Stryker w/stock NiMH Batt., what BEC cutoff voltage to use?
06-20-2006, 05:35 PM
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Stryker w/stock NiMH Batt., what BEC cutoff voltage to use?
Hi All,
I think the stock battery I'm using in my Stryker is 8.4v (7cells, NiMH=1.2v/cell). I am using a Castle Creations Pegasus 35P ESC, which is programmable, but I've been using the stock programmed settings, which has the BEC set to cut the motor out if the battery shows 5volts. I know when the battery is fully charged, it shows just over 10 volts. I also know that batteries are pretty constant voltage wise, and then have a bigtime dropoff when the charge is depleted. My question is this: Is the 5 volt cutoff too low? Or would there still be enough juice in the battery for the servos/receiver to make it to landing assuming the ESC shuts down the motor at 5 volts??
Thanks!
Jason
I think the stock battery I'm using in my Stryker is 8.4v (7cells, NiMH=1.2v/cell). I am using a Castle Creations Pegasus 35P ESC, which is programmable, but I've been using the stock programmed settings, which has the BEC set to cut the motor out if the battery shows 5volts. I know when the battery is fully charged, it shows just over 10 volts. I also know that batteries are pretty constant voltage wise, and then have a bigtime dropoff when the charge is depleted. My question is this: Is the 5 volt cutoff too low? Or would there still be enough juice in the battery for the servos/receiver to make it to landing assuming the ESC shuts down the motor at 5 volts??
Thanks!
Jason
06-21-2006, 04:15 AM
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RE: Stryker w/stock NiMH Batt., what BEC cutoff voltage to use?
I don't claim to be the expert on this topic, but I believe that the cut-off voltage needs to be 0.8 V per cell.
7 Cells*0.8 V/Cell=5.6V cutoff.
I wonder if my number is just for a charger while discharging my pack slowly to run it down before a recharge. Under load your packs voltage will be lower. So I don't see a huge inconsistency here. As soon your ESC cuts off, your voltage will spike back up some.
It sounds like in the right ball park to me. You will be O.K.
I believe if you have the same 5.0V cut-off voltage for an 8 cell, that you would have ended up with a deeper discharge (too deep?).
It always seemed odd to me that the stock Stryker ESC was using the same cutting off voltage for 7 cells and 8 cells Nimh. I never had any problems. But I can not remember its cut-off voltage either.
Have fun
Gryphon
7 Cells*0.8 V/Cell=5.6V cutoff.
I wonder if my number is just for a charger while discharging my pack slowly to run it down before a recharge. Under load your packs voltage will be lower. So I don't see a huge inconsistency here. As soon your ESC cuts off, your voltage will spike back up some.
It sounds like in the right ball park to me. You will be O.K.
I believe if you have the same 5.0V cut-off voltage for an 8 cell, that you would have ended up with a deeper discharge (too deep?).
It always seemed odd to me that the stock Stryker ESC was using the same cutting off voltage for 7 cells and 8 cells Nimh. I never had any problems. But I can not remember its cut-off voltage either.
Have fun
Gryphon
