Car stereo dual power feed

An alchemy of sparks, copper wire and earth

Moderators: User administrators, Moderators

MagicWagon
Registered user
Posts: 263
Joined: 17 Jan 2016, 19:38
80-90 Mem No: 0

Re: Car stereo dual power feed

Post by MagicWagon »

My existing radio wiring is not on a key supply. It had a brown "earth" and a red permanent live. I'm re-using the earth, and re-using the permanent live to connect to the radio memory backup.
What would I look for when trying to find a spare ignition feed ? Mines a 1981, so I guess that would not count as a later one so maybe doesn't have any ?
1983 2.0L Air Cooled Devon Moonraker

User avatar
Mocki
Membership Admin
Posts: 16957
Joined: 29 Sep 2005, 09:27
80-90 Mem No: 428
Location: Mansfield Notts
Contact:

Re: Car stereo dual power feed

Post by Mocki »

Ok .... There are ignition switched lives at the fuse box you can take from but it's a multimeter ( or bulb and wire ) job because it's quite likely someone has buggered about before so I'm not risking telling you something that maybe wrong because I can't see what you have there

Heater fan motor and window wipers are not a good choice tho !! ( should be on same fuse if it's not been messed with )
Steve
tel / txt O7947-137911
👀
________________

1989 2.1LpgWBX HiTop Leisuredrive Camper
1988 2.1 Caravelle TS TinTop Camper 
 

keynsham1
Registered user
Posts: 401
Joined: 27 Sep 2015, 06:41
80-90 Mem No: 0

Re: Car stereo dual power feed

Post by keynsham1 »

I wired the continuous live to the stereo from the leisure battery and also the switched feed, but I had the switched feed running through a relay which is energised by the switched feed from the ignition switch. This means that both continuous and switched feed come from the leisure battery but the stereo is turned off with the ignition. I also wired a 12v illuminated switch across the leisure battery relay switched feed so I could run the stereo without the ignition on. The illuminated switch is to remind me that I need to switch it back when I have finished so the system reverts to ignition switch cutoff.

MagicWagon
Registered user
Posts: 263
Joined: 17 Jan 2016, 19:38
80-90 Mem No: 0

Re: Car stereo dual power feed

Post by MagicWagon »

I went ahead and wired as follows and it works a treat.
Yellow (fused) connected to permanent live (old radio live)
Red (ACC) connected via 2 way toggle switch. One feed to toggle switch is from leisure battery (actually c2 on the relay) and the other feed is from c3 on the relay (only live when the engine is running).
1983 2.0L Air Cooled Devon Moonraker

MagicWagon
Registered user
Posts: 263
Joined: 17 Jan 2016, 19:38
80-90 Mem No: 0

Re: Car stereo dual power feed

Post by MagicWagon »

And also now added a small under-seat type subwoofer behind the fridge and wired power to the same two-way toggle switch. All works well and sounds great now.
1983 2.0L Air Cooled Devon Moonraker

Gordo89
Registered user
Posts: 68
Joined: 29 Apr 2018, 19:16
80-90 Mem No: 16836
Location: West Midlands

Re: Car stereo dual power feed

Post by Gordo89 »

looking to do the same in my bus,

Would it be possible to run the switched live from "G" on the fuse board, and pick up the permanent live from the leisure battery?

my understanding the radio will power on when the key is turned but pull the main power from the aux battery, this would also allow for turning the head unit on with the ignition is off by pressing the power button on the radio.this will draw power from the auxiliary battery preventing a flat starter.

concern is connecting an item to 2 batteries?

Post Reply