OK..

This should be a relatively simple question.

What type of flight time can I expect from my receiver battery.

I have a Futaba 6 channel receiver. Running 4 servos. (1 rudder, 1 elevator, 2 aileron) The plane is electric so none for throttle.

I'm running 3004 BB servos.

Running the standard 600 mAh 4.8v battery.

Pretty much a typical setup in a typical high-wing trainer. I know it'll vary on how I fly. So I'm just looking for a ballpark range.

I'm thinking of spending the extra $$$ and getting the bigger battery...


Thanks in advance,

Lyndon

I ran the same system and I was able to get two fifteen minute flights. I don't know if something was wrong or not, but I got tired of using the field charger so I went out and bought a 1650 mAh 4.8V battery and now I can go from 9AM to noon, usually around 6 or 7 flights.

You can probably safely get at least 2-3 15 minute flights from your battery as long as it is fully charged and in good shape at the beginning of the day. If you haven't already done so, it's really a good idea to invest in a cycler/charger and a volt meter or battery tester that applies a small load. Using a good charger will make sure they are up to peak capacity and a cycler will prolong their life and let you know the condition. Put the meter in your field box and check your receiver pack between flights. It is cheap insurance that avoids a costly failure. I've seen several people take off with a questionable battery or try to squeeze in the "one last flight". It usually turns out ugly.

I would say three 15 minute flights. or however many shorter duration to make that up. Be warned that it can vary greatly if you have tight/binding control linkages or fly with a forced servo. That drains a battery much faster.

A little ESV (expanded scale voltmeter) that measures with a load on the circuit can save a model if you use it before each flight.

Yours is a pretty routine setup (same one I flew last year, BTW). I could get in about 4 ten minute flights before the voltage on the RX pack told me it was time to go home or field charge.

If you don't have one, invest in an Expanded Scale Voltmeter (ESV) which measures the battery voltage while under a typical 300mA load.

On a fresh charge, my 4.8 volt pack will actually measure around 5.4 volts. After each flight, it will measure fewer volts. Once it gets to around 4.5 or 4.4 volts, that's when I call it quits. It will actually stay at 4.8 volts for a fairly long period then drops rapidly.

It's pretty good practice to replace your NiCD packs once every 3 years. This year I went up to an 1100mA NiCD pack. A couple of weeks ago we put in 8 full flights and still had 4.5 volts remaining. That was nearly an hour and a half of flight time!

I replace all my receiver packs with 4.8 volt 2200 Mah packs and add voltwatch monitors to every plane . When i was flying my Superstar Trainer , i flew a whole gallon of fuel one day on that pack , and still had juice to spare . I recommend the voltwatch monitors as cheap insurance , and takes the guesswork out of pack capacity . You can use the voltmeter too , but why mess around with that when you can check your condition at a glance .

i found this on ebay, Futaba NR4RB Receiver NiCd 4.8V 1000mAh J battery
for total of $17.
i use also voltwatch and its more then enough, im getting tierd beffor the batt draines out.

I use JR 700 ma battery's in my .40 size planes. They easily go 5 to 6 , ten minute flights.
On my .60 size planes , I use JR 1100 ma and get a lot more flights, maybe 9 or 10. I also loaded test before every flight , just a good habit.
I never charge my battery's unless I`ve pulled them down to their minimum charge under load. So far it has worked good for me., but I do agree , a battery cycler is the way to go.

Whatever you do, pay attention to battery condition. I didn`t and lost a 4* as a penalty. I`ve started putting a voltwatch on my airplanes. If you don`t have one on a plane, I`d recommend using a meter that`ll check the Rx battery under load between flights. Only takes a second and will save an airplane for you sooner or later.

Thanks everyone...

I think I'll get the larger receiver battery, and a voltwatch straight away... Then as I populate my field box, I'll add a ESV. That'll get my bird flying faster. And as my wallet allows, keep it flying longer.

battry capacity diminishes with age,a new fully charged pack is good for about an hour of normal sport flying with four servos,if you have a cycler you can continue to discharge your battry pack after a days flying to see how much time you had left.but checking voltage before each flight is a good safety measure.when you are not able to fly as much before the voltage drops it is a sign the pack is losing it's capacity and should be replaced .

All of my crashed are on my last flight of the day..lol
seriouly thou, I'm pushing it after the 4th flight, but i do becuase i'm having to much fun.
Always gotta put in that one last flight before I go home. Then I have a drive out the
next day to look for parts and EQ of my plane that i can't find in the dark.

I learned..purchase extra battery packs, tester

The question may be simple, but the answer is a little bit more complicated depending on flying style, friction in the control system, size of control surfaces, etcetera.

In most of my .40-sized sport aircraft I use JR 4.8 V, 600 mAh NiCd batteries.
As an old time C/L-flier I am perhaps more careful than most when it come to reducing friction in the control system. Often I use nylon coated wire in a pull-pull set-up for rudder, balsa/metal pushrods for elevator and ailerons and wire in plastic tube for throttle.
My style of flying can be described as "traditional pattern aerobatics".

I have found that at most I can get 10 fifteen minutes flight out of a freshly charged Rx battery pack. Usually I call it a day after eight 15 minutes flights.

If you have access to a discharger that can tell you the mAh it is a good idea to perform a couple of tests. If you consider 4 flights safe, with a freshly charged battery perform two normal flights. Discharge the pack at C rate (0.6 A for a 600 mAh battery) to 1.1 V/cell. Charge the battery and do four flights. Again discharge the battery pack to 1.1 V/cell and compare the capacities remaining. If after two flights 400 mAh remains and after if after four flights 200 mAh remains, it is obvioius that two flights have used up 200 mAh, i.e., 100 mAh per flight. Thus a 600 mAh can be used for at most 6 flights. Add a safety margin and I would say that 5 flights should be O.K.
Because batteries age, one should repeat the test now and then, say every six months.

Most battery checkers are very conservative when indicating "battery low".

Edit:
Make sure you use a battery checker that actually puts a load on the battery. Some battery checkers don't and require you to "wiggle the sticks". I use a simple digital voltmeter with a 6V, 2.4W bicycle light bulb as a load when measuring the voltage. I stop flying when the voltage reading falls below 4.4 V within 15 seconds of attaching the voltmeter.

Disclaimer: The values indicated above works for me, but it is up to you to decide how many flights you consider safe with your battery, aircraft and flying style.

Put one of these on each of your planes, and you'll always know what you've got left in your battery pack...

Voltwatches look funny on scale warbirds .

Seriously though, lots of good info in here.

The only thing I want to add/reinforce is how much difference your control system can make. It really doesn't make much friction in the pushrods to eat the battery in a hurry. One of the real battery killers in glow planes is the throttle servo. A lot of guys seem to like to stall out that servo at full throttle.

Hooking an amp meter (or, if you have one, one of the electric flight watt meters) between your battery and RX can really tell you a lot about your control system. Hook it up, then move the sticks through their full range and watch the power draw, if there is a problem you'll see the current jump up.

I love my voltwatch2. Its easy, before every flight, I turn the switch on, then look at the voltwatch. Then I do my servo checks to make sure there working right and in the right direction, and I look at the watchwatch when I do that also, because the voltage changes when the servos are used. Then, I know if everythings good to go.

I'm with Red. New pack, good condition, 2 hours. Thats Ideal conditions. Less if the pack is older, if the charge isn't fresh, controls drag, etc. Thats for 4 servos.

I find that I get about the same on a stock 600mAh battery using four standard servos.

I always check the battery with a load meter after the sixth flight.

Usually I try to replace the 600mAh batteries with higher capacity ones. I then take the 600mAh batteries and either place them into planes that I do not fly as often in a given day ( I haul out at least TWO planes to the field on each trip ), or put in two of them on a plane.

MPI,

Get a MPI switch with charge jack and LED indicator lights. When the light on top is green your good to go. When the second yellow light starts to change to yellow when under load you might have one more safe flight. I never let it get to the bottom red light. I must aggree though a volt meter with this type switch is the way to go. At least with this switch you can check the battery without taking off the wing. Don't ever trust lights totally. Get the meter.

JMHO,

Gibbs

What chargers are you guys using to charge at the field? And is a 6v pack better than a 4.8v or would the 6v way too much?

A six volt pack will give you more powerful servo torque but less flight time. Sad but true. You need a 4.8V pack with more maH rating. I switched to 1450 maH Rx and 1650 maH Tx NiMH packs in my models and transmitters and haven't looked back. Cost a little more, but add two flights per pack.

Check out Red Scholefield's battery clinic for some great info.

http://www.rcbatteryclinic.com/

Here is an inexpensive loaded voltmeter I use. It has already saved one plane from battery failure. http://www.horizonhobby.com/Products...ProdID=EXRA502

I also use the Double-Vision Quick Field Charger for the last several years with good results. It will top off the Tx/Rx at the same time in about 12-15 minutes. http://www.horizonhobby.com/Products...?ProdID=HAN114

The only problem i find with my voltmeter is its not precise. Once the battery goes down a bit it starts lighting two or three lights. So when i wiggle the servos a green light could be on and so could a orange. I dont know what this means. Does anyone elses do this?

But I still like having some idea baout my battery level/

P.S. its a voltwatch2 like -pkh- posted a picture of.

I've never had a Voltwatch light up more than one light at a time with no servos moving or loaded. You can have multiple lights flash and appear to be lit at the same time when you have a loaded servo, or when you move the servos around... this is because the Voltwatch is displaying the varying voltage values as the loading on the battery pack changes.

My conditions for another flight are the no load (single light on) case should show it is in the safe region, AND when I move all the servos, the average or middle of the light range that lights up must be in the safe range.

Thats wierd. I've had two come on when no servos where moving, but its good to know that there should be a bunch when moving servos.