dc to dc and 12v battery hook up

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dc to dc and 12v battery hook up

Steve Clunn
I had a though on a way to set up the auxiliary battery .  My goal is
to have the auxiliary battery and dc to dc  completely unhooked when
the car  is off .  Here's how I'm thinking of doing it . I will hook
the auxiliary battery B+ to the wire that went to energize the starter
motor solenoid  .   So when you turn on the key and turn to the start
position the aux battery energies ( back feeds) to the 12v system in
the car . Next we have a relay who's coil is  hooked to the 12v key on
and its points will connect the aux batteries 12+  to the always on 12
v system giving you power to all systems  . When you turn off the car
this relay opens and now there is no connection to the aux battery (
and he won't get drained when sitting ).
     Now the dc to dc converter . I just blow one , a model that I had
been using on over 200v cars , the first time I hooked to to the 300v
car I ran it in series with a load , and it worked ,, but without the
in rush limiter it didn't hold up on the next turn on  so having
something to slowly turn this on ( next and last one I have)   would
be good .  I don't want the dc to dc  on all the time either. I am
thinking of a mos Fet that would connect  the hi voltage side . I will
turn him on with a relay from the keyed 12v system . His source pin
will be on the traction neg  On his gate I'll have a 7v zenor and a
100k pull down resistor  to keep gate from going to hi , I'll also
have a capacitor from b- to gate to slow the turn on time . The points
of the relay will connect another 100 k resistor from the traction b+
to the gate. As the capacitor charges up the dc to dc will come on
slowly . When the key is off the relay open and fet turns off . Am I
missing any thing here ?
Steve Clunn

A fool and a wise man went walking
the fool did all the talking
at the end of the trip
the wise man let slip
thanks for the enlightenment.

Tomorrows Ride TODAY !
Visit our shop web page at: www.Greenshedconversions.com

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Re: dc to dc and 12v battery hook up

If there is no 12 volt aux power on you will loose you clock & radio presets settings every time you turn your car off.