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Mysterious flat batteries

Posted: Fri Jun 08, 2012 9:45 pm
by drivesafe
Hi folks and this is a weird one and I’m hoping someone out there may have come across something similar.

I have a Discovery 4 customer who has had a continual flat cranking battery for around 18 months and the other week the battery was replaced by the dealer, even though at times the dealer has had the D4 for a week at a time and not a problem.

Then the customer would drive his D4 home and with in a day or two, flat battery.

One of my dual battery kits was fitted, hoping to fix the problem because it was thought the problem might have been caused by Shopping Trolly Syndrome, where this D4 is continually only driven for a few minutes at a time, except for the occasional long trip away.

A special version of the SC80-LR battery isolator was also fitted. This had a much higher cut-out voltage, but this didn’t change anything, and no matter what cut-out level was set, the auxiliary battery was always left with it’s voltage at or near the cut-out level.

So the isolators worked, the auxiliary battery never went flat and the owner got into the habit of measuring his cranking battery before he tried starting his D4.

Most of the time his battery was just to flat to start the D4 but on a number of occasions, where the battery was only down to 11.5v, he had no problem starting his D4.

A battery with an SoC of 11.5v will start most vehicles but the battery must be in good nick, so this indicates his battery is not the problem, and because the auxiliary battery is always at the cut-out level of the SC80-LR, this rules the isolator out as being the problem.

While away, there is never a problem, no matter how long he parked his D4 at what ever camping site he was at, and to make things even weirder, today he tells me he was so fed up with his battery going flat that he began backing the D4 into the garage to make it easier to get a jump start, but not once while the D4 was backed in, did the battery go flat.

Now over the last few years I have been hearing of some strange problems being caused by these new Smart Power Meters, so when he told me about only having flat batteries when he parks front first in his garage I asked him if he had a Smart Meter in his house.

About 18 months ago, his old power meter was swapped over to a new Smart Meter and its located on the back wall of his garage.

It’s not that the battery itself is flattened by the meter and in this case, with the auxiliary battery mounted in front of the cranking battery, the auxiliary battery is closest to the meter but is not effected.

What I have read about these smart meters is that they can cause problems with Bluetooth equipped gear and in this case, the Bluetooth in the D4 may be kept active, which in turn means the D4’s computer are not going to full shutdown mode, causing a continual drain on the cranking battery.

This is just my theory at this time and one case does not make it a confirmed cause.

To my question, has anybody else got one of these new Smart Meters fitted and have they suffered any mysterious flat batteries with no obvious cause?

Re: Mysterious flat batteries

Posted: Sat Jun 09, 2012 8:36 am
by chimpboy
I know there was a problem with P38A rangies when they were parked at airports and similar. It was to do with their factory alarm system responding to various signals in the area. I can't recall the specifics but it was a big issue.

I think you may be right that smart meters have bluetooth and they may also put out other signals too; combining that with the P38A problem I woudn't have trouble believing that this could flatten a battery if the car had a dumb response to it.

Unfortunately although I have a smart meter I don't have any bluetoothy stuff or other stuff that might respond to it in my car that would be affected by it.

Re: Mysterious flat batteries

Posted: Mon Jun 11, 2012 10:51 am
by poppywhite
A bit like chimps reply,

I read some time ago about remote for garage door or some type of alarm being the culprit. Not necessarily owners, to long ago to remember.
Basically some electronic chat that was not resolved and continued to flat battery. Change of frequency of one of the modules resolved it.

Good luck with it.

Re: Mysterious flat batteries

Posted: Sun Jun 17, 2012 6:39 pm
by mickyd555
can you wrap the computer in foil and earth that foil out to see if it makes a difference. If you can prove that the electricity meter is causing the problem you would almost certainly be able to claim compensation from the supply authority (not the retailer) for the work you and others have done on the car to solve the problem. The metering equipment should not influence external equipment just like your D4 should not influence the meter to spin backwards for example.