Lipo Discharge Rates for storing ? 1C ?

[Rich D]

Bought myself a fancy new charger that allows me to use a "store" mode aswell as charging 2 packs at once.

If the pack isnt at 60% capacity then the charger either charges or discharges until it is using this mode. As we know, storing Lipos fully charged does them no good.

Im charging my Lipos at 1C - is it best to discharge them at the same rate ?

BTW the charger is a Hyperion EOS 0615i Duo3

Thanks !

[Rich D]

Anyone shed any light here ?

[paulc]

the chargers i have only allow to discharge at 1c so i'd say that was the best way

paul

[Alfonzo]

Hell, I didn't realise storing them fully charged was no good, is this true?

[muratti]

I also have never heard of the fact that storing LiPos fully loaded does them no good... The LRP instructions of my 5900 VTEC LiPo says it shoudl be stored loaded, however they don´t write if partially or fully loaded... where did you get that information from, Rich?

[neiloliver]

It is true.

[Alfonzo]

Oh Cock. I've kept mine fully charged for months.

Check the 'For Sale' section for some cheap Lipo's

[bert digler]

Originally Posted by neiloliver

It is true.

i store them with whatever the finish the last race about 40% is that ok neil never had a problem also my dads lipo off his heli swelled so told him throw it over next door and asked em to poke it with a stick

[Rich D]

Yeah its defintely true fellas.

You should store them at around 60% capacity. I normally do as the stig above , just leave in whats left from the last race.

Im just making use of my fancy new charger

I have heard it from more than one source, ill find a link i read recently ......

[Rich D]

Originally Posted by paulc

the chargers i have only allow to discharge at 1c so i'd say that was the best way

paul

Oh yeah cheers Paul - that will do for me too then

[neiloliver]

Have a read this...

http://www.batteryuniversity.com/parttwo-34.htm

The same stuff applies for Lithium Polymer as it does for Lithium Ion (as the chemistry is really the same). Storing the cells fully charged for prolonged periods reduces their recoverable capacity.. leaving them after a race is perfectly good during the racing season (assuming you charged them before the race!)

N

[Rich D]

http://www.jconceptsevents.com/events/clash/Lipos.pdf

Another link written by a well informed fella ....

If you read the article it also points out that charging at 2C is NOT twice as quick as charging at 1C due to the algorythm that Lipo chargers utilise.
I didnt know that until i read the article. Useful info !

[muratti]

I recently realized that i didn´t get as much power in my LRP VTEC 5900 Stick Lipo as in the beginning. I have charged it 10 times now and always stored it fully loaded but only for maximum a week. Does this affect the capacity? I don´t want to chrage it to 60% and 3 days later to 100% when actually i´m racing.
I saw that in the 6th charge i got 5290 in them, 7th 5270, and now 10th load i got only 5230 in.
In the LRP manual it says that it is normal that Lipo have a chemical reaction everytime you charge them and that it is normal that they loose capacitiy over their lifetime.
I was wondering what a Lipo lifetime is? How often have you charged your lipos until their were down?

[Rich D]

You should certainly get more than 10 cycles out of them. I dont have a definite answer as far as the dropping capacity goes, how do you know that theres the same amount of capacity in the cells each time before you commence charging ? I wouldnt run your car until it stops on the speedo voltage cutout if thats what you are doing mate ?

Because we race only 5 minutes we dont have a problem with capacity as a rule. When i race touring car stock class, a six month old pack feels a little less punchy than a new one. With buggies most of us turn the power right down to make them driveable so the lack of punch is less noticeable.

Personally, i change Lipos about twice a year. Thats not to say that they are spent when i do, i just feel its cheaper for me to sell them for half cost price and upgrade to a new pack for half the cost too. Lay out less capital at a time.

I wouldn`t store your packs fully charged, even if its for only a week. its not a big deal to charge them up before your race from 60%. it should only take around 25 minutes at 1C for your 5900 packs ( 5.9A )

[muratti]

Many thanks for the answers guys. Rich, you definitly helped me a lot today! Many thanks. I raced today and stopped after 20 mins (in total). I think this is about 3-4 minutes before the esc would turn off.
I then immediately charged the pack for about 20 mins with 1C. I think that should be fine for about a week of storing.
If i store them for longer i will charge it for abotu 30-40 minutes.

Thanks for your advice!

[Rich D]

One good turn deserves another Johannes

[moth898]

I have a question for you too, is it ok to fully charge lipos 48 hours before race day?

[neiloliver]

That is no issue at all in my opinion. It is long term storage at high states of charge that causes issues.

N

[kschu]

full charge and store will cause the lipo to bloated/pregnant...
might not good...