Intermittent Battery Problems on the 75

juzza0 · 23rd April 2012, 12:31

Hi Guys, just looking for some advise as this problems got me baffled and as i am a logical person... i'm very confused!!!

I replaced the old battery just less than 6months ago now and for 3months the car was ok, then intermittently every now and then and with no specific patern the car won't start as the the battery is dead dead.

The first time this happened the car started happily was driven for about 15 mins, stopped for 5 mins and then wouldn't start as battery was completely flat. A quick jump from the TF and the car was running again. Drove home 15 mins, left overnight and started first time no problems the next morning. all was well for over a week when, heading out one morning the ignition click of total flatness again. A quick jump-start later and the car is good again and continues for a couple of weeks for before doing it again. Every time i've checked and nothing has been left on to flatten the battery. This saga continues and keeps happening intermittently.

So is the battery faulty? Could one of the cells be defective and collapsing causing the problem but then charging again once boosted, or is there a fault somewhere on the car where something is flattening the battery which i can't see? Could an intermittently faulty starter motor or alternator be problem?

Help i'm confused

HarryM1BYT · 23rd April 2012, 12:39

You need to get yourself a cheap digital multimeter and take some battery voltage measurements.

MrDoodles · 23rd April 2012, 12:40

Have you checked the voltage that the alternator is delivering?

FrenchMike · 23rd April 2012, 12:57

Hi,

BATTERY and CHARGE What you have to know.

Using the On Board Diagnostics in 9.0 is an excellent mean to know the behavior of the battery and charging system.

-KEY in POSITION 2 , you see the current State of Charge:
Voltage State of Charge
12.6+ 100%
12.5 90%
12.42 80%
12.32 70%
12.20 60%
12.06 50%
11.9 40%
11.75 30%
11.58 20%
11.31 10%
10.5 0%
(Battery should not have been charged or used for about one hour before this measurement)

-PREHEATING:
The voltage falls to about 10 volts.

-CRANKING:
The voltage falls to 6 /7 volts depending on temperature ...etc.

- IDLE and CRUISING: the voltage must be at last 14 volts even with lights, heater ..etc ON.

greendriver · 23rd April 2012, 13:01

Quote:

Originally Posted by FrenchMike

Hi,

BATTERY and CHARGE What you have to know.

Using the On Board Diagnostics in 9.0 is an excellent mean to know the behavior of the battery and charging system.

-KEY in POSITION 2 , you see the current State of Charge:
Voltage State of Charge
12.6+ 100%
12.5 90%
12.42 80%
12.32 70%
12.20 60%
12.06 50%
11.9 40%
11.75 30%
11.58 20%
11.31 10%
10.5 0%
(Battery should not have been charged or used for about one hour before this measurement)

-PREHEATING:
The voltage falls to about 10 volts.

-CRANKING:
The voltage falls to 6 /7 volts depending on temperature ...etc.

- IDLE and CRUISING: the voltage must be at last 14 volts even with lights, heater ..etc ON.

Very useful info for all of us. Many thanks

juzza0 · 23rd April 2012, 13:16

The charge at the battery from the alternator is 14.2-14.3V
The battery sits at rest at about 12.0v when left overnight.

Also just remembered that when i replaced the battery the battery was selected by the motor factor from the car reg (this motor factor supplies parts to most of the garages and dealers in our area and everything else they've ever supplied as been spot on). I noticed the battery was about 3/4" to an 1" smaller in length than the old Halfords battery i was replacing, so i questioned this when i returned the old battery for my £10 exchange fee and was told that Halfords batteries are always wrong as they select the closest battery in their range to match the manufacturers and in my case it was one slightly larger than the original specified. This worried me a little at the time as the car is 2.0 V6 Conn SE so fully loaded with all the toys.

HarryM1BYT · 23rd April 2012, 13:29

Quote:

Originally Posted by juzza0

The charge at the battery from the alternator is 14.2-14.3V
The battery sits at rest at about 12.0v when left overnight.

That last figure is very low, which could mean you have soemthing discharging the battery overnight, or that it has a cell on its way out.

Maybe give it a full charge, then leave it disconnected over night before checking the voltage.

Did the Halfords battery completely fill the battery box, or was there an 1.5" of space at the front? The 1.5" of space seems to be the normal, but there is room for an even larger battery.

Can you quote for us the spec of your most recent battery?

Maybe they just sold you the one they happened to have in stock, rather than get the correct one..?

juzza0 · 27th April 2012, 12:44

Quote:

Originally Posted by HarryM1BYT

Did the Halfords battery completely fill the battery box, or was there an 1.5" of space at the front? The 1.5" of space seems to be the normal, but there is room for an even larger battery.

Can you quote for us the spec of your most recent battery?

Sorry for delay in reply... been working 12 hour days since Friday.

No the halfords battery was 2-2.5" shy of filling the box, the new battery about an inch shorter than that.

Battery spec: 420A 55Ah type 027.

Currently its been two weeks without fault again, so dreaded ignition click of doom can't be more than a week away... its like a car starting lottery!

David3807 · 27th April 2012, 16:43

You mentioned that the car was fully loaded. Does it have have the factory fit Sat Nav. If so have you checked that it is actually shutting down ie no red light showing on the sat nav compurer after about 2 mins of taking the key out and not opening or closing any doors/boot (which will activate the electrics) ??

And the spec of the new battery seems a little low at 55ah. I thought it was supposed to be 76ah

SD1too · 27th April 2012, 18:40

Quote:

Originally Posted by juzza0

... the car started happily was driven for about 15 mins, stopped for 5 mins and then wouldn't start as battery was completely flat ... Drove home 15 mins, left overnight and started first time no problems the next morning. all was well for over a week when, heading out one morning the ignition click of total flatness again.

Juzza,

Is your useage mainly short journeys with frequent use of the starter motor? If so, that might be the reason.

Simon.

23rd April 2012, 12:31	#1
juzza0 Mmm Monogram MG ZT-T++ & Rover 75 Connoisseur SE (Workhorse) Join Date: Feb 2008 Location: Nottingham Posts: 948 Thanks: 0 Thanked 1 Time in 1 Post	Intermittent Battery Problems on the 75 Hi Guys, just looking for some advise as this problems got me baffled and as i am a logical person... i'm very confused!!! I replaced the old battery just less than 6months ago now and for 3months the car was ok, then intermittently every now and then and with no specific patern the car won't start as the the battery is dead dead. The first time this happened the car started happily was driven for about 15 mins, stopped for 5 mins and then wouldn't start as battery was completely flat. A quick jump from the TF and the car was running again. Drove home 15 mins, left overnight and started first time no problems the next morning. all was well for over a week when, heading out one morning the ignition click of total flatness again. A quick jump-start later and the car is good again and continues for a couple of weeks for before doing it again. Every time i've checked and nothing has been left on to flatten the battery. This saga continues and keeps happening intermittently. So is the battery faulty? Could one of the cells be defective and collapsing causing the problem but then charging again once boosted, or is there a fault somewhere on the car where something is flattening the battery which i can't see? Could an intermittently faulty starter motor or alternator be problem? Help i'm confused __________________ [SIGPIC][/SIGPIC] Last edited by juzza0; 23rd April 2012 at 12:34..

23rd April 2012, 12:39	#2
HarryM1BYT This is my second home 75 Contemporary SE Mk II 2004 Man. Sal. CDTi 135ps, FBH on red diesel, WinCE6 DD Join Date: May 2010 Location: Leeds Posts: 17,273 Thanks: 2,160 Thanked 2,061 Times in 1,586 Posts	You need to get yourself a cheap digital multimeter and take some battery voltage measurements. __________________ Harry How To's and items I offer for free, or just to cover the cost of my expenses... http://www.the75andztclub.co.uk/foru...40#post1764540 Fix a poor handbrake; DIY ABS diagnostic unit; Loan of the spanner needed to change the CDT belts; free OBD diagnostics +MAF; Correct Bosch MAF cheap; DVB-T install in an ex-hi-line system; DD install with a HK amp; FBH servicing. I've taken a vow of poverty. To annoy me, send money.

23rd April 2012, 13:16	#6
juzza0 Mmm Monogram MG ZT-T++ & Rover 75 Connoisseur SE (Workhorse) Join Date: Feb 2008 Location: Nottingham Posts: 948 Thanks: 0 Thanked 1 Time in 1 Post	The charge at the battery from the alternator is 14.2-14.3V The battery sits at rest at about 12.0v when left overnight. Also just remembered that when i replaced the battery the battery was selected by the motor factor from the car reg (this motor factor supplies parts to most of the garages and dealers in our area and everything else they've ever supplied as been spot on). I noticed the battery was about 3/4" to an 1" smaller in length than the old Halfords battery i was replacing, so i questioned this when i returned the old battery for my £10 exchange fee and was told that Halfords batteries are always wrong as they select the closest battery in their range to match the manufacturers and in my case it was one slightly larger than the original specified. This worried me a little at the time as the car is 2.0 V6 Conn SE so fully loaded with all the toys. __________________ [SIGPIC][/SIGPIC]

27th April 2012, 16:43	#9
David3807 Posted a thing or two 2002 R75 Conn SE 2.5l Auto Tourer, 2001 R75 Conn SE 2.5 Auto Saloon Join Date: Nov 2006 Location: Gravesend Posts: 1,897 Thanks: 0 Thanked 2 Times in 2 Posts	You mentioned that the car was fully loaded. Does it have have the factory fit Sat Nav. If so have you checked that it is actually shutting down ie no red light showing on the sat nav compurer after about 2 mins of taking the key out and not opening or closing any doors/boot (which will activate the electrics) ?? And the spec of the new battery seems a little low at 55ah. I thought it was supposed to be 76ah Last edited by David3807; 27th April 2012 at 16:46..

23rd April 2012, 12:40	#3
MrDoodles Banned MG ZT+ V6 190 Join Date: Nov 2011 Location: Spalding Posts: 13,245 Thanks: 369 Thanked 1,196 Times in 818 Posts	Have you checked the voltage that the alternator is delivering?

23rd April 2012, 12:57	#4
FrenchMike This is my second home Rover 75 Saloon Join Date: Aug 2007 Location: Avignon Posts: 4,466 Thanks: 94 Thanked 661 Times in 554 Posts	Hi, BATTERY and CHARGE What you have to know. Using the On Board Diagnostics in 9.0 is an excellent mean to know the behavior of the battery and charging system. -KEY in POSITION 2 , you see the current State of Charge: Voltage State of Charge 12.6+ 100% 12.5 90% 12.42 80% 12.32 70% 12.20 60% 12.06 50% 11.9 40% 11.75 30% 11.58 20% 11.31 10% 10.5 0% (Battery should not have been charged or used for about one hour before this measurement) -PREHEATING: The voltage falls to about 10 volts. -CRANKING: The voltage falls to 6 /7 volts depending on temperature ...etc. - IDLE and CRUISING: the voltage must be at last 14 volts even with lights, heater ..etc ON.