Looking for a dc transfer switch or dc relay

[ricardogzz]

Hi, I’m looking for a dc transfer switch or a 50vdc 10a dc relay.

Context: I have a grid tie inverter connected to four solar panels and I also have a battery bank connected to an off grid inverter and an mppt charger for power outages, so when a power outage occurs I want to switch my panels from the grid tie inverter to the mppt charger.

I have searched a lot but only find ac transfer switchs and relays with a max 28vdc rating.

Thank you for your help.

 

[pollenface]

In the past I have used 2x 24-28v relays in series (for 48v) but only used one as the load bearer.

A friend of mine uses 4x 12v relays in series, each bearing a portion of the load.

Context: I have a grid tie inverter connected to four solar panels and I also have a battery bank connected to an off grid inverter and an mppt charger for power outages, so when a power outage occurs I want to switch my panels from the grid tie inverter to the mppt charger.

I had the same idea, haven't started it yet though

 

[Hedges]

How frequently?

My idea is to use a DC rated disconnect switch, then unplug PV cables and swap.
Easiest if PV array is 4s for both setups, no reconfiguration and minimum number of connections.

I do this to move a couple PV strings from my operating grid-tie inverters to one I'm testing.
I put MC3 cables in the combiner box, no tools needed. Plan to move them to disconnect switch, ensuring switch is off when connectors accessible.
Just don't mix up inputs and outputs, because then you'll be connecting two inverter or two PV strings to each other in reverse polarity. (blew a fuse when I did that, with inverter caps charged up.)

 

[Rocketman]

I used a Tyco EV200AANA contactor for my bms. Four of those would do the job - wired to a double pole switch - so either path 1 has power or path 2 has power.

I remember a vendor was selling some used ones really cheap (like $12). The relay is 9v to 36v - so you could do the control circuit in 12v.

Sorry don’t remember the vendor.

 

[Rocketman]

Just re-found the Vendor - Battery hookup

 

[J724]

Just ordered a few Tyco EV200AANA contactors from them.