battery question

[kenninny]

Im curious what would be the threshold for fully charged lipo's. As an example, you charge your battery
to go flying, and the weather turns bad, or something else happens, and you can't fly for a week or two
would you discharge you battier or not? (if less than a month)

[flydiver]

Judgement call mostly.
Fact: Full charge and heat are not good for lipos.
The higher the C-rating the more prone it is to damage.
The longer it's fully charged the more the damage. The higher the heat the more the damage. You can ruin a new battery with a full charge by keeping it in a trunk of a car on a hot day, yes you can.
You don't lose capacity, you lose performance (C-rating). When you finally run across someone talking about internal resistance of lipos (IR), that's what they mean. As IR goes up, performance goes down.

Situation:
Charging and discharging batteries is a pain.
Only you can evaluate your personal pain threshold of charging/discharging hassle vs. replacement. Some folks simply want batteries available so they can fly at a moments notice should the weather get nice. They pay the price in replacement. Convenience vs. cost essentially.
The better your charging/discharging system the easier you can deal with this.

Note-you pretty much cannot deal with this issue with the lousy RTF chargers. You NEED to upgrade to a charger that gives you information.
The common $25-50 4-button chargers CAN discharge to storage but are SLOW, limited to 1A/50W, whichever comes first. They charge better than that though.

What I do (and I'm on the finicky side)
No battery, ever, is left charged for more than 12 hours. If I don't use it, I discharge it at LEAST below 4v/cell. That's a critical line.
I try to never leave the field with charged batteries, even if that just means a short flight.
If I'm not going to use it for awhile (more than 3 days>week) they get pulled down to storage level (3.7-3.9v/cell), put in zip-locks and put in the fridge.

I am completely ignoring other critical issues like over discharge, crash damage, and other 'abuses' of lipos that should never be done. Most lipo fires are caused by crashes or the 'nut behind the charger'.