Dr. Gerald N. Johnson writes...
> Altrnators that put out more than 14.2 volts cause batteries to have
> short life.
It depends on how long they do so. At 15 volts, a battery will
eventually get warm and the electrolyte will start to gas off and even
boil. That's bad. But proper alternators and charging systems do not
maintain such voltages for long enough for the electrolyte to get that
hot. Usually, the battery voltage restores itself quickly enough so
that the alternator (or multi-stage battery charger) backs the voltage
down. Typical multi-stage chargers start at 14.something for an
initial fast charge and then back down to 13.8 for a soak charge,
followed by 13.2 or so for maintenance. They usually run it back up
into the mid 14's every day or so during maintenance to minimize
sulfation. Alternators follow a similar scheme, but without the need
for maintenance or anti-sulfation cycling.
The point is that the radio should be able to handle voltages up to 14
volts if it is intended for mobile installations. My Yaesu radio in my
Subaru reports voltage when it powers up, and it powers up at the same
time the accessory circuits turn on following engine startup. It
generally reports 14.5 volts when it powers up. That car is already
three years old with 72,000 miles and the original battery is still
going strong. Ditto the engine battery on my motorhome, which gets
intermittent use, but which routinely gets 14.5-15 volts of initial
charge voltage from one source or another.
Rick, KR9D
---
Richard W. Denney, Jr. PE|Iteris, Inc. |
Associate Vice President |107 Carpenter Dr. Ste 230 | 703.925.3819
rwd@iteris.com |Sterling, VA 20164 |Fax 703.471.1757
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