Page 2 of 2

Re: No Grid AC INPUT

Posted: Tue Jun 04, 2019 5:51 pm
by gpearce52
Do to the high cost of a transformer, I have decided to operate the system strictly off-grid for now except for the air conditioning system and invest in additional batteries.

Currently have 98 Leaf modules and looking for an additional 49 modules which would be about 60 kw and allow operating my air conditioner off grid.


Re: No Grid AC INPUT

Posted: Wed Jun 05, 2019 7:51 am
by pss
Interesting. Your profile does not state anything about your system. In general, if you increase the size of your battery bank, you either have to increase the length of the daytime sun exposure, or add panels and charge controllers to harvest the PV and push it into your batteries. Then, depending on the load of your AC unit, you may even need to add more inverter capacity. YOu also did not say whether or not your AC is a small window type 120V unit or central AC on a 240V circuit pulling 10-20 amps or more when running. These things are important to know.

In my situation, I I find it best to push the AC hard in the daytime when I have plenty of PV available. Then in the evening, I increase the thermostat to reduce load. Depending on the price of a kWh, you may be better off just using the grid in the PM or even using a generator for the dark hours to power the AC unit when needed.

Next, AC units are not a continuous load, so when the compressor is not running, then the extra capacity of your battery bank and I can assume additional panels will have no where to go and this PV could be wasted without a meaningful load.

Ebay has lots and lots of Leaf packs for sale. I'm sure you must have looked there for your needs.

Re: No Grid AC INPUT

Posted: Fri Jun 07, 2019 5:31 am
by sparksalot
The 2.5 ton A/C may put a pretty good dip or in-rush current in your inverter and batteries if/when adding that A/C load to your off-grid.
If this were to be the case then a 'soft-start' for the A/C may be required...even wiring size may be put to the test upon compressor in-rush current.
The system strain can be bad for all componets as the 208 volts is already lower to begin with in this case...

Might look at the Sure-Start from Hyper Engineering...can add years to a otherwise strained system...

For choosing a new A/C unit, I also prefer the 2-stage A/C compressors for they allow for custom toggling of the 2nd stage on and off to suit changing house/building loads and/or PV production amounts.

Re: No Grid AC INPUT

Posted: Thu Jun 27, 2019 11:19 am
by gpearce52

Installed the Hyper Engineering Sure Start on my AC and its working as expected. Running load is 2.2kw on the 8048A and a 7kw gas generator now has no problem starting the AC. AC is usually off-grid during the day and on-grid at night.

Still trying to source an additional 48 Leaf modules locally.