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Old Aug 02, 2015, 06:46 AM
W0WG is offline
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United States, VA, Chesapeake
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Question
What do LiPo battery IR readings signify ?

I just discovered that my charger can display the "IR" value of individual cells, as well as the total battery IR.

Is that information useful to me? If so, how do I use it?

TIA for your responses.

Mike
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Old Aug 02, 2015, 06:51 AM
Rodney is offline
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It is a measure of how much of the voltage is lost across the internal resistance of the cells when you draw current. The smaller the IR, the better the battery and the less internal heat is generated within the battery.
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Old Aug 02, 2015, 09:29 AM
ggcrandall1 is offline
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WOWG,
IR can be useful in determining the health of your battery. When you get a new battery measure and record the IR of each cell. Then periodically measure the IR and compare the numbers to your original record. As the battery ages the IR will increase.

Unfortunately not all devices that measure IR will give the same reading for a given battery so I cannot tell you what a good number would be for your battery.

The measurement will be in milliohms and for a new battery in good condition the reading will probably be in the range of 2 to 10 milliohms

Point of interest: Anytime you mention a device it is good practice to be specific and even include a link to the device if possible. i.e. what charger are you using?

May I also suggest you read this: http://www.tjinguytech.com/charging-how-tos

Glen
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Old Aug 02, 2015, 08:38 PM
yurstruly is offline
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check this thread about IR .. also there's a spreadsheet avail at this thread for the IR of the battery you purchase to give the health , true C rating (based on IR) and estimated life expectancy of your lipos..l

http://www.rcgroups.com/forums/showthread.php?t=1577989

http://www.rcgroups.com/forums/showt...1#post20484169

http://www.rcgroups.com/forums/showp...99&postcount=5


Quote:
Originally Posted by W0WG View Post
I just discovered that my charger can display the "IR" value of individual cells, as well as the total battery IR.

Is that information useful to me? If so, how do I use it?

TIA for your responses.

Mike
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Old Aug 03, 2015, 09:06 AM
W0WG is offline
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Landings are not optional!
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Gents,
Thank you for the info and links - I will give them a look.

My charger is a "Hobby People" TAZR. It was received as part of a recently purchased "package deal". I don't have a manual and discovered the IR check screen by accident while exploring what the buttons do.

I am a new R/C Airplane 'pilot' and purchased two batteries with a Hobby Zone Super Cub S. They are both eFlite 3S/1300mAh/20C. One has never been used (only charged once) and the other has one flight and then re-charged.
Readings:
1. 13, 16, 16 and total battery IR=45 (the unused one)
2. 14, 21, 27 and total battery IR=62 (the one with one cycle).

It looks like the charger simply adds the three cell values to come up with the total battery IR ?

I will start a log and check the IR after each flight to see if there is a trend or change.

Thanks for your help,
Mike
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