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Two questions - battery/receiver

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Two questions - battery/receiver

Old 03-14-2007, 12:51 AM
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fadi
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Default Two questions - battery/receiver

Hello All
I am just wondering why does the battery pack has a signal wire on top of the usual positive and negative wires. Does the receiver need to "communicate" with the battery?
Most of the switches are two wires switches, this is strange, no? Only my charger has three wires connection, is it the one that "talk" to the battery?

Also, if one wants to setup a dual battery system, is it wiser to connect both batteries together using a Y cable and then plug in the Rx? Or better to plug the second battery in an unused channel of the Rx?


Thanks
Fadi
Old 03-14-2007, 12:55 AM
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turbotb0205
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Default RE: Two questions - battery/receiver

umm the third lead is usually dead.. no issue there.. but why do you want 2 batteries? just increase the MAH of the one you have... if you want to use two then you need to parallel them +to+ -to- to keep the voltage the same but increase its capacity.. IMO still better to get a higher MAH battery
Old 03-14-2007, 12:59 AM
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fadi
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Default RE: Two questions - battery/receiver

But basically, I cannot plug the two in the receiver directly?
I need two just in case one battery fails, it is not a mAh issue... and it also better distributes the weight to avoid balancing with lead
Old 03-14-2007, 02:40 AM
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KI8FR
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Default RE: Two questions - battery/receiver

I run 2 batteris in my planes what I do is run 2 swiches. both right in the rx
Here is a link that will tell you all about it..

http://www.rcbatteryclinic.com/

and click on this off to the left of the page

Parallel Operation = Reliability and Flight Time
Old 03-14-2007, 11:09 AM
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Rodney
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Default RE: Two questions - battery/receiver

Two batteries (each connected to the receiver through it's own switch assembly) is often better than a single bigger battery for two or more reasons. Two reasons are, if using high current servos, the battery impedance is only half as large giving you better immunity to glitches due to current draw and for reliability. You can loose one battery due to any cause and still be able to safely land your plane.
Old 03-14-2007, 11:23 AM
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Default RE: Two questions - battery/receiver

36 years ago battery packs had 3 wires and servos had 4.the three wire batteries were center tapped in that not only did they have 4.8 volts but also 2.4 volts.it has been so long now I can't remember if the 2.4 volts was for the servo motor or for the amp.for along time afterwards packs and switches had the 3 wires for compatabillity with the older equipment.
Old 03-14-2007, 11:30 AM
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fadi
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Default RE: Two questions - battery/receiver

tellspin, thanks a lot for the link!
Old 03-16-2007, 01:23 PM
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Harley Condra
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Default RE: Two questions - battery/receiver

The story about the 3 wires for a center tap" is correct. Fourty years ago, in 1967, I had (still have) my first proportional set, a Galaxy 5, made by Ted White of pattern fame. It had seven wires on the servos, ("F&M Titan Magnevac") and three or 4 wires on the battery pack (seven button cells).
We've come a long way since then.

Today, the reason that batteries have three wires is because the radio and battery pack manufacturers use a SERVO LEAD for the battery pack lead. Since it already has three wires, the third wire (signal) isn't hooked up inside the battery pack. It is in there, and you will find it if you ever remove the shrink wrap from an old dead pack.

It is very simple; basic economics 101: If you take the third wire out, you have a very small additional labor cost. If you leave it in, it costs nothing. The labor is worth more than the third wire and terminal.

If you are a manufacturer of radio systems or battery packs and ordered two wire leads for the battery pack, you would need to order it as a seperate line item, recieve it, inspect it, stock it, isssue and kit it prior to assembly. Multiple part numbers equal more steps from the design stage all the way until it is assembled and inspected.

The retail price is generally arrived at based on a formula that includes the manufacturing cost plus a honest profit and a small fudge factor, and maybe other marketplace factors that I am unaware of.

Those costs are generally borne by the consumer.

The battery does not communicate with the receiver. It merely supplies the necessary opertional voltage to the receiver and servos.

Harley Condra
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Old 03-16-2007, 02:11 PM
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ag4ever
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Default RE: Two questions - battery/receiver

My futaba pack only has two wire on it, and I think my HydroMax pack only has two wires. i gues those Mfgs think it is worth wile to not use a 3wire servo lead for their packs.
Old 03-16-2007, 09:22 PM
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fadi
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Default RE: Two questions - battery/receiver

Thanks for your input Harley Condra. I think I totally agree
Old 03-19-2007, 08:44 AM
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pt19 flyer
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Default RE: Two questions - battery/receiver

hi
on some older radio constrol systems the airborne pack had a center tap. this gave 2.4 volts on each side of the center tap. a total of 4.8 from red to black. some of the older 4 wire servo systems required this center tap for power distribution. modern systems don't use this.

good luck and happy flying

pt19 flyer

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