Converter install questions

[Joe70]

I am installing a 24V to 12V converter in my new BJ74. I have a couple of issues I was hoping to get worked out. First, on my last BJ74 I had the converter wired to a fuse block and then took all of my 12V needs off of that. The problem I had was if the truck sat for more then a week, the batteries would not start the truck. Does the converter draw power even though there is no 12V being drawn? If so my solution would be to put a switch between the 24V feed and converter. I'm hoping this will solve that problem. Opinions? This brings me to the other issue I would have. If I switch off the power to the converter, I will lose the memory of the CD player. Is it possible to hook the memory wire up to 24V?

 

[Ron R]

I am installing a 24V to 12V converter in my new BJ74. I have a couple of issues I was hoping to get worked out. First, on my last BJ74 I had the converter wired to a fuse block and then took all of my 12V needs off of that. The problem I had was if the truck sat for more then a week, the batteries would not start the truck. Does the converter draw power even though there is no 12V being drawn?

Yes, depending on the quality and type of converter it draws from a few milliamps to many 200 (?) or more.
So called switching regulators will only draw a few milliamps, say 20 or so. Analogue regulators can draw many milliamps. I've even seen one drawing almost one amp, though not in use at that moment.
Usually an anlogue converter had large cooling ribs, a switching converter virtually none.

If so my solution would be to put a switch between the 24V feed and converter. I'm hoping this will solve that problem. Opinions?

Yes, that's a solution. But you can forget to switch it off, leaving the rig. I solved this by using a bulky, good quality relay in stead of a switch. As soon as I switch the ignition key to 'ACC' the relay is activated and the converter is on.

This brings me to the other issue I would have. If I switch off the power to the converter, I will lose the memory of the CD player. Is it possible to hook the memory wire up to 24V?

No you cannot hook up to 24 V. Unless your equipment is set-up for 24 v but than there is no need for a converter.

Once you switch off the converter memory is lost.
I solved this by building a very small analogue regulator. Essentially this is a small 3-pin 12v voltage regulator (integrated circuit) and a diode. The regulator feeds the memory through the diode. The diode is there to avoid setting up the 'normal' converter.