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-   -   5000mah 2s lipo, discharged to 6.6V?? (http://www.oople.com/forums/showthread.php?t=118763)

Appie53 06-01-2013 08:02 PM

5000mah 2s lipo, discharged to 6.6V??
 
Dear Guy's, need some advice, still trouble with my lipo's. When pack is discharged to 6.6V (5000mah pack), can I say that approx 2500mah is used?

Used this pack today, my shortcourse stopped after 2 min, still at 7.9Volts.
So discharged it with my lipocharger to 6.6V, still got 2500mah out of it.

I don't get this atall, can it be that my esc got to hot? and stopped?
Lipo buzzer did beep after 2min, set at 3.3v per cell.

Confused, confused. Hope for your expertise on this, Thanks again,..Appie:)

RudolfXC 06-01-2013 08:27 PM

It's almost dead at 6.6V

adon30 06-01-2013 09:10 PM

Why did you discharge it fully? I hope you recharged it. Or at least a storage charged.

Maybe a thermal cut out on the esc? Did it work ok with other cells?
What is your voltage cut off set to on the Esc? Under load the voltage can drop further which may have triggered a drop off.
Is your charger working correctly? Can you confirm your cells with a multimeter?

mattr 06-01-2013 09:15 PM

the voltage may have dipped when you hit full throttle. and triggered the low voltage cut out

Appie53 06-01-2013 10:06 PM

Thanks for your support. I fully discharged, because I wanted to know about the mAh. Now recharged this pack to 8.4V got allmost 4000mAh into it.
Tested the volt's with my voltmeter, is says 8.55V.

So can I say this pack is OK? I think so:yawn:
My ecs does have a lowvoltage cutoff, so have to work with a buzzer.
Maybe it's time to get a good esc.

Thanks again..........Appie:)

Col 07-01-2013 12:38 AM

Quote:

Originally Posted by Appie53 (Post 729842)
Tested the volt's with my voltmeter, is says 8.55V.

Take a load out of this pack. Don't leave it like this for long!

Battle_axe 07-01-2013 07:48 AM

Quote:

Originally Posted by Col (Post 729897)
Take a load out of this pack. Don't leave it like this for long!

I have seen float voltages of up to 4.95v per cell on allot of cells data sheets so i wouldn’t of thought that is a problem unless this is the voltage with the charger still connected!! But col is right i would use the cells after this as you will be decreasing the cell's life by storing it fully charged

a good storage voltage is between 3.7 and 3.9v per cell this eqates to 40-65% charge

adon30 07-01-2013 09:33 AM

First things first. If you don't plan on using this battery today then take about 1000mah out of it so it can be stored.

Next. You have a 5000mah battery that you used for 2 mins and then you discharged it further and took 2500mah out. You then fully charged and put 4000mah back in. So in 2 minutes run you took 1500mah out of the cell. This does sound a little high for this short a period, but it was in a short course.
The question is. Did you run again after this with any other cells or was this the only run you did? How hot was the motor, battery, Esc etc?

dirty 08-01-2013 12:00 AM

hi all,
it sounds to me that your lipo may be getting a bit past its best, i have all my cut off's set to 3.4v per cell and my 5600mah packs take 5747mah when charged , my 5300 packs take 5390 , if you have a 5000 that only takes 4000 after being discharged to 6.6v and cant even deliver 6.6 at the current your set up wants then, its a sign that its time for new packs , turnigy and gens ace both offer great value and consistant performance, the gens ace offer a smidgen more voltage under lab testing but oddly the turnigy feels like it has more punch!
all the best


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