I am looking for ideas/suggestions so I can be able to track the daily and to date kw usage for a particular device. I have a freezer in my garage and I am trying to figure out if it makes financial sense if I were to wire it for use of a solar array.
I dont have any solar now but it could be a fun project. Plus I need the ammunition to be able to convince the wife.
I have a Kill-A-Watt device that reads the usage but the readings get lost at any outage.
Some recent readings show a daily use of about 9.5kwh with one day showing 26kwh. The jump in usage was because of the door not being closed tightly.
Take your kW rate from your electric bill and in the US it’s somewhere about 0.10-0.15/kW so 10 kW would be roughly $1.00-$1.50 per day plus taxes and fees. Solar makes sense but there’s a little bit of cost up front but in many cases break even in 2-3 years. They are getting more and more efficient. Much of grid power gets lost in transmission so solar is great. Very little line loss because it feeds your system directly. Take into account seasonal changes to power generation.
The Aldi one has back-up batteries.
(Don't know about international versions. )
Freezers can usually survive a few hours of a power outage without a problem.
If you want want to power a mains freezer from solar panels you will also need a substantial battery bank and a large inverter that can deal with the huge inrush current when the freezer motor starts. I have a modest 40w fridge and it needs a 1000W inverter to handle the startup. I suspect a freezer would need a much bigger inverter.
The batteries will probably need to be replaced every 4 years or so, adding to the cost.
To answer your question, you can get a current transformer to measure power usage. Described in detail here. Save the data to an SD card periodically to cope with any outage.
It sounds though as if your Kill-A-Watt has already given you the data you need to do the ROI calculation.
A brief google tells me that you can expect the freezer to run fairly frequently, so Robin2's point about batteries for the overnight is important and will have a substantial impact on your calc I expect.
Then too, how will you cope with days of low power production i.e. short rainy days in winter. For those times, you may need vastly more panels than you might initially expect which then means surplus power on sunny days.
I wonder if it's possible to get a better insulated freezer that can manage longer without power.