Motoroia 114 converter from Pos to Neg Earth
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If you ‘float’ the radio it will work just fine - just keep + and - as on radio.
But make sure nothing on the radio touches any earth on the car, like antenna etc. No part of the radio frame or connections can touch any earth/frame of the car.
I’ve done this in the past and it works just fine. But certainly have to be careful on how you mount it.
But make sure nothing on the radio touches any earth on the car, like antenna etc. No part of the radio frame or connections can touch any earth/frame of the car.
I’ve done this in the past and it works just fine. But certainly have to be careful on how you mount it.
1966 Lotus Elan S3- Benelli motorcycles (various)
- Lotus54
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There is a real risk with floating the radio. Basically the metalwork of the radio (including it front control panel) will be connected to battery positive do any inadvertent shorting out, by say an unwary passenger with something like a charm bracelet.
Converting (the car) to negative earth is really very simple. Is there any particular reason you can't do that?
Ian
Converting (the car) to negative earth is really very simple. Is there any particular reason you can't do that?
Ian
68 Elan S4 DHC. Built in a weekend from a kit (just like the advert said)
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Elanman99 - Fourth Gear
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Bit of confusion in the posts above.
You do not need to 'float' the radio. The radio needs a +12v supply relative to ground (the negative connection, usually the body on a steel bodied negative earth car).
In the case of a positive earth car, there is no +12v supply relative to ground, only -12v.
To solve this problem, you could use an entirely separate battery to generate the +12v supply relative to ground the radio needs, but it is easier to to use a DC to DC converter. The radio case will remain at ground potential as will the antenna lead and antenna base.
This supply will be at +24v to the other cabling under the dash, but if fused and installed appropriately shouldn't present too many additional risks, certainly better than having the case of the radio 'live'.
You do not need to 'float' the radio. The radio needs a +12v supply relative to ground (the negative connection, usually the body on a steel bodied negative earth car).
In the case of a positive earth car, there is no +12v supply relative to ground, only -12v.
To solve this problem, you could use an entirely separate battery to generate the +12v supply relative to ground the radio needs, but it is easier to to use a DC to DC converter. The radio case will remain at ground potential as will the antenna lead and antenna base.
This supply will be at +24v to the other cabling under the dash, but if fused and installed appropriately shouldn't present too many additional risks, certainly better than having the case of the radio 'live'.
68 Elan S3 HSCC Roadsports spec
71 Elan Sprint (still being restored)
32 Standard 12
Various modern stuff
71 Elan Sprint (still being restored)
32 Standard 12
Various modern stuff
- Andy8421
- Coveted Fifth Gear
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My post added to the confusion, I knew what I was trying to say but certainly did not put it very well.
My concern was having the radio casing not connected to the same ground as the rest of the car and I agree a polarity inverter solves the problem (not that I have seen anything for sale labelled as such).
Still I think simpler to convert the vehicle to negative earth.
Ian
My concern was having the radio casing not connected to the same ground as the rest of the car and I agree a polarity inverter solves the problem (not that I have seen anything for sale labelled as such).
Still I think simpler to convert the vehicle to negative earth.
Ian
68 Elan S4 DHC. Built in a weekend from a kit (just like the advert said)
-
Elanman99 - Fourth Gear
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- Joined: 11 Sep 2003
Elanman99 wrote:
My concern was having the radio casing not connected to the same ground as the rest of the car and I agree a polarity inverter solves the problem (not that I have seen anything for sale labelled as such)
Ian
Ian,
A bit of a boat anchor, but here you go:
https://www.ebay.co.uk/itm/326119597118?itmmeta=01HXVBMWEDFBCB02ZR3C1AK5CV&hash=item4bee3e243e:g:OVMAAOSw171kxh6~&itmprp=enc%3AAQAJAAABAMfonnM%2FPSmZBK%2BUHB8c4OHERjJStZNByGYQAXITl%2BUXXqTpyBI2sjH4Cs5Ng5725XvIrSViBp4%2B8Hl%2FmJDI0IE%2FK5BJqABJWil5UoGD2sGiIbnIZk00E37ZHlSsciKCjUg6kG31qnKVuv9dOxIPiz20t6LFvGL3Z6fIQQU1Wyz1tLbMf0WM4ktEwSEX2iWBDOTo6D2cfU6xnPCTB4fjkMNACzlt486FeLlnVkOy3qjM87mzlCzOFUwS%2FA9eEDzj8WIxVfpvfIGtAaZCmyjZe%2BJJY9WKBtymXIf2YYve3AtPglWskY6Ka5ufGMyefDxO6Dkz3QVNKQXHjBFEww0aj04%3D%7Ctkp%3ABk9SR6bH0-vuYw
Though should the OP have any electrical skill, googling 'Isolated DC to DC converter' will bring up 100s of possible candidates. Converting the car to negative earth is straightforward, but will require the rev counter to be swapped over as well,
68 Elan S3 HSCC Roadsports spec
71 Elan Sprint (still being restored)
32 Standard 12
Various modern stuff
71 Elan Sprint (still being restored)
32 Standard 12
Various modern stuff
- Andy8421
- Coveted Fifth Gear
- Posts: 1252
- Joined: 27 Mar 2011
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