noeifevo 58 4v 8a lifepo4 battery charger for 16s 48v 51 2v lifepo4 lithium battery led display aluminum caseDue to some batteries with M25 charging ports that have integrated charging protocols, our charger cannot support batteries with built in charging protocols. Please confirm with the battery supplier before purchase whether the battery has an integrated charging protocol. For M25 (2+1+5) and M25 (2+4), the standard polarity is 1+ for positive and 2 for negative. If you require a different polarity, please let us know. Contact: You can reach us online