ExpertPower EXP12120 12 Volt 12 Ah AGM SLA Battery

ExpertPower EXP12120 12 Volt 12 Ah AGM SLA Battery is a very popular AGM battery. It can operate in any position, it has very good vibration resistance, it is an almost maintenance-free battery, tolerates deep discharges well, have low-self discharge rate, acceptable price, long float service life etc.

Because of this, the ExpertPower EXP12120 battery is commonly used in both standby applications (UPS battery, for example) and for cyclic use (fish finder battery, for example).

Updated: September 15, 2022.

ExpertPower EXP12120 AGM SLA Battery - Features and Specifications

As its name says, ExpertPower EXP12120 12 Volt 12 Ah AGM SLA Battery is an AGM SLA battery with a nominal voltage of 12 volts and 12 Ah capacity when discharged for 20 hours.

Its physical dimensions are 3.9x5.94x3.86 inches (~10 x 15 x 9.8 cm), weighing around 7.61 pounds (~3.45 kg).

The battery is made using high-impact resistant, non-conductive ABS plastic, making it very resistant to shocks, vibration, chemicals, and heat.

Nonetheless, use your battery, but don't abuse it!

The acid is absorbed and immobilized between lead plates by a very fine fiberglass mat - hence the name AGM. To prevent issues with gassing, the battery is also valve regulated.

All these features mean that the battery can operate in any position, it is spill-proof and almost maintenance-free. We say almost, but occasionally it is recommended to check connections between the battery's F2 style terminals and wires connected with the battery.

Typical applications of EXP12120 battery include alarm systems, communication equipment, security systems, medical and control equipment, UPS, power tools, and of course, a good and reliable fish finder battery.

ExpertPower EXP12120 AGM SLA Battery Capacity

The capacity of lead-acid batteries mainly depends on temperature and discharging current. Other factors also influence capacity, but not as much.

The nominal capacity of the EXP1212o battery is 12 Ah when the battery is being discharged for 20 hours at 77°F (25°C). Capacity/discharge hours dependency is given in the following table - note that the battery is being discharged down to 10.5V (1.75V per cell):

As the discharge current increases, so does the capacity decrease. This capacity loss is typical for lead acid batteries, and EXP12120 is not an exception, although there aren't many batteries in this class (capacity/price/warranty) with better results. On the contrary...

Capacity also depends on the temperature, and its dependency is given in the following table:

Although the increase in temperature leads to an increase in capacity, higher temperatures shorten the battery's lifespan.

When temperatures drop below freezing, consider warming up your battery, or at least insulating it, but monitor its temperature, since, during the use, its temperature increases, and again, high temperatures are not good for SLA AGM batteries.

The battery self-discharge rate is ~3-4% per month (temperature dependent), allowing the battery to be stored for a longer period of time without the need to use the battery maintainers.

However, if the user needs the battery to be ready immediately, a smart SLA AGM battery charger with trickle charge and float voltage of 13.6-13.8 volts is recommended.

Note: storing the battery above 77°F (25°C) leads to a higher self-discharge rate. For example:

Note: when the battery charge drops to 50% (personally, as soon as the battery charge drops down to 80%), charge it - it will last longer.

When the battery is used as a cycling battery, it can be charged up to 14.4-15.0 volts; just keep the charging current below 3.6 Amps.

 ExpertPower EXP12120 AGM SLA Battery Charging Cycles

ExpertPower EXP12120 AGM SLA Battery comes with 1-Year Limited Warranty. But, if treated properly, this battery can last much longer.

When the battery is kept at 68-77°F (20-25°C), its float service life is 3 to 5 years. However, if the battery is kept at 122°F (50°C), its expected float service life is shortened to one year - and this is a very good value for the battery in this class.

When the battery is used as a cycling battery, depth of discharge (DoD) plays a major role in the number of cycles that the battery can withstand.

The following table lists an average number of charge/discharge cycles, depending on the DoD and relative capacity.

For example, if the battery is regularly discharged down to 50%, one can expect 330-410 charging/discharging cycles before the actual capacity of the battery drops down to 80% of its nominal value (from 12Ah down to 9.6Ah).

How To Charge ExpertPower EXP12120 AGM Battery

The maximum allowed charging current for the ExpertPower EXP12120 battery is 3.6 Amps.

In order to charge the battery safely, an intelligent AGM battery charger in the 1.5 - 2.5 Amps range is recommended.

Such battery chargers first analyze the battery and then charge it according to its condition. Also, after the battery is fully charged, the intelligent AGM battery charger switches to the maintenance mode, keeping the battery charged.

Also, if the battery charger features Cell Equalization Mode, Deep Discharge Recovery Mode, and Desulphation Mode, even better.

For example, a 2 Amps AGM battery charger can recharge ExpertPower 12120 battery discharged down to 50% DoD (6Ah remaining charge) in ~3.5-4h if there are no issues with the battery - in that case charging time will be longer.

 ExpertPower EXP12120 AGM SLA Battery Discharging Characteristics

In real life, batteries are rarely discharged using continuous current or power. However, charts showing the battery's current and power in relation to time and end voltage are two common ways to present what a new, fully charged battery can do - when being discharged at 77°F (25°C).

For example, when the battery is discharged for 20 hours down to 1.75 volts per cell (10.50 volts total), a new, fully charged ExpertPower EXP12120 battery is capable of providing 0.60 Amps of constant current - and that is native battery capacity:

20h * 0.60 Amps = 12 Ah (at 77°F/25°C down to 10.50 volts)

Similarly, when the battery is discharged with constant power:

For example, when the battery is discharged for 20 hours, down to 1.75 volts per cell (10.50 volts total), a new, fully charged battery is capable of providing 7.02 watts of constant power.

Also:

- if you have a 12V 7W LED light, the ExpertPower EXP12120 battery will provide 20h of light without the battery voltage dropping below 10.50 volts.

- if you have a fish finder that requires 0.70 Amps of current and at least 10.50 volts, then you can expect some 16-17 hours of operation on a single battery charge.

- if you have a small trolling motor that requires 20 Amps at full throttle and you don't mind draining the battery really deep (down to 9.6 volts, for example), you can expect some 17-18 minutes of operation at full throttle - just be aware that draining the battery very low significantly reduces the number of its charging/discharging cycles.

Long Story Short: ExpertPower EXP12120 12 Volt 12 Ah AGM SLA Battery is a cheap and durable battery and is thus very popular.

It is commonly used as a fish finder battery, providing many hours of constant and reliable power in a compact and mechanically very resistant case.

Like all lead-acid batteries, it is not the lightest battery - it provides 18.9 Wh/pound (41.77 Wh/kg), which is very good.

If you need an affordable battery in this class (12V, 12Ah), consider the ExpertPower EXP12120 battery.

For more reviews and recommendations, check ExpertPower EXP12120 12 Volt 12 Ah SLA AGM Battery Amazon link (link opens in the new window).