I watched the entire webinar on the Helios battery. I downloaded and reviewed all of the sales sheets, specs, installaiion manual and warranty.
What I found lacking was the following:
One battery plus a wirebox and a Sol-Ark 15k stacked adds to over 79 inches. Add any extra height if you need to be above ground level for snow, water, etc and you have a very tall combo stack.
These batteries take up a lot of wall space with the space needed between them.
The warranty for this battery makes them a very risky purchase.
The warranty is governed under the laws of I believe British Columbia, Canada, not USA. There is no USA warranty.
In order to make a warranty claim, logs of the battery use must be furnished to the company.
The battery is only warranted for 10 years, but the limitations are to 60% of original power. This means the battery is not defective if it looses 40% of it's capacity in just 10 years. To put it another way, if you buy 10 batteries, after 10 years, only 6 will be working. That's a big upfront expense.
Lastly, unless I did my math wrong, the warranty throughput averages to 26 kWh charge/discharge per battery per day over 10 years. Go past this and no warranty. So if you charge to 100% and run down to 19%, you can do this one time per day to maintain warranty.
What I don't like is that the webinar said you could lay batteries flat in a stack, but the heaters are at the bottom of the case and this makes no sense if in a stack and the installation manual makes no provision for this. Also, the batteries are left and right sided. If the front and back were the same so you could turn them in either direction to put inverters in the middle, wiring would be simpler.
So in summary, you have a Canadian company touting their great battery and backing it with a poor warranty that will be very hard to make a claim against in a foreign country. Might as well buy a Chinese manufactured unit and be in same boat.