View Full Version : What is the minimum voltage to use the DX7?
Gino CP
10-28-2007, 08:11 AM
What is the minimum displayed voltage of a DX7 that can safely operate an aircraft? I am using the stock 1500mah nimh.
Hughes500Bob
10-28-2007, 11:14 AM
The manual say to never operate at less than 9 volts.
I found out that stock 1500 mAh NiMH battery goes below 9V in about one hour, then it will stay around 8.6V for another 2-3 hours. Then, after 8.1V, it will go down pretty quick.
Looks like stock cells does not hold it's nominal 1.2V well during discharge. It has capacity about 1500 mAh (i've tested it on 1010C) but useful one is about one third of it. If you don't mind "Low battery" warning you can fly twice as longer but it's hard to tell how many mAh you might still have in that battery.
Danal Estes
10-29-2007, 11:37 PM
A lot of people are peak charging the stock TX pack, and only peak charging... and seem to have trouble...
I've never used anything but the wall charger supplied with the TX. The first time, for 30 hours. Now, I charge overnight the night before I go flying. I've flown all weekend on one night's charge, and occasionally, when I forget, even flown the next weeked also. We're talking fun-fly events here, where I fly a lot.
So, try trickle charging it a bunch. See if that helps.
Gino CP
10-30-2007, 01:04 AM
I use the 50ma charger and occasionally the 300ma walwart. The problem is, I have no idea how much charging it needs when I want to use the 300ma. I can safely compute if the pack is flat. But I have no idea when having a partially used pack.
Steel Butcher
11-01-2007, 10:19 AM
I found out that stock 1500 mAh NiMH battery goes below 9V in about one hour, then it will stay around 8.6V for another 2-3 hours. Then, after 8.1V, it will go down pretty quick.
Looks like stock cells does not hold it's nominal 1.2V well during discharge. It has capacity about 1500 mAh (i've tested it on 1010C) but useful one is about one third of it. If you don't mind "Low battery" warning you can fly twice as longer but it's hard to tell how many mAh you might still have in that battery.
This is very different from my experience, I would suggest you received a bad pack. I only charge when it goes below 10 volts and it takes quite a few flights for that to happen! Stock battery.
beeflyer2
11-01-2007, 10:50 AM
I only charge when it goes below 10 volts and it takes quite a few flights for that to happen! Stock battery.
Same here.
I saw on RCGroups
http://www.rcgroups.com/forums/showthread.php?t=746035&highlight=NiMH+battery+test+dx7
You can see that DX7 battery does not hold it's nominal (9.6V) voltage for too long and other battery does better. I can concur this results.
Well, maybe I've got bad battery but instead of spending on postage to Horizon I would prefer to make my own from decent cells. I think I'll go with Sanyo Eneloop or similar ones with ultra low self discharge technology.