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Discussion Starter · #1 ·
A reminder that clocks go back and daylight ends sooner so you need headlamps and blowers on longer.

And this drains your batteries faster.

And if you only do short trips, you will come to start your car one day and it won't turn
over.

Calcium content batteries and AGM batteries need at least 14.4 volts to "accept" charge.

The 2.5-litre and 3.0-litre S Types cannot fully charge Calcium content batteries because their charging system only provides 15.1 volts for the first 5 to 6 minutes after starting, then drops to 13.6 volts until the engine is switched off.

The solution is to fully charge your battery on a home charger or smart charger like the C-tek MXS 5 from time to time.

Other S Types (diesel, 4.0, 4.2) provide variable 14 to 15 volts according to battery current draw and should fully charge Calcium and AGM batteries.

But!...

Check your own car's charging voltages for 20-30 minutes from starting by using a cheap voltage monitor that plugs into your cigar lighter socket.

Note that because of the long cables, there can be a voltage drop of around 0.4 volts from your battery to your cigar lighter socket when the engine is not running.

A fully charged calcium-content battery will show at least 12.7 volts at its terminals.

Don't leave it until your car doesn't start then throw money at new battery, new alternator, mechanic, etc.

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Actually, because I use my bikes more than my cars, I take all the car batteries off around now and give them the full "Recycle" treatment with my C-tek. My S type has my bike smart charger plugged in all the time, but yes it's definitely time to take them all in house and give them a good charge up.
 

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A CTEK is the way to go, I only do short journeys so it's on overnight once a week. A CTEK is money well spent
 

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Discussion Starter · #6 ·
As usual, several low battery problem symptoms being reported on the forums.

Good time to check voltages and charge them up.

Good time to buy a C-TEK.

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I don't think this can be correct for all Jaguars and charging systems.

My XJ has an AGM battery fitted , I put it in around 6 months ago and many said it would be no good ?

My car has a WiFi router in it , left on 24/7 and pulling around 800mA and often stands for 48 hours between use.

In theory this will have sapped around 40aH of the original 100aH , it starts on the button every time.

Two days standing , 6 mile journey with heated screens , seats and lights etc ,repeated with no problems.

When I fitted the AGM battery , I remember it pumping in heavily for a few minutes regularly until over 15 volts.

No battery issues from installation and no voltage related issues yet ......... keeping fingers crossed.

I do also have a Varley red top battery in the boot charged from an inverter , ready just in case.

Prepared as the car is an auto and I know my electrical demands could one day leave me needing an assisted start !
 

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For what it is worth. When the engine is running, with a properly specified electrical system, the generator is supporting 100% of the electrical load and charging the battery. If you do lots of short journeys, lights on or not, the battery doesn't fully recharge between starts and thus will become discharged.

The battery will also discharge if you leave the lights on without running the engine.
 

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Discussion Starter · #9 ·
As expected, there have been several problem threads recently which are symptomatic of low battery voltage so I've bumped this thread back into view.

It's all here chaps, please read if you have ABS, DSC, EPB faults.

They may of course be genuine faults, but a voltmeter to check your battery voltage costs a lot less.

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I also use a C-Tek charger for when the Jaguar is not being used for long periods and can vouch for it.

I also have one of these https://www.amazon.co.uk/dp/B015TKUPIC/?tag=jaguarfcom-21

as I have a 4x4 for knocking around Norfolk in the winter/bad weather and has come in handy helping other people out.

Pezza
 

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Discussion Starter · #11 ·
It's coming up to cold weather and short days again and the usual battery problems.

The 2.5-litre and 3.0-litre S Types and maybe the 4.0-litre S Types too, cannot fully charge modern calcium and AGM batteries, so you are running at between 70% and 80% of full charge.

This is why your batteries won't last long when something that draws extra current happens or when you leave your lights on without the engine running.

Don't panic, just charge your battery on a home charger now and then.

Old chargers really aren't suitable now.

A Smart charger like the C-Tek MXS 5 is better and is aware of different battery charging needs, and also has a Recondition cycle which may restore a weak battery.

Charge up your batteries now chaps, winter is drawing in.

The 4.2-litre V8 S Types and the 2.7-litre Diesel S Types are fine, their charging systems are capable of supporting calcium and AGM batteries.

But if you only do short journeys or don't use the car frequently, check your battery voltage, it should be at least 12.6 volts at the terminals. If it's less, charge it.

If you have other Jaguar models, measure your charging voltage from starting the engine for 10 minutes and see what the voltage is and if it changes.

If it shows variable 14.x to 15.x volts it is fine with calcium and AGM batteries.

But if it is 13.6 to 13.8 volts constantly then it does not fully charge them.

Just be aware of this.

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As we speak Jim the limo. is in my garage with the CTEK doing it's stuff.:-D
 

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Yes. My V6 XJ will need it's battery touching up with the Ctek. In fact I might get some use out of it next week when I go home for my "day off".
 

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I'm looking at ways of re-charging Mrs V's hearing aid batteries because the batteries she's using last (at best) 4 days. Maybe a couple of small clips for the CTEK and plug her in when she goes to bed.
She's not enthusiastic but 'needs must':mrgreen:
Poor old soul is as deaf as a piano leg.
 

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My neighbours got some of those "invisible" things from Specshudders. Cost him quite a bit. I asked him how much they cost him and he told me "It's half past three".
 

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Discussion Starter · #20 ·
My neighbours got some of those "invisible" things from Specshudders. Cost him quite a bit. I asked him how much they cost him and he told me "It's half past three".
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Meaning £1,530?

That's about right for the 2 my friend got too.

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