Deep Cycle Marine Battery

ExpertPower EP1250 12V 50Ah LiFePO4 Deep Cycle Battery

ExpertPower EP1250 is a rechargeable deep cycle ultralight battery based on the Lithium Iron Phosphate (LiFePO4) chemistry, with four cells connected in series internally, and controlled by an advanced Battery Management System (BMS).

ExpertPower EP1250 battery is a very versatile battery often used in off-the-grid applications, as a mid-range marine battery, as float/standby battery, and for applications where the battery cycles a lot.

Published: August 5, 2021.

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ExpertPower EP1250 Battery Features and Specifications

ExpertPower EP1250 battery is based on the Lithium Iron Phosphate (LiFePO4) chemistry and features physical dimensions of 7.7 x 6.5 x 6.6 inches (~19.6 x 16.5 x 16.8 cm) while it weighs only 13 pounds (5.9 kg).

According to the manufacturer, ExpertPower EP1250 battery belongs to the BCI Battery U1 Group, but it is too large since group U1 batteries feature physical dimensions of 7.75 x 5.1875 x 7.3125 inches (~19.7 x 13.2 x 18.7 cm) - ExpertPower EP1250 is too wide by ~1.3 inches (~3.2 cm) to be considered a true "U1 battery".

The nominal capacity of the ExpertPower EP1250 battery is 50Ah (@25°C, 0.2C) with a nominal voltage of 12.8 volts.

Charging voltage should be kept around 14.4V - ExpertPower EP1250 is a lithium battery and as such, it is highly recommended to be charged using a lithium battery charger.

The maximum continuous discharge current is 50 Amps, with the maximum surge current of 100 Amps for up to 10 seconds.

The maximum continuous charging current is 25 Amps, allowing the user to recharge the battery relatively quickly.

ExpertPower EP1250 features F11/M6 battery terminals, ensuring a reliable connection between the battery and cabling.

Since it is a lithium battery, ExpertPower EP1250 comes with the built-in Battery Management System which protects the battery from unwanted events like overcharge, deep discharge, overcurrent, overheating, and short circuit.

Also, the built-in BMS prevents the charging of the battery below 23°F (-5°C).

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As a deep cycle battery, ExpertPower EP1250 supports a large number of charging/discharging cycles.

For example, at 25°C 0.2C, the battery can withstand 2500 cycles down to 100% DOD, 3600 cycles down to 80% DOD, 7000 cycles down to 50% DOD, which is ~10x more than common lead-acid batteries.

How to Charge ExpertPower EP1250 Battery

As a lithium deep cycle battery, ExpertPower EP1250 should be charged using a dedicated lithium battery charger or with an advanced AGM battery charger that features a lithium battery charging mode.

With a maximum continuous charging current of 25 Amps, ExpertPower recommends their ExpertPower EPC125 (12V 5A) and ExpertPower EPC1220 (12V 20A) (Amazon links, links open in the new windows) lithium battery chargers.

expertpower epc1220

Of course, other lithium battery chargers may be used as well - for example, 10-12 Amps battery charger can recharge fully discharged ExpertPower EP1250 battery in 5-6 hours easily.

ExpertPower EP1250 battery can be also charged using solar panels combined with a lithium battery charge controller - for example, 200W solar panels with 50% efficiency (weather, orientation, season, etc.) can recharge the fully discharged ExpertPower EP1250 battery in 7-8 hours.

If the battery has to be recharged faster, feel free to use more solar panels, just remember that the maximum continuous charging current is 25 Amps.

ExpertPower EP1250 as a Kayak Trolling Battery

newport vessels kayak 55lbs 24inch mExpertPower EP1250 battery is often used as kayak battery for powering trolling motors, fish finders, navigation lights, radio, for charging other devices, and similar.

Considering its weight (13 pounds, 5.9 kg), the ExpertPower EP1250 battery stores a much larger amount of energy (~640 Wh) than the lead-acid batteries of similar weight.

Since most kayak trolling motors draw up to 30 Amps, ExpertPower EP1250 battery can power such unit for almost 95-100 minutes continuously. And if such motor is not used at full throttle, its runtime using this battery can be much longer.

The difference in weight of the ExpertPower EP1250 battery and some general-purpose deep-cycle lead-acid batteries, allow the kayaker to carry an additional solar panel with a charge controller, a smaller power station, or some other type of required gear.

ExpertPower EP1250 as an Off-the-Grid/Inverter Battery

bestek 500w power inverter mExpertPower EP1250 battery is commonly used in off-the-grid applications where the battery is recharged using solar panels, wind turbines, small power generators, or similar devices and then used to power various devices, very often using a power inverter.

With its nominal voltage of 12.8 volts, the maximum continuous discharge current of 50 Amps, and a maximum 10 second current of 100 Amps, the ExpertPower EP1250 battery is suitable for powering 500 Watts power inverters with maximum surge power of 1000 Watts.

For example, if the efficiency of the power inverter is 85% and the unit powers 300W load, that means that the battery is providing ~353W (~27.6 Amps @12.8V).

With such load, ExpertPower EP1250 battery can power such inverter up to 1h and 40-45 minutes, depending on the battery condition, initial charge, and temperature.


expertpower ep1250 mLong Story Short: ExpertPower EP1250 battery is a lightweight and versatile deep-cycle battery, suitable for various applications except as the starting/cranking battery.

The battery is able to withstand a large number of charging/discharging cycles, it is energy very efficient with the output voltage of 12.8 volts most of the discharge cycle, it can be recharged quickly, etc.

For all those reasons, the ExpertPower EP1250 battery is a very popular battery in its class, despite being more expensive than similar lead-acid batteries. But, in the long run, it saves money, time, effort ...

For more reviews and recommendations, feel free to check the ExpertPower EP1250 12V 50Ah LiFePO4 Deep Cycle Battery Amazon link (link opens in the new window).



Amazon Search:

- 50Ah Lithium Battery

- Trolling Lithium Battery

- 200W Solar Panel Kit

Note: Amazon links open in the new windows, feel free to check them for the most up-to-date offers and prices.

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