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Old 04-30-2012, 06:07 PM   #1
dpinvidic
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Default How do you test batteries

I noticed my heli's are getting pretty sluggish on fast climb outs. So I tried a new battery, and what a difference. So I wanted to try to try to meassure my old packs to see where they stand. Has anyone done this...and maybe the expensive chargers can do it, but i don't have a expensive charger.

I was thinking of just putting a load on the battery (say 10 50w LV bulbs), and meassure how well the battery holds the voltage. This is about 20c for a 2200mah 3S battery.

Are there any other methods that have worked for other folks?

Thanks,

Dan
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Old 04-30-2012, 06:27 PM   #2
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some chargers allow you to use an external resistor to discharge batteries at a higher current than the built in resistor. I have an iCharger 106 with this feature. It can discharge at up to 5amps. Its a 10 Amp charger but it will only do 5 amps in this mode. The manual does not really tell you this. I bought a 2ohm 225 Watt resistor at Newark. This is the right value for a 3S battery. You would need a different value for a different cell-count battery.

The advantage of this method is that the charger counts the mAh and maybe some of them will log a discharge curve.
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Old 04-30-2012, 07:36 PM   #3
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You don't really need to test them.. if they get tired... toss them. Nothing is going to bring them back. Lipos are expendable. I have yet to get over 80 cycles on a lipo. Although my Gens Ace will go there since they are nearing 70 cycles and fly like new still
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Old 04-30-2012, 10:43 PM   #4
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understood...but it would be nice to know how tired they are. I would feel better if I could get a voltage reading under load rather than just flying it and trying to guess if it is time to throw out. One example...if I am going to be doing some backward flights slow pirous becasue I am still learning these moves, I would not mind using a tired battery. Sorry...I spend enough on parts for crash repair, so I want to get as much mileage out of batteries as possible.
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Old 04-30-2012, 10:48 PM   #5
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Still... that size pack is so cheap! Just replace them IMO.

These are good and only $16.00 each from USA warehouse

http://www.hobbyking.com/hobbyking/s...dProduct=14962
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Old 04-30-2012, 11:04 PM   #6
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What kind of charger do you have? If it can read the IR you could do a quick test and see what the IR of the pack or cells are would be helpful.. also doing a discharge test and measuring how much mAh it puts back in (if it still has 80% capacity left) to test for life.
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Old 04-30-2012, 11:22 PM   #7
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Quote:
Originally Posted by Slyster View Post
Still... that size pack is so cheap! Just replace them IMO.

These are good and only $16.00 each from USA warehouse

http://www.hobbyking.com/hobbyking/s...dProduct=14962
your going to hate me....These have been my battery of choice. I have about 7 of these...and get this, they are over 1 year old...and I fly every day.
But I think I am switching to Sky Lipo. they are 40C and seem to have quite a pop.
But you are right...having that many flights is as good as can be expected.
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Old 04-30-2012, 11:26 PM   #8
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Default The IR is more significant than the mah during recharge.

Quote:
Originally Posted by Shortman View Post
What kind of charger do you have? If it can read the IR you could do a quick test and see what the IR of the pack or cells are would be helpful.. also doing a discharge test and measuring how much mAh it puts back in (if it still has 80% capacity left) to test for life.
I just have some B6 amd B8 chargers...they can't read IR. But measurieng the V during a heavy load, you are actually measuring the voltage that is lost across the IR of the battery. I don't think the mah number tells us much about IR.. After most of my 5 min flights, I put back about 1300 - 1500 mah. But the key is the IR during a heavy load.

Dan
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Old 04-30-2012, 11:30 PM   #9
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Well if you want to just do an actual discharge graph with a load get the CBA III

http://www.westmountainradio.com/pro...code=/cbaLink1
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Old 04-30-2012, 11:37 PM   #10
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Default Good Idea...

Quote:
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Well if you want to just do an actual discharge graph with a load get the CBA III

http://www.westmountainradio.com/pro...code=/cbaLink1
Now your talking....but kinda expensive. But that would justify buying a PL6 - which I think would give me the same discharge info. And I would get a great charger to boot.

I will seriously think about doing that....thanks again.

Dan
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Old 04-30-2012, 11:50 PM   #11
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Yeah it's what a few of the big battery guys on rcgroups are using to do lipo battery testing for some manufacturers. The CBA is a really sweet unit from the looks of it, I've thought of buying one just for my own testing but for now I just use my chargers IR reading for measurement. You can get the add on for the CBA III and discharge lipos at like 160amps if you want to buy their 1000watt discharge set up but it cost a small fortune.
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Old 05-01-2012, 12:27 AM   #12
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Quote:
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your going to hate me....These have been my battery of choice.
Good to know... I figured your were buying overpriced packs like Eflite or TP etc... I myself am DONE with Turnigy packs and am totally on Gens Ace currently... I have 13 of them. They are the best... still cheap but they are a bit more expensive than the Turnigy's. My 8 6s4000's are amazing and so are the 5 6s5000's.

IR is what you want to measure. My Gens Ace packs are nearly 70 cycles now and they are all still in the 0-2 range. Excellent packs and I am anticipating 200+ cycles out of them.

It would of helped if you stated what packs these are that are getting tired and how many cycles they have. So what are they and how many cycles? Turnigy's are cheap.. but they are the very ones that I never got over 80 cycles on.
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Old 05-01-2012, 01:19 AM   #13
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Damn only 80 cycles. I have over 300 flights on my hyperions and the ones i just bought arnt much more powerful. I use a crappy passport charger. And many times leave them fully charged for more that a day or leave them discharged for more than a day. I was thinking of trying the nanotechs or genaces but after seeing so many people needing new packs after 100 cycles or less the extra 20 bucks for hyperions is worth it atleast for the size im using. 2200... I guess big packs would be different.
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Old 05-01-2012, 01:35 AM   #14
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Dumb thought...would you be near any club that perhaps a member would be able to use one of the higher end chargers to evaluate your batteries for you? Or another Heli-freak that may be near you that might check them?

I use a cellpro pl8 to run several cycles for ma in/out and ir on iffy batteries. Actually found a few bats I thought were tired worked much better after using the pl8. In any event, good luck.


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Old 05-01-2012, 09:36 AM   #15
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Quote:
Originally Posted by Slyster View Post
It would of helped if you stated what packs these are that are getting tired and how many cycles they have. So what are they and how many cycles? Turnigy's are cheap.. but they are the very ones that I never got over 80 cycles on.
The Turnigy 2200 3s batteries is what I have. I like the fact that the balance lead is teflon wire, and hardly ever breaks at the solder connection.
I don't log data on the bats, but I fly every day, usualy 4 packs before work. so out of my 6 batteries, most of them have over 150 flights.
I sure can't complain about those batteries. I am going to fly today with 2 new sky lipos, one new Turnigy, and one old Turnigy. This will give me a good comparison.

One problem is that whan you fly every day with the same batteries, they slowly degrade. So you tend to forget how it was when they were new. But it becomes obvious when you try a brand new battery.

Thanks to evryone who posted on this thread...it has been a big help.

Dan
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