I get a lot of calls about battery chargers that are not working after the owner has been out of town for a while. Here is the solution to charging your batteries up after they have dropped too low for the charger to recognize them.

Most of the time people assume the Charger has stopped working, but that is likely not the case. It is more common that the batteries have dropped too low in voltage and the charger needs a certain voltage to turn on.

A lot of modern chargers are too "smart" to do this. They will tell you that your batteries are bad, or give you a fault light of some sort and wont charge the batteries. You may have better luck with a simple adjustable charger like this one here to charge and de-sulfate your batteries.
https://amzn.to/3SjyJZ9