quick LI PO question

[Farmer Giles]

Hi, just a quick one hopefully.

I have 3 flight batteries with my mCX but is it best to leave them fully charged or in the discharged state that they come out of the heli in ??

I am flying every day anyway so probably not that critical, just after a bit of advice really.

What about longer term storage ?

cheers

Martyn

[machasm]

If you are using them alot then leaving them fully charged wont harm them if their kept inside.
For longer term storage they are best kept at around 50% charged.

[Sesame]

dont leave them discharged, but also dont leave them fully charged if its cold (below 10 degrees)

[rceccleston]

It is safe to keep a battery fully charged for no longer than a week.

However, it is recommended to store batteries at their nominal voltage (3.75), as they deteriorate quicker when stored at higher voltages and keep within the 80/20 rule.

[Mojo]

How would we find out the voltage of a battery? and how can we determine the 20% capacity left on it? Would it be a rough guess depending on the flight time of a full battery?

[machasm]

How would we find out the voltage of a battery? and how can we determine the 20% capacity left on it? Would it be a rough guess depending on the flight time of a full battery?

Its a trial and error thing.
Take your fully charged bat and fly for around 4 mins.
re-charge and see how much goes back in.
If it is less than 80% capacity then fly for 4 and a half mins and re-charge.
Repeat until you are close to the 80% mark.

[Farmer Giles]

Its a trial and error thing.
Take your fully charged bat and fly for around 4 mins.
re-charge and see how much goes back in.
If it is less than 80% capacity then fly for 4 and a half mins and re-charge.
Repeat until you are close to the 80% mark.

Sound like you'd need a decent charger to be able to do this rather than the battery powered one you get in the box with the mCX.

Think I will just charge them and fly for 3 or 4 mins and leave them like that if I am going to leave them for a few days and not fly.

[machasm]

Sound like you'd need a decent charger to be able to do this rather than the battery powered one you get in the box with the mCX.

Think I will just charge them and fly for 3 or 4 mins and leave them like that if I am going to leave them for a few days and not fly.

Yeah your right there.
I have a cellpro 10S which gives me that info.
Also does a very good job of ensuring the LIPOs remain balanced well.

[cjcj1949]

I wouldn't worry at all. You're talking about a small effect like 6% a year fully charged or 3% a year at half charge. You mustn't let them get flat though so they advise checking the volts every few months. They'll also last longer if charged at around 3.8v in the fridge not in the freezer. Using them does far more damage in practice. Some batteries are much better than others. The standard mcx one gets charged at 2C and seems to last ok.
Chris