[quickthrowman]

> they will either charge a battery or the current house loads, but never backfeed into the grid.

I’m not sure I understand how this works unless you split off loads into a subpanel that is fed by a UPS which is fed by solar panels, and also isolated from your utility connected electrical service.

As far as I understand it, you can’t have power generated by solar panels feeding loads in your grid-connected panel without backfeeding the grid, same deal as a generator backfeeding a grid-connected panel. You have to kill the MCB or service disconnect to prevent backfeeding.

If you have links with info on how this work (one-line diagram would be extremely useful) I’d be curious. I sell and run commercial electrical work, FWIW. I’ve done zero solar jobs so my understanding could definitely be wrong!

[narism]

Zero export inverters are grid-tied but monitor the meter/CTs for load changes in order to curtail solar production/shift it to battery charging. I think they can technically backfeed a little bit if load is suddenly dumped depending on the inverter response time. Some have a secondary hard disconnect for additional protection.

https://knowledge-center.solaredge.com/sites/kc/files/feed-i...

[quickthrowman]

Thanks for the info, that clears things up!

[Dylan16807]

> As far as I understand it, you can’t have power generated by solar panels feeding loads in your grid-connected panel without backfeeding the grid, same deal as a generator backfeeding a grid-connected panel. You have to kill the MCB or service disconnect to prevent backfeeding.

An inverter can limit its output, right? So measure current at a few different points in the system, do some math, and use that to set the inverter's limit.

[quickthrowman]

Thanks for the explanation, that makes sense. Monitor some CTs and let the inverter only discharge enough power to satisfy the current demand without backfeeding the utility.

[jaredhallen]

Or mine some crypto with the excess. I'm only half kidding. Having too much power is a good problem to have.

[kylehotchkiss]

Wouldn't it be like

Grid < Primary solar > Battery < Secondary Solar

Where the house is powered by inverter directly on the battery (and maybe a second inverter for primary solar to grid?)