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6 volt battery question

Old 09-17-2008, 08:49 PM
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poison
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Default 6 volt battery question

how low can you fly a 6 volt battery savely before calling it a day?
Old 09-17-2008, 09:02 PM
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Gringo Flyer
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Default RE: 6 volt battery question

That depends on the capacity (mah) of the pack and what you are putting it it. A 6v battery wont last as long as a comparable 4.8 pack but its not a lot of difference.

A 1000mah 4.8v pack on 3d plane with high torque digital servos will not last as long as a 500mah 6v pack on a trainer with standard servos.
Old 09-17-2008, 09:13 PM
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Default RE: 6 volt battery question

I'd stop when the voltage reads 5.6 on a loaded voltmeter (assumes 300 mA load).
Old 09-17-2008, 10:15 PM
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poison
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Default RE: 6 volt battery question

Its in a hanger 9 spitfire standered servos 3004 got a seperate 4.8 for retracts, I believe the 6volt is a 1600 mah I flew 3 times and it was on 6.40 I believe still said it was good, I'am thinking that probley I could go to 6.20 or so
Old 09-17-2008, 10:39 PM
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Default RE: 6 volt battery question

If you stop flying when the loaded voltage drops to 6.2 volts you will be very safe. In fact you have probably only used about 10 or 20 percent of the capacity.

Here's what a typical 5-cell NiMh discharge looks like:
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Old 09-18-2008, 06:30 AM
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Gringo Flyer
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Default RE: 6 volt battery question

With that setup you will have a full day of flying on that pack. Its still a good idea to check the voltage after every couple flights. I generally check between every flight.
Old 09-18-2008, 07:29 AM
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Default RE: 6 volt battery question

Normal discharge on a NiMH pack should be around 1.1 volts per cell. With a 5 cell (6 volt nominal) call it quits around 5.5-5.6 volts per cell and you should be good to go. Your setup is probably drawing between 300 and 500 ma during regular flight, which means you have 1600 mah/500 ma = 3 hours of flying time. Assuming 10 minute flights (normal average flight) thats 18 flights. With refueling between flights, thats about 4 flights per hour, which means 4 1/2 hours at the field of continuous flying. Thats a lot of flying!

Brad
Old 09-18-2008, 10:31 AM
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Default RE: 6 volt battery question


ORIGINAL: bkdavy

Normal discharge on a NiMH pack should be around 1.1 volts per cell. With a 5 cell (6 volt nominal) call it quits around 5.5-5.6 volts per cell and you should be good to go. Your setup is probably drawing between 300 and 500 ma during regular flight, which means you have 1600 mah/500 ma = 3 hours of flying time. Assuming 10 minute flights (normal average flight) thats 18 flights. With refueling between flights, thats about 4 flights per hour, which means 4 1/2 hours at the field of continuous flying. Thats a lot of flying!

Brad
Now the good part of this is that typically the RX will still work to around 4.8 volts so you will still have your radio working when you start to kill your pack.
The less you draw the pack down in a normal cycle the longer it will last.
Old 09-18-2008, 10:57 AM
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Default RE: 6 volt battery question

And at 6.4 after only three flights it sounds like it wasn't charged all the way.
Old 09-18-2008, 02:40 PM
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Default RE: 6 volt battery question

At 6.4 volts, you still have 90% of your charge left, a perfectly normal occurance after a few short flights. You can safely fly down to 5.6 volts. Take a close look at DMcQuinn's graph, it is pretty typical. You will note that the voltage quickly falls to 6.4 volts then holds well above 5.5 volts for a long time. Get a Voltwatch (you can get them for 5 cell batteries) and it will warn you as when, at the end of a flight, it falls into the yellow it is time to charge. IMHO a Voltwatch is better than a loaded voltmeter as it is always connected and easy to immediately access the charge level at the end of each flight before turning off the switches.

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