I’m looking for technical help or recommendations on: Brand new battery flattening.
Hi All
New owner of a 5 and all was ok for a few weeks…then I started to struggle to start, as though the battery was dead. I was able to get £50 back from the warranty so I went for a new ‘Yuasa’ battery. All ok for a couple of days, then dead as a Dodo!!
RAC came out ( thought I’d make use of it)
They said that something was draining the battery, and if left overnight it’d be dead by the next day.
Indeed it was…now I just don’t know what to try next?
First and obvious checks, check the boot light goes out (if in the on position) when closed. I always keep mine off.
Same with the interior light.
Apart from that and I guess it’s been checked by the RAC anything connected as an extra either via the fuse box or direct on the battery causing a drain?
First question really is have you got a multimeter that can measure amps and do you know how to use it? You need to measure the current drain then start removing fuses to find out what is causing it. You haven’t got anything plugged in to the diagnostic socket have you? Or any other wired In accessories?
I hope they find it, keep us posted. I’ve got a similar experience with my new (to me) 2010 sport tech. It’s fine for a day or 2 but battery drains by day 3.
Like you, it’s not the interior or boot light, and nothing in cigarette lighter. Only modification is a smart top module which I assume it can’t be? I’ve read about faulty Bose units that continue to draw power but I’ve removed the relevent fuse and the current draw is still there.
Does anyone know if it’s ok to systematically go through every fuse? Any likely candidates to try first?
Apologies Hutcho, not trying to steal your thread. Just sounds like we’re suffering the same problem.
Another option to find current draw without an amp meter is to use an infared temp gun, methodically point the gun at each fuse and relay and you will see a higher temp on the one consuming the power.
If I remember rightly there was a problem on the NC with battery drain if the cruise control was left in the on position when the ignition was switched off
I got my 2020 mx5 sport tech delivered on a flat truck last Friday evening. Saturday morning, the battery was flat. Mazda assistance got it going and all was well until Monday morning. Dead battery again.
I’ve booked Mazda assistance to come on Saturday to start the car, then I’ll drive it 25 miles to the nearest Mazda dealer for a new battery.
Update….
Heard from the dealer who agreed to look at the problem as well as ‘free up’ a seized calliper.
It seems the battery was being drained by the fuel pump. So looks like a new water pump may solve the problem?
Can’t wait to get back on the road now!!
