Electrical question - which way to wire diode with extra battery to keep scanner on?

Status
Not open for further replies.

theTastyCat

Member
Joined
Oct 6, 2007
Messages
151
Hey all - I'm just not sure how to do this. I'm striving to keep my TRX-2 on even when I shut off and restart my truck. Often the battery voltage can dip enough to cause the radio to turn off, requiring a restart complete with lengthy bootup.

A member here shared that he is using a small battery in line as well as a one-way diode between to ensure that power can only flow from the vehicle battery to the small battery (and then on to the radio) and not vice versa, defeating the purpose.

So here's my plan:

Vehicle battery + - - - > diode - - - > small battery - - - > radio.

BUT - which small battery terminal goes where? Seems like if it goes from the diode to the negative, that would be essentially wiring both batteries in series, doubling the voltage. But if I go to the positive, then the radio receives a negative lead from the small battery.

I would be most grateful for your wisdom!
 

theTastyCat

Member
Joined
Oct 6, 2007
Messages
151
Or maybe this! Diode to small battery positive, small battery positive to radio. Small battery negative grounded to frame?
 

theTastyCat

Member
Joined
Oct 6, 2007
Messages
151
Working like an absolute charm!! Can't thank you enough!!

Had a bit of a plot twist - was just about ready to hook everything up and noticed that the little 4aH battery was 6v, not 12, so I had to wire two of them in series and stuff them up under the dash. But working fine! Your chart was an absolute life-saver - thanks again!!
 
Status
Not open for further replies.
Top