Re: [RCSE] 8 Cell Battery Voltage Range..

[Ralph Weaver <rmw00@xxxxxxxxx>]

At 07:20 PM 5/16/00 -0700, you wrote:
> My Zagi-400 is complete.  I am waiting for the battery
> to charge.  I have a multimeter, so I would like to
> know the voltage range for the 8-cell battery.
>
> What is the minimum voltage for the engine to run?
>
> What is the maximum voltage for the battery?
>
> What is the minimum voltage for the radio to work?  (I
> think it is like 7.5 volts)

The voltage range possible would be from 0V if discharged and under load to 
as high as 13V peak during a fast charge.  The voltages will depend on the 
load and the condition of the battery.

The motor should run with just a volt or two.

The radio needs about 5V.  The BEC in most speed controllers drops about a 
volt, so you'd need 6V, maybe 6.5V input to the BEC to run the radio.

In practice:

A peak charge should be at least 1C (C is the capacity of the cells in Amp 
Hours) and should shut off as soon as the voltage starts to drop.

A slow charge should be no more than C/10 and you can leave it on overnight.

Because of the discharge curve shape of a NiCd, measuring the voltage is 
not very useful.  80% full and 10% full can give the same voltage.

Ralph Weaver     "The best time to plant a tree is twenty years
Fishers, IN        ago, the second best time is now."
USA

 My site http://members.home.net/rmw00
 MTI products http://www.magtechinc.net



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