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Re: Re: Kenwood D7



On Wed, 11 Sep 2002, Bruce Bostwick wrote about running the D7 for 7 Hrs:

> > Band A draws about 35 mA, and band B about 55 mA and the TNC about 10
> > mA. WIth both bands running thats 90 mA and for a 600 mA battery, that
> > works out to about 6.6 hours.  8 AM to 3 PM is about 7 hours.  Looks
> > like your battery is right on spec...
>
> Depends on which type of battery it is.  If... it's a NiCd pack ... then
> not all of that 600mAh is going to be usable by the radio, because at
> some point the battery voltage will go below cutoff for that unit and
> the remaining charge will be unusable.

The 600 mAH rating is determined by the point at which the voltage
drops below 1.1v per cell (maybe its 1.2, I don't remember for sure) when
discharged at the 0.1C rate, but the  radio will also work down to that
cell voltage too, and the dischrage of 90 mA is close to the 0.1C rate so
if the battery is rated at 600 mAH then it should produce 600 usable maH.

Thats when you should turn off the radio.  One should never try to run a
NiCd down to get the very last bit of charge out of it (below 1 volt per
cell) or you will be ruining the cells in the long term...

Bob


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