Taking care of Lipos

Started by anwar, March 23, 2009, 09:32:34 PM

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vinay

Thats for the old-school dean boys  ;). (God knows how many will offend me after reading this  >:D)

The latest and the neatest is here:

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=14856

traxxrc1

Hi everybody. I am facing a problem. Three hours ago i discharged my 3 cell  lipo to 8.76V . The battery puffed up a little. What should i do now. When should i recharge? How close i was to get it smoked or fired up?
I'll be back.

anwar

Should be usable.  Watch it the first time you charge it though, and do the charge at a lower rate (just being cautious).

If the charger refuses to charge it as a 3 cell, search this forum for "trickle charge" methods, as an attempt to revive it.
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SunLikeStar

Quote from: anwar on October 18, 2010, 08:04:39 PM
So it would be a good idea to stop using them at 3.7V per cell.
So is there any ESC that allows programming LVC to higher values like 3.7 or even higher may be?

clayboy

what u want is something that monitor each cell in the pack under load. like schultze lipodimatic. it will slow down motor when fist cell is on 3,3v so no cell will go under 3v, it will cut power to motor if 1 cell reach 3v under load
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saurabhhsrivastavaa

The highest that I have used has an LVC at 3.3V. Not sure if there are ESC that can be programmed to 3.7 or higher. Usually they have fixed number of options. (Low, Mid, High) (2.8V, 3.0V, 3.3V)
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Saurabh
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SunLikeStar

Lipodimatic is an awesome system but it also has the same (2.8V, 3.0V, 3.3V) setup option, 3.3V is too low IMO.

clayboy

why?
I can c for low 3d smack down heli flying but that involve any lvc
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SunLikeStar

I had one esc cut down my 3s 2200 lipo in flight, measured each cell had 3.3V. Later i recharged it no problem but on next flight it hit LVC again within 15 minutes, I used to get more than 30 minutes on that battery without hitting LVC. I still have it but dont use it as the capacity seems to drop every time i use it.
And all this on a glider :( no 3D no helli nothing.

clayboy

well that is a bit different, that is 3,3 with no load, with lipodimatic it is under load and when volt is dropping batteries get very unbalanced

and a lvc set on a average of 3,3 even under load 1 or more cell can drop way under 3v,

with lipodimatic it monitor each cell and can not go under 3v mean it will never damage battery,

lipodimatic is made for old formula batteries and today when battery hold volt so good until they are totally empty u have to land pretty quick with a heli, i am not using it anymore do i start to fly alot lower and harder and if low inverted and have to do a hard stop i maight not be able to stop fast enough if slow down motor and maybe crash but if u are up a bit it is no problem or for a car if u not respond to the slow down or the other setting it will cut and u just have to walk and get it
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SunLikeStar

makes sense! thanks for explaining.

clayboy

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Snehal.Samar

I have this charger
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=7637

and have 11.1v zippy 1500mah.....and 1450mah turnigy.
how to store them??.(i will not be using it for atleast 4-5 months)
________________________________________________________________

I had 1600mah turnigy..but it got puffed(but the puffing is not hard,i.e. when i press the puffing area it gets pressed).I left it about 3 months unused .so can i revive it?

Thanks
SS
Snehal Samar

vinay

1)No store function there on that charger. You have to store the cells at approx 3.8X volts per cell. 3.85- 3.89 would be just fine. The charger has a charging current of 800 ma, so if the lipo is completely weak(around < 3.6 volts per cell), then charge the lipos for approx 55 minutes and you should be good to go.

2)If the lipo is slightly puffed during use/store(if stored at very less charge or full charge it will slightly puff), you can still use it. Its hard to judge w/o a pic :)

Snehal.Samar

How can i measure individual cell voltage?by opening the cover and measuring each one?

Can lipo be stored in refrigrator?
Snehal Samar

Swapnil

You don't have to open the cover. You can measure individual cell voltage on the charging plug.
I stored a LiPo (in a plastic box) in a refridgerator for 6 months.  It's safe.
Just don't freeze it below 0 degrees.

vinay

No, just use a cell monitor - something like this - http://www.hobbyking.com/hobbyking/store/__19066__HobbyKing_Cell_Key_6s_Lipoly_Cell_checker.html

If you dont have one, you dont open the cell package - use the balance terminals to measure voltage. If its a 2S lipo there will be 3 wires going to the balance terminal. measure the voltage between the first and second wire - this should be the first cell voltage. Then measure the voltage between 2nd and 3rd terminal, this would be the second cell voltage - which should be same as 1st cell.

Swapnil

Charging plug = balance terminals. :)
Do use DMM probes with nice pointy tips!

vinay

Do be careful when measuring voltage with a voltmeter, sometimes a simple short circuit means the terminals inside the package melt and the cell becomes useless.

Snehal.Samar

http://www.hobbyking.com/hobbyking/store/__18588__Hobbyking_2_8S_Cell_Checker_with_Low_Voltage_Alarm.html


will this device solve all the problem??
i.e. worrying about low voltage while flying
and checking voltage of each cell for lipo storage.?
Snehal Samar

vinay


Snehal.Samar

Quote from: vinay on March 26, 2012, 03:15:24 PM

2)If the lipo is slightly puffed during use/store(if stored at very less charge or full charge it will slightly puff), you can still use it. Its hard to judge w/o a pic :)


unfortunately i am unable to upload pics. but yes it seems like their is air in between.(which gets pressed when pressed with fingers.
when i am trying to connect that puffed lipo3s to the esc nothing happens ...i measured the voltage from discharge plug and is not same as my other 3slipo which works fine but IS LESS.(unable to determine exact coz multimeter reading are faded.)

How can i revive it back??
Snehal Samar

vinay

If its much puffed and cell voltage are low, then it may not be a good idea to revive it back. I have never revived a lipo before, so wait for answers.

Arnab

My charging plug of Turnigy 1600 maH got destroyed !! Is the charging plug replaceable ??
Actually its a four pin entering charging plug and a piece of metal pin got inserted accidentally .
Its now coming out nd its tightly present inside the hole.. Please help me out if the plug is replacable or if it can repaired by an electrician ??  :help:

rastsaurabh

you can remove the particular pin from the connector..... use a pin to press a lock in the connector while pressing the lock pull the wire out. then remove the inserted metal and open the lock notch a little and insert again.