sschwell

I emailed the following to "Great" Planes over a week ago and never received a response. Yesterday I sent it again and copied it to [email protected]. I have received nothing. Well, maybe some of you guys can weigh in on this. I realize that a cuttoff voltage 0.8/cell is not a problem unless you have a very weak cell in the pack, nonetheless I wanted the manufacturer to clarify their position as they did make some contradictory statements in their product manual. And while you're at it, I wouldn't mind hearing your thoughts on the lack of responsiveness (or should that be responsibility) from "Great" Planes Customer "Service".


Sirs:


In the product manual for the Triton you state that:


“When discharging Tx and Rx radio batteries, the discharge cutoff voltage should be set at 1.1 volts per cell. A 4-cell Rx

battery would therefore have a discharge cutoff voltage of (1.1 x 4) 4.4 volts. Do NOT

attempt to discharge cells to voltages lower than recommended.”


Yet for Cycling modes the charger will only operate at a fixed cuttof voltage of 0.8 Volts per cell. The manual states :


“For NiCd and NiMH “Chg to Dsch” and “Dsch to Chg” screens, briefly press then

rotate the dial to select the proper charge and discharge currents. Note: During cycle

mode, the discharge cutoff voltage for either battery type is FIXED at 0.8V per cell.

This is not adjustable.”


I can only conclude therefore that you would recommend against using cycling modes for receiver and transmitter packs. Is this correct? Would you advise against using cycling modes for receiver and transmitter packs?


Moreover, for cycling modes there is nowhere to input the number of cells in the pack being cycled. Accordingly how does the charger know when to stop charging or discharging?


Thanks for your help.


Steve Schwelling

Rodney

The only reason for the 1.1 volt rule is to prevent reverse charging the weakest cell. You can really safely discharge a single cell to zero volts without damage providing you do it at a rate that does not severely raise the internal temperature. If you have a series of cells, the weakest one will reach zero voltage first but the continuing current would reverse charge it if you let the discharge cycle continue. This would most probably irreversably damage the cell. By limiting the discharge voltage to about 1 volt per cell, the probability of reverse charging a singe cell is very remote. The 0.8 volts the Triton uses is perfectly save for 4 cell batteries and nearly as safe for 8 cells. If you get many cells in series, there is no safe (volts per cell limit) you must monitor the voltage of the individual cells and stop the discharge as soon as one or more cells approach zero volts. You might want to check out www.rcbatteryclinic.com for lots of good advice.

Geistware

My Feedback: (16)

I always use 1.1 volta as a cut off at my standard discharge rate while flying which is 1 amp.

sschwell

Thanks for your responses. Finally after alot of hassle and long wait I got a good response from Great Planes Electonics support. Here it is.

Hello,

Thank you for your recent e-mail. I apologize for the delay in response to your original email. After reviewing the manual, I agree with you about the confusing matter of discharging packs. What should be stated is that Tx and Rx battery packs should be recharged if the voltage is lower than 1.1V per cell. Since this value is the lowest voltage per cell that should be safely used in application, it is recommended that this voltage be used for normal discharge cutoff prior to re-charge. The 1.1V per cell cutoff voltage can also be useful to determine the usable capacity of the battery pack. The cycling mode (charge-to-discharge and discharge-to-charge) functions have a fixed voltage of 0.8V/cell cutoff which is not adjustable by the user. This value is lower than what would typically used as a straight discharge cutoff (the 1.1V/cell as referred to above) for the purpose of deep cycling and conditioning packs.

If the battery manufacturer specifically warns against discharging a battery pack to a voltage that is greater than 0.8V/cell, then we do not recommend using the cycle feature. Do note that we have not heard of nay incidence where a battery pack has been damaged due to a discharge
of 0.8V/cell.

Hope this answers your questions

Sincerely,
Craig
Product Support

Hangtime

My Feedback: (19)

The Triton will reliably cycle Rx and Tx packs.. and while it's reasonable to cycle once or twice a year to monitor the packs overall condition and relative capacity it's not necessary to discharge a pack prior to starting a charge.

Hope this helps!