carl24bpool

Okay guys. I've tried to get y head around it but I'm strugging with the wordin in my manual and online.

I have a 9.6v Ni-cad and a 4.8v nicad. The 9.6 is rated 600mA and so it the 4.8.

They are quite old so I want to tyr cycling them so see if htey are of any use.

What do I set the charging current to and what do I set the discharge voltage to? I read discharge is 0.85v per cell. Is that right?

Also how does the charger know when they are charged and to start discharging? I don;t get that bit. Do I need to set an upper limit or not? I can;t see how the charger knows how many cells there are so when to stop charging at what voltage.

I read about something called delta peak sensetivity. Can somebody explain this in simple terms please?

Also to give me an idea how long should 5 cycles take? Am I looking at 16 hours for each charge so were talking days?

carl24bpool

In addition my charger has a safety timer but it can only be set from 0 - 120 minutes.

I have calculated that a 600mA battery charging at 0.1a will take 6 hours so whats hte timer all about? Is my charger going to stop after 2 hours?

carl24bpool

I found this whiich has helped me slightly but any comments appreciated:

http://michaelbluejay.com/batteries/charging-tips.html

mehrshad

No upper limit is needed.
when a nickle based battery got full,its voltage begins to drop and its temp begins to ramp up. so your charger will know its time to finish the charge.
When using delta method its important to set proper charging current. too low or too high values may cause a non complete charging process.
Try a value around C/3 (200ma in your case) for charging and C/2 for discharging.
turn off the safety timer and a 0.7 v/cell is fine for discharging.
the charging time=1.5* rated capacity/charging current and for your case: 1.5*600mah/200ma=4.5h
discharging time= 0.9*capacity/discharging current : 0.9*600/300=1.8 hour

raptureboy

Cycling your batteries will do two things. It will tell you if they are any good and also help revive them some. C= the capacity of the battery in milliamps, so you divide by whatever # you want to get an idea of what you can get back out of a fully charged battery and how long it takes to get to low voltage. So 900mAh / 5 = 180 mAh charge rate. NiMh batteries should be warm not hot when fully charged so its' important not to charge at too high a current, lower is better but not so low the battery does not feel warm when done.Excellent reading on all battery types here www.hangtimes.com You should consider getting new batteries when you get less than 70% of the capacity out when discharging. A typical discharge rate for a receiver battery on a 4 channel plane with std servoswould be 250-300 mAh with a cut off voltage of 0.9 volts per cell 4 cells x 0.9= 3.6v If you don't have a loaded volt meter yet get one, and check your batteries before each flight. I cycle/discharge my batteries at 300 mAh to see how long it will take to go dead and then that tells me how many flights I can safely expect.