> Yep, Ken tx for the pointer to the higher current boosters.
> Good idea for
> the EOC where we'll put an IC-706 in place. The original 706
> we had AF
> quality degraded noticably below 11.5V, and it would
> actually cut out at
> just below 11V. We actually have one of the N4UAU boosters on hand:
Hi, Mark,
This is a real issue with battery operation. Lead-acid batteries may start out
at 12.6 V, but very rapidly the terminal voltage drops off more or less
linearly with time.
I have made discharge curves for a 105 A-H lead acid deep discharge marine
battery and in just a few hours of FD-type operation the voltage goes below
12.0 V. To get the full 105 A-h out of the battery, you have to accept terminal
voltage of well under 11.0 V at the end of the discharge cycle. And as you
point out, many radios can't tolerate this. For some radios, the receiver sound
fine and there is no clue to any malfunction but the transmit signal begins to
have real problems with high intermodulation products, FMing, and other crud.
Anyway, the point I want to make with you is that I have turned to putting
individual nicads in series with the deep cycle battery and adding one at a
time to maintain 13.8V (plus or minus) at the radio. The nicads I use are large
60 to 100 A-H cells, and at 1.3 volts each it only takes two or three to keep
the total battery from dropping below 13.8 V. The reason why we do this is that
many of those electronic devices that "boost" the battery voltage generate RFI
themselves. There have been many posts here about switching power supplies and
RFI, and these devices operate on the same principle. Be careful.
Regards,
Al W6LX
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