MPP questions

[Dennis 1]

Hi all, I have a few questions. I'm looking into a MPP all-in-one solar inverter. I would like to power 2 fridges and a freezer.

They are rated 5.0A,6.0A, and 7.0A all at 115V which together come to 2070W (if my calculations are correct). I would like some advice on which MPP model to go with and would need to consider batteries as well.

Right now I have 6 - 100W panels powering 3 - 12V 100AH batteries and would like to know if I could branch off those panels to power the all-in-one system as well?

The fridges and freezer is all that would be on the MPP inverter. Any help from you would be appreciated.

 

[Bobert]

Hi all, I have a few questions. I'm looking into a MPP all-in-one solar inverter. I would like to power 2 fridges and a freezer.

They are rated 5.0A,6.0A, and 7.0A all at 115V which together come to 2070W (if my calculations are correct). I would like some advice on which MPP model to go with and would need to consider batteries as well.

Right now I have 6 - 100W panels powering 3 - 12V 100AH batteries and would like to know if I could branch off those panels to power the all-in-one system as well?

The fridges and freezer is all that would be on the MPP inverter. Any help from you would be appreciated.

You really need to find out the actual amount of power the freezers will use in real life. The amp ratings won’t do that all they tell you is what the freezers may use while running. A inefficient unit may run almost continuously whereas a efficient unit might only run a few hours a day. Huge difference in equipment. If you can use your existing setup in the mix depends on the specific specs of your existing equipment as we as the requirements for your additional load. You haven’t given enough information for good advice.

 

[FilterGuy]

They are rated 5.0A,6.0A, and 7.0A all at 115V which together come to 2070W (if my calculations are correct).

Your system is more likely to run at 120V so the possible steady-state draw is more likely to be 2160..... but 2070 vs 2160 is not a large enough difference to make a change in your selection.

If those amperages are the name-plate values, the actual steady-state current is likely to be quite a bit smaller than 2160. It is best to get a kill-a-watt or something like it to measure the actual current while the compressor is running.

All three devices have compressors that will be turning on and off. This means significant surge currents. Since there is a reasonable possibility multiple compressors could fire up at the same time, you pretty much have to have a plan that supports all 3 at once. This surge current should be the driving factor for selecting your inverter.

Note: If you do not know the surge current and don't have a surge-capturing clamp meter, you assume the surge current is 4x the steady state current.

When it comes to surge currents, a low-frequency inverter is the way to go. These tend to be a lot more expensive, but they can typically handle surges of 3 to 4 times their rating for a few seconds. (A high-frequency inverter is typically rated for 2x surge for well under a second.