The New Generation Of 12-Volt DC Relays
http://www.ebay.com/itm/New-Solid-State-Relay-SSR-40-DD-DC-DC-40A-3-32VDC-Input-5-60VDC-Output-for-Y5RG-/371290954044?pt=LH_DefaultDomain_2&hash=item5672aa593c http://www.ebay.com/itm...
Forum Discussion
A proper size heat sink bonded by heatsink thermal paste is absolutely necessary. One of the links is to a $2.95 heatsink from China.
The solid state relays contain a optocoupler for ABSOLUTE isolation between load and switch. A good size MOSFET transistor, some small capacitors, resistors, and a freewheeling diode. Unlike an NPN MOSFET device, the solid state DC relays are connected to the POSITIVE or NEGATIVE side of a load to be switched.
If I get a chance I'll do a write-up with links how to do a suppressor circuit for these relays that protects against transient voltage spike damage.
There are rumbles coming from the China manufacturers that a 100-amp version is in the works. It'll need quite the heat sink.
I used to use rubber encapsulated mercury filled relays. They were shockingly expensive but resisted burning of the contacts. The arcing takes place when the contacts part not when they engage.
These relays switch so fast I am using them for 90 Hz LED strobe feeds.
I leave black anodized aluminum heatsink mounting surfaces alone but with shiny aluminum heatsinks and mirror-like bottoms of solid state relays I scuff them with 400 sandpaper. Arctic Silver SILVER heatsink compound is another very useful thing to employ to get the heat away from the device and into the heatsink.
I would tend to discourage the use of a solid state relay in an engine starter motor solenoid circuit. Too many transients and too little benefit over a stout Ford starter motor fender mounted solenoid. Actually a relay but no one calls them that.
The solid state relays contain a optocoupler for ABSOLUTE isolation between load and switch. A good size MOSFET transistor, some small capacitors, resistors, and a freewheeling diode. Unlike an NPN MOSFET device, the solid state DC relays are connected to the POSITIVE or NEGATIVE side of a load to be switched.
If I get a chance I'll do a write-up with links how to do a suppressor circuit for these relays that protects against transient voltage spike damage.
There are rumbles coming from the China manufacturers that a 100-amp version is in the works. It'll need quite the heat sink.
I used to use rubber encapsulated mercury filled relays. They were shockingly expensive but resisted burning of the contacts. The arcing takes place when the contacts part not when they engage.
These relays switch so fast I am using them for 90 Hz LED strobe feeds.
I leave black anodized aluminum heatsink mounting surfaces alone but with shiny aluminum heatsinks and mirror-like bottoms of solid state relays I scuff them with 400 sandpaper. Arctic Silver SILVER heatsink compound is another very useful thing to employ to get the heat away from the device and into the heatsink.
I would tend to discourage the use of a solid state relay in an engine starter motor solenoid circuit. Too many transients and too little benefit over a stout Ford starter motor fender mounted solenoid. Actually a relay but no one calls them that.
