S40 (New) Electrics : - power system service urgent

msh · Dec 15th, 2013, 16:28

Hi
I have just had this massage appear POWER SYSTEM SERVICE URGENT
From other posts I do know that this could mean the alternator is on the way out
Did a voltage test 12.2v before start up 11.5v after start up NO increase in voltage when revved.
I know the alternator is knackered
please could somebody answer the following question if they can

1) Why upgrade to a 150amp alternator
2) How can I tell which alternator I have (120 or 150 amps) (I will have a look on the alternator it's self when it's not dark or raining)
3) I have seen on the forum you need a software upgrade if you change from 120 amp to 150amp. I just wondered why does the car monitor the current of the alternator.
Thanks
Mark

msh · Dec 15th, 2013, 16:29

sorry forgot details 2.0d s40 54plate
Thanks
Mark

pgm · Dec 15th, 2013, 22:15

As I understand it (someone correct me if I am wrong) The ecu will decide what power is available from the alternator dependant on what is being powered and switch any non essential systems down till such time as the power demand drops. There is no need to uprate the alternator but it will work better with the bigger alternator and software ie it will charge the battery a little quicker after starting ect.

Paul

138gat · Dec 16th, 2013, 16:36

I have a 2.0D 54 plate and the alternator is a 150 amp as standard.
Changed mine for exactly the same make/model £185 including vat from local indie auto electrician.
Easy enough to change and there is a good guide on here somewhere

msh · Dec 16th, 2013, 20:53

managed to remove alternator today. It was a 150 amp one
replacement will be here tomorrow
Thanks everybody

Dec 15th, 2013, 16:28	#1
msh Senior Member Last Online: Oct 15th, 2017 11:57 Join Date: Aug 2010 Location: paignton	power system service urgent Hi I have just had this massage appear POWER SYSTEM SERVICE URGENT From other posts I do know that this could mean the alternator is on the way out Did a voltage test 12.2v before start up 11.5v after start up NO increase in voltage when revved. I know the alternator is knackered please could somebody answer the following question if they can 1) Why upgrade to a 150amp alternator 2) How can I tell which alternator I have (120 or 150 amps) (I will have a look on the alternator it's self when it's not dark or raining) 3) I have seen on the forum you need a software upgrade if you change from 120 amp to 150amp. I just wondered why does the car monitor the current of the alternator. Thanks Mark

Dec 15th, 2013, 22:15	#3
pgm Master Member Last Online: Nov 18th, 2023 21:06 Join Date: Jul 2009 Location: Glasgow	As I understand it (someone correct me if I am wrong) The ecu will decide what power is available from the alternator dependant on what is being powered and switch any non essential systems down till such time as the power demand drops. There is no need to uprate the alternator but it will work better with the bigger alternator and software ie it will charge the battery a little quicker after starting ect. Paul __________________ W reg S80 2.5D Auto SOLD; 55 reg V50 T5 AWD Manual SOLD; 59 reg S80 2.4D Geartonic SOLD; X reg V70 T5 Manual SOLD; 10 reg XC60 D5 Geartonic SOLD 65 reg V60 D4 R design Manual

Dec 15th, 2013, 16:29	#2
msh Senior Member Last Online: Oct 15th, 2017 11:57 Join Date: Aug 2010 Location: paignton	sorry forgot details 2.0d s40 54plate Thanks Mark

Dec 16th, 2013, 16:36	#4
138gat 138gat Last Online: Mar 29th, 2020 13:40 Join Date: Jun 2011 Location: Burnley	I have a 2.0D 54 plate and the alternator is a 150 amp as standard. Changed mine for exactly the same make/model £185 including vat from local indie auto electrician. Easy enough to change and there is a good guide on here somewhere

Dec 16th, 2013, 20:53	#5
msh Senior Member Last Online: Oct 15th, 2017 11:57 Join Date: Aug 2010 Location: paignton	managed to remove alternator today. It was a 150 amp one replacement will be here tomorrow Thanks everybody

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