Inventist Alkacharger Alkaline Battery Charger Alkaline batteries can be recharged 3-5 times before they should be discarded. After that the battery may not be able to be recharged, even with the AlkaCharger. For best results, recharge your batteries in the AlkaCharger for a minimum of 3 days. Heavily discharged batteries need to be charged for about 5 days. Completely discharged batteries cannot be charged again, even with the AlkaCharger. Insert batteries positive side (+) down into the appropriate slots, failure to do so may damage the unit and void your warranty.