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Old 05-02-2015 | 12:18 AM
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Default LiFe cut off?

Quick question. I have ordered a 6.6v LiFe battery for my MT4 transmitter. I am just curious what I should set the voltage cut off to on the transmitter? I've done some searching and can't seem to find any info.
Thanks
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Old 05-02-2015 | 01:14 AM
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Life can as low as 2v a cell, in ur case that is 4v. Bt is adviseable not to go lower than 2.5v a cel, so 5v
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Old 05-02-2015 | 01:47 AM
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Great. Thanks for the info
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Old 05-02-2015 | 03:00 AM
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Yeah LiFe is great, I use 2S LiFe packs in my Nomadio transmitters too.
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Old 05-02-2015 | 03:24 AM
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Good to hear. I wasn't to keen on using a LiPo.
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Old 05-02-2015 | 02:52 PM
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LiFe batteries don't use a cut off , they discharge like a nimh battery So no cut is necessary , It shouldn't matter in a transmitter ,but if you set it in a high draw current use like an esc You will trigger the cut off upon full acceleration due to the current draw dips below the cut off value even though the battery is fully charged .
Found out when switched from lipo to life in my merv , kept cutting out even though fully charged , After talking to tech support found out had to turn off the lipo cut off , runs great now on 9.9 volts .
I'd leave it off {cut off}personally just to be safe and use the battery as it's intended to be used .
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Old 05-02-2015 | 05:13 PM
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Ok cool. What voltage do they go flat at?
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Old 05-02-2015 | 05:29 PM
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Originally Posted by strykerakamack
LiFe batteries don't use a cut off , they discharge like a nimh battery So no cut is necessary.
This is incorrect. The minimum voltage of a LiFe cell is about 2.5V. Lower than that can cause permanent damage. (Roelof already answered this correctly.)
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Old 05-03-2015 | 09:00 AM
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If you use a life battery in a high draw situation It will draw more voltage than what your cut off is set for , hence you would get shutdown condition , while still having a usable battery with amperage available .
A lipo batteries voltage does not vary during use while a lifes' battery does . So just like a nimh battery you can drive a vehicle till it becomes to slow to go .
Like I said in a transmitter it might not matter but would rather err on the side of caution using the proper settings of life battery , that being cut off is not used , low voltage detection yes , cut off no
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Old 05-03-2015 | 09:26 AM
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Originally Posted by strykerakamack
Found out when switched from lipo to life in my merv , kept cutting out even though fully charged , After talking to tech support found out had to turn off the lipo cut off , runs great now on 9.9 volts .
I'd leave it off {cut off}personally just to be safe and use the battery as it's intended to be used .
That is because your ESC has no standard LiFe shut off or has it? With most ESC you can set the LVC voltage as low to 2.7v or maybe lower. If your ESC can be programmed in that way you should do it!
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Old 05-03-2015 | 11:31 AM
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Originally Posted by Roelof
That is because your ESC has no standard LiFe shut off or has it? With most ESC you can set the LVC voltage as low to 2.7v or maybe lower. If your ESC can be programmed in that way you should do it!
I must have over 500 plus cycles thru my life batteries and never had to worry about low voltage , its more of how many amps are left .
LiFe batteries have a lower operating voltage of about 3.2V – 3.3V, the minimum discharge voltage is 2.8V and the maximum charged voltage is 3.6V
Think of it like a car battery you need 12 volts , and if the battery gets to 10 volts its bad so you put a low voltage cut out in to solve the problem .Now you try and start the car, the the starter pulls the voltage down to 9 volts .What Happens ? Your car doesn't start because the LVC kicked in, BUT your battery is still fully charged .
Same principle in the RC for a Life Battery . LiFe Voltage rises and falls according to demand .LiPo batteries hold constant voltage durning demand
So you can drop below a LVC during use and not cause a problem except your not using your vehicle due to the LVC cutting in where its not needed
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Old 05-04-2015 | 07:01 AM
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Originally Posted by strykerakamack
A lipo batteries voltage does not vary during use while a lifes' battery does .
This isn't true. A lipo voltage curve under load is pretty flat, but its constantly dropping.

I'm concerned with your examples because I find them incorrect. If your real car battery drops to 9V when you start your car, that means either the battery is at the end of its life or it isn't sized to handle the starting amps.

Same with the LIFE/Lipo examples - if the battery drops below the min voltage under load, that battery is not able to handle that load and you're shortening its service life.
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Old 05-04-2015 | 07:17 AM
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I have a question about LiFe's. I looked around at some on Ebay and didn't see a burst rateing like a Lipo. What's the deal? To me, using a LiFe and triggering LVC is an indication of low burst rate. That's how it would work on Lipo's. What are the adavantages to using a LiFe?

I guess I stand corrected, I assume the 10C is the burst rate on these?
http://i.ebayimg.com/00/s/MTAwMFg3NTA=/z/2ZcAAOSw7ThUqhjR/$_57.JPG
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Old 05-05-2015 | 12:00 AM
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My MT4 wouldn't allow me to set the cut off at 5v. I just set it to alert me when it's at 5.3v. Which should still give me a lot of use compared to AAs.
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Old 05-05-2015 | 03:26 PM
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I USE THE TURNIGY 1450 MAH LIFE BATTERY IN MY MT4 BEEN GOING ON 3 OR 4 MONTHS WITH OUT A CHARGE I AM THINKING AT THIS RATE A ONCE A YEAR CHARGE WHETHER I NEED IT OR NOT.

SO I WILL CHARGE EVERY TIME ITS TIME FOR A BATH LOL
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