What's this thing?

[vixen1700]

Rooting around the passenger shelf in the car and found this thing that goes into the cigarette lighter.

It then lit up with 11.7 and 12.0.

Am I being really stupid and it's a thermometre which is hopelessly wrong?

It doesn't have any connections to it btw.

Just seems an odd little thing.

If that's what it is.

[Scrump]

Voltmeter.
Indicates the battery voltage (actually the voltage at the accessory socket).

[vixen1700]

Great, thanks! I had no idea what the hell it was doing.

[Spare tyre]

It should go higher than 12 when engine running

[vixen1700]

It wasn't running, I was just sitting in the supermarket car-park waiting for my mrs. , found it, stuck it in the fag-lighter and it lit up.

I'll have to have a look when the car's running.

[Spare tyre]

vixen1700 said:

It wasn't running, I was just sitting in the supermarket car-park waiting for my mrs. , found it, stuck it in the fag-lighter and it lit up.

I'll have to have a look when the car's running.

I had a phone charger with a voltmmeter built in, I noticed once daynthat I was on 12.something whilst going along the motorway - alternator had failed, it allowed me to exit the motorway and find a garage

[shtu]

As above, a voltmeter. eg, https://www.ebay.co.uk/itm/156191349734