Ian Barrett Posted March 9, 2012 Share Posted March 9, 2012 Guys, I have a battery isolator on the -ve side as one of my barage of anti-theft deterrents but now I've got round to installing a radio I forgot I'd lose my presets when I isolate the Landy. I was all set to run a dedicated -ve line to the radio, and have the necessary cables and in line fuse etc, when I came across an isolator with a fuse which bridges the terminals specifically to keep your radio presets. Brilliant. I already have the fuse holder and a load of fuses. I could do this to mine. But just to be sure I thought I'd confirm with you Am I'm OK to do this? What will be the effect if I turn the key without the isolator key in place - will it just blow the fuse? I'll learn that lesson quickly if thats the case, it will be an absolute pig to get to ! What size fuse would you recommend? Thanks chaps. Ian Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted March 9, 2012 Share Posted March 9, 2012 It will blow the fuse when you try turning the engine over, choice of fuse size could be as small as you like really the radio won't take a noticable amount of juice (we are talking milliamps) to keep the presets, you can have a look in the radio manual as it should be in the tech specs. Another way to decide what current fuse to choose would be to have the battery isolated and then connect an ammeter across the isolator terminals and see what current flows..... Quote Link to comment Share on other sites More sharing options...
mmgemini Posted March 9, 2012 Share Posted March 9, 2012 You have a PM Quote Link to comment Share on other sites More sharing options...
landmannnn Posted March 9, 2012 Share Posted March 9, 2012 If you run a dedicated 12v to your radio which doesn't touch any other circuits you won't blow the fuse. Suggest a 3A fuse would be suitable. Quote Link to comment Share on other sites More sharing options...
miketomcat Posted March 10, 2012 Share Posted March 10, 2012 Put a small fuse between works well the thief gets in interior light works turns ignition on some lights come on trys to start all goes dead gets board knocks the old Ford down the road instead well hopefully anyway. Mike Quote Link to comment Share on other sites More sharing options...
simonr Posted March 10, 2012 Share Posted March 10, 2012 A resistor works better than a fuse. Something around 1k Ohm is enough to preserve the radio memory but will only deliver 10mA to anything else. Not enough even for the interior light. This has an advantage that if you accidentally try to start the vehicle with the isolator off, you don't have to replace the fuse! Si Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted March 10, 2012 Share Posted March 10, 2012 A resistor works better than a fuse. Something around 1k Ohm is enough to preserve the radio memory but will only deliver 10mA to anything else. Not enough even for the interior light. This has an advantage that if you accidentally try to start the vehicle with the isolator off, you don't have to replace the fuse! Si I had been going to suggest a resistor but then thought that when you opened the door and the interior light attempted to turn on the voltage dropping would also mean the radio presets would be lost...... Quote Link to comment Share on other sites More sharing options...
simonr Posted March 10, 2012 Share Posted March 10, 2012 Possible! To be fair the vehicle I had it fitted to didn't have door switches. Si Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 12, 2012 Share Posted March 12, 2012 Wire the radio to the 2nd battery Quote Link to comment Share on other sites More sharing options...
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