What peak voltage are most of you getting on your RX batteries. I am peaking at 5.3 volts after a 16 hour charge. The battery is almost new. I have only been using the stock charger for it, and am using my voltmeter to deplete the charge. I have noticed that volts drop sharply to 4.8-4.9 volts after 3 x 8 minute flights. I don't fly it once it reaches 4.8 or 4.9 volts.

While trying to deplete the charge with the voltmeter it seems to hit a wall at 4.7v - 4.8v for approx 20 minutes, and then slowly depletes.

What rules of thumb do most of you use for voltages when flying. My TX has a Volt indicator + low volt alarm. Its just the RX thats my concern. Whats the lowest safe voltage you should fly on?

According to the guys at the club where I fly, some people stop at 4.9, and everyone stops at 4.8.

Your best bet would be the Battery forum . It depends on the capacity of your battery your charger, and battery type.

That sounds good, about what I am getting.

All 4.8 batteries have an extended run time at the 1.2 volts per cell level. You can get extra flights at 4.8 voltage, but the only problem is you don't know where in the plateau you are, and it drops off sharply afterward, so it's not worth a big risk.

Your peak sounds good for the charge time. Most of the guys I fly with use this rule of thumb. It's not perfect and it does allow for a margin of error. others will have different opinions on this so that this into consideration as well and then make your own decision. Fly when your tester shows 4.9 volts but stop flying at 4.8 volts. As another poster stated, a healthy NiCd cell will hang a good while around 4.9 to 5.0 volts. Once it does begin to drop below 4.8 volts it can go very quickly depending on many things. You could still probably fly at 4.7 volts, but man, you are really getting very close to the danger point and it's just not worth the risk. When they go out they go very quickly.

Also, cycle your batteries about every three months and throw them away and replace at three year intervals or less but don't go beyond 3 years. Will they potentially last longer, yes! But, here again, you really need that safety margin and a battery pack is much less than an airplane cost wise. If the batteries are still good after three years break the pack apart and use the double a cells in a small flashlight to get your full value.

You may also want to get a good field quick charger that will usually peak charge your battery pack in about 30-45 minutes, but don't use this method all the time. I like the overnight method as a standard and then use a quick charger when I want to keep flying a littler longer. Just my 2 cents.

I would expect a little higher voltage. At least around 5.8 to 6 volts following a fresh charge. Your voltage seems a little low. As far as when to stop. I would recommend 4.8 volts at your rated load. If you have regular servos and trainer, then 4.8 at 200ma is good. If you have a larger plane with lots of digitals then 4.8 at 750ma may be the ticket.