Battery question

[azza690]

If you charge your batteries for a fly and don't happen to go out but the next weekend you go to fly. Should you recharge or recycle the batteries before flying or will they have enough stored charge in them????

[BR289]

No, cycling doesnt have to be done all the time, BUT you should not fly without first checking your batteries anyway....Doesnt matter if you charged them a week ago or not...anything can happen!

[Dr. Yankem]

Generally speaking you should recharge before every time out even if you charged and didn't fly a few days ago. All batteries discharge, to some extent just sitting unused. Nicads and nimh have the highest unused discharge rate and can lose 10-15% capacity in 24 hours. Lipos and liions have a much slower discharge rate unused and you could get away of not recharging, but I wouldn't push it too far in time. A123s' have the slowest discharge rate of all, and will have only lost 5 to 10 % capacity after being unused for months. BUT...why take any chances with an expensive airplane. Get in the habit of recharging before any flying.

[f5air]

just get a volt tester and you are done.

[jamesrxx951]

personally i always charge before the day of flying. even if i just charged the day earlier. even my a123's if i charged them one day and decided not to go. if it's the next day i still recharge. just to make sure. charging is free. a bad result isn't

[STLAV8R]

	Quote: Originally Posted by azza690
	If you charge your batteries for a fly and don't happen to go out but the next weekend you go to fly. Should you recharge or recycle the batteries before flying or will they have enough stored charge in them????

What type of batteries?

[classclown]

	Quote: Originally Posted by f5air
	just get a volt tester and you are done.

Don't you mean a load tester?

[f5air]

	Quote: Originally Posted by classclown
	Don't you mean a load tester?

aaa that tool too... lol just kidding. I have a 8 ball from fromeco to check the volts under load of my li-ion batteries and also one for my nimh packs. Its a peace of mind to used.

[dick hanson]

load testers and volt testers -as commonly used in the hobby-are of no real use for A123
If you think they will do the job -you do not understand how the A123 cells function.
Basically -the A123 cells keep a fairly flat voltage and a fairly constant discharge capability for about 90%of the rated capacity
most other technologies, have a easily readable slope in either voltage or load capability
For these type cells -yes-load meters and voltage meters can be used effectively.
A good, balancing charger - can quickly tell you what is REALLY available in a A123 pack.
No other devices I know of, can do this.
A divining stick (or a crystal ball)is as good as the other stuff.

[rcakropilot]

Have 3 2s1p A123 packs from NoBS batteries. Love 'em.

Question is should these packs occasionally be cycled? I only do a couple of flights at each flying session and do not discharge the packs very much. I use an A123 balance charger and only put in 3 to 400 Ma after each flying session.

Also what do you use to discharge them? I read a post that someone said they used a Futaba 2000 discharger. Seems this would work well but does not give any readout of what was left in the pack.

Also in another post someone said they used a Triton. Could this work also?

[TooBizzy]

If you want to use a Triton, I explain how I discharge an out-of-balance pack it in this post:

http://www.flyinggiants.com/forums/f...tml#post726033

By making up the two leads and soldering them up correctly, you can discharge each cell individually thru the balance lead. I had bought my balance taps off Ebay. They came with male and female pluggins. But if your cells are balanced already, you can just plug in to the main lead and discharge down to about 4v on a 2s1p. I used the nicad setting and set the discharge @ 3amps and the cutoff at 4.0v......Works great!

[Badams]

	Quote: Originally Posted by dick hanson
	load testers and volt testers -as commonly used in the hobby-are of no real use for A123 If you think they will do the job -you do not understand how the A123 cells function. Basically -the A123 cells keep a fairly flat voltage and a fairly constant discharge capability for about 90%of the rated capacity most other technologies, have a easily readable slope in either voltage or load capability For these type cells -yes-load meters and voltage meters can be used effectively. A good, balancing charger - can quickly tell you what is REALLY available in a A123 pack. No other devices I know of, can do this. A divining stick (or a crystal ball)is as good as the other stuff.

Interesting item from the Radical RC website. They developed a way to check the A-123 batteries. Here is the text from their website:

We are developing correct procedure for load checking these packs in between flights. Our best advice currently is:
Leave model on after flight, plug loaded voltemeter directly into pack balance plug (charge port ok but not preferred) hold load engaged, switch model off. Allow pack to drain into meter 5 to 10 seconds, take your reading. If load is 1 amp (1000mah), do not start flight below 5.35 volts. If load is .5 amps (500mah) do not start flight below 5.72 volts. Meters with lower loadings should not be utilized. The most stable and repeatable readings are taken in this fashion. The idea here is to preserve the existing condition that the battery has been loaded for some time prior to your taking the reading. Pilots are accustomed to taking readings prior to a flight and thus the reason for the often printed myth that these cells cannot be load checked. Check them immediately after your flight and certainly recharge if they fail the above test.

Pretty interesting. I haven't tried testing my A-123's this way but plan to see how it works.
I, like probably everyone else know approx how much I use per flight and recharge after 4 flights. My cell pro does give me a percentage after I plug it in. I would think someone could make an accurate tester that pops up the remaining percentage like the cell pro does, but it may have to start to put a charge on it or something before it can make that determination, so a small tester may not be practical.
Bill

[STLAV8R]

	Quote: Originally Posted by Badams
	Interesting item from the Radical RC website. They developed a way to check the A-123 batteries. Here is the text from their website: We are developing correct procedure for load checking these packs in between flights. Our best advice currently is: Leave model on after flight, plug loaded voltemeter directly into pack balance plug (charge port ok but not preferred) hold load engaged, switch model off. Allow pack to drain into meter 5 to 10 seconds, take your reading. If load is 1 amp (1000mah), do not start flight below 5.35 volts. If load is .5 amps (500mah) do not start flight below 5.72 volts. Meters with lower loadings should not be utilized. The most stable and repeatable readings are taken in this fashion. The idea here is to preserve the existing condition that the battery has been loaded for some time prior to your taking the reading. Pilots are accustomed to taking readings prior to a flight and thus the reason for the often printed myth that these cells cannot be load checked. Check them immediately after your flight and certainly recharge if they fail the above test. Pretty interesting. I haven't tried testing my A-123's this way but plan to see how it works. I, like probably everyone else know approx how much I use per flight and recharge after 4 flights. My cell pro does give me a percentage after I plug it in. I would think someone could make an accurate tester that pops up the remaining percentage like the cell pro does, but it may have to start to put a charge on it or something before it can make that determination, so a small tester may not be practical. Bill

I can't wait til' they come out with a bullet-proof way to check A 123's.

[rede2fly]

personaly i charge before a day of flight nomatter what. i use A123's and i will allways charge before the first flight. i have done this since fast field chargers have been on the market why even take the chance?? i had a battery pack go bad inbetween flights once and it sucks.