Hi respected senior flyers, builders & moderators and my friends!!

This topic has been discussed a lot but still I'm scratching my head that what and how this problem can be solved or it's just tinkling of my brain.

I have JR's Ni-Cd battery charger Input 120V 60Hz 3W, Output Tx 11.6 @ 50mA, Output Rx 5.8V @ 50mA. I had 2 battery packs made those were 2,300 mah Ni-Mh for Tx 8 cells 9.6V. I tried to charge them with the same charger and different adaptors, both didnt work right, both drained out so quickly. I returned them both. Now I bought 8 Camelion cells Ni-Cd of 1,000 mah for Tx exactly 9.6 volts. As I got the battery pack made it already had nearly 9.6 volts in it. I did not discharge it, I charged it for nearly 20 hours on and off as we do have power problem in my city, still thats pity, but after charging them when I turned on the Tx it showed nearly 10.9v rather than 11.1 or more. Now as I don't have a recycler or I don't know how to recycle it or do I have to recycle it or just charge it? Second, in order to drain them out, I just extend the antenna of my Tx, turn the Tx on and let it drain out and Im doing it now. After it completely drains out, Remember its 1,000 mah Ni-cd, Im going to charge it again for how many hours? and after that would it give me exactly 11.1 volts, it won't do any glitches or nothing, and turning on the Tx and let it drain out with antenna extended is the right way?

Please advise, and remember, I live in Pakistan, and we don't have a lots of gadgets available here for especially R/C cos not everybody uses it, if they do, I don't know and those who use it they visit, canada, dubai, singapore and USA and get from there.

Thanks for the advices and replies in advance. Please don't be bored

Mody

Rule of thumb is you charge at 10% of rated capacity. The 2300mah pack needs to charge at 200ma.

It is not necessary to discharge your batteries befor recharging for either NiMh or NiCad. If you are charging at 0.1C it wont damage the NiCads if you overcharge them a few hours. You will get approximatelly twice as much life (number of charge/discharge cycles) from the NiCad's than you will get from NiMH. Also, the NiCad's will withstand a bit more abuse than NiMh will, especially with respect to any overcharge at low rates. The belief that NiCads need cycling to prevent memory is pretty much a myth in the way RCers use them. The only reason for ever discharging either NiMh or NiCad is to check their capacity against factory specs and that has to be done under the conditions that the discharge rate is held ot 0.2 to 0.25C and that you discharge down to 0.9volts/cell. Check out www.rcbatteryclinic.com for some good reliable advice on the care of your batteries.

Thanks mscic and Rodney for the reply.

Modoy

So it means as Im using Ni-Cd 1,000 mah, I should be using a charger of 100mah?

Mody

Just so you know, you can charge at nearly 5C if you really need a quick charge. These types of batteries are relatively cheap and VERY durable and reliable. There is no need to cycle these packs, and they will usually last about 400-500 cycles.

I stopped using them and switched to Li-Ions a wjhile ago, but I still have NiMH and NiCD in my TX packs. That's um...over 400 cycles on the one pack 1100MAH NiMH. I have mostly used the wall wart, but have quick-charged at 5 AMPS a number of times at the field. These things are bulletproof these days and require no special care.

Just fly, if you lose a pack, buy another they are almost as cheap as alky batteries these days if you go to one of the sites that advertize on RCU.

Thanks agexpert,

Well, I dont have any quick charger, so I wanna know for how many hours I should charge my 1,000 Ni-cd battery pack with a 50 mah charger?

Mody

You cannot charge a 1000 ma pack on a 50 ma charger. It will not charge fully. Use the 10% rule.

Thanks P-40 Driver,

Im gonna get a 100mah charger for it. Im sure it would work and charge it fullly.


Mody

Yes it will charge, just not particularly fast. The 10% rule isn't the minimum level that will charge a battery, it's just a good safe level.

Divide the capacity by the input of you charger.= 20 hours; the rating of the batt is In MAHOURS You can charge a battery with any small charger as long as the voltage is higher than the battery voltage.

Yes you can charge your 2000 mah battery with the 50 ma charger, it will just take a long time. The lower the charge rate, the more inefficient the charging so it will take a lot more than 20 hours to charge it. Even charging at 0.1C (200 ma in your case) it would take 14 to 16 hours to fully charge and equalize all cells. All is not bad using the low charge rates though as your batteries will last much longer, i.e. more charge/discharge cycles.

Hi again,

My Tx battery pack is not 2,000 its 1,000 mah Ni-Cd. The charger is 50mah, I calculated it would take nearly 20 hours to charge, but I still noticed that in 20 hours, it did not show 11.1 volts, anyway, I asked the guy who I got the battery pack made, he said, you need to charge it and drain it, after couple of times or may be more it should charge better and show 11.1 volts. I asked him to get me a 200mah charger which probably have 12 volts capacity, so is it ok to get that charger if I can get?

Thanks for advices again

Mody

FYI: [link=http://www.csgnetwork.com/batterychgcalc.html]BATTERY CHARGE CALC[/link]

opjose

Great link, good website

Thanks

Mody