You equalize deep cycle batteries by charging with a higher than normal voltage for a short period of time. Consult the manufacturer for details.
a deep cycle battery i a battery that you can charge and discharge over and over without harming the cells in the battery unlike a normal battery . deep cycle batteries are normally used in boats
You can run a deep cycle battery completely dead without damaging the battery. They are designed to be run down.
According to the document linked to, that battery will run down to 1.8V, which I believe qualifies as deep cycle.
When the battery looses it charge. It is designed to be run completely down before recharging.
You don't. This would put a strain on the alternator and may burn a diode out. Charge it with a deep cycle battery charger.
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