Good Morning Everyone,

I bought the futaba 6ex, what battery should I buy for the receiver? How many cells / voltage, eta? I looked at tower and ebay, and there are a lot to pick from just dont know which one to buy. This will be in my sig lt 40 if that helps. thanks for your help!

Patrick

That radio comes with a 4-cell, 600mah pack, which, for an LT-40 is plenty.

If you want to prepare for bigger and better things in the future, you could go with a 1000 - 1200mah pack

Any four cell 4.8v pack Nicd or Nimh that is rated at around 600 Mah or more is perfectly fine for your airplane. That is the rating of the packs included with most new systems.

You can also use a five cell pack 6.0v but it will not buy you anything in that airplane or improve your learning experiance in any way.

Running the higher voltage will slightly improve the servos speed which at this stage you will not be able to tell the differance and using the five cell battery will also use more current so the battery will not last as long.

Thats why when using a five cell the capacity should be higher than than what you may use with four cells packs.

Also keep in mind when using five cell packs and higher capacitys to assure full and complete charges you are going as a practical matter need a more capable charger.

John

I agree with what has been said. A 4.8V 4 cell 600 mAh battery is plenty for your current needs. At the same time I will tell you that there is not much difference in cost $20 vs $25) between that and a 5 cell 2000 mAh 6.0V Nimh battery pack. The larger pack will give you slightly quicker servo response time, and more torque. While niether of those may mean much now, they might when you move up to a larger plane. After reading that bettery problems are the second leading cause of crashes, I decided to replace all of my 600 mah batteries with 2000 mah packs. In addition to more torque and quicker response time the larger pack will give you significantly more flying time. Since switching mine I rarely use more than 10% of the capacity, which gives me a warm, fuzzy feeling. Just my two cents.

I agree with what has been said. A 4.8V 4 cell 600 mAh battery is plenty for your current needs. At the same time I will tell you that there is not much difference in cost $20 vs $25) between that and a 5 cell 2000 mAh 6.0V Nimh battery pack. The larger pack will give you slightly quicker servo response time, and more torque. While niether of those may mean much now, they might when you move up to a larger plane. After reading that bettery problems are the second leading cause of crashes, I decided to replace all of my 600 mah batteries with 2000 mah packs. In addition to more torque and quicker response time the larger pack will give you significantly more flying time. Since switching mine I rarely use more than 10% of the capacity, which gives me a warm, fuzzy feeling. Just my two cents.

All great advice. How are you going to charge your new battery? I asume (hate that word) you have the original wall charger. Do you belong to a club, or have any local flyers near? Lots of 600ma 4.8v packs around, which is all you need, and can charge from your wall charger. Someone local may want to up size, and give you a recent 600ma.
If you go to a 5cell pack at this time, look at how you are going to properly charge it. A 5 cell pack, as earlier stated will be benificial in the future although not necissary now. But don't think your wall charger will charge it properly! That could become a dangerous, false sense of security. In time a reasonably good charger/cycler will show, and prove it's worth. But first go injoy your LT40 they are great. 600mah, to 1100mah at 4.8V has my vote. On 72mhz equipment.
-Snuts-

The cost issue with using very high capacity and/or five cell packs is not the initial purchase price, thats not a big deal. What is a big deal is the fact many are not prepared to purchase a good capable charger that most are going to need.

Many coming to me for flying help and using high capacity/five cells packs in everycase showed up undercharged when attempting to use their wally warts cutting their flying day short.

I do not reccomend using five cell/ High capacity without the right tools to use and that is a capable (expensive) charger.

John

Think this post just confussed me more, but I bought a 4 cell 600 battery pack. That is what I got from this. Thanks for your help and input from this thread. I guess I could always buy a backup battery incase I want to fly longer that day. what are your thoughts on swapping battery at the field?

That pack will be perfect. That is what the vast majority of new flyers use throught out their training and beyond. Fact is there are legions of flyers that have never used anything else.

Remember everyone starting out feels like a five minute flight was a full hour. Also all the learning will occur in the first five to ten minutes for the average folks and flight longer than that do not accomplish anything.


John

Good choice, Today I flew a 40 size High wing airplane similar to your LT40. Total on time on the transmitter for that model today was 1:45hrs The receiver pack only required 274mah to replenish on the way home, with my good charger/cycler. Hope this example instills confidence in you good choice of batteries for the task at hand.
-Snuts-
(37yrs Experiance)

Hi!
All wall chargers (that comes in Futaba, JR, Hitec and Spektrum radios) that put out 50-150mAh ca be used to charge most NiCad and NiMH batteries!
In case you got a 50mAh wall charger and a 4,8 or 6V , 2000 or 2800mAh NiMH battery ...you just charge longer time ! I have done so for the last 25 years and it works just fine.

The problem with all fast chargers (have several) is that they all false peak when charging NiMH cells! This mean they will cut the charge before the battery is fully charged! If you understand that and want to live with this, Fine! But for ordinary NiMH batteries in receivers and transmitters I use my thrusty 30 year old JR chargers (3 of them).

By the way...are you still using NiCad batteries in America???
Over here in Sweden NiCad batteries was faced out 10 -15 years ago. All our radio systems contain at least 1500mAh NiMH batteries , both in transmitter and in Receiver.

Just disregard everything said about 5 cell (6 volt) packs for now. At this point, fly your LT40 with the 4 cell that you have and have fun. Later on, after you are a bit more experienced, you can experiment with 5 cell packs. For now, though, don't get confused with all the mumbo-jumbo about 5 cell packs.

CGr.

I am flying a escapade w/ 5 futaba 3004 servos and a ar6200 reciever. I am using a 5 cell 2000mah reciever battery. How long could I theorectically fly with this battery. I imagine there is some formulas for this.

There is no real formula, just some common sense based on your flying style.

If you are heavy on the sticks, meaning if you do a lot of corrections while flying, your servos will work more and you will eat up more battery power. Conversely, if you are easy on the sticks and allow the plane to "fly itself" in straight lines, meaning no over-correcting when no corrections are really needed, then you will get more flight time out of your batteries. You would be surprised at how often RC'ers try to correct something that is perfectly normal

But, I have several planes with 5 servos and use a 1200mah NiMH 5 cell pack and get four or five flights before I put it on the charger. By that time, I've either changed to another plane or am ready to head home.

We sit around and shoot the bull between flights, so the time goes by, and four or five flights is plenty for one day.

I've always recommended the use of the Voltwatch on your planes. It gives you a quick look at the battery condition before and after each flight so you can decide if the last flight was the last before you recharge or if you are ok to fly again.

http://www3.towerhobbies.com/cgi-bin...&I=LXHDJ2&P=ML

CGr.

Rather than swapping out your tx and rx batteries at the field with charged ones, you can always invest in a quick charger to recharge the ones you are currently using if they start to get low.

Here is a popular quick charger that will recharge your batteries at the field in hardly no time at all. I see this charger being used at my field more than any others.

http://www3.towerhobbies.com/cgi-bin...?&I=LXCTZ5&P=7

What about the 2.4 radios?

If I was a beginner I'd stick with the 600 mah nicad batteries that come with the system. I only use futaba radios so I can only speak for them.

I don't fly anything larger than 60 size planes and I don't use more than 5 standard 3004 servos using 600 mah batteries and I get 7 to 10 flights in on one charge using my wall wart. If I want to fly more I just recharge them at the field with my trusty hobbico quick field charger that I mentioned above.

As far as the Futaba 6EX 2.4 Fasst system goes, I can give mine a full charge with the wall wart and play with the sticks for 3 hours and 5 minutes before it goes dead. I see no reason (on a personal basis) that I would need any larger battery packs than the 600 mah batteries it comes.

The way "I" normally charge and discharge my batteries seem to make them last longer at the field and also give them a longer life. Stay away from fast chargers and dischargers if at all possible and they will last longer!

big dan

For all JR/Spektrum radios I'd prefer a large capacity 4 cell or better yet a 5 cell due to the Rx cutoff voltage being higher than the others. For non JR/Spektrum radios the 600MAH pack is a good starting point but with digital servos I'd increase capacity and stick to 4 cells because you wouldn't need to change chargers (just charge longer if fully discharged). WHATEVER you choose be sure to check them before every flight.

The mah ratings imply a linear discharge. The reality is the stored energy loss is not linear, a heavy load drawing several hundred ma or more will dissipate more of the stored energy than an equivalent few hundred ma load over a longer time period. If you read the fine print on some battery spec sheets you'll see something like "2500mah" rating (at 200ma max. load). The higher mah rating of NiMh will not be realized unless the load is limited to a few hundred ma.

NiCd has the lowest internal resistance and can, therefore, deliver higher current then a NiMh of the same or higher mah rating. NiCd will work better for intermittent heavy load currents but you pay for it in weight and have to deal with the nuisance or cycling them every month or two.

The main advantage of NiMh over NiCd, and reason for their development, is the environmental impact. Cadmium is a toxic "heavy" metal that, in many countries, is banned or must be disposed of properly or face heavy fines. NiMh is environmentally friendly but has the highest internal discharge rate in addition to higher internal resistance. Leave a fully charge NiMh sit for a few days and you'll bleed off half the charge.