Receiver battery failure.

Hi Folks,
Can anyone help me. I'm quite new at this game, about 6 months, and I had my first serious crash a week or so ago. It appears that my receiver battery had gone from fully charged to flat in less than 25 mins of actual flying. I've been using this battery (1700mah) for some little time and it has been giving me well over one and a half hours before recharges. I appreciate thare can be a lot of factors governing the discharge rate so I purchased a similar new battery and gave it another try. The same thing occured again...about 30 mins before...splut!! no more battery power! The only recent change I've made to the heli is to fit a CSM heading lock gyro. Does anyone know if it's possible to monitor individual current drains to each servo/gyro/receiver? Any suggestions most welcome as I really dare not fly again till I've sorted this fault.
Many thanks.
Mac

Ok, first things first- are you discharging the batteries fully after flight and recharging them fully? Are your servos all high speed high torque?

I use a inexpensive product called VoltWatch from Hobbico to watch my battery in flight. It goes inline with the battery/receiver and gives a read out with colored LEDs as to your power setup. My favorite use for this is to turn everything on, move all the servos and the tail (to make the gyro work a little) and see how low the lights go. If it gets to red on a full charge with lots of servo movement you may need to either charge longer or get a more powerfull battery.

I fly with a 1400mah battery and it normally lasts over an hour of intense flight. I use a CSM heading lock gyro as well and love it along with a high speed servo for the tail rotor to keep up with the gyro.

Something you need to get for your batteries is a charge/discharge system that will allow you to discharge the battery at a known rate and give you the lenght of time at that rate. For example if your battery is rated at 1500mah and you discharge it at 500mah it should take 3 hours to drain it. I normally get about 2 hours at that rate with a 1400 mah battery.

Ok- enough of what you need and not enough answers!

No there really isn't any way of telling if one of the devices is drawing too much power. The problem is that most of the ammeters on the market measure AMPS, not milliamps. You may want to check with the manufacturers and get the max draw from each device (receiver, gyro, servos etc) and see what they add up to (can't imagine it'd be more than 1700mah!).

You may also want to check and make sure that all connections from the servos to the receiver and such are tight. If for some reason there is corrosion or something on the contacts, that can cause an unusual draw on the battery too.

Are you sure nothing is coming unplugged? How new is your on/off switch? Can you bypass it? Are there any vibration problems that may jiggle things during flight?

I suppose voltage could be a problem too- see if you can check the battery voltages. Each cell should be about 1.25 to 1.5 volts- even after a flight. It is possible to fly on voltages from 3.3 to 7.2. at the 3.3 end you've got a bad battery cell or one going bad and a gyro and all moving servos will eat that up REALLY fast.

Let me know what you find out. I'd love to know more or the cause!

Sounds like either one of your servos is working to hard, or maybe your new gyro is putting to much stress on the battery. I guess it is possible that the gyro is faulty and draining to much juice. Since you tried with a new battey, that rules out a fault on the battery.

Make up a device/lead which you could use to measure the amp's drain of each servo or gyro. Just get hold of a spare servo/battery extension lead, chop of the + connector and then hook a fairly good multimeter on each end of the + lead (which should be able to measure as low as down to 20 mAh).

Sit down on a table and play with it for 20-30 minutes and move the cable around. See if you can locate which service/device is draining your battery.

I would certainly recommend an on board battery/system checker. I personally recommend the Gem2000 from http://electrotekrc.com/. Cheap and is more advanced than most other on-board battery checkers.

It can easily be seen from the air when flying around. No need to come down to hover. I mounted my first one about a month ago, and it has already saved my heli once.

Regards, Thomas