# Solid state relays for switching ceramic heaters?



## Overlander23 (Jun 15, 2009)

Does anyone think that using a couple of these Solid State Relays would be a bad idea to switch ceramic heater elements? It's hard to find electromechanical relays that handle 200vdc, other than expensive contactors.

Magnecraft 6312AXXMDS-DC3

Looks like a 10A contact rating, 3-200v load voltage. 1.6v voltage drop. At 10A that would only be 16W which is manageable. They're about $20 each.

Or if anyone has a more conventional suggestion, I'm all ears.

My battery pack voltage will be 205v nominal, and I'd like to use two ceramic elements for two heat settings, so two relays. Each 110v 1500w ceramic core has two sets of elements that are usually switched in parallel to control heat output. I'll be using both elements of one core in series for the 200v pack... Two cores, for two levels of heat.


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## Stunt Driver (May 14, 2009)

Isn't 220v AC relay not good enough? Seems like mechanical relay would care only about current, and it isn't huge for a heater


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## Tesseract (Sep 27, 2008)

Overlander23 said:


> Does anyone think that using a couple of these Solid State Relays would be a bad idea to switch ceramic heater elements?...
> Magnecraft 6312AXXMDS-DC3
> ...


These look perfect for the job, and if you can get them for $20 then you certainly can't beat the price.

Stunt Driver - no, you can't use a regular relay or contactor meant to switch AC loads on DC, or not without drastically reducing the voltage and current rating (not unusual for a 20A/240VAC relay to get derated down to 1A at 60VDC). There are a number of reasons why, but the biggest one is that 60Hz AC crosses zero 120 times per second, automatically quenching the arc that forms when the contacts open.


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## Overlander23 (Jun 15, 2009)

Tesseract said:


> These look perfect for the job, and if you can get them for $20 then you certainly can't beat the price.



Thank you much, sir... I will be a guinea pig and try them out.


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## 300zxev (Dec 5, 2008)

I purchased one of these off ebay for my ceramic heater running at 156V ...

http://cgi.ebay.com.au/Solid-State-...emQQptZLH_DefaultDomain_0?hash=item5ad4f85fed

Worked fine on my test bench. Still yet to fully install


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## tomofreno (Mar 3, 2009)

I'm using one of these to connect my 30A DC/DC converter to the battery pack. Pack max V is 130V, current output to the DC/DC is only about 3A. This relay is rated for 27A inrush current. Haven't used it much, but its working so far.


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## gdirwin (Apr 7, 2009)

I understand that the better SSRs are Mosfet based - the cheaper Ebay ones are not, and will heat up more. Look at detailed specs to see what current they can switch with and without a heat sink, and what current they absorb under open and closed conditions...

Crydom SSRs get good comments, but seem to be more expensive.

I have not used SSRs yet, but plan to use many of them (mounted on a large heatsink) to allow adjustment of the temperature dial via a rotary switch for my ceramic interior heaters...


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## 300zxev (Dec 5, 2008)

Yeah ... I purchased a large heatsink off ebay for use with my controller & 2 SSRs ...

Check this out ...
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=170399644193&ssPageName=STRK:MEWAX:IT


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