Thread: Beware Charging Dual Battery in D4.

Originally Posted by Graeme

They didn't put a big enough one in the D4s for the showroom floor, with so many of them with a flat battery from people opening the doors for a squiz.

....and the same could apply to camping - people getting in and out of the car for various reasons. Having the battery half flat on top of this sounds risky.

Originally Posted by drivesafe

So Wilbur, what your saying is that 10% difference between what I use, 50% and the 60% that Dave has quoted is a huge difference but 40% lower than your claim of needing a fully charged battery to start a vehicle is not that much different.

Mate, as previously posted, you wouldn’t know what the truth was if it jumped shook your hand.

But surely there must be some reason why Land Rover spec such a large (expensive) battery? If half the capacity was adequate in all foreseeable situations, surely they would save the money and weight and fit a smaller battery?

First of Wilbur, the LR battery is NOT an expensive battery, it is in fact quite a moderately priced battery.

An Optima of half the size and twice the price will do the same job.

Next, again stating that a 10% difference is worse that a 40% difference is nothing but out and out dishonesty.

Originally Posted by drivesafe

First of Wilbur, the LR battery is NOT an expensive battery, it is in fact quite a moderately priced battery.

An Optima of half the size and twice the price will do the same job.

Next, again stating that a 10% difference is worse that a 40% difference is nothing but out and out dishonesty.

But even so, surely a battery half the size would be cheaper? Why would they put in a battery twice the size it needs to be?

Not sure what you mean by 10% and 40%?

Originally Posted by Wilbur

But even so, surely a battery half the size would be cheaper? Why would they put in a battery twice the size it needs to be?

Not sure what you mean by 10% and 40%?

I would suggest the primary reason for choice of battery size would be to be adequate for 98% of normal customers or suchlike, ie to reduce warranty claims to an acceptable level. Most new vehicles get used daily but enough get used 1-2 times a week for this to figure in engineers calculations of battery size. This is how manufacturing works, to optimise production for lowest cost overall.

Originally Posted by Wilbur

But even so, surely a battery half the size would be cheaper? Why would they put in a battery twice the size it needs to be?

Not sure what you mean by 10% and 40%?

the reason they put such a large battery in is simple..

its a requirement for the electrical system to operate the vehicle for a given period of time following Alternator failure. ((Duh hows the battery supposed to help you in an emergancy if its dead?)

its also a requirement for the battery to be able to start the car reliably from a lower state of charge.

sure a battery thats just about big enough will start a vehicle from a fully cahrged condition but wont do it from say 80% charged.

you can start a td5 from a motorbike battery if you want to... try running a td5 for 30 minutes with the alternator disconnected from the same motorbike battery.

Originally Posted by Wilbur

But surely there must be some reason why Land Rover spec such a large (expensive) battery? If half the capacity was adequate in all foreseeable situations, surely they would save the money and weight and fit a smaller battery?

At -40C, very few batteries seem large enough, particularly when you are on the Tundra; it is dark all the time in the winter, and no go means you probably freeze to death in less than 3 hours if not properly dressed. Also my Land Rover is not by any means the only LR3 around here - there are many to the north in the land of the midnight sun and that means dark 24 hours per day and cold for five months a year, and then 24 hours of daylight for about 2 months solid and still cold.

I installed a second battery, the same CaCa as the main starting battery, using the Traxide system, not because I have a fridge to run, (that we get free here), but because I do not wish to look like the contents of the icebox.

Here in the Great White North, there is no such thing as too large a battery or battery's. It was the physically large battery and the provision for a second that most impressed me when I was looking for a new vehicle. This is the reason all Ford, Chev, and Dodge pickups here also have provision for a second battery, and most of the true field work trucks are ordered that way - nothing special so to say, just what is needed for the job - that and when in the field, we sometimes do not turn them off - some not all winter, (the diesels), and they remain running when being fuelled. I might also add the the LR3 has a very good heater and yes, my 3 to date, has always started so I guess the conditions were foreseeable by Land Rover.

I attached a typical picture of the North in the late spring; can't take a picture in the winter.

Originally Posted by bbyer

not because I have a fridge to run, (that we get free here)