Amount of capacity needed
05-13-2008, 04:03 PM
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Amount of capacity needed
I am new to the battery forum, so please forgive me if I am repeating something covered many, many times.
I fly sport planes (usually 40 size glow) and sometimes 60 size. The batteries I use are the ones that come with the radio or almost alike replacements (500 to 700 MAH) and I use the chargers that come with the radios.
I used to get (many years ago) A good six flights on a charge before I quit flying, but lately I have started getting nervous after only 3 flights, and my voltmeter starts showing marginal voltage. I am now using a computer 6 channel Futaba (also some old non-computer radios) and am wondering if they use more energy, or am I just becoming too cautious? Should I stick with nicads, and is the charger I am using O.M. What capacity would you suggest (six 10 to 15 minute flights are enough) and don't think I need 6 volt. Would apprecite your thoughts. I realize that a higher capacity battery would take more charging time, but would simply a longer charge time be adequate, or do I need to consider a different charger.
I fly sport planes (usually 40 size glow) and sometimes 60 size. The batteries I use are the ones that come with the radio or almost alike replacements (500 to 700 MAH) and I use the chargers that come with the radios.
I used to get (many years ago) A good six flights on a charge before I quit flying, but lately I have started getting nervous after only 3 flights, and my voltmeter starts showing marginal voltage. I am now using a computer 6 channel Futaba (also some old non-computer radios) and am wondering if they use more energy, or am I just becoming too cautious? Should I stick with nicads, and is the charger I am using O.M. What capacity would you suggest (six 10 to 15 minute flights are enough) and don't think I need 6 volt. Would apprecite your thoughts. I realize that a higher capacity battery would take more charging time, but would simply a longer charge time be adequate, or do I need to consider a different charger.
05-14-2008, 07:16 AM
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RE: Amount of capacity needed
Sherman:
First, your observation about the power consumption of your computerized system is probably correct. You didn't state whether the servos were didgital or analog but they are probably digital with increased torque which consumes more battery power. Secondly, 500-600 mah Nicads for the flight pack may be sufficient for 3 flights but it doesn't give you a lot of reserve power as you can see from your volt meter. I recommend that you go to a greater mah battery pack. In my flight packs, I usually use 2700 mah or greater Nimh batteries so I can easily get 6 flights out of the pack. However, if you step up to these larger capacity batteries, you must also ensure that the battery charger you have can handle them. The typical wall charger you get with your radio system usually can only handle up to 1000 mah so don't use it with these batteries as they will not fully charge your battery. Lastly, you may also want to go to a greater mah battery in your transmitter. I usually replace the factory battery provided with the system with a 1650 mah battery.
Finally, if you really want to step up the technology of your batteries, take a look at the A123 battery thread. I just started to get into these batteries and they are a great improvement over Nicad, Nimh, and traditional Lipo batteries. If you plan to spend money on new batteries and a charger, the A123 technology may be a better investment. These batteries re-charge in as little as 10 miniutes, hold the charge well, do not have explosive or fire cahacteristics of Lipo's, and give you good flight time.
First, your observation about the power consumption of your computerized system is probably correct. You didn't state whether the servos were didgital or analog but they are probably digital with increased torque which consumes more battery power. Secondly, 500-600 mah Nicads for the flight pack may be sufficient for 3 flights but it doesn't give you a lot of reserve power as you can see from your volt meter. I recommend that you go to a greater mah battery pack. In my flight packs, I usually use 2700 mah or greater Nimh batteries so I can easily get 6 flights out of the pack. However, if you step up to these larger capacity batteries, you must also ensure that the battery charger you have can handle them. The typical wall charger you get with your radio system usually can only handle up to 1000 mah so don't use it with these batteries as they will not fully charge your battery. Lastly, you may also want to go to a greater mah battery in your transmitter. I usually replace the factory battery provided with the system with a 1650 mah battery.
Finally, if you really want to step up the technology of your batteries, take a look at the A123 battery thread. I just started to get into these batteries and they are a great improvement over Nicad, Nimh, and traditional Lipo batteries. If you plan to spend money on new batteries and a charger, the A123 technology may be a better investment. These batteries re-charge in as little as 10 miniutes, hold the charge well, do not have explosive or fire cahacteristics of Lipo's, and give you good flight time.
05-14-2008, 10:33 AM
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RE: Amount of capacity needed
I use 1500 mah capacity in my 40-60 size planes. I usually top them off at the field after the 4th flight with a Field Charger. Though I could probably get more flights without field charging .... its simply (to me) not worth worrying about ..... especially with the 2.4 radio systems that do not tolerate lower voltages. 15-20 minutes on the field charger and I am again nearly at peak capacity ..... no worries. The Hobbico Quick Field Charger is around $ 49 and well worth the money. Bob
05-14-2008, 12:51 PM
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RE: Amount of capacity needed
Thanks for the answers and advice. I will go to the higher capacity, and also check out the A123 technology (why haven't I heard of it?)
These forums are terrific and have often given me not only excellent advise, but often steer me in the direction of obtaining more information.
These forums are terrific and have often given me not only excellent advise, but often steer me in the direction of obtaining more information.
05-15-2008, 07:48 AM
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RE: Amount of capacity needed
Sherman:
Like you, I hadn't heard of the A123 technology until recently. It seems that it has been around for a few years but in the RC world it hasn't been commercilaized on a large scale but that is starting to change. Based on my limited experience with it, I find A123 batteries to be a substantial improvement in battery technology. I went flying yesterday and didn't charge my batteries until I got to the field. The charged up in 10 minutes, held the charge well, and recharged for many more flights. I purchased my batteries and Cellpro 4 charger at this web site: www.sincityjets.com I hope this helps you.
Like you, I hadn't heard of the A123 technology until recently. It seems that it has been around for a few years but in the RC world it hasn't been commercilaized on a large scale but that is starting to change. Based on my limited experience with it, I find A123 batteries to be a substantial improvement in battery technology. I went flying yesterday and didn't charge my batteries until I got to the field. The charged up in 10 minutes, held the charge well, and recharged for many more flights. I purchased my batteries and Cellpro 4 charger at this web site: www.sincityjets.com I hope this helps you.
