DX7 v JRx9303
04-01-2008 | 11:07 AM
#26
My Feedback: (3)
RE: DX7 v JRx9303
ORIGINAL: opjose
Yup, the poster stated a problem with the DX7 e.g. "battery issues".
AFAIK there ARE NO "battery issues".
Even standard servos can draw upwards of 1800mA at full stall torque, and higher torque servos even more.
That means that ONE fully deflected servo hitting a limit can quickly deplete a battery, or push a battery beyond it's capacity to supply current, exactly as you said.
However this is NOT a problem with the transmitter as Kavik alluded to... nor is it a problem with the receiver or radio system...
Rather it's a "user error", where the pilot has not calculated the required battery capacity needed and adjusted accordingly.
ORIGINAL: MikeEast
the problem was not with the recievers, the problem is using the wrong batteries for the application. This is true with any radio system. I would say that if you are performing aerobatics on a plane with several high output servos (100+ ounce rated output) then you might need to use a 6V setup and high capacity batteries especially if you are not very aware of what to look for and when you are at "no go" voltage.
the problem was not with the recievers, the problem is using the wrong batteries for the application. This is true with any radio system. I would say that if you are performing aerobatics on a plane with several high output servos (100+ ounce rated output) then you might need to use a 6V setup and high capacity batteries especially if you are not very aware of what to look for and when you are at "no go" voltage.
AFAIK there ARE NO "battery issues".
Even standard servos can draw upwards of 1800mA at full stall torque, and higher torque servos even more.
That means that ONE fully deflected servo hitting a limit can quickly deplete a battery, or push a battery beyond it's capacity to supply current, exactly as you said.
However this is NOT a problem with the transmitter as Kavik alluded to... nor is it a problem with the receiver or radio system...
Rather it's a "user error", where the pilot has not calculated the required battery capacity needed and adjusted accordingly.
[8D]
04-01-2008 | 11:28 AM
#28
My Feedback: (3)
RE: DX7 v JRx9303
I think there are a lot of people that still are under the impression that the issues that were reported early with the DX7 systems was DX7 system related. They still dont understand that the problem was not with the equipment, the problem was low voltage cutoff due to low batteries. I have talked with Horizon, and several of the power distribution system guys and they all seem to agree that you have to be sure that you do not hit that cutoff voltage. There are 2 PD systems companies that have clearly suggested that I not use 4.8V on JR, Spektrum or Futaba in demanding planes. It takes about 8 seconds for the system to reboot from an LV shutdown and that is too late. But this is true with ALL systems regradless of what freq band. They all have low voltage cutoffs. I think it just got blown out of proportion because it was a new system so the blame automatically fell in the wrong place.
Again,
Solution 1. If you are going to run 4.8V or any voltage but ESPECIALLY 4.8V with low capacity batteries be sure you understand the loads that you are inflicitng on the battery so that you can have a clear understanding of when its time to stop and recharge.
Solution 2. If you are flying power hungry servos, just move up to a high capactiy and high output 5 cell NiMH or 2 cell Lithium or A123's or something that is not as prone to hit <4V under load as long as it still has a decent charge.
Again,
Solution 1. If you are going to run 4.8V or any voltage but ESPECIALLY 4.8V with low capacity batteries be sure you understand the loads that you are inflicitng on the battery so that you can have a clear understanding of when its time to stop and recharge.
Solution 2. If you are flying power hungry servos, just move up to a high capactiy and high output 5 cell NiMH or 2 cell Lithium or A123's or something that is not as prone to hit <4V under load as long as it still has a decent charge.
