P12441: Thermoelectric Stove for Haiti
Battery Discharge Test Procedure / 3

1.  Test Name: Battery Discharging

Test Author: Andrew and Xiaolong

Battery is connected to a decade resistor box, the resistance is set to 8 ohms (6.5V and 750mA) to simulate the current draw, voltage across the terminal of the battery is measured every 15 minutes with the resistor box is connected. The results are collected and a scatter graph can be created to show the relationship of battery discharging. Then high voltage and low voltage disconnected voltages can be determined based on the resulting curve.

2.  Required Equipment

Equipment Description / Quantity / Settings
1 / Multimeter / 1 / Measure voltage
2 / Decade resistor box / 1 / 8 ohms
3

Table 1: Required equipment and its settings.

3.  Test Procedure

Step 1: Set the decade box as close as possible to 8 ohms

Step 2: Connect the decade resistor box across the battery terminals.

Step 3: Measure the voltages across the terminals of the battery every 15 minutes when the resistor box is connected. Record the value is MS Excel.

Step 4: When the battery terminal voltage drops below 5.8V disconnect the decade box and battery.

4.  Test Results

Step # / Description / Spec / Measurement
1 / Length of time for the battery terminal voltage to drop below 5.8V / 4 Hours / Time (Minutes): 250 Minutes

Table 2: The results of the test procedure.

Xiaolong (Battery B) / Andrew (Battery A)
Time (min) / Connected Voltage (V) / Disconnected Voltage (V) / Minutes / Voltage (V)
0 / 6.23 / 6.5 / 0 / 6.492
15 / 6.23 / 6.38 / 15 / 6.376
30 / 6.22 / 6.34 / 30 / 6.360
45 / 6.19 / 6.32 / 45 / 6.330
60 / 6.17 / 6.27 / 60 / 6.300
75 / 6.14 / 6.25 / 75 / 6.290
90 / 6.11 / 6.21 / 90 / 6.255
105 / 6.08 / 6.18 / 105 / 6.235
120 / 6.05 / 6.16 / 120 / 6.200
135 / 6.01 / 6.13 / 135 / 6.178
150 / 5.97 / 6.09 / 150 / 6.145
165 / 5.93 / 6.06 / 180 / 6.070
180 / 5.88 / 6.02 / 195 / 6.032
195 / 5.83 / 5.97 / 210 / 6.012
210 / 5.75 / 5.92 / 225 / 5.900
225 / 5.66 / 5.86 / 240 / 5.800
240 / 5.46 / 5.73 / 255 / 5.000
255 / 5.11 / 5.41

Table 3: Terminal Voltage vs. Time

Figure 1: Battery Terminal voltage vs. Time

5.  Pass/Fail

Did the unit pass or fail the test? Defend your decision.

PASS / FAIL
Pass

Table 4: PASS/FAIL