With a basic 100 watt solar panel (from Harbor Freight) providing power, and a pair of 75 amp hour agm batteries (same source) this inexpensive solar charger has done well. If I wanted to charge a big lithium system, I'd probably go with a nicer charger, but for small to modest needs, I'm quite satisfied.

I would like to know if this product has dioides so stored energy doesn't reverse out.

Be careful of the your application. The listing has the DC input voltage is 15-55 volts. That is not accurate. When charging a 12 volt battery, the DC input rating is only 15-20 VDC. So match the solar array carefully. If you want to use a pair of panel to increase the charge rate, you'll likely need to wire them in parallel. Select panels carefully. A panel rated at 15.1 VDC at SCT is not going to make 15 VDC is the summer heat. So keep your VOC's towards the middle of the range. Start out too close to 20VDC, and winter time cold temperatures will push the VDC over 20. They stop charging in either situation. Its a very narrow window to play with, so do your VOC calculations based on expected high and low temperatures, and the temperature coefficients shown on the solar panel's label or specs.

Otherwise these are well built units I've used several times for the past 5 years in remote equipment 12V battery charging conditions.

Loved it works good

Bought a 20A version for a small DIY solar for a shed. It is 100% waterproof, completely sealed off, a nice feature to have. The instruction manual is not the best but the device is very easy to install, just connect the wires (the battery first) and it will start working, no on/off switch. You need to select your battery type and the charging voltage. The display is quite primitive but it does the job. While working, it cycles through the input and output data. It starts to show error codes if the input current or battery charge are too low. Would be better if they had something more informative.
It offers a temperature sensor as an option, but mine already came with it. It is helpful for optimal charging, but note that the sensor won't do anything if lithium is selected, it must have it's own BMS. In other words, you don't need this sensor if you have a lithium battery.
If anything to complain about is that it is supposed to be installed on a wall, but there's no access to wires when it is attached to the wall, so if later you need to re-connect something you'll have to take the device off the wall for that.
Overall, seems to be a good cost/benefit choice for a small system, let's see if it lasts. Mine is about 9 month old now and it had no issues, survived the NY winter.