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A123 charge testing

TnAeroNut

TnAeroNut

50cc
How is everyone testing their A123's? I've been using them for a couple years now and mostly go by counting number of flights based on the number of mAH's put in last charge. I'm looking for a way to reliably check charge before each flight, but the discharge curve is so flat it's hard to detect the "knee" before it's too late. Has anyone used the ElectroDynamics tester? Is it any different than a common voltmeter with built - in load?
 
3D-Joy

3D-Joy

50cc
The discharge curve being so flat, the checker needs to be that much more precise to actually have a worthy reading.



Once or twice a year I fully discharge my batteries to check their real capacity. It also tells me how healthy my batteries are. I charge every flight so I don't check my batteries with a checker but with the mah I put back from the previous flight.



I once saw the batteries drop while being discharged on my charger. Its FRIGHTENING how fast they drop. Litterally a matter of seconds from apparently good voltage to dead at only 1A load.
 
Terryscustom

Terryscustom

640cc Uber Pimp
You never want to "fully discharge" your A123's. Discharge to 2.0 volts per cell. Let it rest a bit then re-charge at about 2 amps and see what it puts back in. I only do this to batteries that are over a year old. Only ones I've had drop off so far is the LiFe packs, my "real" A123's remain in perfect condition.
 
Terryscustom

Terryscustom

640cc Uber Pimp
3D Joy;19022 wrote: You mean 2 volts per cell?

Yeah that's what I meant by fully discharging them.
Click to expand...


Ooops, yup, thinking faster than typing. Just wanted to clarify since I've heard of people running them down way deep like a NiMh or something.....not good.
 
Jetpainter

Jetpainter

640cc Uber Pimp
Ohio AV8TOR said


Bunky F. Knuckle;19006 wrote: A battery tester that has a "fuel gage" in it.

http://www.taildraggerrc.com/gt-power-digital-battery-capacity-checker-great-for-a123s/

http://www.futaba-rc.com/accessories/futm4166.html

I have the Futaba checker. Actually won it at an event. But keep in mind, that both checkers are a static check only. Not loaded.
Click to expand...
Do you set the battery chemistry type or does it recognize it ?


I have a similar tester with a fuel gauge and it defaults to LiPo's so you have to set it to others. I find it's not very reliable for LiFe or A123 style batteries. I use a 2100mah LiFe pack in my 550 helicopter and before the first flight it will read in the high 90 percents. After one 6 minute flight it reads 56% after that it only drops around 2% per flight. The heli is using about 275mah per flight. I still use it between every flight whether it's accurate or not just for a little piece of mind.
 
mndless

mndless

Don't know a thing..
For those that check their batteries between flights....  is there a bulkhead access port you are using ???
 
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