Camper
/ Trailer Application Notes
 When
it comes to RV or trailer camping, the usage on your battery differs substantially from
that of your vehicle primary starting battery. When you set up for camp, you
need lights, power for your water pump, maybe a fan, radio, or TV etc... You
operate these during times when the engine is not running. During this time,
your RV battery slowly empties its charge. With your trailer or RV battery
connected to your charging system, your starting battery will share the current to your
loads. The problem is, your starting battery was never designed to perform in
this manner and, as a result, will fail early in its expected life. The other
problem is a little more serious. You may be enjoying your stay so much that
you stay put for a while. Eventually you may run out of battery charge,
leaving you stranded without starting power!
People have utilized many different ways to save your starting battery from this
annoying situation. They have used diode isolators, relays with switches,
relays wired to ignition circuits or accessory circuits, high current switches, or
automatic mechanical combiners. Each of these methods have their own
advantages and disadvantages. Some are more complex than others.
Now, you have the choice of using a system with more advantages than ever
before! The Hellroaring BIC-75150A and BIC-75300A Battery Isolator/Combiners are the best solution on the
market today.
RV Starting Battery
Isolation
For motorhome types with high output alternators and large house loads while operating,
consider the RV starting battery isolation technique as a simple solution to multiple use
batteries. With this setup, a high output alternator can supply maximum charge
current to large house battery banks. All batteries receive proper alternator
voltage from an internally sensed alternator due to the very low ON resistance of the
BIC-75150A (less than 0.008 ohms). Since there is no diode drop, the starting
battery stays fully charged. Electrical loads on either battery will not draw from
the other. If you choose this method, we recommend that you contact our technical support staff for assistance.
Basic Auxiliary
Battery & Trailer Application
For most applications, (i.e. slide-in camper, trailer, RV's with
required continuous loads under 50 amps on the auxiliary side during engine operation,
etc...) consider the basic deep cycle application. Your primary objective is
to prevent your starting battery from draining while you consume power from your
house (deep cycle) battery. (Don't be fooled by low
cost battery disconnect devices as a solution. If you try to use these, your
starting battery will get deep cycled and will result in early failure.)
You also want your house battery to obtain full charge as quickly as practical
while operating your vehicle. With the BIC-75150A installed as shown below,
you will obtain those two objectives! The BIC-75150A has very little
resistance (less than 0.008 ohms) when ON during charging and it automatically isolates
the two batteries when charge voltage stops, even if your alternator fails. If
desired, you will have the ability to combine the batteries manually for a starting
boost (the main battery must still supply substantial cranking
current). It has no mechanical moving parts to degrade or wear out! For
those on a budget and who want the simplest installation, the BIC-75150A
basic Auxiliary setup makes an excellent choice for full charging without the voltage drop
or bulky physical size associated with diode isolators! Works great for alternators
sensed at the alternator output (internal sense.)
Trailer
/ Camper mounted battery isolation
With a Hellroaring
BIC-75150A, you can install it in the camper itself. There is no need to alter the tow
vehicle electrical system. Since the BIC-75150A is basically a DC Solid State Relay with
integrated control electronics designed for dual battery systems, you do not have to run
any wires from this isolator to the main battery! Because it never receives all
of the alternator output, it does not require ratings based on the alternator, like a
diode isolator does. Rather, the BIC rating need only be higher than the maximum
continuous current expected in the camper charge line. And then, you normally
protect it and the wiring by installing an in-line fuse or circuit breaker.
With common 10 AWG tow vehicle charge wire, this would be no more than 40 amps because
this is the highest continuous rating for that wire. This is well within the
BIC-75150A continuous capability of 75 amps. If you used 8 AWG, this would be 60
amps. For those applications where even more continuous current is required, the
BIC's can be wired in parallel for double or more capability.
With this setup, you can connect your trailer to the tow vehicle and
leave it connected for as long as you want. The trailer loads will not drain your
vehicle battery. If your tow vehicle is already equipped with a towing
package, you should have a charge wire available near the trailer hitch. If you have
sufficient alternator capability, you can increase your charge rates by upgrading the
charge wire to 8 AWG, 6 AWG, or even 4 AWG.
With the AC charger connected as in the diagram, you will charge your
camper battery only. If you connect it to terminal "A" instead, then you
will charge the vehicle battery also.
Tow Vehicle
Backup Battery System
If you like to disconnect your trailer and drive around to enjoy the scenery, you will
not have your trailer loads to worry about. But, suppose that, while you are
out and about, your alternator fails. They always seems to fail at the most
inopportune time. You may not notice the problem until it is too late and your
engine dies or will not start. You may be parked 20 miles from nowhere, walk
back to your vehicle after a nice afternoon fishing, and find your vehicle unable to
crank. It sure would be nice to have a spare battery at a time like
this. Then consider the Basic Backup Battery setup illustrated
below. With this setup you have an emergency backup battery that is always
fully charged, even when you disconnect your trailer and your alternator
quits.
If you look closely at why you need an isolation system anyway, you will discover that
it is for one primary reason. That is; to have the ability to start and operate your engine when you have inadvertently
drained your starting battery. Most people only foresee the possibility
that their house loads will drain the starting battery. Because they aren't
aware of other possibilities, their focus goes toward preventing that condition
only. We believe that you should not limit your security to only one of the
possible ways to drain you starting battery. When you spend time in the field, you
should cover all likely possibilities, including alternator failure. Those who
connect relays to your ignition system obtain a false sense
of security. If their alternator unknowingly fails, their vehicle
will continue to operate until both batteries are drained. All the while they
believed that their backup battery was being charged! Our BIC units will
protect a spare backup battery from discharge due to either draining your house/trailer
battery, if your alternator quits, or even if
your main battery effectively gets disconnected due to
corrosion!
Consider this installation suggestion:
Suppose you install a super combination deep cycle/starting battery such as an Optima
Yellow top as your starting battery (It is rated for deep cycle use, yet it has plenty of
cranking power - 750 CCA.) Then install, in your vehicle, a regular starting
battery as a spare backup battery isolated with a Hellroaring BIC-75300A
configured for high current. With this setup, you don't need isolation to your trailer
or house battery. You will always have a spare capable of cranking your
engine! If your house loads drain your starting (deep cycle) battery, you can,
with the simple flip of a micro-switch, crank your gasoline
engine (You will need two units in parallel for a Diesel
Engine.) An added benefit to this system is that you will gain battery capacity by
the amount of your main battery. This will add life span to your
batteries because you will not need to discharge either one as deeply than as with a
single battery. With this setup, you will need less circuit breakers, less
hardware, less space, and will receive more security.
Sure, there are less expensive individual isolation products available.
But, none stack up to all the benefits that the BIC-75300A is
capable of. After considering all the parts and labor needed to perform the
same functions, We believe this setup is one of the simplest, most convenient to
use, most reliable, most economical and practical system available for Tow Vehicle
applications.
Here is one very nice benefit from this setup. If you use your tow vehicle
in cold climates, then you can have double
the cranking power when you need it the most as the temperature drops to below
-10F. There is no need to even get out of the vehicle nor open the
hood! Simply flip a micro-switch on the dashboard and you are on your way!
We believe that this is one of the very best setups
available!
With this setup, we believe that you do not need isolation between the trailer battery
and main battery for two reasons. 1) You will have the backup starting capability,
and 2) The trailer battery usually is not connected all the time. However, if you
feel you must have isolation here in addition to having the backup capability, it is very
simple to add a BIC-75150A between the alternator and trailer battery or in the trailer itself as described above.
If your application is extreme such that you want multiple and different isolated
batteries/loads, you can add a BIC-75150A for each battery bank in addition to the
BIC-75300A backup. |
