Hello one and all. I've just stumbled across this forum and hoped I could tap into the extensive knowledge base on here.
I'm wanting to build a power supply for my car, so that when I have my laptop plugged into it to run diagnostics and spftware updates (which requires the ignition on for extended periods, i had it on for 45 minutes yesterday and drained the battery!) I can prevent the battery from draining.
As I understand it, i'd be looking for about 14V dc with a good 30A of current. I know that having current so high means expensive componants, there is an off the shelf product available for about £150, but I figured I'd see if I can build one cheaper.
I'm an Aircraft Avionics engineer by trade, so not an electronics greenhorn, but I want to do it right first time, not mess it up and end up buying off the shelf anyway! Hence me coming here with cap in hand!
I figure that I'm looking at a transformer to get the mains (240v ac as I'm in the UK!) down to a 16v ac (i know you should always aim for slightly more V than you actually want to use, and 16 V means 15:1 ratio on the transformer). Then rectify it to get your DC, probably add some protection between the transformer and rectifier circuits, then smooth the DC off and filter it to get a nice clean output.
The theory sounds fine, but I've been trying to draw the circuit diagram, and can't work out what to do for the best!
Please help!
Thanks guys.
I'm wanting to build a power supply for my car, so that when I have my laptop plugged into it to run diagnostics and spftware updates (which requires the ignition on for extended periods, i had it on for 45 minutes yesterday and drained the battery!) I can prevent the battery from draining.
As I understand it, i'd be looking for about 14V dc with a good 30A of current. I know that having current so high means expensive componants, there is an off the shelf product available for about £150, but I figured I'd see if I can build one cheaper.
I'm an Aircraft Avionics engineer by trade, so not an electronics greenhorn, but I want to do it right first time, not mess it up and end up buying off the shelf anyway! Hence me coming here with cap in hand!
I figure that I'm looking at a transformer to get the mains (240v ac as I'm in the UK!) down to a 16v ac (i know you should always aim for slightly more V than you actually want to use, and 16 V means 15:1 ratio on the transformer). Then rectify it to get your DC, probably add some protection between the transformer and rectifier circuits, then smooth the DC off and filter it to get a nice clean output.
The theory sounds fine, but I've been trying to draw the circuit diagram, and can't work out what to do for the best!
Please help!
Thanks guys.