To charge two 12V LiFePO4 batteries as an assembled 24V bank, use that method only when the instructions for the specific batteries permit it and the charger meets their requirements. If they do not permit it, or you cannot establish that the charger suits the bank, use a documented separate-charging method only if the battery instructions allow it; some require disconnecting the series link while charging.
Check the batteries and charger
Check each battery’s instructions for permission to connect in series and for its charging limits. Check the charger’s output voltage, current, and LiFePO4 profile against those limits, and confirm that the battery instructions permit the charger arrangement you plan to use. A “24V” label alone does not establish that a charger is suitable.
If the instructions permit charging the assembled series bank, use a charger arrangement that meets the requirements for that bank. If they permit a multi-bank charger that charges each battery individually, use that arrangement as specified. If the documents do not establish either method or the charger requirements, the correct setup cannot be determined from the voltage label alone; do not guess at settings or wiring.
Follow the instructions for the charging stage
Initial setup: Requirements before first connecting batteries in series can differ from routine charging. One documented battery system requires each battery intended for a series bank to be charged individually before the bank is assembled. That procedure applies to the system it covers, not automatically to other batteries.
Separate charging: A particular battery family permits charging its batteries individually only when the series connection is disconnected during charging. Apply that condition only if the instructions for your batteries specify it, and use a charger that meets each battery’s individual charging requirements.
Routine charging as a bank: When the instructions for your batteries permit charging them in series as one bank, follow those instructions and the charger’s specified setup. Do not transfer a method or setting from another battery system to your own.
FAQs
Can I charge two 12V LiFePO4 batteries while they are connected in series for a 24V trolling motor?
Yes, but only if the instructions for both batteries permit charging them as an assembled series bank and the charger meets the bank’s requirements.
Do both batteries need to be charged individually before their first series connection?
Follow the battery-specific instructions: one documented system requires each battery intended for a series bank to be charged individually before the bank is assembled, but that procedure does not automatically apply to other batteries.
