I only used that example because I'd love to see a V8-powered unicycle. I've seen a V8 chainsaw, why not a unicycle?
Anyway, if you hook them up so that both spotties and the light bar come on with the same switch, it will all work - and done precisely as you've described (triggering both relays with the same source) you're keeping the input power separate so not overloading one or the other - that's great.
My personal preference is to be able to individually turn each one off. On a recent trip where we spent many hours late at night towing, I found that killing all but the light bar on the front was more than adequate - this lowered the power drawn from the alternator, providing more available power for the fridge in the caravan (I was driving a 600W inverter to run the van's fridge on 240V, thus engaging the fridge's thermostat which is inactive on 12V).
You might consider leaving the light bar separately switched until the legislation arrives in NSW to allow lightbars. They are working on it, but another check of the VSI bulletins (here's the list) shows that they haven't released it yet.
Anyway, if you hook them up so that both spotties and the light bar come on with the same switch, it will all work - and done precisely as you've described (triggering both relays with the same source) you're keeping the input power separate so not overloading one or the other - that's great.
My personal preference is to be able to individually turn each one off. On a recent trip where we spent many hours late at night towing, I found that killing all but the light bar on the front was more than adequate - this lowered the power drawn from the alternator, providing more available power for the fridge in the caravan (I was driving a 600W inverter to run the van's fridge on 240V, thus engaging the fridge's thermostat which is inactive on 12V).
You might consider leaving the light bar separately switched until the legislation arrives in NSW to allow lightbars. They are working on it, but another check of the VSI bulletins (here's the list) shows that they haven't released it yet.
