Knackered battery causing errors

[Mattt]

Hi all,

First post on the forum, but have been reading for a while - very useful!

I've got a MY2009 V6 Petrol SE, and had been getting error messages on start-up saying the EPB auto-release wasn't functional (but no other problems).

Land Rover (Gold Coast) say that this is due to the battery, and it should be replaced ($307). I find it hard to believe a 3 year old car should need a new battery, but never mind!

The car gets little use, due to my working routine so often sits for a couple of weeks - and between those periods only gets small runs around the city. So believe the voltages have probably dropped quite a lot.

I've now bought a CTEK to leave on it, and am hoping this can 'recover' the battery condition and keep it topped up.

Any thoughts?

Matt :)

[drivesafe]

Hi Matt and the damage is probably done by now but see how it goes.

Unfortunately in your case it is not the battery or vehicle’s fault. Short drives and/or long periods between uses are not good for any cranking battery but in D3/D4s the problem is exacerbated by the amount of power that is used while the computers shutdown after each drive.

So with short drives and being parked up for long periods, your battery has actually done quite well to last this long.

Just a suggestion and depending on where you park your disco, a solar panel might be a better solution for the next battery!

[Malcolm]

Hi Matt and the damage is probably done by now but see how it goes.

Unfortunately in your case it is not the battery or vehicle’s fault. Short drives and/or long periods between uses are not good for any cranking battery but in D3/D4s the problem is exacerbated by the amount of power that is used while the computers shutdown after each drive.

So with short drives and being parked up for long periods, your battery has actually done quite well to last this long.

Just a suggestion and depending on where you park your disco, a solar panel might be a better solution for the next battery!

Prob a dumb question, but any reason why I can't simply put the battery charger on the Disco's battery in-situ? There is no risk of upsetting the car's computers, is there?

[ADMIRAL]

Prob a dumb question, but any reason why I can't simply put the battery charger on the Disco's battery in-situ? There is no risk of upsetting the car's computers, is there?

I have used the same method to keep the main battery fully charged, when it was getting only short runs. I have not had to bother since replacing the battery.

[Mattt]

I normally run my battery conditioner on my other car (TVR) through the cigarette lighter, but I noticed on the Disco this is a switched feed via the ignition - so assume it wouldn't work?

If not, I'll just hook up under the bonnet.

[drivesafe]

Prob a dumb question, but any reason why I can't simply put the battery charger on the Disco's battery in-situ? There is no risk of upsetting the car's computers, is there?

Hi Malcolm and there is no problem with connecting the charger while the battery is in place.

If a problem occurs with the charge, your battery is the only thing that is likely to be damaged because your ignition will be off so nothing else is in danger of being damaged.

[rufusking]

I normally run my battery conditioner on my other car (TVR) through the cigarette lighter, but I noticed on the Disco this is a switched feed via the ignition - so assume it wouldn't work?

If not, I'll just hook up under the bonnet.

The left hand (caraven) trailer plug has a direct feed to the battery and is unaffected by the state of the ignition or lock. You can back feed into the battery from there. I don't have my D4 stuff with me for the pins but it's easy to find on the forum or net or with a multimeter.

[Graeme]

Hi Malcolm and there is no problem with connecting the charger while the battery is in place.

If a problem occurs with the charge, your battery is the only thing that is likely to be damaged because your ignition will be off so nothing else is in danger of being damaged.

Lots of the electronics (eg the suspension ecu, alternator, immobiliser) never disconnect from power, not that it would stop me from connecting a charger to the battery in-situ with the normal precautions of good cable connection practices.

[Ivan]

It's pin 4 on the 12S (white socket). See this link (http://www.electronics2000.co.uk/pin-out/trailer.php)

HTH

Ivan

[drivesafe]

Lots of the electronics (eg the suspension ecu, alternator, immobiliser) never disconnect from power, not that it would stop me from connecting a charger to the battery in-situ with the normal precautions of good cable connection practices.

Hi Graeme and yep, the suspension ecu and immobiliser could be at risk but not the alternator, as the battery would have to be removed from the charging circuit before the alternator was put at risk and in this case it would take a reversal of polarity.

But the primary ECU and things like the sound and nav system would only be at risk if they were turned on while charging, which sort of defeats the purpose of charging.

Furthermore, you would still need to have a battery charger failure where the voltage was in a runaway situation that takes it way over 18v before any of the vehicle’s electronics was put at risk.

On the other hand, just keeping the charge voltage above 15v for an extended time will cook any battery.

Even with the battery being cooked by too high a charging voltage, the battery would still hold the voltage down for quite a long time, depending on how big the charger is.

I have read of quite a few Cteks that have cooked batteries but had no effect on the vehicle’s electronics.

[Graeme]

I was thinking primarily of reversed polarity with a charger that doesn't detect polarity.

[drivesafe]

Hi Graeme and if the battery is in place, and the battery charger does not have reverse polarity protection, then you will most likely destroy the battery charger first.

The battery itself, because of it’s size and ability to withstand low current polarity reversal, even if dead flat, will protect the rest of the vehicle’s electronics.

Reversing the battery’s leads is a different thing but reversing a battery charger’s leads would see the battery charger’s leads melt and/or the charger cook itself.

[Mattt]

Is there somewhere in Brisbane I can get a connector made up for the trailer power point that connects to my CTEK?

I've got a CTEK lead that can be cannibalised which just has black/red cables on it.

[Barryp]

I have used one of the large round trailer plugs and depending on the brand you can rearrange the pins to suit the LR socket with the live to battery connection. If you unscrew the wire retaining screw on the pins you can slide them out and rearrange the pins to suit the required positions in the LR socket.
Perhaps a poor description but it should be obvious if you dismantle a plug.
Regards
Barryp