I have a Victron temp probe connected to the negative on a battery and tbe temp side of the cerbo. I’m told the 12v 100 watt heaters are too much for the cerbo relay #2. The goal is to have the cerbo turn on/off the heaters at certain temperatures. Any suggestions fir the best way to do this? Th…

Use an additional 12V relay, that can handle the current, powered by the Cerbo’s relay to drive the heater. For example a 12V / 25A relay or any similar or bigger automotive relay.

As @alexpescaru said, but make sure the relay has flyback protection otherwise surge current switching the relay may damage the Cerbo relay. Driving another relay with the Cerbo.

Thank you for this info. All makes sense.

I put battery heaters from UltraHeat.com on my 48v battery. Four heating pads total. Two heating pads on each of the two 8s column of cells. The current draw from the heaters would have been a little too close to what the Cerbo GX relays were rated for. So I put in two relays that are rated for …

The same wisdom applies to BBQ :slight_smile:

[Screenshot_20250214_143755_Chrome] Can anyone tell me, based on this image does the yellow and blue wire connect to each other? If not, where does the blue go? Thanks in advance

Each of the numbered items on the relay are a terminal that a wire gets connected to. What the diagram doesn’t show is the negative feed to your device. The negative is not switched, only the positive. So no, the yellow/blue wires do not connect to each other externally (outside the relay). The …

[20250214_095448] Specs say 30amp = closed. How does that affect this? Thanks Jim

I believe that Normally Closed is typical and doesn’t change anything.

Thanks Jim If I understand correctly., I don’t connect the yellow wire to anything. The rest I understand where they go.

Looking to heat batteries

DIY

Remy1 February 18, 2026, 8:15am 13

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Looking to heat batteries

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