Single Interface 1000; Vertical Stacks; Interface Power Hub Systems - Gamry Interface 1000 Operator's Manual

Let's look at the power in three typical, high current battery discharges:
• If we only have a single battery and its voltage is 5 V, the maximum power dissipation is 37 W.
• If the battery stack has a voltage equal to the largest measurable Interface 1000 cell voltage (12 Volts) the
maximum power dissipation in the instrument is 44 W.
• In an unusual experiment, a resistive voltage divider on the voltage measurement could allow Interface
1000 operation with battery stacks with voltages as high as 20 V. In this case, the maximum total power
dissipation is 52 W.
Note that the maximum power drawn from the instrument's power input jack is largely independent of the cell
voltage. The maximum is 32 W (divided by the power supply efficiency). The higher power levels mentioned
above occur because the battery is sourcing power.

Single Interface 1000

Gamry has tested a single Interface 1000 operating at its most extreme condition: discharge of a 20 Volt cell at
1 A current. The unit was run in its normal horizontal position, with 1 A cell current and a 20 V cell voltage.
The air-flow though the unit was unimpeded.
In this test, the unit could be operated indefinitely, with no over-temperature events seen, even with a 45 ˚C
ambient temperature. The highest temperature measured on the outside of the Interface 1000 chassis was
15 ˚C above ambient.

Vertical Stacks

Gamry also tested a system with four Interface 1000s stacked one atop another (a vertical stack of horizontal
units). In this configuration, the Interface 1000s run hotter, since power dissipation in one unit can radiate heat
to adjacent units and also preheat the air used to cool other units. The units higher in the stack run hotter
because their cooling air is preheated by the units below them. The cooling air entering the unit on the bottom
of the stack is unheated, so this unit runs significantly cooler than all the others.
We saw over-temperature events in this configuration when the units are operated at the unusual condition of
discharging a 20 V battery. The over-temperature events occurred on upper units and only occurred after at
least 20 minutes of continuous worst case power operation. The case of the hottest Interface 1000 was also
more than 25 ˚C above ambient.
The system operated indefinitely with no problems when the cell voltage was limited to 12 V or less. The
highest temperature measured on the outside of hottest Interface 1000 chassis was 20 ˚C above ambient.

Interface Power Hub Systems

The Interface Power Hub uses forced air cooling to lower temperatures in stacked Interface 1000s. The units
are turned 90˚ to run in an array of vertical instruments.
Gamry tested a system with eight Interface 1000s mounted in an Interface Power Hub. All units were operated
at the worst case condition of 52 W power dissipation - discharge of a 20 V cell at 1 A.
In this test, the system could be operated indefinitely with no over-temperature events seen, even with a 45 ˚C
ambient temperature. The top of the Interface Power Hub chassis got warm, but stayed at less than 15 ˚C
above ambient.
Appendix D – CE Certificate--Single Interface 1000
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