Posted by fredy on July 30, 2006, 7:09 am
hi just like to sound out pros and cons of an idea.
In my setup I dump load when the battery volts get above 28 volts then
drop to 26 volts for float. This is as normal in most commercial
controllers. However as I am using a PLC (programable controller) for
simplicity I dump 1000 watts via the invertor for a period of time to
my water heater (usually 10 seconds) the batteries then recover at full
charging current. commercial units use proportional control balencing
the dump to maintian a set voltage. My method I have decided has a lot
of advantages in that the current flow in the batteries is larger and
connections do not corrode up as they tend to with small currents.
Posted by daestrom on July 31, 2006, 9:41 pm
If I understand you correctly, you're discharging the batteries slightly,
then letting them charge at high current back up to 28 volts.
If that's true, you probably are going to use more water to maintain level
than if they were on float all the time. Also not clear, but the cycling
may have an adverse affect on total battery life.
Posted by fredy on August 3, 2006, 5:36 am
The discharge is only 10seconds then returns to charge .
also I only hold 28 volts for 1 hour accumulated time (computer prog
works this out) then drop to float at 26 volts but still use the
switched dump 1000watts.
in a way it is nearly diverting the charge from the batteries to the
water heater plus some.
water usage is normal generally top up once a month or when i remember
batteries were old forklift batteries some cells are failing now after
7 years i am happy with that . supply of old cells is still around.
Posted by daestrom on August 3, 2006, 8:08 pm
Indeed. 7 years is good service from such a battery, even new. To get them
at a discount and still get seven years seems like a bargain.