TexasAirBoss

My Feedback: (22)

I have my first NiMH 4.8 volt battery. What are the voltages it should read when 1.) I take it off the charger, 2.) I should stop flying, 3.) there is a dead cell?

thanx

HighPlains

My Feedback: (1)

This web site shows what the discharge curve is for both NiCad and NiMH batteries.

http://shdesigns.org/batts/battcyc.html

1. ~ 5.50 Volts
2. ~ 4.75 Volts
3. Divide by 4, multiply by 3

markhamregular

According to the information I got from another post,

It's 1.2 v per cell and the fully discharge is 1.1 per cell.

So, 4.4 is the fully discharged.

According the my instructor you should stop flying at 4.78 depending on what coltmeter you use on a load of .5A.

jimmyjames213

My Feedback: (2)

i would stop at 4.8 to be safe, anything more and your starting to push it, ive had throttle servos break and weird stuff like that where i had to fly for much longer than planned....with a battery that was almost dead it wouldnt be worth it...just buy a bigger battery here
www.all-battery.com a 6 cell 2000 mah is like 6 bucks lasts all day

SeamusG

There is another situation that you should test for - voltage with a load. Get a voltmeter that will display your pack's voltage with and without a load. When testing with load the voltage should step down (maybe .4 volts) and hold rock steady. When you release the load the voltage will jump back up.

IF the voltage continues to drop when you apply a load - not settling to constant voltage - DO NOT USE THE PACK (yea, I'm shouting) even if the voltage returns to a normal voltage. Why? If you happen to be doing some pattern that requires constant servo input (like multiple circles or figure 8's) and using some rudder to maintain altitude - the load may result in dropping the voltage below the minimum level for your Rx putting it into a non-responsive state. Really good chance that you need to grab a trash bag, a couple of buddies and go for a recycling walk.

KW_Counter

The problem with stopping at 4.8, the nominal voltage,
it stays at 4.8 for a long time; you could deprive yourself
of a lot of flying.
I stop flying at 1.1 volt per cell.
When cycling I go down to .9 volt per cell.
Good Luck,
KW_Counter

Rodney

What KW Counter said, you can still have over half of the available energy left when the battery voltage drops to 4.8 volts under load. You can really quite safely go down to 4.4 volts. To prove this to yourself, some day when you have lots of time, just monitor that voltage as you cycle the servos for the required time to drive the voltage down to that value, not just sitting there doing nothing, you must be exercising the servos under a simulated load all the time just as if you were flying.

jimmyjames213

My Feedback: (2)

i am refering to 4.8 unloaded
but yes under load 4.8 you still have alot of life left,
ive actually gone as low as 4.7 ish unloaded and its still good for a flight or so but i wouldnt push (i was also useing nicd's which drop alittle faster)

markhamregular

There's one thing I don't understand.
I have a Ncad 4.8v, 1,100 mlamp battery.
After it's fully charged, my charger shows 6.30v.
However, when using my voltmeter, it only shows 5.44 without load. It's a big difference.
Under a load of .5A, it goes to 5.20
Why the difference of 6.3 to 5.44?

Thanks,

jaka

Hi!
Your charger is not working properly!