Portable telephone batteries for RC plane

Hello.

I was wondering if there'd be any problem with using a portable phone's rechargeable battery, if I got one of the same voltage, to power a small RC plane. The replacement batteries from the plane manufacturer are expensive, and phone batteries can come in a much larger capacity at the same voltage. Would there be any problems besides finding batteries of the proper size and weight?

Thanks,

Pete

Reply to
huitsing
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check to see if they are nicad or nimh or what. If they are the same type and similiar capacity then it will probably work fine for operating the radio equipment and servos. I wouldn't expect them to do well connected to a propulsion motor though, a really small plane then it might be ok, larger and it probably wont, ymmv.

Reply to
Steve Banks

Hello.

Well I can find NiMH 6v cells using froogle. It is a small electric plane (Firebird Scout). The stock batteries are 300mah, and I can find some phone batteries at 700 or more mah, so I was wondering if they would work OK.

Thanks again.

Reply to
huitsing

I am just visiting, but I do know something about power supplies. The general rule goes like this.

Unless you know better, your new battery pack voltage should be close as possible but not greater than the old battery pack (fully charged) voltage.

For what it's worth.

Technically speaking, for what it's worth. The maximum battery voltage depends on the input voltage tolerance, data I guess you cannot easily find for most aircraft. Increasing the voltage won't help your plane fly faster.

Since you're dealing with batteries, you probably do not have to worry about source current. Just in case, the new battery pack source current should be equal to or greater than what the old battery pack could supply. Again, current is probably not a concern, in my opinion.

Reply to
John Doe

snip

I'm afraid you are sadly mistaken, and this is the problem he will have. The motor pack for an electric R/C airplane generally only lasts

5-10 minutes. This is a 6-10 C discharge rate. The pack used in a phone is intended to last for hours at well under sub-C rates. These batteries are not intended to charge or dischange fast. Doing so will: 1) not work very well (the internal resistance of the cells is too high and will greatly restrict the current flow.) 2) will burn out the pack in short order. (they just aren't made to dissipate heat.)
Reply to
Steve

I guess that is why you're here.

I usually speak in amps. The greatest current would be when speaking. Transmitters suck current.

I would use the same battery type. I think cameras use NiMH. Some major electronics supply stores will package rechargeable batteries for you.

It's an interesting subject to me. If I enjoy this stuff, I probably will be doing batteries. I might begin by replacing the nine-volt battery in my first transmitter.

Reply to
John Doe

why mess with the clunky old style batts at all?go with lipos designe

for modern e flight models and be done with it.i fly exclusively wit lipos in all my electrics while my nimhs and nicads are collecting dus

-- daddio

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Reply to
daddioz

Two issues:

  1. I'm guessing that the originals are nicad. The stock charger may cook the new battery pack. If so you would have to apply some electrical knowledge to limit the current to like C/20 (.7/20) and make a trickle charger out of it, or shell out bucks for a nimh charger.

  1. I can't tell you if the batteries can support the current demands of the motor, you will likely need to try it to determine that. It will probably work, and fly about twice as long (if the battery manufacturers are being honest), but that is not a guarantee.

Good luck.

Reply to
Steve Banks

The key to your problem is you are looking for the replacements from the manufacturer. Find another source. Doesn't matter whether you are looking for receiver packs or motor batteries for electrics, buying from the manufacturer is going to be the most expensive, and the least choice. I've had good luck with receiver packs from Batteries America

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Many people swear by NoBS Batteries
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Reply to
C G

Hi, I went to a computer show and they had a junk bin, anything in it for a dollar. I picked up several cordless phone batteries.They were brand new and they are Nicad 300 MAH. Wired 2 of them together and use them on my Slo Stick park flyer. Work just like the original battery and only $2.00 plus the connector. Dan.

Reply to
DANNYSPEED

I bet there are lots of discarded rechargeable battery packs like that in various places. The local Goodwill has a dozen wall adapters for $2 apiece. All you have to do is match the voltage and current. Same thing costs $15 at RadioShack. I should check it out for battery packs, thanks for the hint.

Reply to
John Doe

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