Enlightened suggestions please.
since the last century I have run various Garmin GPS on my m/c. all 12 supply. No different from the car. Used switched and unswitched power. both were fine. One issue that always arose was the fact that using the electric start sometimes switched the GPS. Obviously the switched power version didn’t if the switch was off. Trying to avoid that as the it doesn’t come naturally to keep switching it off before you start, just like we don’t switch the radio off in the car.
I suspect I need some form of relay to create a one way system. Any suggestions or diagrams?

I’ve fitted one on both bikes we have in a the garage: My NC700X and Mrs PPs Ducati ST3s.
Both are wired straight to the battery. No problems at all. 🙂

Just out of interest, but you could actually run a cigarette lighter in there too yeah?

Both are wired straight to the battery. No problems at all.

That’s what I did on both my bikes.

Yeah, it doesn’t always happen. Suspect that it will be inked to battery condition at that particular start. Got a camping trip planned and its a good way to charge stuff so no big deal anyway.
Just realised that the damn Garmin 800 won’t display whilst being charged so that’s one pain.

It will be a fag lighter socket that is the working end of the wire in this case. That’s what I did before I starting making GPS cable

I used the Optimate connector and make up a 12v lighter socket to connect to that. So over winter the battery was connected to Optimate and over summer a 12v power socket for GPS etc….

Can you find the wiring diagram? There should be a couple of fused, unswitched spare feeds knocking around somewhere on the loom for wiring in accessories.

Also if your bike conforms to the standard Lucas colour coding system, there will be wires of a certain colour that are switched and unswitched fused and unfused spares but you need to Google the Lucas wiring colour codes to find those.

i used the optimate connector as well. its a no brainer.

V something point something used the Optimate connector. Done it on 5 bikes in 15 years, 4 of which were CCMs. Used all ways to wire . none of which stopped the electric starter seemingly tapping into the GPS battery occasionally.
I do however, whilst typing this last post, suspect that the common factor is CCM which could explain everything. 😆
time to try it again.

You’ve not mentioned what bike you have but many now come with an accessories connection wiring that is hidden away behind the body work until you connect it up to something; extra lights, socket, alarm etc.
On the previous bike I used this for the switched feed to a waterproof cigarette socket. In addition to this I also connected a live feed from the battery to the same socket with an inline fuse and waterproof push button switch so I could use it with the ignition off. After once forgetting I’d left it switched on from the battery and unable to start the bike afterwards I fitted a tiny LED to highlight the fact the socket had power.

Been there and done all of those and more. I have come to the conclusion that it was all the fault of a Rotax motor. This forum does open up the thought process a bit.

Thinking outside the box, is there not a setting in the garmin which tells it to ignore fluctuating power supplies? My Tomtom rider has this option:

Just out of interest, but you could actually run a cigarette lighter in there too yeah?

Yes, though most bike power outlets are the smaller din socket type.

On the KTM I have a switched feed (from the factory fitted fused connector behind the headlight) to the tomtom and heated grips. I’ve also got a USB outlet under the seat (spliced into the tail light feed) to keep things like phones and cameras topped up. There’s yet another feed to run the autocom & two-way radios, but I gave up on them a long time ago.

Not clear if your problem is the GPS see’s the dip in voltage during starting and switches itself off, or if the starting is pulling the bike battery down enough that power is also being drawn from the GPS battery, ie backewards through the charge cable.

Case 1, this setting may be overideable on the GPS as mentioned above.

Case 2, you could power the socket via a normally closed relay (or the appropriate connections on a change over relay which is more readily available) that is triggered by the starter motor exciter wire. This will have the same effect as manually switching off the the feed to the socket while you start the bike, only it will do it automatically.

I’ve just fitted one of these, connected to the fixed battery charging socket http://www.optimate.co.uk/o-101.htm

Seems to do the trick.

I like how it has “1000mA” eblazoned on its side. That’d be 1 Amp then? 🙄