Battery Equivalents and Replacements

Mighty Max ML5-6S 6V 5Ah Sealed Lead Acid Battery

Mighty Max ML5-6S is a rechargeable 6V lantern battery with spring terminals based on lead-acid chemistry.

Mighty Max ML5-6S is a sealed battery that can be mounted in any position, very resistant to shocks and vibrations, with a low self-discharge rate and high discharge rate, and good recovery after deep discharges.

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Mighty Max ML5-6S Features and Specifications

Mighty Max ML5-6S features physical dimensions of (L x W x H) 2.63 x 2.63 x 4.50 (5.29 with terminals) inches (6.68 x 6.68 x 11.43/13.43 cm) and weighs ~1.88 pounds (~0.85 kg) - it is heavier than the typical non-rechargeable 6V lantern battery that weighs ~1 pound ±1 ounce (~0.45 kg ±0.029 kg).

Mighty Max ML5-6S features a nominal voltage of 6 volts and a nominal 20h capacity of 5 Ah - like all similar sealed lead-acid batteries, its capacity depends on the battery age, temperature, discharge current, and similar.

The internal resistance of the fully charged Mighty Max ML5-6S battery @25°C is 15.8 mΩ Mighty Max ML5-6S is not intended for cranking/starting applications - it is intended for deep cycle applications where discharge currents are not stronger than 2-3C (10-15 Amps max).

The following charts list the constant current and constant power discharge characteristics of the Mighty Max ML5-6S battery, measured at 25°C.

Constant current discharge chart:

Battery End Voltage Cell End Voltage 5 min 10 min 15 min 30 min 1h 2h 3h 5h 8h 10h 20h
4.80 1.6 17.95 11.45 9.22 5.58 3.10 1.72 1.23 0.84 0.54 0.46 0.24
5.10 1.7 17.07 10.86 8.85 5.35 2.98 1.70 1.21 0.83 0.54 0.45 0.24
5.25 1.75 16.54 10.52 8.62 5.22 2.91 1.68 1.20 0.82 0.52 0.44 0.24
5.40 1.8 16.01 10.19 8.40 5.08 2.83 1.66 1.18 0.81 0.53 0.43 0.23

Constant power discharge chart:

Battery End Voltage Cell End Voltage 5 min 10 min 15 min 30 min 1h 2h 3h 5h 8h 10h 20h
4.80 1.6 99.91 64.51 52.38 31.96 17.99 10.06 7.32 5.04 3.25 2.74 1.46
5.10 1.7 95.06 61.11 50.44 30.70 17.27 9.93 7.23 5.00 3.22 2.68 1.46
5.25 1.75 92.15 59.17 49.18 29.92 16.83 9.82 7.13 4.92 3.21 2.62 1.43
5.40 1.8 89.24 57.23 47.92 29.15 16.39 9.71 7.03 4.85 3.19 2.56 1.04

Constant current discharge chart:

End Voltage
Battery / Cell
5 min 15 min 30 min 1h 3h 5h 10h 20h
4.80/1.6 17.95 9.22 5.58 3.10 1.23 0.84 0.46 0.24
5.10/1.7 17.07 8.85 5.35 2.98 1.21 0.83 0.45 0.24
5.25/1.75 16.54 8.62 5.22 2.91 1.20 0.82 0.44 0.24
5.40/1.8 16.01 8.40 5.08 2.83 1.18 0.81 0.43 0.23

Constant power discharge chart:

End Voltage
Battery / Cell
5 min 15 min 30 min 1h 3h 5h 10h 20h
4.80/1.6 99.91 52.38 31.96 17.99 7.32 5.04 2.74 1.46
5.10/1.7 95.06 50.44 30.70 17.27 7.23 5.00 2.68 1.46
5.25/1.75 92.15 49.18 29.92 16.83 7.13 4.92 2.62 1.43
5.40/1.8 89.24 47.92 29.15 16.39 7.03 4.85 2.56 1.04

Thanks to such performances, Mighty Max ML5-6S 6V 5Ah battery is suitable for applications being powered by non-rechargeable 6V lantern batteries - for camping, for hunting/fishing, for off-the-grid applications, in emergencies, for medical/security systems, and similar.

If the Mighty Max ML5-6S battery is not connected to the smart battery charger/maintainer, it will self-discharge over time - it is a good practice to fully recharge the lead-acid batteries when they drop down to 20% DoD (or 80% SoC).

Self-discharge rate depends on the temperature, and the Mighty Max ML5-6S reaches 20% DoD/80% SoC after:

- 0°C: 16-17 months,

- 10°C ~9 months,

- 25°C: 6-7 months,

- 30°C: ~4 months,

- 40°C; ~2 months.

So, if You plan on storing the Mighty Max ML5-6S battery, be sure to store it in a cool area, preferably connected to a smart 6V lead-acid battery/maintainer.

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How to Charge Mighty Max ML5-6S Battery?

Depending on its use, Mighty Max ML5-6S battery should be charged (@25°C):

- Cycle use: 7.25-7.5 volts, initial charging current less than 1.5A,

- Float use: 6.8-6.9 volts.

Again, this is a 6V battery, not a 12V battery. Personally, a good 0.5-1.0 Amps 6V smart lead-acid battery can recharge the Mighty Max ML5-6S battery quickly and keep it charged over a longer period of time.


mighty max ml5 6s mLong Story Short: If You are looking for a rechargeable 6V lead-acid lantern battery, consider the Mighty Max ML5-6S battery.

It can withstand a large number of charging/discharging cycles, especially if it is not discharged below 50%, it also recovers well from deep discharges, it can provide relatively strong currents, it has a low self-discharge rate, etc.

For more reviews and recommendations, feel free to check the Mighty Max ML5-6S 6V 5Ah Battery Amazon link (link opens in the new window).

Amazon Search:

- 6V Lantern Battery

- 6V Rechargeable Lantern Battery

- 6V 500mA Lead Acid Battery Charger

- 6V 1A Lead Acid Battery Charger

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