Jump to content

Solar contactor


Recommended Posts

Working through adding a couple of 100W panels.  I need to have a contactor in the feed so the lithium BMS can switch off the panels if necessary.  I've been recommended the Gigavac P115bda but I am having a real problem sourcing them for reasonable $$.

Any suggestions for an alternate?

Here is the P115 spec.

https://www.gigavac.com/products/p115bda

 

Link to post
Share on other sites

Why would you use a mechanical relay? Consumes power with the coil.. What about a solid state (mosfet based) relay - about $20-30 on amazon... Use a normally closed, opens when BMS turns it off. Whats the solar controller? You need to be sure that it can either be switched off, or can deal with a disconnect.

Link to post
Share on other sites
6 minutes ago, Island Time said:

Why would you use a mechanical relay? Consumes power with the coil.. What about a solid state (mosfet based) relay - about $20-30 on amazon... Use a normally closed, opens when BMS turns it off. Whats the solar controller? You need to be sure that it can either be switched off, or can deal with a disconnect.

Do you have an example of the solid state relay?  The P115 is normally open and apparently is low power consumption (I wish I knew more about this stuff....).

Looking at the Victron Smartsolar MPPT, with the relay between panel and controller.

Link to post
Share on other sites

I'm only looking at the 75/10 or 75/15.  I'd run a separate controller per panel to deal with shading.

Thanks for the link!  That is a great help.

Link to post
Share on other sites

If you are using a Victron Smart Solar MTTP,  you do not need a relay or a switch for a BMS.  You just need someone to program the Victron properly for you. PM me if you need help.

Also what BMS are you using?   Most are overly complicated for little reason. 

@Island Time Solid state relays generate heat when closed as well,  because of high internal resistance.  A mechanical latching relay would be the most idea relay for this instance,  if it can be controlled from the devices. 

Link to post
Share on other sites
2 hours ago, mcp said:

If you are using a Victron Smart Solar MTTP,  you do not need a relay or a switch for a BMS.  You just need someone to program the Victron properly for you. PM me if you need help.

Also what BMS are you using?   Most are overly complicated for little reason. 

@Island Time Solid state relays generate heat when closed as well,  because of high internal resistance.  A mechanical latching relay would be the most idea relay for this instance,  if it can be controlled from the devices. 

Agreed, a latching relay would be ideal, but should not be needed with the Victron controller, which can be set up for Lithium...

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...