[aprssig] battery charging
WB4GQK at aol.com
WB4GQK at aol.com
Tue Jul 12 22:33:23 CDT 2005
Deep Cycle settings will NORMALLY bring a wet cell to 14.45 +/-.05V due to
temperature/ AC input voltage/condition of battery. Generally the current will
be stabilized near 25-35% of maximum charging capability. When the charging
voltage reaches 14.45, it will automatically shift over to a float charge,
generally 2 -4% of the charger's current capability. The voltage will generally
settle out at 13.35 V. Again depending on the factors listed above.
Normal charging is accomplished by setting the charging voltage to 14.45 V
and keeping it there until the charging current slowly drops to around 4 amps
when it switches over to a float charge.
You can look at it as a constant CURRENT charging with varying voltage
compared to a constant VOLTAGE charge with varying current. The primary difference
is the amount of time required to bring a battery up to 85% of full charge.
Very obviously the constant current will charge a battery much faster than the
fixed voltage technique. It is somewhat controversial, regards the effect on
battery life being shortened when deep cycle techniques are used.
Finally some chargers such as my XANTREX 40Amp has a 21 day automatic reset
feature that applies an equalization charge of 15.55V that raises the battery
charge to it's highest level and PRESUMABLY dissolves some of the lead sulfate
that has accumulated on the plates. This is supposed to extend the life of the
battery. The key point here is the battery cannot be "physically hot" when
this extended voltage is applied. Otherwise the over temperature will
definitely shorten the battery life.
De Jim wb4gqk
More information about the aprssig