When do you retire battery packs for EDFs?

[Flash Jorden]

What is your criteria for deciding that a Lipo is no longer suited to power your EDF, and may be better used in a lower performance demanding plane?
Is IR (Internal Resistance) a good criteria? If so, what is the cut-off value?
Anything else?

[Evan D]

I usually fly them for a 3-4 years and then sell them at a swap meet or to other pilots. Replacement is usually because there are newer, better, lighter packs available more than they need replacing. I do have some batteries that are 6-7 years old with hundreds of cycles on them that are still working great and there's nothing in that cell size better so I still use them. I am slowly replacing all my older packs with Hobby Star or Roaring Top if there is a suitable cell size.

I don't have a way to measure IR though that would be a good way to tell if they need replacing.

What is your criteria for deciding that a Lipo is no longer suited to power your EDF, and may be better used in a lower performance demanding plane?
Is IR (Internal Resistance) a good criteria? If so, what is the cut-off value?
Anything else?

[fhhuber]

Load test

Fresh charged pack has to withstand at least 45 seconds 100% throttle without tripping LVC or you don't want to use it in the airplane.

Its a real bummer to hit LVC cutoff just as the wheels leave the pavement....

[Beeg]

What is your criteria for deciding that a Lipo is no longer suited to power your EDF, and may be better used in a lower performance demanding plane?
Is IR (Internal Resistance) a good criteria? If so, what is the cut-off value?
Anything else?

Here's a video to help with testing battery health. Pretty much what fhhuber was suggesting. If you fly EDF enough you'll know when your batteries need to be retired just by how they perform.
https://www.flitetest.com/articles/L...stance_Testing