Portable propane-fueled battery charger

1. A battery charger comprising:

a housing that supports a battery connector configured to receive and support a battery pack, the battery connector including

electrical terminals configured to engage electrical terminals of the battery pack, and

a mechanical coupling configured to engage a mechanical interface of the battery pack;

a carrying handle coupled to the housing;

a propane fuel line;

an engine including an output shaft, the engine configured to receive propane via the propane fuel line and rotationally drive the output shaft;

an alternator including a rotor and stator coils, wherein the output shaft is mechanically coupled to the rotor, the rotor is rotationally driven by the output shaft, and an electrical current is induced in the stator coils by rotation of the rotor;

an electrical circuit that receives the electrical current and is configured to

determine when the battery pack is coupled to the battery connector, and

charge the battery pack based on the determination;

a first plate that supports the engine and the alternator, wherein the engine is a propane engine configured to drive the alternator that provides the electrical current to the electrical circuit;

a second plate that supports the electrical circuit and the first plate and that is in a stacked relationship with the first plate such that the second plate is positioned below the first plate; and

the housing further including a lower housing portion and an upper housing portion, wherein

the upper housing portion houses the alternator, and

the lower housing portion houses the second plate and includes the battery connector coupled to the electrical circuit to receive charged current.

2. The battery charger of claim 1 , wherein the battery pack is a first battery pack and the electrical circuit is configured to simultaneously charge a second battery pack.

3. The battery charger of claim 2 , further comprising a first set of battery connectors including the battery connector and a second set of battery connectors, wherein the electrical circuit is configured to simultaneously charge the first battery pack coupled to one of the first set of battery connectors and the second battery pack coupled to one of the second set of battery connectors.

4. The battery charger of claim 3 , wherein the electrical circuit is configured to charge a third battery pack coupled to the first set of battery connectors when the electrical circuit determines that the first battery pack is fully charged.

5. The battery charger of claim 3 , further comprising

a first sequence switch, wherein the first sequence switch is configured to selectively control the electrical circuit to provide a first charging current through one of the first set of battery connectors; and

a second sequence switch, wherein the second sequence switch is configured to selectively control the electrical circuit to provide a second charging current through one of the second set of battery connectors.

6. The battery charger of claim 1 , wherein the electrical circuit is configured to

determine a state of charge of each of a plurality of battery packs coupled to the battery charger;

select, based on the state of charge, a selected battery pack from the plurality of battery packs; and

electrically connect the selected battery pack to a motor drive circuit, wherein the motor drive circuit drives the alternator to start the engine.

7. The battery charger of claim 1 , wherein the electrical circuit adjusts a speed of the engine based on a charging current being provided to the battery pack.

8. The battery charger of claim 1 , further comprising a tilt switch that indicates when the battery charger is tilted in excess of a predetermined tilt threshold, wherein the electrical circuit shuts down the engine when the tilt switch indicates that the battery charger is tilted in excess of the predetermined tilt threshold.

9. The battery charger of claim 1 , further comprising:

a toggle switch; and

an input unit;

wherein the engine is configured to start when the toggle switch is in a first position and

the input unit is activated.

10. The battery charger of claim 1 , wherein the carrying handle is coupled to the housing via a connection to the second plate and extends out of through-holes in the housing, and wherein the second plate is substantially parallel with the first plate and an upper surface of the first plate is partially exposed through a cut-out of the upper housing portion.

11. The battery charger of claim 1 , further comprising a second battery connector coupled to the electrical circuit, wherein

the housing encloses the electrical circuit and includes a first side face and a second side face,

the electrical circuit is positioned between the first side face and the second side face,

the battery connector is positioned on the first side face of the housing, and

the second battery connector is positioned on the second side face of the housing.

12. A method of charging a battery pack, the method comprising:

receiving and supporting, by a battery connector of a housing, the battery pack, the battery connector including electrical terminals that engage electrical terminals of the battery pack, and a mechanical coupling that engages a mechanical interface of the battery pack;

receiving, by an engine, propane via a propane fuel line;

starting the engine;

rotationally driving an output shaft of the engine, the output shaft being mechanically coupled to a rotor of an alternator;

inducing an electrical current in stator coils of the alternator by the rotational driving of the output shaft;

providing the electrical current to an electrical circuit in the housing;

determining, with the electrical circuit, that the battery pack is coupled to the battery connector;

charging, with the electrical circuit, the battery pack;

supporting, by a first plate, the engine and the alternator;

supporting, by a second plate, the electrical circuit and the first plate, wherein the second plate is in a stacked relationship with the first plate such that the second plate is positioned below the first plate,

housing, by an upper housing portion of the housing, the alternator; and

housing, by a lower housing portion of the housing, the second plate, wherein the lower housing portion further includes the battery connector coupled to the electrical circuit to receive charged current.

13. The method as claimed in claim 12 , wherein the battery pack is a first battery pack, the method further comprising charging, with the electrical circuit, a second battery pack.

14. The method as claimed in claim 13 , wherein charging, with the electrical circuit, the first battery pack includes charging, with the electrical circuit, the first battery pack when the first battery pack is coupled to a first set of battery connectors, and wherein charging, with the electrical circuit, the second battery pack includes charging, with the electrical circuit, the second battery pack when the second battery pack is coupled to a second set of battery connectors.

15. The method as claimed in claim 14 , further comprising charging, with the electrical circuit, a third battery pack coupled to the first set of battery connectors when the electrical circuit determines that the first battery pack is fully charged.

16. The method as claimed in claim 14 , further comprising:

selectively controlling, with a first sequence switch, the electrical circuit to provide a first charging current through one of the first set of battery connectors; and

selectively controlling, with a second sequence switch, the electrical circuit to provide a second charging current through one of the second set of battery connectors.

17. The method as claimed in claim 12 , wherein starting the engine further comprises:

electrically connecting, with the electrical circuit, the battery pack to a motor drive circuit; and

driving, with the motor drive circuit, the alternator to start the engine.

18. The method as claimed in claim 12 , further comprising adjusting a speed of the engine based on a charging current being provided to the battery pack.

19. The method as claimed in claim 12 , further comprising:

determining, with a tilt switch, when a battery charger is tilted in excess of a predetermined tilt threshold; and

shutting down the engine, with the electrical circuit, when the tilt switch indicates that the battery charger is tilted in excess of the predetermined tilt threshold.

20. The method as claimed in claim 12 , wherein starting the engine includes

receiving, from a toggle switch, a toggle switch signal indicative of a position of the toggle switch;

receiving, from an input unit, a start engine signal; and

when the toggle switch signal indicates that the toggle switch is in a first position, starting the engine.