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Thread ID: 78358	2007-04-12 12:06:00	12v 15A battery lead to car CD player	Strommer (42)	PC World Chat

Post ID	Timestamp	Content	User
540447	2007-04-12 23:04:00	... in the old days the batt was just for the memory, but these days with 4x100w+ amps built in they need some decent power hence the 15amp fuse. Ahhh, maybe that is why the BATT lead is marked 15 A, since there is provision for connecting an amplifier to the CD player.	Strommer (42)
540448	2007-04-12 23:32:00	Ahhh, maybe that is why the BATT lead is marked 15 A, since there is provision for connecting an amplifier to the CD player . Some of the composite units DO use a 15 amp circuit to turn on the amp or subwoofie when the head unit is on . . . ergo, the 15 amp requirement . Others use the 15 amp to trigger a remote cd-stack or player to go on and off with the head unit too . (15 amps is not a very big subwoofie though . . . people here use over 200 amps . . that's right . . . 200 amps in a capacitor-discharge circuit for street thumpers and window breakers) Some even use it (incorrectly) to trigger electric operated antennas too . . but there is usually a special circuit for that on modern units . I see some use it to fire up custom lighting when the system's on too . The switching would go thru the "always-on" battery B+ side of the head unit, and be available to use for power on things like that . But, in reality, and without any heavy equipment on the system, it is primarily used as a memory maintenance circuit for volatile presets and the clock and stuff like that .	SurferJoe46 (51)
540449	2007-04-12 23:50:00	Thanks tweake . But guess what? I went down to the local auto electrician - well established business - and showed the head honcho the wiring and explained the situation . Surprisingly he told me to leave as is, without bothering to run a heavier wire to the battery or elsewhere . The old tape player set up only had a 1 amp fuse and he said to leave that in and if it blew, try a 5 A . He said that most CD players would not take nearly the 15 A marked on the wire . What I did yesterday was to replace the 1 A fuse with a 5A . If that blows I will try a 10A fuse (bought an assortment at SuperCheap) . If the 10A blows I will run a wire to the battery . To clarify: the new CD-mp3 player has two 12v leads: one is the ACC/IGN and the other wire is the Battery lead marked 15A . shoot the sparky :groan: Ahhh, maybe that is why the BATT lead is marked 15 A, since there is provision for connecting an amplifier to the CD player . Some of the composite units DO use a 15 amp circuit to turn on the amp or subwoofie when the head unit is on . . . ergo, the 15 amp requirement . Others use the 15 amp to trigger a remote cd-stack or player to go on and off with the head unit too . (15 amps is not a very big subwoofie though . . . people here use over 200 amps . . that's right . . . 200 amps in a capacitor-discharge circuit for street thumpers and window breakers) Some even use it (incorrectly) to trigger electric operated antennas too . . but there is usually a special circuit for that on modern units . I see some use it to fire up custom lighting when the system's on too . The switching would go thru the "always-on" battery B+ side of the head unit, and be available to use for power on things like that . nope . the 15amp batt line is not a remote amp power line . a head unit will often have a seperate remote amp turn on wire . all it does is sends a signal (12v very low current) to tell the amp/cdstcker/eq etc to turn on . ditto to aerial tho it is often a seperate one for the aerial . the 15amp line is the headunits main power line just for the head unit (tho sometimes they will power a cd stacker via the headunit) . the ACC/IGN is simply a signal to tell the headunit to turn on/off . run the batt line to the battery, its not worth risking the car wiring or damage to your speakers due to the extra distotion caused by the low voltage caused by the undersized wiring . shoot the @#$%ing sparky :thumbs:	tweak'e (69)
540450	2007-04-13 00:34:00	15 amp fuses can cause kidney stones too.....depends how they are ingested, I think	SurferJoe46 (51)
540451	2007-04-13 01:34:00	Just hook into the 5A wire. It'll be all gravy. Thats what I did - put a 5A fuse in the BATT line. I just installed it and it is sweet. No smell of burning insulation. So far the auto sparky appears correct. Sounds great. Everything works, including mp3s. Wife's car - she is going to love it. I've learned a few more things about auto electrics. Thanks for everyone's input.	Strommer (42)
540452	2007-04-13 02:35:00	As an ex sparkie, I too would have put a 5amp fuse in & tried it. However because I have the test meters I would have checked the amps at full volume. PJ	Poppa John (284)
540453	2007-04-13 03:40:00	Good to know I was right :D	roddy_boy (4115)
540454	2007-04-13 06:20:00	groan. i hope i never have to say "i told ya so". putting a 15amp on to a 1amp line with an stereo that will proberly peak around 30amp when on max is just plain wrong. no respect for decent audio at all :(	tweak'e (69)
540455	2007-04-13 06:36:00	It's probably OK. This time. :D He's only using a 5A fuse, and the player is working OK. The lightest wire in a car loom would probably handle 15A or 20A, just for mechanical reasons. But I wouldn't want to replace a 1A fuse with a 15A one. Ever.	Graham L (2)
540456	2007-04-13 09:28:00	But I wouldn't want to replace a 1A fuse with a 15A one. Ever. Tweake and Graham: You must understand that the 1A fuse was with the old tape player and that is gone, so forget the warnings about a 1A rating being pushed to 15A. The wire itself can handle 5A easily, probably 10A or 15A, but remember I have a 5A fuse in the line and it has not blown. And that is the worst that can happen - the fuse will blow. If it does, I will find the current rating for the gauge of wire and put in the appropriate (higher amp) fuse.	Strommer (42)
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