- My model of MX-5 is: 2005 NB
I discovered the battery in my NB was completely flat this morning (at 10:30am). I took it inside and it measured 2.5 volts. I hadn’t used the car since Wednesday last week (most unusual for me) and it’s been unseasonably cold for the last few nights but even so, something’s amiss.
It’s a nearly new Panasonic battery, bought last November from the local Mazda main dealer. I replaced the Yuasa battery that was in the car because it was unvented and I was worried about fumes causing corrosion. Miraculously it was still reading 12.5v although it has been sitting (indoors) unloved and forgotten for the last 5 months. I put the Yuasa in the car and it fired right up so there’s nothing wrong with the starter circuit. (Quite impressed with that, nice one Yuasa!)
I’ve had the Panasonic battery on charge since 11:00 and at 4pm it was at 12.2v. Not ideal but I wanted to check the charge circuit so I put it back in the car and after a sluggish start it fired up and is being charged at a healthy 14.4v.
I’ve taken the battery back out and put it on charge again. I will disconnect it when I go to bed tonight, make a note of the voltage and then check it again tomorrow morning to see if it’s holding charge.
If it is, I’ll put it back in the car and put my multimeter in series with it on amps to see if there’s something draining it. (With the car turned off obviously…)
I checked to see if anything was inadvertently left switched on (lights, wipers etc,) but no.
Comments most welcome, thanks in advance.