Lead acid batteries come in several different forms and are quite troublefree. OK, so they don’t like to be overcharged, but the charger unit can take care of that. What they really don’t like is when their cell voltage drops so low that the battery enters a deep-discharge state. To avoid this situation we need the help of some electronics; that’s where the protector comes in.
 
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Lead-acid batteries are not only used in cars and other types of vehicles; they also are a good choice for powering equipment in remote locations where plugging an adapter into a wall outlet is not an option. In these situations it’s important to arrange some protection for the battery to ensure it doesn’t get irreversibly damaged by becoming completely discharged. Besides designing some method of battery charging it’s also necessary to implement some protective circuit to automatically disconnect the load when the battery voltage approaches its deep discharge level. That’s where the protector circuit comes in.