AC SSRs are Triac driven. You cannot use them on DC. Get a MOSFET or IGBT
based SSR designed for DC.
The "trick" would be the same thing used in the SCR controllers, you have to
drop the current to zero or reverse it to get it to stop conducting. This
would require more parts than it's worth.
Either that, or you can add a conventional relay in series... =)
-Phil
----- Original Message -----
From: "Roger Daisley" <
[email protected]>
To: <
[email protected]>
Sent: Monday, July 30, 2007 9:36 AM
Subject: FW: solid state relays
>I have a related question that I have been meaning to write about:
>
> I have a box of new Crydom (CSD2450) SSR's that I bought on eBay. The
> input
> is 3.5-15VDC and the switched output is 240 VAC @ 50A.
>
> I had planned on using them in my conversion for switching low power DC
> circuits, such as horns, lights, radio's, etc. The problem, I have
> discovered, is that AC switching loads will not work on DC. (I'm sure most
> people on this board already that ... And are chuckling at my ignorance!)
>
> Through experimentation, using a 12-v headlight, I find that the relay
> will
> switch the light ON, but when the input is removed ... The light stays ON.
> So much for that idea!
>
> The purpose of this message is to see if there is some "trick" that I can
> use to shut the SSR down, when switching 12-VDC loads ... Or should I
> start
> looking for different SSR's?
>
> Thanks,
> Roger Daisley
> Pullman, WA
> http://www.96-volt.com
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~!//!~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
> You can get solid state relays from www.allelectrolnics.com for less than
> $10.00 that may work for you. Yes, the ITE solid state relays I have been
> running for 22 years every day cost me about $80.00 for a 40 amp at 100
> VDC
> back in 1985.
>
> Roland
>
>
> ----- Original Message -----
> From: "Al" <
[email protected]>
> To: <
[email protected]>
> Sent: Sunday, July 29, 2007 10:39 PM
> Subject: solid state relays
>
>
>> I am considering using solid state relays in a battery balancer system.
>> The
>> DC models seem to be very expensive. I wonder why? Don't they consist of
>> just a pair of high power mosfets and an optoisolator/driver?
>> Could I build my own?
>>
>> Al
>>
>>
>
>