Is it necessary to have an "ignition-on" warning lamp. My electrics are basically on/off with a starter-button and I have access to a race alternator with no tell-tale.

Nope.

Not needed for SVA, but it is required for the alternator to work right in many applications IIRC.

adrian

Yes, without a bulb (or equivalent circuit as in Bright6) a lot of alternators won't start charging.

But no it's not required for SVA.

as inak says.

I don't think I have seen anything in SVA manual that states you need an alternator.

Alternators that are designed to have ignition lights use the current through the bulb to supply the exciter circuits. Without this current the alternator will not work.
Not all alternators have ignition light take-offs though.... (typically race ones).

So usually not having an ignition light is a bad idea. But in circumstances its fine.

The small amount of current that goes through the bulb initially "excites" the field windings (ooh err missus)

Once it is charging it "excites" itself.

Test the alternator by running the engine and put a volt meter accross the battery. Should be 13.8 to 14.4 volts.

If this is so then the alternator is working and there is enough magnatism within your rotor to get it going so don't worry about it.

If it's not charging you can run a feed from the main battery terminal on the alternator to the light connection to excite the field temporarily.

Don't leave it connected though because it draws about 2 amps and to leave it connected would flatten the battery.

Permanent solution if it's not charging at the moment would be to fit a light. + ignition feed at one end of the bulb. Down to the alternator at the other. Bulb goes out when + at one end and + at the other. "potental difference = 0"

Hope that helps.