Bad battery or parasitic drain?

[Mr Miata]

Hi. My car is constantly having symptoms of low voltage… difficulty in starting first thing (but starts better after a journey), stop-start won’t work due to “electrical load too high”, occasionally had a low battery warning light on the dash.

However I have both a dashcam hard-wired in and a tracker.

While I can simply unplug the dashcam. I don’t think the tracker has its own fuse but is an in-line splice somewhere, probably to keep it hidden. So I can’t remove a fuse overnight for diagnostics.

I’m wondering what’s causing this fault? Is it the battery or the 2 devices that can be running in the background? I would have thought their current draw / power consumption would be low and they’d automatically cut off if battery gets too low.

Edited by Mr Miata on Monday 21st February 01:15

[mad4amanda]

My bet is the tracker, they have an internal battery if the battery in iy goes flat , faulty or say your subscription expires the tracker becomes a parasitic drain and in a remarkably short time can drain a battery . With regard the subscription it was a tracking company that said it becomes like a mobile in a bad signal area constantly checking for a signal and draining the internal then external batteries .
We replace several a month at work even though they are a reputable company which have bricked themselves and will no longer communicate, how old is the tracker? the earlier ones (up to 2020) have a much higher draw that the latest.

[vx220]

Silly question, but do you lock your car overnight?

I read somewhere that certain cars don't properly power down until locked, so if left unlocked in a garage they can flatten batteries.

[RazerSauber]

You can test it yourself pretty easily with a multimeter if you have one, if you don't then just about any basic £9.99 unit would do.

Remove battery negative clamp
Plug multimeter negative probe in the 10A port
Put multimeter in 10A setting
Put probes between battery negative terminal and negative clamp

The multimeter screen will display an amp reading. Anything below about half an amp is normal, if you're drawing more than that then something is draining your battery. If it's less than half an amp, it would appear your battery isn't holding charge and needs to be replaced.

Alternatively, if you're a member of a breakdown company synonymous with brightly coloured vans, call one of them out and they have a battery testing machine onboard and can look at it for you.

[Spare tyre]

How old is battery, could be worth swapping as easy test