Bad Batteries or Faulty Reading?

Hello Gang. I have another mystery. I charge my Ford Think overnight. The display shows it’s fully charged. I drive for about three minutes (10 mph, no lights or other devices running) and stop. Get back in the vehicle a few minutes later and the display shows 2 bars. After about a minute there are no bars - just an empty, flashing rectangle. I plug it back in for just ten seconds and it shows fully charged. I start driving again and it runs down to zero bars just in a few minutes. I’ve done this “experiment” several times - always with the same result. I’ve never actually run out of juice to the extent that the vehicle stops - but then I’ve never wanted to push it that far and find out. I’ve read it’s a bad thing even to drop below two bars. Are the batteries really discharging that quickly or is there some sort of sensor that could be causing an inaccurate reading? Thanks for any perspective you might be able to share. - David

You will have to check battery voltage to know.

1 Feel each connection for being hot if not go to 2

2 Check all connections for bright and tight

3 After running - before charging take a voltage reading on each battery. If no bad battery shows up go to 4

4 Check each battery cell with a Hydrometer and record readings. If no bad cells go to 5

5 Charge battery’s and repeat 4. After charging reading of each cell should be 1250 or higher

How old are the batterys?