Is this relay sufficent for my project? - Page 1
Forum section: electronics / beginners

author: Albert
author_rank: Newbie
timestamp: December 21, 2013, 07:43:08 am
content: Hi,I am a mechanical engineering student from Germany.I am planning on building a web controlled heater for my car for the wintertime. My car stands outside and I hate to scrub the ice off the windshield every day.I just bought the spark io device with the relay shield.I am using a 2000W, 230V heater.My question now is, if this mechanical relay they have on the board can take up to 2000W, 230V, 8,7 A?The datasheet is here. It is 1 Form a typ.http://pewa.panasonic.com/assets/pcsd/catalog/js-catalog.pdfHere's a picture of the relay shield.The 1 Form A typ is rated at 2500W max VA. This gives me a 20% safety margin over the 2000W expected power.Is this sufficent or would you go for a solid state relay instead?

author: peter.mitchell
author_rank: Super Contributor
timestamp: December 21, 2013, 08:10:51 am
content: I'd say it's sufficient. The relay being from a reputable manufacturer the ratings have been tested thoroughly. No idea about the board itself though.Remember, the board will have high voltage present on the terminals/pins/ect so put it in an enclosure or insulate them appropriately, mistakes can happen.

author: Rerouter
author_rank: Super Contributor
timestamp: December 21, 2013, 08:41:59 am
content: yes it can handle it, though the contacts are only rated for 50000 make/breaks so if your trying to do on off temperature control rather than just a preheater keep the switching period long

author: Albert
author_rank: Newbie
timestamp: December 21, 2013, 08:50:07 am
content: Thanks!Yes, I am worried about the high current and high voltage at the terminal as well. I am thinking about putting the board inside the enclosure of the heater, where not much heat is absorbed. Probably into one of the foots.Than I need to think about the heat ratings of the coil. As the temp goes up, so does the resistance of the coil and the opperating current will go up as well, when doing that solution.But it will be the neatest. Just having a cable coming out of the heater without anything more attached to it. I want to use the 230V current to power the board as well and was thinking about using a small apple charger, like this:to transform it down to the operating voltage/current the board needs.@Rerouter:I won't do a temperatur control. Just switching it on 10 mins before I get into the car via my smartphone, so it is warm and the windows are icefree

author: kripton2035
author_rank: Super Contributor
timestamp: December 21, 2013, 09:40:16 am
content: I dont trust these apple charger clones... too small, too little protection insidebetter use some power supply like this one, quite cheap too :http://dx.com/p/hzdz-switching-power-supply-module-green-5v-700ma-271900also I'm not sure a smartphone is the way to go : a simple fm remote control would be easier for that simple task.

author: bookaboo
author_rank: Frequent Contributor
timestamp: December 21, 2013, 11:26:08 am
content: A 230V heater in a car sounds like trouble. I presume you plan to get an inverter?It would soon drain your battery, though you would still be able to see out clearly when it doesnt startAlso, there's fire hazard issues.Why not just get a heated windscreen fitted? Then you can do the remote control monitoring just the same except its more efficient and safer.It may cost a little more but you save money on the inverter.

author: lapm
author_rank: Frequent Contributor
timestamp: December 21, 2013, 12:08:00 pm
content: Maybe OP has mains connection to car, that's common in my country because long winters and owners of car like to have a block heaters in cars engine to allow easier start in morning. Meaning hes car parking spot has one of those mains distribution boxes..Some of those can have external heater connected into it as well, so you can use extra heater. But that's going to eat a lot of power unless you do some sort of timer/control of it..

author: Albert
author_rank: Newbie
timestamp: December 21, 2013, 06:52:52 pm
content: It's very cold where I live in the winter time. I have a 220V power outlet near where I park my car. I don't use the battery. That would be silly with 2000W.The heater I am using has a safe switch against overheating.The spark io lets you use wifi on the board. So I can switch the relais in my bed with my smartphone.