Jaguar Forum banner
1 - 20 of 249 Posts

·
Registered
Joined
·
206 Posts
Discussion Starter · #1 ·
Dear all,

do I really have to change my alternator?
Today my Jag showed the battery warning lamp with "Battery is not charging".
My batteries are 2 years old. This fault is shown the first time.
The big one had 11.9 V to 12.2 V while the engine was running or not. I checked the current. Even with the engine running
the Jag is discharging the big batterie (battery 1). Battery 2 is charged while the enginge is running. But the voltage
is too low. Under 14.0 V.
I should measure min 14 V from the enginge block to battery 1 plus pole while the engine is running. Right?
If not, the alternator is broken. Right?
Please tell me something like "It is only a broken fuse of the headlamp" :cool:

Rectangle Font Parallel Electric blue Number


Have a nice evening
Dirk
 

·
Registered
Joined
·
3,462 Posts
Psst! Want to buy an alternator? Phil;)
 

·
Registered
Joined
·
2,413 Posts
You should get about 14.6v with engine running.
It is possible that you have a bad earth connection but.......
 

·
Registered
Joined
·
206 Posts
Discussion Starter · #5 ·
Thanks Popeye. So I have to start measuring the output directly at the generator :confused: Easy access.... :rolleyes:. Maybe the test mode , as @PeteA discribed in another thread, will show some other details? I m not very convinced because sdd couldn't perform a bms or battery check. Ends up with a fault "couldn't perform this test" after 20 sec. :(

Dirk
 

·
Registered
Joined
·
2,413 Posts
You can measure it at the battery. No need for any contortions :)
 

·
Registered
Joined
·
10,387 Posts
Thanks Popeye. So I have to start measuring the output directly at the generator :confused: Easy access.... :rolleyes:. Maybe the test mode , as @PeteA discribed in another thread, will show some other details? I m not very convinced because sdd couldn't perform a bms or battery check. Ends up with a fault "couldn't perform this test" after 20 sec. :(

Dirk
Your memory is better than mine Dirk!

And as Popeye says, measure at the batteries first, it's quick and easy and will also make sure that the car is telling the truth and not sending you on a wild goose chase, it probably isn't but it's worth a quick check.
 

·
Registered
Joined
·
206 Posts
Discussion Starter · #8 ·
Thank you so far...."contortions"...nice...didn't know that yet :) . In German you say "No need for a handstand" :)

So I did the right things yesterday :)
I measured both batteries at their terminals. The current is measured with a current probe and the direction (charge or discharge) has been checked and respected:)
Engine not running:
  • battery 1 (big one) = 11,99 V
  • battery 2 (auxiliary one) = 13,74 V
  • discharge current battery 1 = 500 mA
  • discharge current battery 2 = 170 mA
Engine running for about 1 minute and measured with running engine:
  • battery 1 drops down to 9,9 V during cranking (good value :) )
  • battery 1 after 1 minute = 11,70 V
  • battery discharge current = 21 A
  • battery 2 = 14,2 V
  • battery 2 charging current = 1,2 A
  • Voltage from the engine block to battery 1 plus terminal = 12,35 V

From my point of view, the generator is dead :(

Dirk
 

·
Registered
Joined
·
1,311 Posts
As the BMS will never let the battery volts go below 12.2 I think you can say that the generator is shot.
 

·
Registered
Joined
·
206 Posts
Discussion Starter · #10 ·
You are right. I am still not sure, if I should buy a Jaguar part or an after market part. Not the cheapest, but even if I buy a high-price after market part, it is still half of the Jaguar part.
400 EUR after market vs 880 EUR Jaguar part.

Dirk
 

·
Registered
Joined
·
10,387 Posts
Thank you so far...."contortions"...nice...didn't know that yet :) . In German you say "No need for a handstand" :)

So I did the right things yesterday :)
I measured both batteries at their terminals. The current is measured with a current probe and the direction (charge or discharge) has been checked and respected:)
Engine not running:
  • battery 1 (big one) = 11,99 V
  • battery 2 (auxiliary one) = 13,74 V
  • discharge current battery 1 = 500 mA
  • discharge current battery 2 = 170 mA
Engine running for about 1 minute and measured with running engine:
  • battery 1 drops down to 9,9 V during cranking (good value :) )
  • battery 1 after 1 minute = 11,70 V
  • battery discharge current = 21 A
  • battery 2 = 14,2 V
  • battery 2 charging current = 1,2 A
  • Voltage from the engine block to battery 1 plus terminal = 12,35 V

From my point of view, the generator is dead :(

Dirk
From that it would seem that there are two separate feeds from the generator to the batteries, I don't think I knew that.. but then you don't have an XF anymore..

Definitely sounds like the generator has gone through too many contortions and is now dead/dying..

:D
 

·
Registered
Joined
·
206 Posts
Discussion Starter · #12 ·
Contortions are the root cause :)
All measurements are plausible except the 14.2 V from battery 2. I just measured it again befor plug in the CTEK. In fact it is only 13.7 V. But is an Exide EK151 12V battery. Seems to be an upstepper in between. Even the reaction of the management system is ok. Charging the battery 2 with battery 1 while the engine is running. Ok, maybe it is only plausible for me, because it is warm and sunny outside, weekend, cake, wine,..... :cool: . Left home office earlier this day and visited my Indy around the corner. He can't order the generator. His suppliers don't have it on stock and can't order it. So I will order the part and we will play dice who will assemble it :)

@PeteA
I tried to enter the engineering test mode......I didn't succeed.......contortions? :)
Battery charging Problem
 
  • Haha
Reactions: PeteA

·
Registered
2021 F-Pace P250 SE R-Dynamic, 2004 XK8 Coupe 4.2
Joined
·
5,084 Posts
The 2nd battery shouldn’t be a concern, it is only used when S/S kicks in to run any “other” electrics momentarily when the main battery is prompted to restart the car.
 

·
Registered
Joined
·
655 Posts
There's a connection point under the r/h wheel arch (near the washer bottle) If you take a reading from there with the engine running it should give you alternator output voltage! Easier than trying to get to the back of the alternator.
 

·
Registered
Joined
·
206 Posts
Discussion Starter · #15 ·
There's a connection point under the r/h wheel arch (near the washer bottle) If you take a reading from there with the engine running it should give you alternator output voltage! Easier than trying to get to the back of the alternator.
Thanks! I will check that out.
 

·
Registered
🏴󠁧󠁢󠁳󠁣󠁴󠁿X260 R-Sport in Aurora Red
Joined
·
13,040 Posts
You could always go into the engineer menu and it will show you the alternator voltage and battery voltage without getting dirty
 
  • Like
Reactions: The vast minority

·
Registered
Joined
·
71 Posts
After
You are right. I am still not sure, if I should buy a Jaguar part or an after market part. Not the cheapest, but even if I buy a high-price after market part, it is still half of the Jaguar part.
400 EUR after market vs 880 EUR Jaguar part.

Dirk

after market with a decent warranty would be my choice.


[/QUOTE
 

·
Registered
Joined
·
206 Posts
Discussion Starter · #19 ·
Thanks Horlicks. I belive 280 EUR to 400 EUR is a reasonable price for good quality. New or re-conditioned.

Dirk
 

·
Registered
Joined
·
206 Posts
Discussion Starter · #20 ·
Just saw in the manual that this type is written there: Denso SC6 220A
I found only 150 A generators during my search for suitable generators.

Is Denso SC6 220A the right type?

Dirk
 
1 - 20 of 249 Posts
Top