outrun.

The ashtray solution shown above with the matching display color looks nice.

I‘m using a bluetooth voltmeter installed on the battery. It‘s invisible, has graphs like voltage over time etc on the app and can be checked from outside the car too.

Antigravity

We make a simple Bluetooth Product that has a couple very cool features, and for your use case might be a great option due to its ease of use and actually 24hour 30days of tracking battery voltage as well as giving you the real time voltage. It will also test your alternator for basic charging as well as test the voltage drop when you start your car which is a simple data point to see if you battery is strong.

Its called the "Battery Tracker", and made by Antigravity Batteries. Installation takes about a minute and is as simple as loosening your battery clamp bolt, and sliding in the Battery Trackers terminals behind the loosened bolt and tightening. No need to discounnect the battery or do anything more than loosen and tighten the bolt on the clamps. Then put the app on your phone and then it will give you real-time voltage and a history of voltage up to 30 days. It can also send you warning in your notifications on your phone.

You can see it here> https://antigravitybatteries.com/pro...ker-lead-acid/

Video below.....

IXLR8

I have a few of those BM2 voltage monitors available on Amazon and ebay. The problem is they run on Bluetooth and a piddly 30 feet of unobstructed range. I bought them so that I can monitor my vehicle battery voltages from my home where cars are parked in my driveway or in my garage. Well talk about totally useless unless I am pretty well standing next to the vehicle. Also, some of us are not glued to our phones. I prefer a gauge in my car.

And why does the silly App need a "location" for improved accuracy for it to work? BS like that pi$$es me off. Taking a voltage reading has nothing to do with where I am on planet earth. LOL