All Electronics LiIon Battery Discharge Notes
d. bodnar 4-20-14
The batteries discussed here are available (as of 4-17-14) from All Electronics - see: http://www.allelectronics.com/make-a-store/item/lbat-148/14.8v-2200mah-rechargeable-li-ion-battery-pack/1.html
They are from Tenergy and supply 14.8 volts at 2200 mAh.
I tested one of the six that I ordered by mounting the battery on an Aristo Craft center cab switcher (two motors, four axles). I ran the engine on a 28 foot oval of track with a volt / amp meter mounted on the engine. I ran it until the voltage dropped below 12 volts. I am not sure if the battery would automatically shut down or at what voltage so, to be safe, I pulled it when it dropped below 3 volts / cell.
Throughout the run the engine drew about 0.57 amps. The results are shown below. Note that I collected less than two dozen data points. Since the engine was on a loop of track it was not convenient to collect voltages automatically. I just jotted down a reading each time that I thought to do so!
The engine ran for well over six hours. If you divide the mAh rating (2200) by the current draw (about 570 mA) you get 3.8 hours. It appears that the battery delivers at least the power that is advertised on its label!
A second test was performed with the same engine on rollers. It drew considerably more current, perhaps partly due to the fact that the rollers have not been lubricated recently.
The results are below. I used my bench VOM to gather this data and a reading was taken every 60 seconds.
Charging
I charged the battery using a
bench power supply that can be set to provide
a fixed current. I charged at 17 volts at about 200ma.
The graph for charging is below. With the current restricted to 200mA it took about 12 hours before the circuitry in the battery shut down the charging (note the spike in voltage at the end indicating that it stopped taking a charge)
