nute12

My Feedback: (14)

you must mean c/.10 &.20 which is about what a factory wall wart puts out. Even on a 700 mah pack.... my charger will not put out 14 amps....which is a c20 charge for it. nimh usuallly .4c max
On ,my 2500 mah tx pack (aa batts) i charge it at .4 amps. If I try to charge any faster i get a false peak. And they do get warm when right at the end of the charge. I charge my 2300 mah A123's at 4.6 amps.

JPMacG

My Feedback: (2)

Yes, C divided by 10 or 20. Or, C times 0.1 or C times 0.05.

Rodney

I did some temperature test on what happens when you slow charge a Nixx battery. I was surprised to find that even at slow charge rates (0.1C) there is a slight temperature increase when the batteries are fully charged. It is so slight that you can not detect it by feel (at least I can not) but using an infra red thermometer I did detect a slight increase when the batteries reached full charge. How much change: depends on the surface area of the battery and how it is connected to the environment, if lying on a metal bench you will get less temperature rise than if it is sitting in a still (no air flow) environment on a wooden bench. Worst case for heat rise would be inside a fuselage wrapped in foam and no circulation. Heat, especially lots of it, is a big enemy of any type battery. That is why your batteries will last a lot longer (more charge/discharge cycles) if always slow charged rather than fast charged using peak detection.

kurt2022

My Feedback: (18)

I would take this as a good time to change over to life batteries, I have dealt with nimh batteries for over five years and have now upgraded to life batteries! I fly mainly larger planes with digital servos and didn't know how big of voltage drops I was getting in flight when most of the servos were moving until I bought a dx8 with telemetry and checked the min. voltage of the flights! All my life batteries are 6.6 volt 10 to 30c discharge with NO voltage regulator and the voltage drops that nimh batteries gave me have completly become a thing of the past! Move up to the new technology and you will be pleasantly surprised with them! My life batteries are usually completely charged in 30 minutes or less and that beats the heck out of overnight any time! I use lipos on my 4.8 and 7.4 volt ignitions and add regulators for the 4.8 volt ones!

raptureboy

Some of the best battery info you will find. http://hangtimes.com/rcbattery_faq.html

Stick 40

I guess I have not been following battery updates, what are "life batterys "

I guess I am looking to replace some of my batterys and now would be good time to look into the new ones out.

jester_s1

LiFe batteries are a newer lithium chemistry. They have all the good things about Lipos (fast charging, no self-discharge, high amp capacity) with a usable voltage for our receiver packs and none of the fire danger. A 2 cell pack gives 6.6v nominal, but the actually voltage to the receiver is very close to the same as a fully charged NiCd. I'm a fan because I can charge them when I have a chance during the week on planes I don't fly much and they'll be ready when I am. They are also a touch lighter than NiCd's but close to the same weight as comparable Nimh's.

Stick 40

wow, sounds great. Toledo weak signals is coming up, I will diffidently look into them.

back on the subject of battery life, I went out flying with one of our club member yesterday and we talked about battery life.

He said he has run battery for up to 10 years if treated right, now that seems a little long. Now this guy is very good and ( also he is a doctor ). He only fly's elect. and has a very good working knowledge of battery's and elect. planes.

I have never lost a plane to radio problems, and that means battery no problems also ( dumb thumbs , maybe ). I have run many battery for 4 and 6 years with no problems. I am not saying that I recommend this, but I have done it.

All my battery's are 4 years old. I plan to cycle all before summer and see how they check out.

Rodney

Properly treated, a Nixx battery will last a long time. The manufacturing techniques are critical in determining lifetime. The usual failure is the deterioration of the separator material used to insulate the cell material. Once this material starts to disintegrate, the cell is history. Heat is the big enemy here, overcharge, excessively high charge rates or discharge rates accelerate this. Any thing that build up pressure internally (like heat) can rupture the seal at the positive terminal and once that happens, the cell dies a slow death. If properly used, NiCads will serve you well for several years.

Stick 40

I got a good check on my tx battery, its the 2500 Ni-Mh.

when I got it 4 years ago , I tested it and came up with about 23xx capacity.

Now I get 2250 capacity, question. Do I look at the 2500 for the figure to use the lower figure .

I know the 2250 is well withing the 80% range, just wondering which to use.