Bike electrics, accessories, fuses and relay advice request

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Planning to add some extra lights (front and back), those wrap on heated grips plus GPS power cable to the bike. For some reason having difficulty getting my head around vehicle electrics and I'm seeking some advice. Three little queries:

(1)
Plan A
This was to fit additional fuse box powered from battery by a relay from a switched source (i.e. no power unless bike turned on).
Then from the fuse box run power to the accessories via switches as required.

Plan B
From another friend who insists for me not to switch the power this way but to fit the fuse box AND individual relays and switches for each circuit.

Now Plan B requires me to get my head around a lot of other wires and square relay blocks to attach and squirrel away. I'm also not sure it's required. As an example the instructions for the heated grips just say take it straight off the battery (but I want it via the fuse box as then can't be accidentally left on). There are no other relays in the heated grip circuit.

So I'm left a little confused. Ideally I want to give myself an easy life so a simple solution (is that Plan A?) would be appreciated.

(2)
Could anyone also please let me know what specification of wire I should be using (I'm assuming max. 30A circuit).

(3)
As it's an old bike for touring I did fancy fitting 4 way flasher. This is a separate project as I'm thinking it'll need some piezo sounders. The circuit will be active direct from battery (so can be active if ignition circuit dead) so sounders required to put off anybody passing by 'accidentally' switching it on. Does this sound like a good plan?

Thanks in anticipation
____________________
...and the whirlwind is in the thorn trees, it's hard for thee to kick against the pricks...
Gibbs, what did Duckie look like when he was younger?

[benc]

I would go with plan a as there is a lot less to go wrong. as long as you get a suitable relay(that will take the current from all the lights ect.) it should be fine

[stinkwheel]

Either will work fine providing you use thick enough wire to cope with the load. I would also fuse those things seperatley as you are talking about very different power demands. You will almost certainly need a relay for the grips, maybe not for the other lights (depending on draw) and probably not for the GPS.

So what I would do is run a big fat wire from the battery through a fused relay that is activated by an already existing switched supply (the rear brake switch or flasher relay is often a conveniant place for this.)

Use that to supply a mini fuse box then run your wiring up to the different accessories as required. As I said, you will probably need a relay for the grips as they would require a very heavy duty switch and wiring attaching to your handlebars otherwise.

Kind of like this (earths not shown for clarity):
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

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[stinkwheel]