11 month old Gel batteries still under warranty.
This really does not mean much unless you know how the batteries were used, maintained, and cared for. A brand new set of batteries can be flogged in 3 mos if not cycled or charged correctly. Check the details on the warranty, Many times they are pro-rated for XX months towards a new set.
Also- What size are these? They should be Gp31 cart rated.
All checked with multimeter reading 13.8-13.11.
Depending on WHEN you took these readings, they may be giving you false confidence. Fresh off charge is going to be higher than allowed to “cool down/rested” for 30 mins or so. You’d be surprised how fast the surface charge can be knocked off by a single Brake Stand in place or run down to the corner mailbox and back.
Balancing - Try power cycling the charger (when/if it ever finishes a cycle). It would be nice to get these voltages tighter. If not, boost the low ones with a separate 12v charger to bring them up. Goal is to get them within 0.1v of each other. This is called balancing. Keep track of all of these voltages and monitor them as they all get to the bottom of the cycle. A perfectly aged pack, Voltage differences between each battery should all go up/down and stay the same. The first one that reaches 12.0v means that the pack is depleted and in need of a charge.
You should also check your charger to make sure it is set to the correct battery profile. (This might be why your charger is never going to green light)
Tachometer is now flashing when I plug in the car
Not sure what you mean by this. Verify what part of the display is flashing?
Normally, when you plug in the car to charge, the Battery SOC/bar graph lights up, does a little stair-step animation/dance as the battery is charging, and a yellow plug icon appears (showing the charger interlock* is active). The large Speed indicator changes to the estimated % of charge during this charge cycle. Some Dash displays may go dark after a preset time, showing only the yellow plug.
*When interlock is active, the car will not drive.
If your dash was flashing, perhaps you triggered the turtle? This happens when the pack dips to a low voltage during the drive, and car switches to low power mode so it can try and get you home. Turtle is reset by a charge cycle.
Be careful about messing about in that “secret menu”. It is hidden/not well documented for a reason. There are only certain conditions where one should be in there poking about and adjusting settings. Usually, if the Dash SOC display is not reading correctly, it means something is not right with the battery pack. Simply calibrating the battery bars is not going to fix it.