Skip to content
View in the app

A better way to browse. Learn more.

Power Forum - Renewable Energy Discussion

A full-screen app on your home screen with push notifications, badges and more.

To install this app on iOS and iPadOS
  1. Tap the Share icon in Safari
  2. Scroll the menu and tap Add to Home Screen.
  3. Tap Add in the top-right corner.
To install this app on Android
  1. Tap the 3-dot menu (⋮) in the top-right corner of the browser.
  2. Tap Add to Home screen or Install app.
  3. Confirm by tapping Install.

48v DC smart switches

Featured Replies

  • Author
12 hours ago, Scorp007 said:

What load do you want to switch and do you need energy monitoring?

I want to switch 900W load and energy monitoring will be great to have but not really necessary 

41 minutes ago, hoohloc said:

I want to switch 900W load and energy monitoring will be great to have but not really necessary

I have not yet seen SAFE dc relays with power monitoring available in SA.
You could do a DIY switch/relay/monitor using a good wifi/rs485 coulomb counter and DC Solid State relay.
And you would most likely need to get this direct from china.

100 AMP Solid State DC Relay with DC control

+

Heatsink

+

Coulomb Counter with RS485 Comms to control and read

That should work nicely with any or most home automation systems.

 

Edited by WannabeSolarSparky

  • Author
19 minutes ago, WannabeSolarSparky said:

I have not yet seen SAFE dc relays with power monitoring available in SA.
You could do a DIY switch/relay/monitor using a good wifi/rs485 coulomb counter and DC Solid State relay.
And you would most likely need to get this direct from china.

100 AMP Solid State DC Relay with DC control

+

Heatsink

+

Coulomb Counter with RS485 Comms to control and read

That should work nicely with any or most home automation systems.

 

Yep, something like this will definitely work. I just need to get one with Out-put as DC,  the control can be AC. The plan is to be able to switch ON and OFF DC load 

7 hours ago, hoohloc said:

Yep, something like this will definitely work. I just need to get one with Out-put as DC,  the control can be AC. The plan is to be able to switch ON and OFF DC load 

Why not just use a relay with AC coil for control and DC rated contacts. You can even use contacts in series but a 900W @ 48V is above most 11 pin relay ratings.

  • Author
58 minutes ago, Scorp007 said:

Why not just use a relay with AC coil for control and DC rated contacts. You can even use contacts in series but a 900W @ 48V is above most 11 pin relay ratings.

AC coil and atleast 21A DC rated contacts will do. 

  • Author
45 minutes ago, TimCam said:

If you are looking for "old style" contact relays have a look at the one below:-

https://www.dc-contactors.com/dh50-high-voltage-dc-contactor/high-voltage-dc-contactor-dh50c

It's (only) a 50A, but is good enough for 2.4 kW DC.

Using a nano, ESP32 or Pi pico and a shunt you could make up a nice DIY solution. :)

this is perfect, where can I get this locally? 😀

 

10 minutes ago, hoohloc said:

AC coil and atleast 21A DC rated contacts will do. 

Buy any 3 phase contactor with 30A rating. Wire the 3 contacts in series. They normally come with 230 or 400AC coils. Get from an electrical wholesaler or Voltex branches

3 main contacts at the back and 2 signal contacts on the front.

IMG_20220810_203532.thumb.jpg.d10492f8bcf0298b18ca44dccf0d177e.jpg

Edited by Scorp007

  • 9 months later...
  • Author

only seeing now that I never updated this. I did manage to get my DC supply of the geyser element working, thanks to @Scorp007 and the contactor works perfect for switching on and off the supply. This install has been running for nine months now. I use a SONOF to remotely control my ON and OFF and there is also a program or timer that switches it On every day at midnight and off at SUN rise, for the morning shower. Then my batteries gets charged till mid day to 100% and then I use both AC and DC supply to power the geyser again. Depending on the weather and loadshedding. When we have loadshedding or poor weather, I only use the DC to power the element for the rest of the day. 

 

DC Element power .jpeg

DC Element power2.jpeg

On 2022/08/10 at 10:42 PM, TimCam said:

Haven't sourced one myself, but aliexpress might have one, just the courier charges are high, as the Post Office is now dead.

https://www.aliexpress.com/w/wholesale-48v-200a-dc-contactor.html

 

Strangely enough, I actually managed to pick up an Aliexpress package last week from the Post Office!!

No reply from either their customer service email address or phone number so i took a chance and stopped by the post office cause the tracking said it was ready for collection. Feel sorry for the people working there, they are the last passengers on a sinking ship.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

Account

Navigation

Search

Search

Configure browser push notifications

Chrome (Android)
  1. Tap the lock icon next to the address bar.
  2. Tap Permissions → Notifications.
  3. Adjust your preference.
Chrome (Desktop)
  1. Click the padlock icon in the address bar.
  2. Select Site settings.
  3. Find Notifications and adjust your preference.