Ok so on Tuesday my 2010MY 3.6TDV8 decided it didn't want to start coming out of the supermarket, would just Get a click from the solenoid but no cranking. Got my housemate down to jump start and it worked grand.

Decided to change the battery the next day as its a 2013 battery so just presumed dead, fitted a new Yuasa AGM battery, did the battery reset with my IIDTool and plugged in a ctek charger to fully charge it overnight,

now the range will start (sometimes) and under live values on the IIDTool shows it not losing current, even with every single electrical item on , the car isn't faultering.

The mechanic I'm dropping it to in the morning is determined that its the alternator and wants to remove it, have it checked and probably replace it because its reading 13.7 volts (he's saying it should be 14.5 but its an AGM battery so I'm pretty sure its just in float charging mode) . the alternator out is a much bigger job and more time consuming.

the car will start after 3-4 times on its own usually, sometimes 6-7 times or a jump start (no idea why jumping it works) , I think its a dead segment on the starter.

car has 87000 miles on it if that makes any odds. Current Vehicles :
L322 2010MY TDV8 Autobiography
BMW E38 735i
BMW E63 645ci

Could be the leads between the battery alt and starter motor - may need cleaning all terminals and reseating

Could also be earth strap connections from engine block to body.

cheers , any easy enough way to check the wiring ? Current Vehicles :
L322 2010MY TDV8 Autobiography
BMW E38 735i
BMW E63 645ci

See thread on Quirky starting. Try the windscreen wiper trick!! 2011 4.4 TDV8 Vogue SE
1993 Discovery 1 3.5 V8i

I swear to christ if that actually works.... this seems like the most ridiculous thing ever Current Vehicles :
L322 2010MY TDV8 Autobiography
BMW E38 735i
BMW E63 645ci

that is absolute witchcraft , why does that work. Current Vehicles :
L322 2010MY TDV8 Autobiography
BMW E38 735i
BMW E63 645ci

Absolutely no idea why it works but this morning I had three attempted starts and three clicks, did the windscreen wiper thing and it started immediately.

It is either witchcraft or dodgy software I reckon  2011 4.4 TDV8 Vogue SE
1993 Discovery 1 3.5 V8i

Is it not just the same as with lithium batteries in Cold temps ?
The battery needs to see a draw to wake it up . It’s common on bikes to switch headlights on prior to starting a llithium battery equipped bike 4.2 SC - sold , now bought back
4.4 AdBlu Tractor - Stolen

Well when you press the starter button a whole bunch of things fire up including ECUs, glow plugs, TFT screen etc which I would have thought would wake something up even if that theory also applies to AGM batteries. 2011 4.4 TDV8 Vogue SE
1993 Discovery 1 3.5 V8i

I've searched on "quirky starting" and not found anything.

Could someone explain what the "windscreen wiper trick" is, please as I to occasionally experience the click and no start phenomena and had it in mind to change the starter.

It is described in item 2 below


 2011 4.4 TDV8 Vogue SE
1993 Discovery 1 3.5 V8i

^ Excellent; thank you!

Kevin

The issue was the starter, now replaced, but rhe wondow washer thing works Current Vehicles :
L322 2010MY TDV8 Autobiography
BMW E38 735i
BMW E63 645ci

Cheers, Eric.