HELP! Sonoff SV (Tasmota) crashes whenever relay is turned on

I have repurposed a set of LED rope light (approx 4metres) and connected it to a Sonoff SV so I can connect to HA.

The problem however, is that as soon as the relay is triggered to the on position a problem occurs with the SV and it resets itself.

Looking at the console I can see the following log R.E the restart reason:

17:30:58 MQT: tele/groundFloor/garden/lights/INFO3 = {"RestartReason":{"Exception":4,"Reason":"Software Watchdog","EPC":["400043e6","00000000","00000000"],"EXCVADDR":"00000000","DEPC":"00000000"}}

When I connected a single LED to the output terminal there was no problems at all so I assume the size of the rope light means that another approach is required.

Here is the setup:

The USB power is 5V.
Tasmota 8.5.1

FYI: I soldered the red / black wire the wrong way round.

You need an appropriately rated 5V power supply. It cant supply enough current for both the SV and light.

Ah ok, Do you know how i would go about determining such a rating?

Usually you just add the power requirements found in the product specifications.

I just had a look at the sonoff website and this is not published for the SV. A quick search online revealed this to be 150mA peak and 20-40mA average.

So that just leaves your LED lights. Do you have any data for them?

I have basically no information on the LED lights. All I know is that it was being powered by one of these AA rechargeable batteries

Do you have a multimeter?

If not, I’d be surprised if the LEDs draw more than 2A, since they were AA battery powered.

Try a 5V 2A supply.

I do have a multimeter but it’s dark and raining now so i’ll have to try that tomorrow.

I’ll also look out for a 5V 2A power supply. I just checked the one i’ve repurposed and that’s only 1A.

Thanks for your response! :slight_smile:

You could check the voltage of the 5V power supply when trying to turn it on. Also if you still have the battery pack you could measure the current drawn by the LEDs.

I have the battery but it’s as dead as a door knob.

Do you think one of these would suffice? Annoyingly they ain’t cheap.

Parts came today and everything is hunky dory. Thanks!!!

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