whats coming

[Greg Masters]

I'm probably being very dull here (& not for the first or last time ), but if you're not hard wiring the unit in, would the +ve/-ve earth problem apply? I remember it being a snag when wiring a radio into my Triumph Herald, but wouldn't expect that to be a problem with supplying power from a cigar lighter.....

Mike (electrical numpty)

OK, here's the simple explanation:

There's positive and there's negative. For the sake of this argument, let's assume that electricity flows from +ve to -ve (the electrons actually go from -ve to +ve, but we'll leave that bit out!).

Historical convention says that +ve uses a red wire, -ve a black wire.

If your old Triumph Herald had a fag-ash lighter, the central tip in the middle would have had the black wire attached, the outer casing would be earthed to the car's body (to which the battery +ve terminal was joined ie +ve earth).

Later cars, say a Triumph Dolomite, were wired -ve earth. So the lead going to the tip in the centre of the fag lighter would have been red, so the electricity would flow through the cigarette lighter coil in the opposite direction to the Herald.

No that's not a problem when dealing with bulbs, heating elements, horns etc, but it is a problem when you are connecting an electronic device (that doesn't have reverse polarity protection). They have to have the electricity going in and out in the correct direction first time and every time.

You can sort this easily when you hard wire the device. If the vehicle is -ve earth, connect the negative wire to the frame, the other to a live feed and if it's +ve earth connect the +ve wire to the frame etc.

Trouble is, the Garmin power-cum-speaker lead is wired to anticipate a +ve connection to come from the tip of the cigarette lighter. If the car is -ve earth, that's OK. But if the car is +ve earth, the flow will be back to front and the unit will be wrecked (there is a polarity warning in the SPIII handbook)!

Lesson 2 (Maxwell's Cyclic Currents) follows next week!



Greg

 

[MikeO]

Thank you

 

[jenks]

I meant to mention on my earlier reply that an SPIII would get mighty upset if you pluged the cigarette lighter attachment into a classic car that was wired +ve earth (as many before about 1960 were)

Greg


Thanks Greg, I wouldn't have thought of that, and as it's an Austin Healey cira 1961, it would have blown it to pieces. I owe you a beer as you've just saved me £850.00.

I understand that it comes with re-chargable batteries, how long is the charge? because if it's 10 hours plus then I wouldn't hard wire the Healey, The other cars are alright, so I can hard wire those.

Andrew

 

[MikeO]

Andrew,

the unit doesn't come with batteries. It takes 6 AA cells (which it eats up at a formidable rate - you really need an external power source, which, for car* use, is supplied in the form of a cigar lighter plug). You can, of course, fit re-chargeable batteries, but these will not re-charge in the unit - you'll have to use a separate charger.

Mike

*if you're using this in your Healey, it should be relatively easy to sort out some form of adaptor to allow the cigar lighter plug (which also incorporates the loudspeaker) to be used....

 

[jenks]

Greg / Mike,

Maybe this is a stupid question, but seeing as the Healey doesn't have a Fag lighter, can I install one in neg earth off a pos earth car??????????

Andrew.

 

[Simon Eassom]

I understand that it comes with re-chargable batteries, how long is the charge? because if it's 10 hours plus then I wouldn't hard wire the Healey,

If you're using top quality batteries (Duracell M3s for example) and you turn down the brighhtness of the unit, then battery life isn't quite so bad. I've had 12 hours or more out of them. Don't use cheap batteries from Poundsaver or the market stall; they won't even manage about 90 minutes.

Re-chargeables can manage 2 hours plus but they're not really a viable alternative.

I got a great deal in my local Sainsburys a couple of months ago. They had packets of 8 Duracells (8 for the price of 4) and I'm sure they got the price packet wrong: £1.95. So I bought 24 batteries for £6 and I'm still not through them.

If you've got no alternative but to use batteries, then it's not that bad . . . 12 hours of driving for £1.50 . . . that's peanuts compared to the petrol costs of a 12-hour drive.

 

[Greg Masters]

Greg / Mike,

Maybe this is a stupid question, but seeing as the Healey doesn't have a Fag lighter, can I install one in neg earth off a pos earth car??????????

Andrew.

Andrew

Out of curiosity, are we talking 3000 Mk1 or 2 here or 948 Sprite Mk II?

You appear to have 3 options:

1. Run the StreetPilot on its own batteries (but it eats them!)
2. Hardwire the StreetPilot using the Garmin plug/bare-ends lead (in correct orientation!)
3. Convert your car to -ve earth - actually not that hard assuming that you are using a Lucas dynamo and have no other +ve electronics (radio, tacho, ignition etc) on the car. Send me a PM and I'll tell you how to do it (I hope that I can remember!)
   [/list=1]
   
   Greg

 

[jez]

here's another way, solar power.

What a fantastic product! Not only will this Solar Charger recharge 4AA rechargeable batteries, but it also contains a 12v cigarette lighter socket to enable you to power your GPS anywhere - even when your batteries are flat.

A multi-jack to run various other small appliances is also included as is positive and negative power clamps to maintain your vehicles' 6V or 12V battery.
Availability: In stock - order before 3pm for delivery next day before 12noon!! £25.49
(excl. VAT)
£29.95
(inc. VAT)

http://www.globalpositioningsystems.co.uk/accessories.php?product_id=150&category_id=58



I'm also con sidering the spIII and saw this in the accesories section of the above website. A lot cheaper than the pther methods methinks.

 

[AdamZ]

If you're using top quality batteries (Duracell M3s for example) and you turn down the brighhtness of the unit, then battery life isn't quite so bad. I've had 12 hours or more out of them. Don't use cheap batteries from Poundsaver or the market stall; they won't even manage about 90 minutes.

Could not agree more, the unit is one which is very sensitive to the quality of the battery...

Tesco's own last bout 2 to 3 hours Duracell etc last 10 hours plus...

I have not yet wired my Cooper S up and the cigarette plug is used for the radar detector so use the Garmin battery mode no probs...

 

[jenks]

Andrew

Out of curiosity, are we talking 3000 Mk1 or 2 here or 948 Sprite Mk II?

You appear to have 3 options:

Greg,



Greg,


It's a 3000 MK1, we've had it about a year now, my wife made be buy it, before child three was born we used my Morgan Plus 8 (4.6 L,300bhp, 290 torque) for weekends away couple of touring holidays etc, so when baby came along she said we needed a 4 seater classic, hence the Healey, We use it regulrally when the sun shines.

She is now expecting baby number 4 (16th July)(her second, my 4th if that makes sence) so not sure we'll keep it long term, but I'v never been that good at letting toys go, so in the mean time
I think that it will be best to hard wire the GPS in +EARTH,


Just as an update, I'v had the GS serviced today at CW Motorcycles, and mentioned to Dave the Co Owner that I was treating my self to the GPS, well should have kept my mouth shut, he told me that it should be the BMW navigator as 2yrs warrenty, insured on bike, non-reflective screen etc etc, so he came up with a good??price, and I am now the prowd owner of a gps system, .....when it comes in stock, .

Thanks for ALL the help, I'm sure once it arrives I'll be asking all sorts of dumb questions.

Andrew

 

[Jon]

Brand New Streetpilot on ebay, currently £698

But reserve not yet met.

If anyone's interested.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=4668&item=3028167757

Think it could be a business rather than private person selling, as he's also selling a brand new Garmin eTrex Vista, a brand new Garmin eTrex Legend & a brand new Garmin GPS V...........which is most of the popular range if I'm not mistaken

 

[ralphy]

Street Pilot III

Just bought meself a Street Pilot III Deluxe from Maplins on Friday.
Went there Thursday & had a look at it; only one in stock was v4.01 - so thanks to the info I'd picked up on the BB I knew that v5 was now available. So I e-mailed Garmin & asked what the situation was regarding upgrade. 'No problems' was the prompt reply, 'we will send you v5 f.o.c.'.

So back to Maplins (I'd reserved the unit) & asked 'best price' (it was up for £845) - result = £790.46p!

Today it took me on a 140 miles return trip & did everything I wanted from it. Excellent bit of kit & far superior to the satnav built into my ex-car.

ps A big thanks to Simon Eassom for his time taken to talk me through the kit last week.

pps BTW, the guy in Maplins warned me 'do NOT wire the 12v cable in the wrong way; it blows the unit & isn't covered by warranty'.