Relays for 48v system

[Krystian0]

I need to automatically switch off and on some things like CCTV, wifi equipment and lights in off-grid cabin. Especially in the winter because sometimes there isn't enough sun, if battery gets fully discharged everything will stay in a deadlock until I come and reboot it manually
So the maximum voltage is 56vdc, current switched not more than 2amp. Everything is powered by buck converters so there will be inrush current I guess. I want to switch it before converters so there's no standby power loss. Relays will be controlled by ESP32.

I can't find appropriate relays with reasonable price. If I search for 48vdc relay, I get results for ac relays with 48v coil... what is the best option in this situation?
So far I've considered:

• Solid state relays. But I've seen some opinions that they fail often. Also I think they waste a lot of power https://www.aliexpress.com/item/1005005837105164.html
• MOSFET module. Very cheap and seems to meet requirements but idk if it's a good choice. https://www.aliexpress.com/item/33048275939.html
• Use ordinary relays. If they are rated for 30vdc 10amps, they should handle 2a 56v I guess. Circuits are fused so there won't be any more current
• Strap servos to DC circuit breakers. But I think it's a stupid idea because these breakers are rated just for several thousand operations

 

[wpns]

I can’t see the specs, but I’d go with the SSR.

 

[Delmar]

Look for a golf cart relay. Amazon example

 

[wpns]

ESP32

12mA maximum drive current, so you are going to have to add drivers unless you use SSR or that mosfet (which has the added advantage of opto-isolators).

 

[hwy17]

There is this series, but the coil might still be a bit heavy like wpns says.

https://www.digikey.com/en/products/detail/cit-relay-and-switch/J115F31AH48VDCS61.5U/14001763

 

[yabert]

You can find plenty of relays rated for 60Vdc or more on Digikey or Mouser for few bucks.
But if you want a bullet proof solution, look at EV relay with coil economizer.
Many 30A to 100A new relays available or a 500A used relay available here: https://batteryhookup.com/products/te-connectivity-ev200aaana-500a-0-900vdc

 

[yodamota]

can't imagine 6 dollars SSR would last long. I believe mine was 50 bucks. Omega brand.

 

[Sennen]

You can find plenty of relays rated for 60Vdc or more on Digikey or Mouser for few bucks.
But if you want a bullet proof solution, look at EV relay with coil economizer.
Many 30A to 100A new relays available or a 500A used relay available here: https://batteryhookup.com/products/te-connectivity-ev200aaana-500a-0-900vdc

That specific relay is for 36v max.
Need the ADANA or AJANA for 48v systems. Which as stated in the battery hookup site are ludicrously expensive.

edited: Disregard, I can't read.

 

[profesor79]

As you will be driving the coil by ESP32 then we have a need to drive the coil at around 3.3V.
As the max current is 2A - we don't need to use a "MONSTER" to switch it on/off, so honestly I will rather use a bi-stable module like this: https://es.aliexpress.com/item/1005001718085663.html with a chep voltage sensing module like this: https://es.aliexpress.com/item/1005005931385626.html to confirm the state of the system (or resistor divider...)..

 

[yabert]

That specific relay is for 36v max.

Where do you read that Krystian0 need to have a 48V coil?
It need to switch 48V, it's different.

 

[Sennen]

Where do you read that Krystian0 need to have a 48V coil?
It need to switch 48V, it's different.

Note to self: Stop replying before drinking coffee. I see now that's the coil voltages. Carry on!

 

[yabert]

I see now that's the coil voltages.

Yeah! Rated 900Vdc