The 'E' Type Forum

My Series 1 is a positive earth car soIi have been given and cigar lighter adapter which basically switches the wire over to make it negative earth for plugging in the Sat Nav etc. However it keeps blowing the fuses in the adapter.
I have increased the size of the fuse to 3 amp. Is there something wrong here as I would have though a 3 amp fuse could handle a Sat Nav load?

I am a bit confused with a Positive earth car and it principles.Does that mean the whole car is live and if I earth it to the ground it would drain the battery or blow a fuse?.

Any thoughts would be appreciated

Tony : +ve earth merely means that the current flows from the negative side of the battery and is returned via the +ve terminal. In fact, cars are not earthed at all in the true electrical sense , except through the tyres to some very limited extent because of the carbon in the tyres . In Metal cars ( this does not apply to fibreglass bodyshells) when the circuit diagram shows a wire to earth ( always a black wire ) what it really means is a wire to the common return path, which is the bodyshell . If you look at your car , you will find that the +ve red wire should be bolted directly to the metal of the body shell . Just a thought - no one has already changed your car to -ve earth have they ? Just because it has a dynamo does not automatically mean it is still +ve earth

As far as your short is concerned, it rather depends what is blowing the fuses. If you have used the lighter itself probably takes more than 3 amps. Have you tried rigging up a test bulb of say 5 watts ( approx 0.4 amps) and seeing if that works in the adapter? And have you ensured that, with the adapter in use , the output polarity is as required i.e. live pin +ve , return -ve?

I think you need to be very careful the new socket does not 'earth' (and for this discussion let's call anything metal and part of the bodywork an earth) to the dash panel. The gizmo you have bought sounds like trouble to me especially as you are heading into France. Basically if it goes wrong in your garage there will be a very good chance it will go wrong on the road!

I suggest you do what I did: http://etypeuk.com/forum/viewtopic.php?t=168 and fit an auxiliary power outlet in the glove box. This is pretty bullet proof because the glove box is non conductive fibre and you can swap the connectors over to put the +ve on the central pin without blowing anything. It also means you will not have any changes in the dash panel which helps if you are trying to explain to a French garage that the car is totally original except for this funny little .........................

Tony

2nd solution: how about a good old fashioned paper road atlas?

John H.

John

Requires a navigator who understands maps and the French road system, especially if you are heading out on the D roads. However you need a map as well because the Sat Nav WILL get you lost!

Paper road Atlas?. That will mean long discussions with my wife on where we (she )went wrong. I am not sure I am ready for that. We have only been married for 40 years and while I maybe the boss, she is the head boss.

All the same it was an interesting thought that will result in me having bad dreams. At least with the Sat Nav we can both blame the lady in the Tom Tom. My Tom Tom has an interesting quirk. I live need the Welsh boarder and if I cross it by one meter she starts talking to me in Welsh. What's all that about?

Tony wrote: My Tom Tom has an interesting quirk. I live need the Welsh boarder and if I cross it by one meter she starts talking to me in Welsh. What's all that about?

That's the Taff Taff upgrade If you look under Places of Interest, it shows you every midden and sheep shelter in each county, in case you want to take a leek

Bora da

Pete

Update on the inverter.

It is still working and so far the car has not burnt down. I will do an update after my French trip. 2,500 miles in hot weather should be a good test. Wish me luck.

PS: Nice one Mr Crespin :)

Just an update on the inverter/adaptor I fitted to my positive earth Series 1.
I have now done approx 3,000 miles in France and Spain and it has worked well in some very hot conditions with no problems so far.
So if you want to run a negative earth devise in a positive earth car, this seems to work and is easy to fit. I will let you know if it goes wrong.

The inverter/adapter was bought from Raysmith.co.uk and cost ?59.

http://www.raysmith.co.uk/catalogsearch ... &x=25&y=20

I came direct off the ignition switch, with a on/off micro switch fitted in the supply line as well as an inline fuse. The former allows me to turn it off when not using the Sat Nav or Ipod.

The Inverter/Adapter was screwed direct to the body of the car behind the glove box compartment and a cigarette lighter outlet was fitter on the under panel of the glove box. You cannot see anything so it does not detract from the cars original spec dashboard.