Hypothetical SCC load terminal usage

[Dustin Henderson]

I know this forum despises hypothetical questions. I can’t help myself. I am sorry for this.

• Assume 400 nominal watts of solar input, 40v at 10A feeding a 100/40 solar charge controller.
• Assume the SCC feeding a 100Ah 12V LFP through the typical output terminals to the battery.
• Assume the 100Ah LFP battery is fully charged.
• Assume MC4 connectors are wired to the LOAD terminals on the SCC, but not plugged in to anything.
• Assume the load terminals are manually controlled to be off or on, and are currently switched “on”.

If we measure the MC4 connectors’ pins using a multimeter, what will we observe?
Will there be any negative effects as a result of leaving these MC4 connectors in this condition.

 

[FilterGuy]

Will there be any negative effects as a result of leaving these MC4 connectors in this condition.

It depends on how the load terminals are theoretically configured

Will there be any negative effects as a result of leaving these MC4 connectors in this condition.

Not that I can think of.

 

[Dustin Henderson]

It depends on how the load terminals are theoretically configured

As stated, LFP battery is "full", and load terminals are "on". What load terminals configuration would effect the measurements of an activated load terminal pulling from a full battery? Like some sort of amp limit configuration?

 

[pollenface]

If load is switched on it shows battery voltage.

Current limitations depend on the controller.

Example. 40a controller, 40a max may be drawn from load terminals unless otherwise stated

You can do anything you like really, your imagination is the limit. I run the streetlight function to trigger 20w led lights and a relay for a dc-dc charger.

 

[yodamota]

so you want to put MC4 connectors on the load terminals?

 

[Dustin Henderson]

so you want to put MC4 connectors on the load terminals?

1) It's a hypothetical scenario.
2) You can't think of any use case for wires on the load of an SCC with MC4 connectors?

 

[Dustin Henderson]

If load is switched on it shows battery voltage.

Current limitations depend on the controller.

Assume the controller has a 20Amp limit on the load terminals.

Is the current pulled over this load line limited by the device ultimately connected to the load terminals, or by the 20 Amp limit specified by the controller? Said another way, if a device limited to 10 Amps is connected to the load terminals, will the current be 10 amps, or will the SCC try to push 20, as is it's limit?

 

[pollenface]

Assume the controller has a 20Amp limit on the load terminals.

Is the current pulled over this load line limited by the device ultimately connected to the load terminals, or by the 20 Amp limit specified by the controller? Said another way, if a device limited to 10 Amps is connected to the load terminals, will the current be 10 amps, or will the SCC try to push 20, as is it's limit?

20a controller, 20a limit, unless otherwise stated

10a device assumes 10a draw

 

[Q-Dog]

Assume the controller has a 20Amp limit on the load terminals.

Is the current pulled over this load line limited by the device ultimately connected to the load terminals, or by the 20 Amp limit specified by the controller? Said another way, if a device limited to 10 Amps is connected to the load terminals, will the current be 10 amps, or will the SCC try to push 20, as is it's limit?

The SCC doesn't "push" amps through the load terminals. It supplies what is demanded up to its limit. If your load wants 10 amps you ar fine. If you load tries to draw more than the SCC can supply it should shut down.

 

[Dustin Henderson]

The SCC doesn't "push" amps through the load terminals. It supplies what is demanded up to its limit. If your load wants 10 amps you ar fine. If you load tries to draw more than the SCC can supply it should shut down.

Makes sense.