Is there any chance your new battery was no good? Have you checked the connection of the black battery cable (all the way to ground)? What about the big fusable link on the battery?

 

The cables are tight and look brand new. The fsiblink is on the negative or the positive? I checked the negative and there is no resistance between the battery pole and the earth connection at the end of the cable so I assume it is OK. Could a bad contact at positive cause this? By 'bad' I mean a slight looseness?

 

OOps - little bigger than I expected. Which of these do I test and how?
thanks

 

No resistance means nothing as a poor connection can conduct fine until under actual load. I had a similar issue with my fuel pump, got a 12v reading on my meter all day long but pump would not run. Finally fond a very corroded wire barely hanging onto life. Basically enough to pass a voltage rating, not enough to handle the amperage. Resistance works the same way of course, so just keep that in mind.

So looking at your battery....
On the positive lead, remove it and that black box below pull up and out. Take it apart and replace/insect that fuse. They can fail internally. 400 amps I believe. But check for corrosion, I had some corrosion issues on mine at one point. But what is that wire for?
On teh negative lead... what the heck is that attached? Kinda looks like the delivery cutout that the dealer is suppose to remove before selling. I have not seen anything like that before personally. But whatever it is, could be disconnecting the battery ground randomly. That may not seem like a big deal when running, but it certainly is as the battery itself acts a bit like a capacitor on the power system stabilizing/smoothing alternator output. So when disconnecting/connecting a battery on a running car can cause weird stuff.

 

The thing on the negative is the battery monitoring module apparently and it is this that has zero resistance and I think the thing on the positive is a pyrotechnic device designed to blow up (yes..) in the case of an accident to cut out power.

 

I've never seen or heard of whatever that is on the negative either. I'd get rid of it and have the proper cable go direct from battery to ground if it was mine...

 

I concur. Now I hat I had a chance to look at the pics more closely that is not normal and I'd bet it's related to your issues.

 

yes that’s it

 

Page 3812 of the european workshop manual. Seems to be the battery monitoring module but that is all they say

 

Very weird. Both the explosive disconnect and battery monitor only show up as equip in Rang Rovers and the LR4, nothing in the LR3 beyond the transit relay - which after looking over the docs appears to not be what that is on the negative post and is indeed a monitor. Your setup must also mean you have a secondary positive post for jumping the vehicle as attaching a positive jump lead to the positive post of the battery can set off the disconnect charge.

Interesting read about charging the battery and why you can not use the negative post.
https://www.expedition-parts.de/en/b...eim-discovery/