No Diode Voltage Drop
The Hellroaring battery isolator /
combiners BIC-95150B and
BIC-95300B do not drop significant voltage like a typical
diode isolator does.
Instead, they act more like just a
few feet of large gauge
wire when it is switched ON!
When full charge is approached, a
diode isolator still
drops from 0.55 to 0.7 Volts. This voltage drop
reduces the voltage
available to the battery which inhibits full and complete charging
Now the Good News!
When using the Hellroaring BIC-95150B or BIC-95300B, the
voltage drop is expected to be less than 0.005V at full charge (Our
test vehicle measured
about 0.001 Volt across a an original BIC-75150A. ) This
insignificant to the battery charge! To put this in
will usually be more voltage drop in the wires to and from the battery! This drop is even less with the BIC-95xxxB models because their ON resistance is less than half of the original model.
When you install a second or more
batteries either in your vehicle or towed vehicle, you need a way to
prevent discharge of one battery circuit as a result of a load on the
other. For RV trailers, as an example, it is most
desired to prevent a load in the trailer (such as lights, appliances,
etc...) from draining your vehicle starting battery. The least
expensive method is simply to disconnect your trailer plug every time
you turn OFF your engine. The drawbacks to this technique
are as follows:
You must remember to disconnect!
It doesn't work if you don't disconnect.
Some connections are frustratingly
difficult to remove.
You must remember to reconnect when on
your way again!
If the spare battery is in your vehicle,
the choice of disconnecting and reconnecting is even less
desirable. To make the isolation more automatic, some people will
place a diode in series with the alternator and main battery. The
drawback of this technique is:
A voltage drop, inherent in the
diodes, reduces the charge voltage to the battery causing the charge
current to be significantly reduced. As a result full
charge will not be achieved unless you operate the vehicle for very
long periods. Often, the vehicle is not operated long
enough and then, the battery sits for a while with less than full
charge. This condition causes the battery plates to
sulfate, which will gradually degrade its performance and lead to early
To overcome this problem, a second diode
is placed in series with the auxiliary battery and the alternator
output is modified to output a higher voltage. The
drawbacks to this technique are: