Relay for Solar PV input

Hardware
1

Does anyone recommend a ‘good’ SSR for high current DC operations?

I have a scenario that I would like to control my Solar Panels as an input to my charge controller remotely or rather automatically.

Basic path would be Solar to Breaker to SSR (with external smart controller) to Charge Controller.

Panels are max ~66 VDC and <63Amps

And if anyone questions, it should be controllable via the charge controller but basically that control sucks which has left me manually tripping a breaker when needed and I want a better HA solution :slight_smile:

2

Your question kind of rambles, but I think you are saying that you need a better controller.

My experience with solar is a bit limited, but why don’t you just leave the solar panels connected to the controller all the time? That’s how they are designed.

3

What I really need are more Solar panels but that is probably a year out so looking for a temporary solution.

I have a Renogy 48V 3.5kW charge controller which overall I am pleased with the functionality of but the settings/controls leave a lot to be desired.

My Solar panels sometimes generate enough power to power the load and keep the batteries charge but not all the time. The way the controller works is if the panels are supplying power then they are the ‘source’ and when the solar power drops to 0 then it will switch back to mains.

I want to be able to disconnect the solar panels when they are low input (as opposed to 0) and that will trigger the controller to move back to mains.

4

Are you sure?
How many panels do you have?
And current is mostly < 15A

5

I have 2 panels, 320 Watt connected in series. Eventually I’ll add at least 2 more in parallel to these 2 which will increase the current. There is currently a Suntree 63A breaker in-line from the panels to the controller.

Here are the panel specs (each):

  • Maximum Power: 320W
  • Maximum System Voltage: 1000V DC (UL)
  • Open-Circuit Voltage (Voc): 40.1V
  • Optimum Operating Voltage (Vmp): 32.7 V
  • Optimum Operating Current (Imp): 9.79 A
  • Short-Circuit Current (Isc): 10.36 A
  • Maximum Series Fuse Rating: 15A
  • Operating Temperature: -40°F to 185°F
6

I am rereading the manual after 3 years (installed in 2022), I may have initially misunderstood some settings that may give me the desired outcome.

That said, still could be useful information to me if anyone can recommend a 60-100A relay.

7

Blockquote
So 2 panels give 80,2VDC

8

In theory yes. Per the Vendor when I initially installed them.

image

Input voltage range of the 48V3500W inverter is 60V-145V.

9

Why that high if your PV is 10A?

10

I suppose it doesn’t have to be but the ‘final’ design of the system will likely another 2-3 pairs of panels which could potentially have current >40A and there is already a 63A breaker there.

That said, multiple 20A or 30A could also be utilized, if I put then on separate legs of the solar circuit.

11

Not likely.
Above 40A they are getting pricey, this is about the cheapest I could find (I exclude chinese nobrand / fake ones).

https://eu.mouser.com/ProductDetail/Carlo-Gavazzi/RM1D200D50?qs=DPoM0jnrROVr0O82rL%2FiWw%3D%3D

1 Like
12

Thank you - I had not seen this one yet although it looks similar (suppose it would) to ones I found on Amazon. I was worried about the ones on Amazon as they had few and not great reviews.

13

Don’t buy SSR from AE or Amazon, they are mostly chinese crap.
Carlo Gavazzi is serious manufacturer.

For your amps I would prefer 40A relay from reputable source instead of some 100A fake Fotek that has 20A mosfet inside and traces that melt at 15A.

Schneider SSP1D440BDT
TE Connectivity SSRDC-200D40

are costing about half of that Gavazzi.

14

I agree completely. That i s part of what has kept me away from messing with higher amperage SSR - the likelihood of the part being inferior.

Thank you again for the suggestions!

15

I love cheap chinese components. But when the case is high amp SSR or about anything related to big batteries, I close AE page on my browser :wink:

1 Like