Modern Vespa

BV wrote on Sep 10
I see some new motorcycles when ignition key turns on, the headlight does not light up until next few seconds; this feature to prevent the battery stress during crank up the machine. Does anyone know any device that can install to headlight hot wire? This feature can help when battery is not full charged. Thanks.
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However when I called Napa and ask for part # MPEAR272 SB they told me that it does not exist. Is there another part number that I need for this type of relay:?:

Thanls

It would be helpful if you referenced the original thread so we can see what you're on about.

Here it is: https://modernvespa.com/forum/topic53328

I'm kinda curious about this myself.

Ah yes. Any standard automotive SPDT relay will do. It must have the centre 87a NC (Normally Closed) contact though.

It would be awfully nice if somebody with expertise and access to the appropriate knowledge could post a few commonly-available (at least in NA) brand/part numbers.

Er - can't you just walk into an auto-shop and pick one off the shelves?

Or look online. These things are generic, made by loads of different manufacturers, and don't have part numbers as such except for the individual shop ones.

e.g.:
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=1782012

Tridon is a manufacturer of relays. You should be able to find one of their and Napa has tons of relays. You should be able to find one in stock at in any larger parts store.

Thanks for the info. I guess my problem is that I don't understand what purpose they normally serve; so, I thought they were specific to individual vehicles. Perhaps it would make more sense if I knew what SPDT stood for.

Single pole double throw
http://en.wikipedia.org/wiki/Switch

Most, if not all cars, have operated this way for years. When the key is turned to START all other power is cut to allow max battery output to the engine starter. This is actually implemented in the car's ignition switch. It can be done with a SPDT relay when the function is not built into the ignition switch. Any decent auto parts store should have an SPDT relay with contacts labeled 85, 86, 87A & 30. I get them on ebay. They come with different amp ratings. I just get the 40 amp ones. Get the socket or use spade connectors. The earlier mentioned link has the wiring schematic. The relay will open the headlight circuit when power is supplied to the starter circuit.

Thanks again. So, in a car, the relay simply does what we want to accomplish with a scooter. I somehow thought a clever redeployment had been discovered for a device that's intended for some other purpose.

[/quote]Thanks again. So, in a car, the relay simply does what we want to accomplish with a scooter. ...[/quote]

The relay will accomplish the headlight cut-out in a scooter.
In a car there is more room for a larger ignition switch. Inside a car's ignition switch will be a few contact configurations. The accessories are switched out when the key is turned to START.