Smart phone Battery Monitor - multiple batteries

[NJSS]

I'm looking for a smartphone battery monitor app. & associated hardware to monitor & report on battery condition for at least two batteries in my SL350 & one in my Land Rover Discovery 4.

If cheap enough I would add the stop/start battery in the Discovery 4 and batteries in my 2 MGs as well.

I need them to alert me to when charging is required regardless whether the vehicle is "switched on".

The CTEK 40-149 Vehicle Battery Monitor would be my first choice but at £45 per battery it's expensive & I'm not even sure it will accommodate 3 or more batteries.

NJSS

 

[markjay]

The CTEK 40-149 Vehicle Battery Monitor would be my first choice but at £45 per battery it's expensive & I'm not even sure it will accommodate 3 or more batteries.

NJSS

How does this work then? I understand that it will report the battery charge level when the ignition is switched-off, but how does it work with the engine running, both batteries online (starter and auxiliary), and the alternator chipping-in?

 

[markjay]

Also, this is from the Q&A on the Amazon website:


Q: I have a car with twin linked batteries. Will this gadget cope with that.

A: It measures voltage and transmits it via Bluetooth to a mobile phone app. It'll do that as long as the voltage it's connected to is within normal input parameters. It'll assume it is connected to one battery, so the results will be an average of the two batteries condition.

So, are the two batteries (starter and auxiliary) 'linked' when the ignition is on?

 

[Chrishazle]

Auto Battery Monitor BM2 Bluetooth 4.0 12V Device Car: Amazon.co.uk: Car & Motorbike looks interesting, mentioned in the reviews of the CTEK linked by Markjay above. Various vendors on Amazon of exactly the same item at prices from £20 to £35!

 

[merc07]

You would have to be just a few feet from your car to receive any updates, better with a WiFi system - but then you need WiFi near your car !

I wanted one for monitoring water temperature but they are ridiculous money so I built one.
It runs off 3AA batteries so I also send battery voltage - simple to build and code using Arduino.
Updates every hour over WiFi to an application on my phone.
The app is free, it's called Blynk, look it up..