Tekin BC 112 & NiMH Rx pack

[CNSelf]

Can someone help me set this unit to charge a 5-cell 1100mah rx pack? I cannot find any info about the BC 112 and NiMH cells.

Thanks

 

[Çh®i§tiªñ]

Charge at 1 amp if you can.

 

[scottm]

Hate to disagree with you again today Christian, but rx/tx batteries should be charged at 1/10 to 1/5 C for best life and capacity. I have Trinity 1150 nimh rx packs and I charge them at .2 amps.

 

[Çh®i§tiªñ]

lol - no problem.

Whats your reason for charging them at .2 amps? And how long does it take to charge a 5 cell hump pack at .2 amps?

 

[scottm]

.2 amps is about 1/5 C or capacity. Since they discharge at low current, you should charge it slowly too.

C stands for capacity in mah. 1/10 C is .1 amp per 1000 mah, 1/5 C is .2 amp per 1000 mah capacity. So charging at 1/10 c will take 10 hours, 1/5 c will take 5 hours, and 1 c will take 1 hour.

 

[Çh®i§tiªñ]

Hmmmmm..... While I can agree that looooooong charging any of your packs is a good thing, I also have to disagree with the practicality of it.

For instance, in the field, that wouldnt be practical at all.

I sometimes even re-peak my rx pack after 3 tanks just to keep my steering in check. Especially on my MT's. The dropoff on 1,100 mah packs is pretty soon, all things considerred.

Now my racing packs are a totally different story (6 cell packs - 3300 mah). The initial charge on those packs, at 1 amp, took about 4.5 hours and came in at a whopping 3947 mAh. Thats HUGE! I discharge them at 20 amps with a .9 v per cell cutoff and charge at about 5 amps for regular run use. The packs never broke a hundred degrees. The most important factor IMO.

The difference between high amp and low amp charges is the tradeoff of mAh for Voltage. Charge at a higher amp setting and the voltage will be high. Charge at a low amp setting and the mAh will be high.

At the end of the day, temperature is the most important thing to NiMh cells. And if you can find a sweet spot, where you get voltage you desire AND runtime you are looking for, then you are winning. Todays high torques servos for steering alone, require BOTH to be worth it.

While there is NOTHING wrong with charging a 5 cell, Nimh, 1100 mah pack at .2 amps, it just doesn't work for me. 1 amp, even 1.5, has ALWAYS treated my packs very well, with no harm done and no bad results.

oh, a the 3mv per cell cutoff is key for me too. But I dont think we are coverring the cutoff mv's and why. Of course, not to cause the packs to get too hot and possibly explode lol

Peace out.

 

[CNSelf]

Thanks for the replies - all stuff I basically never knew. Is it going to make a difference that the charger I was given is a BC 48 instead of a BC 112? If .2 amps is the best rate for this pack, should I use the trickle charge (.2A) ?

Thanks again!

 

[Çh®i§tiªñ]

Charging rates for receiver packs can go as high as one times their capacity. For example, a 1200mAh pack can usually withstand a charge rate of up to 1.2 amps, a 700mAh pack up to 0.7 amp and so on. Calculating charge times is as simple as dividing the battery capacity by the rate of charge. If you're charging a 1000mAh pack at 0.5 amp (or 500 milliamps), it will take two hours to completely charge a dead receiver battery.

Charging receiver battery packs requires a charge rate of 1 amp or less. I've experienced false peaks (the charger shuts off before the charge is complete) when charging at a 1A rate, so I chose not to charge any faster. A general rule is that you don't want to charge these smaller cells at a higher rate than their capacity, so an 1100mAh pack would be charged at no more than 1100mA (or 1.1 amps). Charging at the same rate as the capacity of the pack means it will take roughly one hour to charge the pack.

Trickle-charging is the practice of charging at a very low rate (150mA or less) for a longer time. The wall chargers that come with some radios are adequate for this purpose, but they typically charge at 50 to 100mAh, which would require 20 hours and 10 hours, respectively, to fully charge a 1000mAh receiver pack. Battery expert Rich Hawkes from Trinity cautions that, even if they're given sufficient time to charge fully, wall chargers can only charge to about 80-percent capacity for NiMH receiver packs. He went on to say that this is probably good for beginners because it's easier on the receiver battery pack, but it doesn't allow as much run time as a pack charged with a peak-charger. The only precaution concerning using a wall charger or any other trickle-charger is not to leave the receiver pack charging indefinitely. Trickle-chargers aren't as "smart" as peak-chargers, so they don't know when to shut off; they just keep going until you unplug them. They do that mostly because they charge at such a low rate that external harm is unlikely to result from over-charging. It appears the only harm is that it may compromise the performance of the pack over the long term.


That came from:

http://www.rcnitro.com/articles/gs_batteries3.asp

 

[slodsm]

The Tekin chargers are not capable of peaking NiMh batts becuase they do not have the updated software for the lower threshold required my NiMh, don' t leave it unattended or it will smoke your pack. And no, charging at .2 amps is a joke, you will be there all day and have no voltage. I charge mine at 1 amp and have for years, they are fine that way.