Heavy load latching relay that works with arduino

Other Hardware General Electronics
1

I am looking for and have been unable to find a heavy load latching relay that can handle up to 40 amps and 12 DC.

2

Hi,
Welcome to the forum.

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html

Why does it need to be latching?
Can't the Arduino output hold it ON via a driver MOSFET?

Can you tell us the application of your project please?

Thanks.. Tom... :slight_smile:

3

Why use a relay? They are slow, unreliable and expensive, especially in that DC current range.

4

TomGeorge:
Hi,
Welcome to the forum.

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html

Why does it need to be latching?
Can't the Arduino output hold it ON via a driver MOSFET?

Can you tell us the application of your project please?

Thanks.. Tom... :slight_smile:

The relay would be hooked to a vehicle battery allowing power while items are drawing power. it would be a long term application so it would draw less power not sending a constant current to the relay.

5

jremington:
Why use a relay? They are slow, unreliable and expensive, especially in that DC current range.

What would you recommend using other than a relay for this application?

6

Describe the "items" to be powered.

7

Have you looked at HASCO?

8

dougp:
Have you looked at HASCO?

I just looked at the HAT901-L Series Latching SPDT but would the Arduino be able have enough power to switch the relay on and off?

9

The Arduino should never be used to power motors, servos, relays or solenoids. Doing so will damage the Arduino or cause it to malfunction.

You would use a transistor and an external power supply to energize the relay coil.

10

An h-bridge (or poor man's h-bridge) must be used for this single coil latching relay.
Leo..

11

You can build a latching heavy duty relay from a normal heavy duty relay and a small latching dual
coil relay that the Arduino can drive more easily with two transistors+diodes. Small latching relay
drives the coil of the big relay... (don't forget freewheel diode for that coil too).

Note that latching relays retain state across power cycles, sometimes this is not what you want
because the device can come up in a random state on switch-on due to its past uses.