How much current does a receiver battery monitor draw?
For all the years I've been flying RC my method for making sure my batteries are charged is to put em on the charger overnight before I go flying the next morning. Touchwood this has served me well and I don't believe I've ever lost a plan to flat batteries. I've never monitored the state of my receiver batteries throughout the day though. How many flights are they good for? 5, 10, 15? For me, I never seem to get a full day of flying, maybe 5 or 6 flights at the most and the receiver packs hold up fine but it still left me wondering, how many electrons are left in the tank after those flights.
I saw some cheapy battery monitors on ebay and thought I'd try one out. The two I bought didn't actually state the current draw but identical looking versions were touting 5 mA. I was keen to put them to the test.
Test 1: Current draw of just the battery monitor. 10mA.
A 4.8 volt, 1100mA NiCd battery is connected directly to the battery monitor with a multimeter in line. The monitor shows a reading second from the top in the "Perfect" range.
Test 2: A JR RS70 36Mhz synthesised receiver. 24.7mA.
Test 3: Futaba 36MHz crystal Receiver. 15.2mA.
Test 4: JR Rx & Voltage monitor. 40.1mA.
I expected a little lower at 10 + 24.7 = 34.7mA.
Test 5: JR Rx, Voltage Monitor & 1 micro servo. 45.2mA
Test 6: JR Rx, Voltage Monitor & 2 micro servos. 52.2mA
Test 7: JR Rx, Voltage Monitor & 3 micro servos. 57.8mA
Test 8: JR Rx, Voltage Monitor & 4 micro servos. 63mA
