Hi guys, whilst I like the calculator, I must urge a little caution, the calculator will give you numerical answers but without a real understanding of the theory underpinning the questions a little knowledge can be a dangerous thing. As Douglas Adams said in The Hitch Hikers Guide to the Galaxy, "...the answer to Life, the Universe and Everything is 42, but what is the question".
Be aware that there is far more to this subject than simply being told answers to calculations, there are considerations outside of the calculations that only experience teaches, and the bad thing about experience is that you usually get it just after you really needed it. For example, I saw a circuit diagram in one of the forums a little while ago which had a 20A fuse feeding a 30A cable to two 40A relays, the thing about this is that the current is controlled by the lowest common denominator, which in that case is the 20A fuse, so the 40A relays were twice as big as required. Probably more than twice as expensive as required and certainly physically bigger than required.
There has recently been a lot of talk about relays and their use and requirement. In reality a relay is simply a switch, off and on only, and you use them simply so that you don't have to route the whole current required through the operating switch. For example, who wants to have all the current required to operate two or more HIDs (20A or more) having to be carried up the handlebars using 30A cable, through a big bulky 30A switch and back down again through 30A cable? no-one. It is unnecessarily risky when a simple relay installation means you only need run thin cables capable of handling no more than 1/4A to a small switch because the real current is routed through the relay.
Relay coils and contacts can have diodes put across them to reduce switching transients and thus reduce the effects of arcing in heavy current circuits.
Lastly heavy currents mean voltage drops in cables and heat generated in cables which means wasted energy and lower operating parameters at the items being powered. Less efficient systems are caused by badly designed installations and only experience can teach the best way to create the installation in the first place, not a calculator.
I'm not saying that the calculator isn't a useful tool, but it is only one of many tools in the toolkit required for good solid installations that are safe and reliable and will not fail you when you most need them. I'm certainly not saying that you shouldn't do your own mods, what I'm saying is that you should think about asking advice from those people who have a deeper understanding of the subject, they will probably think of things you hadn't simply because they have more experience of the broader subject.
Brock, any comments?
