[VHFcontesting] Rovers: Your battery choice is...???

[Eric Smith]

>  
> What I really need to look into is a battery combiner or
> isolator so that I  
> can charge the batteries from the car alternator. Any
> good proven  ideas?
> Mike WB8BZK/R
> 
The diode isolators work OK provided the alternator is
externally regulated.  Alternators with internal regulators
with external sense wiring require a special diode isolator
with the sense wire output connection.  Follow the
installation instructions EXACTLY.
The good ol' continuous duty high current relay may be the
more reliable situation.  Can be switched automatically via
the ignition circuit to parallel when the engine is running
or manually switched.

I just switch on the 60 amp DC breaker which isolates the
vehicle charging system from  the radio system when I want
to charge the batteries, or switch it off to prevent
discharge of the vehicle battery.  Obviously operator
headspace problems may result in dead vehicle battery, but
a catastrophic short circuit in either system will open the
breaker, reducing the destruction.

My battery bank consists of four deep cycle wet cell pallet
jack batteries, with the ground or negative side paralleled
together and bonded to the vehicle chassis.  Each battery
is tied to a busbar with its own individual circuit
breaker.  Wiring from the vehicle system is #4 welding wire
to the charging disconnect breaker, located on the front
operating position distribution busbar. Front and rear
distribution busbars are tied together with #3/0 welding
wire, breakers at both ends.  Another #3/0 cable ties the
battery combiner busbar with the rear distribution busbar,
with a breaker at the rear distribution busbar end only.
 An ordinary 8d starting battery is series wired to the
rear distribution bar to make the 24VDC for the 903 amp.
 This battery is only charged pre-contest with its own
charger, or could be placed in series with the big bank and
the whole mess charged with a 28VDC source from "shore"
power.
The only real problem is the pallet jack batteries do not
have the rated capacity anymore.
But the price was right (free)...
Eric
KB7DQH