TeamSkunkwerks

iTrader: (142)

You know......I'm wondering if he's just charging one cell at a time, instead of like the other poster mentioned 8AA batteries? That would make a big difference!!

jbjints

I am charging a pack. The pack is a Futaba NT-8JY pack. Sorry if I did not provide enough information.

Dave H

Hey it’s OK, probably a silly question on my part anyway. I suspect the guys mentioning the safety timer are correct.

In addition to the timer issue, if too low of a charge rate is used the delta peak detection of a typical RC fast charger frequently won’t work correctly. Which I suspect is the case for the recommended amp settings, likely why Futaba also specifies the charge time for each amp setting. Thus you might need to rely on time anyway. Ideally by adjusting the safety timer up, or by manually resetting the charger to get the time, or by getting it into trickle charge mode and manually timing.

Sounds like your charger, like many, only goes in 0.1 amp increments, so you need either 0.1 amp for about 7.5 hours, or 0.2 amp for about 3.75 hours. I don’t think the slightly higher rate will be harmful, based on my experience with the same Sanyo 600mAh AA cells.

You could consider a higher rate I think, I occasionally used around 0.5 amp on those cells when in a hurry with reasonable success, however they weren’t in shrinkwrap, which might trap more heat. The thing to watch for is temp, the pack should not get very warm until the end of charge, even then it should still be comfortable to hold in your hand. Hotter is not so good. Generally if the pack is in decent condition the peak detect should work with a such a charge rate.

But be aware, while nicads can generally take relatively high charge rates, it will reduce the run time. Much different than the lipos many are used to or only familiar with now days. If you have the time the lower rate is probably the way to go for a transmitter pack. Also be aware the pack should be discharged most of the way before recharging, as nicads have a memory effect. Down to 1V per cell usually works well for such transmitter batts, some go to 0.9V per cell.

All that said, nicads are kinda high maintenance and low capacity compared to more modern batteries. If you have a chance to upgrade, I think the Low Self Discharge / Ready To Run nimh batteries make great transmitter batteries. Most of the advantages of lipo, with perhaps less down side. Although lipos are still a good choice too as wingracer mentioned earlier.

Hope this helps. Good luck with whatever approach you choose.

Dave H

Why would that be? The cells are in a series circuit, they all see the same current.

newracer69

Futaba NT8JY NiCd 8-Cell 9.6V 600mAh Transmitter

thanks..small mah so the lesser charge rate would apply. .6 amp or 1/2 amp..you might have a short amount of Run time with ur radio with that pack..a 3 cell a123 1100mah will last alot longer and half the weight..9.9v

Dave H

Curious, is that with the batteries discharged, or just topping them off? Reason I ask is that is not very much total charge for typical AA nimh. Even accounting for the near notorious shortfall in rated capacity that seems to be the norm for AA nimh cells, especially ones rated well over 2000mAh best I can tell.

TeamSkunkwerks

iTrader: (142)

Some chargers will let you enter the Mah & automatically set the amp rate, & cutoff voltage.

Dave H

As long as the charger can maintain the chosen amp rate, which is highly likely for a transmitter pack, they will charge in roughly the same time. 1 cell, 4 cell, 8 cell, makes little difference.