Commando - satnav power supply

Hi Mike

I think you'll probably get some more expert opinions but they will all say - whatever you do don't swap the leads over!

When I connected a Garmin Zumo to my '72 Commando Roadster, I started out simply connecting the cable to the battery terminals (+ to + , - to - of course) but immediately found that the unit used so much electricity that my battery died almost immediately! I then wired the unit in to the 'Switched circuit", so that it only charged when I turned the key. I did this by soldering the positive leads into my rear light circuit and left the negative going to the battery.

This worked really well and depending on which model you have, will probably work for you too. I now anticipate getting shot down in flames by Al Osborne!

Cheers

Peter

Hi Mike,

As this unit looks like it may be isolated, it really does not matter if you use it on positive or negative earth. As long as the red wire goes to positive (On the commando this is earth) and the black wire goes to Negative, (Suggest after the ignition switch).

It would make sense to swap the fuse over to the negative side but personally I would not bother.

What you should investigate is if the shroud of the USB connector is connected to 'earth'. Simply use a meter to check if the shroud has a direct connection to either the red of black wires.

If the shroud is connected to the black wire then you need to investigate the device you are going to be plugging in. If for example the SatNav mount is earthed and the USB connector is connected to this earth you will get smoke.

So what it really comes down to, if there is going to be any metalwork on the Phone / SatNav / Mount that is connected through the adapter to the black wire then you need to make sure this metal does not come into contact with any metalwork on the bike.

Regards

Tony

Previously mike_sullivan wrote:

Oh dear I am about to demonstrate why I failed O Level Phyics...

I'm looking to use my car satnav in Europe next week, I've looked at a number of options & have ended up looking at a usb cable that could power my satnav or phone via their associated usb cables: http://www.powerlinkproducts.co.uk/usbcharger.html

I am confused regarding the connection of this piece of wiring, my Commando is positive earth so how would I connect this? (don't want to fry satnav or phone) Is it really just a simple case of swapping the leads over i.e putting the live wire onto the negative terminal and negative to the positive (earth side) (the one with all the red wires),

Can any body steer me in the right direction please?

Mike

Accentuate the positive, eliminate the negative, latch on to the affirmative & watch out for Mr Inbetween.....

Hi - when we bought our latest car (fitted with integral satnav) our old Garmin unit was surplus to requirement thus I looked to use it on my Commando and BSA Rocket 3. I bought 2 x suitable power cables via the web with 'normal' cigarette lighter plugs fitted and wired these via a fuse to the 12v power on both bikes. I also purchased a suitable waterproof case and handlebar mounting bracket for the Garmin unit. This allows me to use the satnav on both bikes (takes about two minutes) to fit.

Previously Peter White wrote:

Hi Mike

I think you'll probably get some more expert opinions but they will all say - whatever you do don't swap the leads over!

When I connected a Garmin Zumo to my '72 Commando Roadster, I started out simply connecting the cable to the battery terminals (+ to + , - to - of course) but immediately found that the unit used so much electricity that my battery died almost immediately! I then wired the unit in to the 'Switched circuit", so that it only charged when I turned the key. I did this by soldering the positive leads into my rear light circuit and left the negative going to the battery.

This worked really well and depending on which model you have, will probably work for you too. I now anticipate getting shot down in flames by Al Osborne!

Cheers

Peter

Peter,

Perhaps a 'near miss' this time Peter! Certainly the first point to remember without fail (or you get SMOKE!) is that +and - must be observed. Please try not to think about EARTH. Then as above if your extra gubbins ie sat nav has a negative earth and it does NOT have any metal to contact the Positive earth of your bike then you should be ok. There is always a possible problem with having the wrong earth that might give some interference with any electronic gubbins so although you don't get smoke you still might get a 'strange' result. You can always change the polarity of your bike to negative earth! Ignition and battery charge regulation are both reversible, lights, horn don't care.

On the other hand, ink on paper-ie map is NOT polarity conscious neither does it flatten batteries. It can also be studied when not on the bike, and you can make your own idea up of where you are going! Sat nav-Once your battery is flat you are b*gg***d.

Ink on Paper!

Al Oz