Battery under voltage lock out and reverse polarity charger protection circuitry

A battery system comprising:

• a battery having one or more battery cells for generating a battery voltage;
• an electrical load configured to receive the battery voltage to power the electrical load;
• and
• a battery protection circuit comprising:
• a battery input configured to receive the battery voltage;
• a reference voltage input configured to receive a low battery reference voltage;
• a comparator for comparing a first signal indicative of the battery voltage with a second signal indicative of the reference voltage and generating at a comparator output a comparator signal indicative of a low battery voltage;
• a feedback resistor coupling the comparator output of the comparator to the reference voltage input to create hysteresis;
• and
• a battery disconnect circuit to disconnect the battery voltage applied to the electrical load.

A reverse polarity battery charger protection circuit comprising:

• a battery charger input configured to receive a charging voltage from a battery charger;
• a battery connector configured to couple with first and second polarity outputs of a battery;
• a relay coupled in series with the battery charger input;
• a diode configured to be coupled in parallel with the battery charger;
• and
• a transistor coupled to the relay and the diode, wherein the diode and relay allow charging of the battery with the battery charger and prevent charging of the battery with the battery charger when a reverse polarity connection of the battery to the battery connector is detected.

A battery charging system comprising:

• a battery having one or more battery cells for generating a battery voltage;
• a battery charger generating a charging voltage to charge the battery;
• and
• a reverse polarity battery charging protection circuit coupling the battery charger to the battery, the reverse polarity battery charging protection circuit comprising:
• a battery charger input configured to receive a charging voltage from the battery charger;
• a battery connector configured to couple with first and second polarity outputs of the battery;
• a relay coupled in series with the battery charger input;
• a diode coupled in parallel with the battery charger;
• and
• a transistor coupled to the relay and the diode, wherein the diode and relay allow charging of the battery with the battery charger and prevent charging of the battery with the battery charger when a reverse polarity connection of the battery to the battery connector is detected.