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diy solar

Battery Energy Storage leveraging Time of Use charging versus Solar Array - Cost / ROI


New Member
Feb 24, 2023
Hamilton, Ontario
Hi Everyone,

Big fan of the channel. I'm located in Hamilton, Ontario and our Solar hours can vary widely and be somewhat inconsistest depending on the season.

I was wondering if for example I built a battery storage array and charged it only during our low charge back (time of use) time which is 11 pm to 5am. The price per kilowatt hour is half that of peak charge during 9am to 11pm. Say it's 17 cents per kilowatt hour during high peak time versus 8 cents per kilowatt hour during low peak charge. Would it be cheaper/return on investment then buying/installing a large solar array over time?

That would be an interesting video for sure!?!


Solar is much cheaper on a kWh basis. If you try to arbitrage Time Of Use rates, don't forget to factor in the conversion losses. You get about 80-90% back for every kWh you put in the battery.
Rick, I can tell you yes, it is a good deal in Ontario to have Solar to reduce the peak power consumption during sunny days.
I live in the NW far further North than your 43-degrees Latidude and still, just PV alone, can bring in enough energy to offset the peak rates during the day, and be worth-while (in my experience).
Less obvious, is the use of LiFePO4 cells (Solar parts Store Orangeville's SOK and their own branded rack batteries are a pretty good deal for us) or DIY cells and BMS if you have the interest (about half the cost per kWh) in my own experence with the batteries, the cost is about 3-cents (Canadian) per kWh per full cycle, assuming the cycles they claim will actually occur! but I have faith, given what we see in industries that already rely on server rack batteries.
I don't know what the Ontario Energy Board are going to approve, but I am certain it will be 'more'.
I never buy power at peak rates and on Nov. 1st the deal is going to be even better. I’ll buy all my grid supplied power between 11 pm and 7 am when the ultra low rates start. I have 7000 watt solar with 13kw split phase inverter with 28kwh lifepo4 batteries.