AGM battery test 133 Ah Ventura GPL 12-120

Lead batteries are still relevant: they are fireproof, cheaper than lithium batteries, and easy to use.

I reviewed and tested the Ventura GPL 12-120 battery, designed for use in backup power and alternative energy systems.

For most manufacturers, the numbers in the name indicate the capacity in amp hours, but the Ventura has a higher capacity than the number in the name. According to the table with manufacturer's websiteGPL 12-120 has a nominal capacity of 133 Ah.

The specification states the weight of this battery is 35.4 kg ± 3%. The tested specimen weighs 35.2 kg.

To test the battery I used a new device Yarostanmash ACK500.30.40.1providing a discharge current of up to 30 amperes.

The manufacturer indicates an average monthly discharge of no more than 3%, so first I measured the residual capacity of the battery, discharging it to 10.5 V with a current of 6 A. The result surprised and pleased: 133.3 Ah, which is even more than the nominal capacity.

For the main test, the battery was charged according to the method proposed by the manufacturer: charging with a current of 13.3A to a voltage of 14.3 V, ending 8 hours after reaching a voltage of 13.5 V, then recharging with a voltage of 13.5 V until the current drops to 133 mA.

By the way, I highly recommend studying instructions for all types of Ventura batterieswhich describes in great detail the methods of charging, discharging and operating features of AGM batteries.

To determine the capacity, the battery was again discharged with a current of 6 A to a voltage of 10.5 V. The process took twenty-two and a half hours.

Result: 134.8 Ah, 1613 Wh.

The specifications indicate that a fully charged battery should have an internal resistance of 3.5 mOhm (milliohm), according to the results of my measurement it turned out to be a little more – 3.89 mOhm.

The manufacturer provides in the specifications a table of discharge times at different currents.

Based on the table, at a current of 30.1 A, the battery should work for 3 hours, delivering 90.3 Ah. I charged the battery again and measured its capacity when discharging with a current of 30 A to 10.5 V.