View Full Version : Duralite Voltage has Dropped
I've got Duralite 4000 mAh in my Fury and after being left for about a year, the maximum voltage I seemto get after an overnight charge is 7.25V. Before this I used to get around 7.6 http://www.cjwoods.com/Duralite.htm.
The voltage whilst in storage never dropped below the minimum (can't remember what that was but when I recharged the other day starting voltage was about 6.8V).
Haven't given them a proper test out flying yet, only a couple of flights.
Just wondering if anyone has encountered a similar problem after a lay up and if after a few charge discharge cycles they'll go back to normal?
Cheers
bkervaski
08-19-2006, 04:10 PM
You should get 8.4 volts with an overnight charge with the Duralite charger. Anything less is probably a bad pack. You're charging and checking with the yellow lead?
DavidH
08-19-2006, 06:35 PM
Voltage Parameters
7.4 Volt Li-ion Packs measured under 1 amp load
Stop Fly
—6.9 volts under 1 amp load
Fully charged
—no load - 8.2 - 8.4
—under 1 amp load - 7.5 volts & above
http://www.duralitebatteries.com/tech-ion.html
If your not in the above range. I would say you probably have a bad cell. The pack is usuable with a bad cell. You just want have the normal capacity.
David
WillJames
08-19-2006, 06:38 PM
THe other thing is that after sitting that long, it may take 5-10 cycles to see what the pack has got left. I have seen packs that acted like that on the first charge after sitting a year rebound very well.
bkervaski
08-19-2006, 06:44 PM
I have two fairly new Duralite 4000's that I'm only getting about 4-5 flights out of on my Stratus w/9255's. They charge to 8.4v no problem.
Dave -- know a way to check the load on my heli? Surely I didn't get two bad packs. I was getting 10 flights on my Evo 90's w/9252's.
WillJames
08-19-2006, 06:47 PM
Call Jack Bill.
bkervaski
08-19-2006, 06:56 PM
Will - so you're under the impression that I have two bad packs, however unlikely?
WillJames
08-19-2006, 07:14 PM
No I have no idea, but Jack would know. It would be your fastest way of knowing.
bkervaski
08-19-2006, 07:17 PM
I have some DL 4300 LiPoly's I just got. I'm going to give them a shot tomorrow and see what kind of flight times I get. It's a new product replacing their 5000 LiPoly (according to Mark at DL).
WillJames
08-19-2006, 07:24 PM
I run mostly LiPo packs with DL regulators in all my electric machines to save weight, they work very well.
DavidH
08-19-2006, 07:33 PM
I doubt the 9255's draw much more current than the 9252's There is only 20 ozs of torque difference between the two.
If the Duralite packs are showing 8.4 volts when fully charged with no load and above 7.5 volts with 1 amp load. There is nothing wrong with the packs. When there is a bad cell, the pack will not show 8.4 volts when fully charged. If there is a bad cell in the pack, the light on the charger will not go out when charging, even if left on several hours.
David
THe other thing is that after sitting that long, it may take 5-10 cycles to see what the pack has got left. I have seen packs that acted like that on the first charge after sitting a year rebound very well.
Thanks, hope that's the case and the pack hasn't gone bad.
Thanks for the replies, all tests under 1A load and charging correctly etc. I'll give them a few cycles (when the weather gets a little better anyway) and see what happens.
After a little more investigating I think it's actually the voltage tester unit that's gone bad. When I measure the voltage across the resistor inside the unit, voltage reads 7.5 - 7.6V, before I opened it up the LCD display had started to go a bit flakey as well.