Go down and check coupons out. Remember to check price history if it is available. What is best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
USB output: 5V/3A, Discharge stop: 21.4V, Float charge: 27.4V, Voltage: DC 12V/24V, Self-consume: <10mA, Buck charge: 28.8V, Current: 10A/20A/30A/40A, Model: PWM, Output voltage: 12V/24V Automatically distinguish voltage, Working temperature: -35℃~60℃, Rated working current: ≤20A, Discharge reconnect: 25.2V, Max solar input: <50V
Banggood
Banggood warehouse is located in Europe 
. There are no active coupons for this product, but the price is pretty low isn’t it? I don’t want to misguide you about the price. I don’t know if it’s good, because I don’t have enough records in my database…
Link: Banggood product page
Price: $-3
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BG42df5e, BG589b2e, BGET10
(these codes were not working in latest coupon update, but you can check them out anyway)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. China – 50A 12V/24V Solar Charge Controller ($17.54)
Price history and price alert
It’s a new item in our database, so I can’t create price history chart. We have saved this price in database: $15.79.
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).