Fish till dark. Lift 100 lb less.

A lithium iron phosphate (LiFePO4) battery matched to your motor's voltage. For a 24 V motor (70 to 100 lb thrust), the Redodo 24V 50Ah ($299.99 when we checked) replaces two lead-acid batteries at 21.14 lb in total; for long days or cold mornings, the Redodo 24V 125Ah Self-Heating ($629.99). For a 12 V motor, the Redodo 12V 100Ah ($242.89) or the 12V 120Ah Group 24 ($329.99).

For most anglers, yes. A 12V 100Ah lithium gives 1,280 Wh you can use, about double a 100 Ah AGM you should only run to half, at 22.05 lb against 63.9 lb. Counting cycles, fishing 60 days a year it costs about $24 a year against $50 for the two AGMs it replaces. It also holds full power to the end of the day instead of slowing as it drains.

It depends on thrust, speed, wind and how much you use features like spot-lock. Redodo's own figures: its 12V 120Ah runs a 55 lb thrust motor up to 19.2 hours at 1/8 power, and its 24V 125Ah up to 18 hours at a 7 A trolling draw. At full throttle any battery lasts only a few hours.

Yes, by wiring two identical 12 V lithium batteries in series, or buy a single 24 V battery, which is simpler, lighter and keeps the cells balanced. Never mix lithium and lead-acid, or old and new batteries, in one string.

Yes: use a charger with a LiFePO4 (lithium) setting at the right voltage, such as 14.4 V for a 12 V battery or 28.8 V for 24 V (Redodo's figures). Many on-board marine chargers have a lithium mode; older lead-acid-only chargers can undercharge it, and desulfation modes must be off.