13
4 FREQUENTLY
ASKED
QUESTIONS
Q
The BCDC2420(-LV) turns ON at 13.2V(12V) and OFF at 12.7V(11.9V), but you say it operates down
to 9V, explain?
A
The BCDC2420(-LV) will turn OFF for a split second every 100 seconds to measure the unloaded
voltage at the battery. When the BCDC2420(-LV) turns off it is not drawing any load from the start
battery, no load means that there is no voltage drop over the cable run. This allows the BCDC2420(-
LV) to measure the actual battery voltage, or the voltage at the battery. If this actual battery voltage is
below 12.7V(11.9V), the BCDC2420(-LV) will turn OFF. At any other time during the charging process,
if the voltage at the BCDC2420(-LV) drops below 9V the BCDC2420(-LV) will turn OFF.
Q
How does the BCDC charge an Auxiliary battery at 29V when it only gets 9V in?
A
The BCDC can act as both a reducer and a booster, so it can operate from a voltage of above, equal
to or below the desired output voltage. The unit is also microprocessor controlled allowing it to
output a Redarc proprietary charging algorithm independent of the input. This allows the unit to
charge specifi c to the battery type even if the input voltage is low due to voltage drop.
Q
Where should I mount the BCDC Unit?
A
The BCDC should be mounted as close as possible to the battery being charged (generally called the
Auxiliary or House battery). If the Auxiliary battery is located under the bonnet, pick a location for the
BCDC that is close to the battery and away from any direct engine heat. If the BCDC is to be mounted
into a Caravan or Camper, near or in the battery compartment is generally the best position. It is also
a good idea to mount the BCDC to a metal surface if possible to ensure optimal heat dissipation,
though this is not crucial.
Q
What does the charger do if the temperature around it rises above its operating temperature?
A
As the temperature of the BCDC rises above a certain level the current capacity of the output is
decreased gradually in order protect both the battery and the BCDC unit.
Q
If I use the BCDC to charge my auxiliary battery do I still need to install a battery isolator?
A
The BCDC incorporates the functionality of a battery isolator, it will turn ON and start charging when
it senses that the vehicle has started and similarly it will turn OFF when the vehicle is turned OFF.
Q
I’ve heard that you shouldn’t charge 2 batteries of different chemistries from the same source,
will I have any problems charging my AGM or Gel auxiliary battery from my Lead Acid start
battery?
A
The BCDC does not ‘link’ the batteries together like a battery isolator does, it is a DC-DC battery
charger. The output from the unit is tailored specifi cally to the selected output battery type, and
therefore allows the optimal charging of the auxiliary battery, no matter what chemistry your start
battery is.
Q
My BCDC is setup for 12V Alternator input but will not start when the vehicle is turned On, I’ve
followed the trouble shooting guide and the setup is fi ne, what’s the problem?
A
The most likely cause of this issue is that the BCDC is somehow ‘stuck’ in 24V mode. Try removing
the ‘Source Select’ (Blue) wire and reconnecting it. If the problem still exists please contact Redarc
Electronics.
