I am wondering how many flight i can get on a 600mah nicad. I did two flights and had someone charge it with a triton charger. It put in 66mah or 33mah per 10 min flight. Does this sound right? If so is 10 flights reasonable and safe for a trainer?

Thanks
Dan

There are many variables regarding batteries. I would recommend you if don't have a voltmeter, get one and measure your receiver battery after each flight. You will then be able to observe the discharge rate and react accordingly.

Tower sells an analogue expanded scale voltmeter for $8.99 or a digital meter for $24.99. Either choice would suit the bill.

DaveB

I have plenty of students that show up and have the same standard receiver battery that you do. A good rule of thumb would be 2-3 10-14 minute flights. Anymore than that and you'll be pushing your luck. As said above, the best money that can be spent right now would be to purchase an Extended Scale Voltmeter. It's important to get an Extended Scale meter over a standard voltmeter because it gives you a better picture of the condition of your battery. The ESV measures your batteries with a load on them which will approximate the load that the radio equipment puts on the batteries, so it's really giving you a reading of what the battery has available for when the radio is in use. In addition, there are some problems (such as a dead cell) that won't show up until a load is placed on the battery. A regular voltmeter won't show you these problems.

Hope this helps

Ken

I know a voltmeter would be good but i read that the battery stays at 4.8 volts for so long. How do i get an idea of how long itll stay at 4.8 volts before the voltages crashes. the charts make it seem that itll stay at 4.8 volts or higher for 80% of the batteries charge. So if i know the mah per flight, ill have an idea of how long i have left and when the 4.8 is gonna drop rapidly.

My real question is about 33mah per flight. Is that a reasonable number?

33 mah per flight sounds low, but I don't have alot to base it on and I don't know what you are flying.
I am averaging 80 to 90 mah per flight w/ 5 standard servos and a Voltwatch2 monitor running.
In either case with a 600 mah battery I wouldn't trust more than 3 flights without a good way to check the battery.
I am running 1500 mah pack in my plane so I can get a long day of flying in without much worries (plus, of course, I am using a battery monitor so I can fly closer to exhaustion without worries)

He answered your question
there is no way to tell you what is normal because
things like servo type, what kind of flying etc vary the drain on rx batt
the esv meter is the best way to monitor your batt

Ok, the "official" answer for how long is that you will need to buy a battery cycler. What this does is take a fully charged battery and discharge it at a given level and will return you the number that you are looking for. It can also give you an indication when a battery pack starts to go bad, by telling you that the capicity of the battery pack has decreased.

Ok, real world time. Getting into this hobby is expensive and all the advice here tells you that you need to spend more money. Heck, the cycler I refer too can run anywhere from $50 to $150. So how do you tell without one. It's really pretty simple, but you are going to have to have a voltmeter to check it. Sorry, but you do have to buy one. It's an important piece of equipment that no pilot should be without. As I said above an ESV is preferred, but you can get by with a regular voltmeter if that's all you have. You'll need an evening free, a fully charged battery, and make sure that you are at least 5 miles away from any flying field (you don't want to shoot somebody else down while you are doing this). Turn on your transmitter and receiver and start moving the sticks like you would during a regular flight. Keep this up for the same period that you normally fly for (for example 10 minutes) and then check your battery voltage, make sure you record that time and voltage. Now go back and "make another flight" meaning to keep moving the sticks for your flight period again. Now recheck your voltage and record. Keep this up until your battery voltage drops to 4.7 or 4.6 volts. This will be the MAXIMUM flight time that you have. By recording these values you will also know how long that pack is going to stay at 4.8 volts. Now that you have a record on that pack you can start to tell when it's going bad. When you get less flying time before the voltage drops to 4.7 then the pack is starting to go bad and it's time to replace that pack.

Hope this helps you out.

Ken

Tower-Voltwatch-$10-12- when the voltage is out of "safe" the plane is not safe to fly, easy, all my planes have them...Rog

I use Hobbico Voltwatch myself and they work great. I noticed that at the Tower site it is listed as discontinued !!!! Does anyone know if Hobbico is still making the Voltwatch2 and if so who online stocks them?

I get nervous after four flights. I've taken a fifth occasionally, if I felt the first four weren't too long, but that's it. Ten flights would be like Russian roulette with six bullets.

I go by the meter on my transmitter.

One thing you can do is charge your batteries for 18 hours with the wall charger that came with your radio set. Then turn on your transmitter and receiver and find how much time it takes for your transmitter to go dead. That will give you a good idea of how long your batteries last.

I have a Futaba 4 channel radio and it stays on for 4 1/2 hours by doing that. On the other hand I have a newer version of the same radio and it only stays on for 3 hours. Same type of batteries in each but why one last longer than the other I have no idea.

Actual useage time can vary; depends on the numbers of servos you are using, how large the control surfaces are, how hard you are flying your plane, etc.

I have a falcon lll with just rudder and elevator, no ailerons and a 6 oz. tank and I have gotten up to 15 flights and it still had a charge in it on the older version futaba radio.

I started flying in 1973 and have never used a volt meter to check my batteries nor have I ever used anything other than my wall charger to charge my batteries...and I have NEVER had any batteries fail on me YET!

(If I fly 3 or 4 times in one day I give my radio a 7-10 hour charge if I plan to fly the next day. If I won't be flying for a week, I run my batteries down and give them another 18 hour charge and I am good to go for the next time out.)

You wanted an answer so that is mine!

Good Luck

----------------------------------------------------------------------------------------

(I'm not an RC Pilot, I'm an RC Airplane Transmitter operator)

Well this is what i thought. I am obviously using more than 33mah. I was always tought to only do 4 flights. I have one question though. Do voltmeters that you mount on the side of the plane measure the battery under a load?
Thanks
Dan

If you are referring to something like Voltwatch the answer is yes. It plugs into an empty slot in your receiver and is only on when power to your receiver is on.

bigda...., the length of time your transmitter works is no indication of how long the receiver battery will sustain flight. The receiver under typical use will probably draw much more current than the transmitter does, especially if you have many servos and do lots of manuvering. Current drain on a typical servo can be as high as .5 amperes (500 milliamperes) durring maximum load and will most probably each draw 25 to 50 milliamperes just sitting doing little or nothing. The receiver will draw about 30 milliamperes all the time it is on. The suggestion to use a Voltwatch or equivalent is excellent, much better than a meter as you can check it at the end of each flight before you turn off the receiver and transmitter, to get a good actual condition of your batteries; much better than an expanded scale voltmeter.

the volt watch is a life saver generally I try to cram the larger size tank in my planes a 15 min flight is the norm after 3 flights it starts to get close to the line if I havn't been pushing it then a fourth might be a posibility only if I have enough green lights on the watch meter