Radio feed

Discuss Electrical problems here.
Forum rules
By using this site, you agree to our rules. Please see: Terms of Use
Post Reply
ayr41
Minor Friendly
Posts: 94
Joined: Mon Dec 06, 2004 6:42 pm
Location: South Ayrshire
MMOC Member: Yes

Radio feed

Post by ayr41 »

Can someone kindly advise the best place to connect a 12v feed for the radio in my van.
Chipper
Minor Addict
Posts: 858
Joined: Thu Apr 26, 2007 11:43 pm
Location: Kent
MMOC Member: No

Re: Radio feed

Post by Chipper »

Depends whether you want an ignition switched live or not. If so, you will need to find the suitable wiring diagram for your particular model and tap into the wiring coming from the ignition switch that becomes live when the ignition is turned on; there are usually spare 'bullet' connectors you can fit the new feed into, to save having to resort to Scotchloks.

If you can live with the radio having a permanent live, you can either tap into the existing wiring or run a new length of wire though the bulkhead, and attach it to the +12V side of the battery, via a fuse of suitable rating.

Don't forget to use a rubber grommet where it passes though any metal holes to avoid potential shorting due to chafing.
Last edited by Chipper on Sat Feb 06, 2021 12:33 pm, edited 1 time in total.
Maurice, E. Kent
(1970 Traveller)
User avatar
geoberni
Minor Legend
Posts: 3565
Joined: Fri Aug 04, 2017 11:19 am
Location: North Leicestershire
MMOC Member: Yes

Re: Radio feed

Post by geoberni »

I agree with Chipper, apart from the colours.
On Minors, the permanent live is Brown until it gets to the Fuse, it then changes to Purple.
This apples to all models according to the wiring diagrams.

Brown/Blue is a permanent live that goes to the IGN Sw and the Light Sw.
Basil the 1955 series II

Image
jagnut66
Minor Legend
Posts: 3635
Joined: Fri Apr 11, 2008 7:28 pm
Location: Mansfield, Nottinghamshire.
MMOC Member: Yes

Re: Radio feed

Post by jagnut66 »

Hi.
If it is a modern radio then you will need a permanent live for the memory circuit, otherwise you will loose all the presets and the speaker set up when you switch off.
I usually wire both as permanent live, as it has the advantage that you can have the radio on or a CD playing even when the ignition is off.
Both with inline fuses of course.
Best wishes,
Mike.
1954 Series 2: 4 door: "Sally" -- Back on the ground with (slave) wheels and waiting to be resprayed......
1970 Triumph Herald 1200: "Hetty" -- Driven back from Llangollen in Wales (twice.....)
oliver90owner
Minor Legend
Posts: 1655
Joined: Thu May 12, 2016 6:33 am
MMOC Member: No

Re: Radio feed

Post by oliver90owner »

2 points.

Live side of battery, not necessarily the positive depending, of course, on the polarity of the vehicle and/or radio).

There is a risk of seriously, or completely, discharging the battery if wired direct to the battery.🙂
jagnut66
Minor Legend
Posts: 3635
Joined: Fri Apr 11, 2008 7:28 pm
Location: Mansfield, Nottinghamshire.
MMOC Member: Yes

Re: Radio feed

Post by jagnut66 »

There is a risk of seriously, or completely, discharging the battery if wired direct to the battery
Hi,
To clarify, I'm talking about connecting in with a permanent live on the loom, at the fuse box, and then including an additional inline fuse, not connecting directly onto the battery itself.
Best wishes,
Mike.
1954 Series 2: 4 door: "Sally" -- Back on the ground with (slave) wheels and waiting to be resprayed......
1970 Triumph Herald 1200: "Hetty" -- Driven back from Llangollen in Wales (twice.....)
oliver90owner
Minor Legend
Posts: 1655
Joined: Thu May 12, 2016 6:33 am
MMOC Member: No

Re: Radio feed

Post by oliver90owner »

jagnut66 wrote: Sun Feb 07, 2021 8:32 pm
There is a risk of seriously, or completely, discharging the battery if wired direct to the battery
Hi,
To clarify, I'm talking about connecting in with a permanent live on the loom, at the fuse box, and then including an additional inline fuse, not connecting directly onto the battery itself.
Best wishes,
Mike.
I quite agree, a fuse should always be incorporated in a circuit. What I was meaning was the radio with only a manual switch in circuit. It will be left on, sooner or later. Deeply discharging a modern automotive battery is quite a costly exercise - even if if it does not show up in the short term. In the old days, batteries were constructed to even power parking (side) lights overnight. Try that these days and the battery will soon need replacing!

Virtually all modern cars have a ‘lights still on’ audible warning, so the car manufacturers know these things can happen.
jagnut66
Minor Legend
Posts: 3635
Joined: Fri Apr 11, 2008 7:28 pm
Location: Mansfield, Nottinghamshire.
MMOC Member: Yes

Re: Radio feed

Post by jagnut66 »

Ah, so you meant that the battery could discharge via the 'human error' of leaving the radio on.
Plus that modern batteries are not made as well as they used to be..............
That has been said of lots of things and is equally true in each case...........
Built in obsolescence, a wonderful way of keeping the punters buying more of your product.
All you have to do then is keep putting the price up and you'll soon be rich.....
Best wishes,
Mike.
1954 Series 2: 4 door: "Sally" -- Back on the ground with (slave) wheels and waiting to be resprayed......
1970 Triumph Herald 1200: "Hetty" -- Driven back from Llangollen in Wales (twice.....)
User avatar
geoberni
Minor Legend
Posts: 3565
Joined: Fri Aug 04, 2017 11:19 am
Location: North Leicestershire
MMOC Member: Yes

Re: Radio feed

Post by geoberni »

Well actually modern batteries are far more capable designs than their basic lead acid forbearers, the problem is that the vehicles they are fitted to require so much of them.
A Battery for a Minor may have 35-45 AH capacity and a Cold Cranking of 300 Amps.
Batteries for a modern Diesel will be in the region of 90-110AH and 750Amp Cold Cranking.
Something unheard of from a single battery 40-50 years ago.

Battery life is very much a produce of it's Use/Abuse, including the climate it operates in.
I got 10 years from the battery for my current 'Modern' car.

When I lived in Nevada, the operating conditions of the desert temperatures gave a typical battery life of 2-4 years. Starting a car when the ambient air temperature is 100+F take a lot from it.
Basil the 1955 series II

Image
Post Reply