Harleyflyer

My Feedback: (9)

I recently ordered new higher capacity NiMH receiver and transmitter battery packs. Should I cycle the battery packs a couple of times before I really use them or is this not really necessary. I thought I had read somewhere about cycling new battery packs in order to get the packs to operate at their intended capacity/duration...not sure if I am using the correct terminology here. Also, I know that NiCD batteries should be cycled periodically and I have heard that with NiMH batteries, you don't really need to do this.....but just wasn't sure if new NiMH packs should be treated differently.

Thanks in advance.

Mayday!Mayday!

Harley, on nihms most people don't think you should but I do. Slow charge the batteries and slow discharge them for 3 cycles and the will be just fine. I do this with all of mine, except for 2 of them I was in a hurry to fly after I bought them and fast charged them and they both lasted about 5-6 minutes. The ones I cycled lasted 15-17 minutes.
So I am a believer in slow charge-slow discharge cycle.

JNorton

My Feedback: (2)

Most people on this forum are learning you should always slow charge and cycle new NiMh packs.
John

EDIT -> The charge should be C/10- for 14 to 16 hours. The discharge should be C/5 to .9 volt per cell. Also called forming. C is thr rated capacity of the pack.

John Murdoch

My Feedback: (11)

It's called conditioning... Sometimes, it may take up to a dozen cycles or so to get a NIMH up to capacity.

gm72

You'll also hear the term "formation charge" used frequently to suggest a slow initial charge cycle. I personally cycle my new batts 3 times using a very slow C/10 rate.

gerwen

I do this three times on new packs.

Rodney

I agree with Mr. Norton and my experience has verified the necessity of doing the forming charges if you want the most life and capacity from either NiCad or NiMh. It is also a good practice to do this forming charge again if the battery has sat inactive for more than 30 days. It also helps to do this slow charge (forming charge) periodically on all batteries, especially if they have been given a lot of fast charges. It will often rejuvinate packs that seem to have lost their edge.

MannyEdge

My Feedback: (9)

I see many posted the formula for slow charging c/10. How many hours would it take to slow charge 2000 nimh 4 cells?

Thanks

JNorton

My Feedback: (2)

C = the pack capacity. So if you use a C/10 charge the time is the same in all instances, because the charge rate changes to match the pack. 14 to 16 hours.

MannyEdge

My Feedback: (9)

I have another question. I am charging the battery now and it gives me reading of 1900 mah for capacity, but the battery is only a 1650 mah. How is that possible? Note: This is the first charge so far. Could it be giving me a false reading since it is the first charge? I am doing a slow charge - .15 amps.


This is NiMh, 4 cell and 1650 mah.

Thanks,

JNorton

My Feedback: (2)

That's about 14% over the label. All it means is you've got a good pack. No worries.
John

Floater-RCU

John my new NoBs 1100 NiMH packs have info about the formation charges. It says the same as you for charging and down to 1.0V per cell for discharge. The problem is my Triton charger goes down to 0.8V per cell in the cycle mode. (according to the manual, fixed value) Is this OK or will it hurt the packs? All I have for a wall charger is my JR which is only 50mAh so I was hoping to use my Triton for cycling.

Floater

JNorton

My Feedback: (2)

You can go to .8 volt without hurting the pack. I usually just use the single discharge mode which you can set to .9 or 1 volt per cell threshold. U-dUd has more information on using a Triton for form charging here. [link=http://www.rcuniverse.com/forum/m_3920172/anchors_3939058/mpage_1/key_/anchor/tm.htm#3939058]Link[/link] Read down to post 17 you will have to change some settings. I prefer to use a wall wart charger for a C/10 charge. Radical RC has a Cermark CH84 TX & Rx Wall Charger - Output Rx = 6.0V 125mA or 4.8V 150mA, Tx = 9.6V 90mA for $12.00 http://radicalrc.secure-mall.com/sho...58&cart=396449
John

The idea of using C/5 discharge to .9 or 1 volt per cell is that it mimics what the manufacture used to rate the pack. By going down to .8 volts you'll inflate the capacity results a little. Not a big deal if you note it for future reference. Use the packs capacity when new - verses down the road. When the packs capacity diminishes by 20% less it is time to replace the pack. I just note mine on a sticky taped to the pack itself.

Floater-RCU

Thanks John.