Headlight switch help

My apologies. I saw in another thread that we're talking 25-30amps for a headlight circuit.

Thirty amp relays seem to be the accepted norm - but there's a healthy safety factor built into that.

Old school sealed beam bulbs are 35 watts each, or 70 the pair. Divide 12 (volts) into that to figure the current draw and you get just under six amps. Higher performance bulbs might be rated up to 60 watts, 120 the pair, for a 10-amp draw.

In the old days, the rule-of-thumb safety factor was to double the expected load, so a 20-amp relay would be about right.

Today though, there's also the 'country-of-origin' safety factor to consider, owing to where most of this stuff comes from. This shouldn't be a new concept to anyone driving a replica Speedster.

I'd spec a 30-amp relay.

Just as an interesting side bar, because so many different cars built all over the world use both tab-style fuses (regular size and so-called "mini-tab" fuses at half size) and relays, the industry set some dimensional standards decades ago for the socket configurations of them.  That means that all of those little 1" cube size relays all have the same pin configurations with more or less pins, depending on the relay circuit (single or dual-sided switching action - spst or spdt )

That said, when I'm running low on relays I wander around through a local junk yard and just grab a few handfuls of them.  Most of them are marked as to function and current rating (you may have to pull them and look at the pin side to see what they do) and if you get them from reputable makes (no Yugos, please) the quality should be really good.  I can usually walk away from the place with 10-15 of them for under $10 bucks - often the guy just tells me to take them, no charge.

I've also found that, turning their backs on the "Dark Lord Lucas's reign", some British  car builders are running pretty high quality Bosch electrical systems within.

What better way to spend a Saturday morning than to wander around an automotive junk yard, coffee in hand and grabbing relays and whatever else tickles your fancy for really, really short money........

I went with 30 amp relays

Funny that this discussion occurred right when I'm about to wire my dash (I'm working from the back forward). So last night (with Gordon's help) I bought a fuse box from a newer Jag XJ6. Short money ($35) and I see Hella, Siemens, and the size looks right. More than I need but there's room for growth.

Nice score, Boothy.

The only problem with using electrics from a Jag is that every day, no matter where you are, precisely at 4:00 pm, everything will shut down for twenty minutes.

Ahhhhhh......Tea Time!

I'll take mine Camomile.....And you, Grommit, Lad?

There is much discussion of this accessory over on the TD replica site. Go with a 20-amp fuse for that.

Ah, yes......And a proper "Cupa" that would be, too!

None of this brown emulsion produced by Microwave ovens and Keurig machines, but a proper "Cupa" made with a pot of boiling water.

Ahhhh........Civility!

One of my good friends and his wife are of British heritage from South Africa, and they do enjoy their tea.  It's fun to be in their garage working on John's M3 race car and have Corrine bring us tea.  I've developed quite a taste for it.

My tea is carbonated and has a delightful, frothy head on it -and I rarely wait till 4:00.

Boothy, the English have some experience with your kind of tea, too.

I think the Lucas model was used for making iced tea.

FWIW, I asked Henry about what he uses, and he has a switch that is really simple and works well for him, he says.  Little to no trouble, he says. Comes from a guy in Brazil, or somewhere in So America.  Very reliable, he says. $25 including shipping, he says.  So I says: "Here's my credit card number, pls send."  Meanwhile, regardless of what switch you use, run with relays for headlights and driving lights.

PS: Pretty soon I will have a genuine VW headlight switch available for whomever wants to pay the shipping.  It has the rheostat for dimming the inst lights.  trouble is (wish I had figured this out ahead of time) this switch does not mount the same way the Speedster switch does, so requires a larger hole in the dash and will not have the same bezel and blah blah blah.  Would send a picture if needed.