Video: XD

Video transcript

What the XD tells you about a battery, how it is connected and programmed, and how a discharger becomes an automatic cycler. A fleet of batteries ages unevenly, and a voltage reading will not tell you which ones are weak. A controlled discharge will. The XD measures the ampere-hours each battery really delivers, and records the curve that proves it. Inside, an active electronic load with IGBT hybrid

high-frequency control holds the discharge current constant from the 1st 2nd to the last, whatever the battery voltage. Up to 20 kilowatts and 200 amps. The same unit works on lead-acid, whether vented, gel, AGM or TPPL, on lithium, on sodium-ion, and even on supercapacitors. And custom profiles let a test simulate the real duty cycle of the battery. There are 3 versions: two at 200 amps, for American and European supplies, and one at a 100 amps that reaches higher battery voltages.

All 3 at 20 kilowatts, in the same cabinet. The control panel sits on top and tilts up to 90 degrees, so it can be read standing or kneeling. The battery lead comes out on the front, with its connector. Forced-air cooling on the sides, and castors, because the unit goes to the battery. On the panel, 4 LEDs show the state of the cycle at a glance, and a two-line display gives voltage, current, time and the ampere-hours delivered. Three keys drive every setting.

On the right of the panel, the on-off switch, which is also the emergency stop, and the socket for the optional battery temperature probe. With the unit off, earth the cabinet first. Then the battery lead: positive to positive, negative to negative. If you use the temperature probe, fix it to the battery. The mains plug goes in last, and only then is the unit switched on. Two values define a capacity test. The current: one 5th of the five-hour capacity,

so a 200 ampere-hour battery is discharged at 40 amps. And the end voltage: 10.2 volts for a 12 volt block, 81.6 for a 96 volt battery. When it recognises the battery, the unit offers the values of the last test. Current, end voltage, the capacity that ends the test, and the maximum time: each one is changed and confirmed from the keypad. Then the test is launched. This is the real panel. It prepares the discharge, the LEDs come on, and the test runs. The display shows the battery voltage, the current and the ampere-hours delivered,

with a bar that fills as the capacity comes out. A battery outside the voltage range is refused before the test starts, reversed polarity leaves the unit in safe stand-by, and the probe stops the test if the battery overheats. After a mains failure the unit waits for a new start. And the last 150 tests stay in its memory. Every test is saved in the built-in datalogger, and exported over USB to the PC software.

There it becomes the discharge curve, the ampere-hours actually delivered, and a professional report for the customer or for the maintenance file. Paired with an XMV charger, the XD becomes an automatic cycler. The charger charges, the discharger discharges, and the cycle repeats up to 20 times on the same battery, with a programmed wait for the charge and the cooling in between. And when a battery is bigger than one unit, several XD work in parallel on the same battery, so the capacity you can test has no upper limit.

And the rules that matter: qualified people only, the unit off before any connection is made or broken, a dry, ventilated place with no flammable gas, room around the unit for the air, and eye protection near the batteries. It is used for capacity tests to international standards, for data-driven predictive maintenance of battery fleets, in multi-brand service centres and test laboratories, and, as a cycler, in research and battery regeneration. Battery maintenance, from Amperis.