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Will my VHF let me down when I need it?


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I bought an ICOM M73 2-1/2 years ago. I charged it once after purchase. I only turn it on 5 seconds on occasion to check its battery status. It always announces a full charge. I’ve never done a radio check with it, so have not transmitted to challenge the battery. I have listened to WX on a few occasions just to see if doing that for 20 minutes reduces the charge. It has stayed stubbornly at “all bars”.

Has anyone else made this experience and then noticed a precipitous decline in charge once they started transmitting? Do my “all bars” give me a false sense of security? Should I just buy a fresh battery after 2 years?

Thanks for any insight!



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Andy, I'm always surprised how long the battery in my M-73 holds a charge. I've had my radio turned on for hours during a paddle. I've not noticed any sudden,  precipitous decline. I think Icom claims 10 hour battery life. I have an M-73 that's over 5 years old and the battery still holds a strong charge. I'd be interested to hear what other people have experienced.



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11 hours ago, Inverseyourself said:

Thanks, gentlemen. Mike, at the bottom of page 4 of the icom manual it says “wise to exchange battery every 2-3 years”, max seems to be 5 years. I’ll buy a new battery next year.

I'd suggest charging the (not really!) "old," backup battery 1X/year, perhaps in the spring, or your start to the season?  $0.02

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Just as an aside, might be prudent to actually use the radio to transmit to see how it functions and how to hold it, etc. to get the best signal strength and audio from it.

Also prudent to rely upon ICOM's white paper on batteries  with the caveat their expected usage of the radios is much greater that the usage by the typical kayaker.  As a practical matter we never will reach the charging cycle limits and our concern should be the battery aging out. I use my ham radio VHF radio much more than my marine VHF radio and its battery life is noticeably less.

It is very hard to know what information  the charge indicator on the screen is really providing.  Batteries are going to discharge over time so even if the indicator says it is fully charged months after it was charged, that is simply not possible.  Li-on batteries have a flat discharge curve before it declines precipitously  which means they will supply the rated voltage even as their charge gets low.  So a battery that is significantly discharged can still show the rated voltage.  It is also possible the indicator will show a battery is fully charged even though the working capacity is inherently low regardless of its charged status.  When you need to transmit extensively, the critical factor is the working capacity of the battery.

Given that the VHF radio is a safety device of some importance and in the event it is needed you may well use it far more than you ever have, due consideration to Icom's advice would seem prudent.  A little like will those old, expired flares work when I need them or should I get current dated ones?

Ed Lawson

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