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Posted by Mike Dubovsky | Mar 01, 2018 @ 02:44 PM | 1,907 Views
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Posted by Mike Dubovsky | Sep 01, 2017 @ 11:56 PM | 2,335 Views
Quote:
Originally Posted by vollrathd
I'm an admitted when it comes to using A123 battery packs for receiver power on our model airplanes. FYI, my RC models have over 150 A123 cells in them, mostly used for electric motor power, where up to 40 Amps per cell is pulled out of them on a regular basis.

I've got a Western Mountain CBA battery analyzer that has been used to conduct near 1000 discharge tests over the past many years on all sorts of batteries, including electric power, and receiver power.

Those tests have shown that the typical failure mode for a LiPo (And LiFe) is high internal resistance, or open circuit. The LiPos slowly wear out after many cycles, resulting in higher internal impedance. I've tested three of my RC club members LiFe's that had an open cell. A wild guess suggests that perhaps those 3 LiFe's had a pin hole in their plastic baggie.

That leaves the A123's for receiver power. These cells hold 3.3 Volts per cell, or 6.6 Volts per cell at current levels under 10 Amps or so. They hold that voltage until right before they are totally discharged. Compare that to around 7.3 Volts DC or so for a LiPo. I've only had two A123's from my RC friends that failed. One had been left completely dead for several years. That cell was jump started, and still put out 2.7 Volts DC at 10 Amps. But, it would go dead on its own after several months. The second A123 cell had an open circuit. El-stupido
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Posted by Mike Dubovsky | Apr 12, 2017 @ 05:11 AM | 4,741 Views
A handy device for testing individual cells. It's made from a servo extension cable or servo plug from a defunct servo. The plug on the other end can be whatever matches your test equipment.

Adapter for charging one cell at a time through the balance plug. Thanks rcdog69.

Name: 1 cell lipo.jpg
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Posted by Mike Dubovsky | Mar 11, 2017 @ 08:59 PM | 4,969 Views
Posted by Mike Dubovsky | Mar 11, 2017 @ 08:18 PM | 5,040 Views
Quote:
Originally Posted by ian444
you can use two needles to remove this type of circlip shown in the picture, and they hold the circlip captive so it can't fly off, never to be seen again. Just spread the circlip enough to be able to slide it off the end of the shaft. The end of the needle can be filed, if required, to get the holes right at the end.
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Posted by Mike Dubovsky | Jan 29, 2017 @ 11:47 PM | 5,130 Views
Posted by Mike Dubovsky | Jul 09, 2016 @ 06:10 AM | 6,283 Views