Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. There is one coupon right now! Check this out.
Link: Banggood product page
Coupon (908.03 USD): BG589b2e
(CouponsFromChina.com tip: you should apply the coupon in your cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): Terence, BG68ef53, Tabby20, 2203ActiesNL, BG1efeb0, MVC8SPRING, 8BGwbg2204, Cuponation9, 9OFFSUMMER
(there’s a little possibility that old coupon will work)
Price history and price alert
Price history (for all/most countries) for Growatt Hybr1d SPF 3500-80A Solar Inverter is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).