To fully charge a 24V LiFePO4 battery, you need a charger that provides a voltage between 28.4V and 29.2V. Using a charger with a lower voltage will still charge the battery, but it will not achieve 100% capacity.

Trickle charging is unsuitable for lithium batteries. Using a trickle charger not specifically designed for LiFePO4 batteries can result in overcharging or damage because lithium batteries have different charging requirements than traditional lead-acid batteries.

Yes, you can charge a battery to less than 100%. Doing so, along with avoiding complete discharge, enhances cell longevity. Operating lithium batteries within a 20%-80% state of charge (SoC) range significantly extends their lifespan. For instance, Redodo deep cycle lithium batteries can endure over 4,000 deep cycles at 100% Depth of Discharge (DoD), over 6,000 cycles at 80% DoD, and more than 15,000 cycles at 60% DoD.

Leaving a lithium-ion battery on the charger overnight is generally safe if you use a charger like the Redodo lithium battery charger, which is designed to stop charging once the battery reaches full capacity. Most modern lithium-ion chargers include this feature to prevent overcharging.

It's crucial to ensure your charger provides the appropriate current and voltage for the LiFePO4 lithium battery you are charging. For instance, using a 24V charger on a 12V LiFePO4 battery is not advisable. Always use a charger specifically designed for your battery's chemistry. If you use a standard lead-acid charger for a LiFePO4 battery, make sure it doesn't have features like desulfation or dead battery mode, as these can damage the LiFePO4 battery.