ExpertPower EXP12330 AGM 12V 33 Ah Deep Cycle Battery

ExpertPower EXP12330 Absorbent Glass Mat (AGM) 12V 33 Ah battery is a spill-proof Sealed Lead Acid (SLA), a general-purpose battery. It belongs to U1 BCI Battery Group and intended for deep cycle and float/standby applications like security systems, medical system, UPS battery, wheelchair battery, for electric vehicles, marine applications, and similar.

ExpertPower EXP12330 AGM battery is a very popular, well-balanced battery that comes at affordable price.

Published: June 19, 2020.

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ExpertPower EXP12330 AGM Features and Specifications

ExpertPower EXP12330 physical dimensions are (L x W x H) 7.72 x 5.16 x 6.34 inches (196 x 131 x 161 mm) and it weighs 23.81 pounds (10.80 kg).

 Battery features two sub-models, differing only in terminals:

- B2 terminal (photo above) with M6 bolt (included),

- T3 terminal which uses M5 bolt&nut to connect the terminal with the battery cables.

ExpertPower EXP12330 is labeled as 12V 33 Ah battery, but its nominal 20h capacity is almost 35 Ah - 34.4 Ah. Like all other SLA AGM batteries, ExpertPower EXP12330 battery's capacity drops with the increase in discharge current:

- 20h rate: 34.4 Ah capacity - 1.72 Amps down to 10.8 volts,

- 10h rate: 33.0 Ah capacity - 3.30 Amps down to 10.8 volts,

- 5h rate: 31.5 Ah capacity - 6.30 Amps down to 10.5 volts,

- 1h rate: 21.09 Ah capacity - 21.09 Amps down to 10.5 volts,

- 30 min rate: 18.79 Ah capacity - 37.58 Amps down to 10.2 volts.

A one can see, ExpetPower EXP12330 AGM should not be discharged below 10.02 volts, not even when being discharged quickly.

Also, battery's charging voltages depend on the intended battery use:

- float use: 13.5 - 13.8 volts (-20 mV/°C),

- cycle use: 14.40 - 15.00 volts (-30 mV/°C).

 It is highly recommended to charge ExpertPower EXP12330 and similar AGM/Gel-cell batteries with intelligent battery chargers that test the battery's condition, measure ambient temperature, and adjust charging voltage.

The maximum recommended charging current is 9.90 Amps, ensuring that the 50% discharged battery can be fully recharged in under 2 hours.

Personally, ~10 Amps charging current is a little bit too much for such and similar batteries, and in order to prolong the battery operating life, the maximum charging current should be kept around 5-6 Amps. IMHO, of course.

ExpertPower EXP12330 AGM battery features low self-discharge rate which strongly depends on the storage temperature (like in all other similar AGM SLA batteries), for example:

- at 104°F (40°C): battery charge drops down to 80% in ~40 days, down to 70% in 2 months, and down to 60% in slightly more than 3 months,

- at 86°F (30°C): battery charge drops down to 80% in slightly less than 2 months, down to 70% in 3.5 months, and down to 60% in 6 months,

- at 77°F (25°C): battery charge drops down to 80% in 3 months, down 70% in slightly more than 6 months, and down 60% in 10 months,

- at 41°F (5°C): battery charge drops down to 80% in ~10 months, and down to 70% in ~20 months.

As one can see, if you have to store AGM battery (or batteries) for a longer time, the best procedure is to fully charge the battery using intelligent AGM battery charger and leave it connected to the battery (AGM battery charger will eventually enter the maintenance charging mode) or attach a battery maintainer to the battery, and keep the battery and the charge/maintainer in a dry, cool area, but above the freezing temperatures.

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ExpertPower EXP12330 AGM SLA battery is intended for both float and cycle applications.

When the battery is being kept charged by a smart battery charger, one may expect a float life of up to 5-6 years.

When the battery is being used in cycle applications, the number of charging/discharging cycles depends on the depth of the battery discharges:

- 100% DoD: ~190 charging/discharging cycles with the capacity loss down to 80% of nominal capacity, ~230 cycles charging/discharging cycles with the capacity loss down to 60% of nominal capacity,

- 50% DoD: ~370 charging/discharging cycles with the capacity loss down to 80% of nominal capacity, ~450 cycles charging/discharging cycles with the capacity loss down to 60% of nominal capacity,

- 30% DoD: ~850 charging/discharging cycles with the capacity loss down to 80% of nominal capacity, ~1130 cycles charging/discharging cycles with the capacity loss down to 60% of nominal capacity.

If You want to prolong the operating life of ExpertPower EXP12330 battery, try not to discharge it below 50%, although battery tolerates well much deeper discharges.

ExpertPower EXP12330 AGM Battery Discharge Charts

Constant current discharge features for the ExpertPower EXP12330 battery are given in the following chart - values are given in Amps, measured at 77°F/25°C:

Cell End Voltage Battery End Voltage 5 min 10 min 15 min 30 min 1 hour 2 hours 3 hours 4 hours 5 hours 6 hours 10 hours 20 hours
1.67 V 10.02 V 143.39 81.12 63.76 39.68 21.69 12.54 9.63 7.91 6.48 5.28 3.46 1.80
1.70 V 10.2 V 130.25 74.77 58.77 37.58 21.46 12.41 9.53 7.82 6.41 5.23 3.43 1.78
1.75 V 10.5 V 119.49 70.54 55.44 36.14 21.09 12.19 9.36 7.69 6.30 5.14 3.37 1.75
1.80 V 10.8 V 117.29 69.24 54.42 35.47 20.70 11.97 9.19 7.55 6.18 5.04 3.30 1.72
1.85 V 11.1 V 115.09 67.94 53.40 34.81 20.32 11.74 9.02 7.41 6.07 4.95 3.24 1.69

Constant power discharge features for the ExpertPower EXP12330 battery are given in the following chart - values are given in watts, measured at 77°F/25°C:

Cell End Voltage Battery End Voltage 5 min 10 min 15 min 30 min 1 hour 2 hours 3 hours 4 hours 5 hours 6 hours 10 hours 20 hours
1.67 V 10.02 V 1677.66 949.08 745.92 464.28 253.8 146.7 112.68 92.52 75.84 61.80 40.5 21.06
1.70 V 10.2 V 1523.88 874.8 687.54 439.68 251.1 145.14 111.48 91.56 75.00 61.14 40.08 20.82
1.75 V 10.5 V 1398.06 825.3 648.66 422.82 246.78 142.62 109.56 89.94 73.68 60.12 39.36 20.46
1.80 V 10.8 V 1372.32 810.12 636.72 415.02 242.22 140.04 107.52 88.32 72.36 58.98 38.64 20.10
1.85 V 11.1 V 1346.58 794.94 624.78 407.28 237.66 137.40 105.48 86.64 70.98 57.90 37.92 19.74

When the ExpertPower EXP12330 is fully charged, at 77°F (25°C), it features internal resistance of 8.5 mΩ - ExpertPower EXP12330 is not the best choice for starting applications that require few hundred Amps, but that is not what this battery is intended for.

ExpertPower EXP12330 AGM SLA Battery as Trolling Motor Battery

ExpertPower EXP12330 may be used as an excellent trolling motor battery for kayak trolling motors that feature maximum thrust levels in 18-30 pounds range and have a maximum current draw in 15-30 Amps range.

ExpertPower EXP12330 weighs 23.8 pounds (10.8 kg) and is able to provide, for example, 20 Amps for one hour easily and 30 Amps for 30 minutes with some energy even left for safety.

If You need a stronger/larger AGM battery, that AGM battery will also be heavier. However, lithium trolling motor batteries are much lighter, although they also cost more, at least initially.

But, 100Ah lithium batteries are able to provide 20 Amps for almost 5 hours and they weigh ~30-33 pounds (13.6-15 kg), just slightly more than ExpertPower EXP12330.

But, lithium batteries also cost more, at least initially.


expertpower exp12330 mLong Story Short: ExpertPower EXP12330 AGM SLA battery is an affordable and reliable U1 general purpose battery, very liked by its users.

ExpertPower EXP12330 should NOT be used as cranking battery and should NOT be discharged below 10 volts - not much time is gained when the battery is discharged below 10 volts, except that the battery is being very stressed internally.

But, for both float/standby and cycle use where the discharge currents are kept below 30 Amps, this U1 battery is a suitable power source.

For more reviews and recommendations, feel free to check ExpertPower EXP12330 12v 33 Ah AGM Battery Amazon link (link opens in the new window).