Need help understanding what a hard start relay helps

[schwim]

Hi there everyone!

I understand what they do but what I don't understand what it helps. Not the cranking power, right? It shortens the length of the relay trigger wire but if the starter turns the engine, is it of no benefit?

Since the power for the starter is a battery less than 2 feet from it, it's not increasing the cranking power, correct?

Would a bug in need of one just not engage the starter?

Thanks for your time!
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Zippy the Wonderbug's achingly slow meandering toward roadworthiness

[richparker]

It shortens the distance the power needs to travel to engage the starter. Beneficial in a bus, I one in mine, but not needed in a Bug.
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[OldSchoolVW's]

Using it helps extend the service life of the ignition switch because only the small amount of current necessary to trigger the relay passes through the ignition switch instead of the current needed to engage the starter. Original switches were better built (more substantial contacts) so could handle this current with no problem. 60 or so years later, those contacts have become worn. Usually still good enough to carry enough current to trigger a relay, but struggle to deliver the necessary current to the starter solenoid. Most new replacement ignition switches just aren't built as well, so a HSR will help keep those working longer. Installing one is easy, inexpensive, and I don't see a downside to doing it.
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Tom

"Following distance is proportional to IQ."

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[wdfifteen]

I've seen a lot of people put in "hard start" relays when what they really needed is a new starter bushing or to clean the battery terminals. As has been stated, the only advantage is to take some of the current load off of the ignition switch.

[ashman40]

[Eric&Barb]

[zerotofifty]

[EVfun]

If you attempt to measure the resistance of the starter solenoid (terminal 50 to ground on the starter) you will find it is nearly a dead short to ground. There are 2 windings on the starter solenoid. One is heavy and low resistance and it will draw a huge current surge when you first engage the starter. The other one is more turns of smaller gauge wire, this one hold the starter in. A reason for this is to have lots of kick to engage the starter gear. A stout relay right next to the starter can help provide that current surge.

Below is a picture from SW-EM:

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[Blue Baron]

[RWK]

A starter button installed to bypass a failing ignition switch helps also, it also adds the ability to crank engine for oil pressure when it's sat for a time, adds a degree of theft protection also.
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73 Type 181
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[zerotofifty]

For 12 volt cars...

https://www.jbugs.com/product/WR-1.html

Or do a google search for VW Hard Start Relay. many sellers

I run a 12 volt 30 amp relay on my 12 volt car


For a 6 volt car, you need a 6 volt relay, 60 amps should do it.

When voltage is half as is 6 volt verses 12 volt, then the amperage (current) should be doubled. This is because Amps x Volts = watts. Watts is power and that is what is doing the "work" in an electric system. Example an 8 amp 6 volt light bulb is 48 watts (6 x 8 = 48 ) the light bulb is as bright as a 48 watt 12 volt light bulb, and that 12 volt 48 watt bulb uses 4 amps (4 Amp x 12 volt = 48 watt)

Also note that the minimum required wire diameter is determined by the amps that pass thru it, NOT the voltage. Since a 6 volt car uses more amps in a circuit than a 12 volt car, the wires used in the 6 volt car MUST be thicker in order to pass that twice higher amps with similar resistive losses as in the 12 volt lower amp circuit. If the wire is too thin then there will be losses in that wire that are unacceptable, this means that the voltage coming out of that wire will be lower. When voltage is lower do to losses, that is known as voltage drop. Too thin a wire means too much voltage drop.

So besure that the wires you use are rated for the amps you intend to pass thru them.

Here is a very handy tutorial and wire size chart for wiring. always select the recommended wire diameter or larger for your intended amps...

https://www.westmarine.com/west-advisor/Marine-Wire-Size-And-Ampacity.html

Have fun, it is electrifying!!!!

[Helfen]

[EVfun]

[Glenn]

[ashman40]

[zerotofifty]

Here is a heavy duty six volt starter relay...

https://www.amazon.com/CJOAOJC-Terminals-Solenoid-...&psc=1

[pastellgreen]

[schwim]

[Glenn]

[zerotofifty]