need help with latching relay circuit

Try to make the diagram yourself and we can look at it!
Question: Do the latching relays have one or two coils?

 

Ok,here are some hints and questions:

1. You must measure or in another way find out the current of your accessories at 12VDC.
I am afraid your loads will draw too much current. The shown 5V latching mini relays can (should) only switch maximum 1A @ 12VDC.

2. How do you want to switch off your fans and pump? All together with one push button (could easily be made with one common push button)? Or each accessory with separate push buttons (2 push buttons/relay)? Or do you intend to toggle the relay state with each pulse you give on the respective push button?

3. If you intend to use the toggle approach with only one button per load, that will not work well with those Aromat relays. They are normal bi-stable, latching relays and would need additional components to act as sequencing toggle relays. As I understand, the "Headlight Dimmer Relay" is such a toggle relay and could be used with one push button only.

4. To use the 5V Aromat relays with 12V, you should add a 180 Ohm serial resistor to the coils (coil resistance 125 Ohm). See diagram.

5. Because you have enough contacts on the relays, the function can be indicated with bi-directional LEDs as seen in the other circuit diagram.

 

One of our members (CocaCola) recently posted an off the shelf kit. It featured a single button, press ON press OFF and a high current FET switching element. You would need one board per circuit though but they're small and inexpensive. If I find the link I'll post it.

 

Here is the link, 10A capacity

http://www.pololu.com/catalog/product/750


Great little low cost ready to go solution...

 

Well, that settles the matter for the Aromat relays! They are neither suitable with respect to function nor when it comes to the current.

You would probably need more of those "headlight dimmer relays".
I don't know the contact rating of that relay, but it looks like a power relay. (If it wouldn't be enough, at least it could be used for driving the pump and other, stronger relays.)

The suggested "Pololu Pushbutton Power Switch" does not work.
Firstly, it can not handle 15 or 18A loads and secondly, as far as I understand, it does not have the sequencing toggle function, but seems to work like the normal "2-coil" latching relay (probably without memory function when power removed). It has an on-board push button "on switch" and another "off input". You wouldn't be able to use your bi-directional LEDs in an easy manner either.

 

It can with the addition of a relay, using the module as the latch... Or two modules in parallel if you want to really simplify it...

The button does not come installed, and the off input is an optional off trigger for the slave device it's not the only way to turn it off... It's operation is push once on, push twice off and so on, unless the off pin is held high then it's off...

And no it will not remember it's last state if the power is removed, and thus should be hooked to an always on power source if you need it to remember state, using an external relay to do the switching the module can remain on and retain memory while the on/off could also be controlled by a vehicles accessory on/of sequence...

No more complicated than any other application...

 

CocaCola, thanks for finding my post and saving me having to search for it.


Chris

 

It latches itself.

Edit: Btw, did you read the dimensions? It's very small and you don't need to install the header.

•Dimensions: 0.4" x 0.9" x 0.125" (without header pins and pushbutton installed)

 

With the proper relay the Pololu is easily capable. I was too lazy to draw the Pololu so I just copied and pasted it but it's clear enough for you to see the relay interface.

 

Yes, no problem. Gotta hit the sack.

Chris