Review on Renogy Solar Battery Maintainer Trickle by Dwight Tim

On paper this solar charger looks nice. In real use, however, it does not do its job. I had a van that ran about a week between trips. I bought this 10w charger thinking it would be perfect for keeping the battery going. However, after first charging the battery with a conventional charger and then connecting it directly to the battery for more than three weeks, the battery was still draining. I checked the power supply on a sunny day and it showed over 19 volts. So something else is going on with this charger, probably at night. I bought a 1.5w solar charger from a seller with the same name as Hello Friday. This item actually held the battery charge. I can't tell what the problem with the Renogy charger is, but it was draining the battery instead of keeping it going. It was knocked out by the charger with less than a quarter of its capacity. Unfortunately, the supplied documentation is missing. It does not apply to the limitations/restrictions of the charger. No explanation for typical use for battery maintenance. If there are built-in limiters, then no word on them. Looks good, sounds good but drains battery when plugged in. If I didn't want a refund I would take it apart to find the fault. Maybe it was just a bad batch?