not turning the starter motor, but what could be causing the voltage drop? Where is all my voltage going??
Thanks!

Title: Re: Low battery voltage at ignition
Post by: BooG on April 16, 2017, 05:35:20 AM

As an answer to myself....I have a cheap battery from an electric wheelchair manufacturer...has all the right spec; about 18 months old and has been on an optimiser, but it's that which I am suspecting right now....?!

Title: Re: Low battery voltage at ignition
Post by: Bob_Roller on April 16, 2017, 02:35:35 PM

Can you have the battery load tested at an auto parts store ??

Just to make sure it is the battery .

Title: Re: Low battery voltage at ignition
Post by: skippyc on April 16, 2017, 05:55:54 PM

If you had a clamp meter you could test the current flowing from the battery. I have removed the battery lead and tested if it has a large spark in the past.