Ymiko Boost Converter Module XL6009 DC to DC 3.0-30 V to 5-35 V Output Voltage Adjustable Step-up Circuit Board Apply to Laptops Voltage Regulator for Solar Panels

I had a dead 40V battery, and after watching some online videos on how to fix it, I bought this unit. It easily converted the 12V my power supply was putting out to 35 V. It helped in resetting the battery so that it charged easily and quickly once it was on it's proper charger. Before using this to bump-charge the battery it was showing as a bad battery. This helped to get it over the hump and it now a fully operating 40V battery.

I watched a tutorial on YouTube to reclaim Ryobi 40 volt battery. I followed a link and purchased this. It did exactly as promised and was able to renew battery and save about $130 over purchasing new battery, and will be able to preform this on future problems.

based on other reviews, I decided to order two of these. As warned, one did fail to powerup. Inconsistent placement of heat sinks between the two and bent over capacitors on the bad one seem to indicate a manufacturing issue. The one that worked was capable of adjusting 12v input to over 35v - I didn't try higher. Reported failure and was sent a replacement for no additional cost - increased my overall rating as a result of good customer service.

It will not work at 3.7 volts. lights come on but you can not adjust the output voltage. Works fine about 6 volts but i bought it to work with 1s lipo.

I bought this to try to boost old power tool batteries back to a level where the charger would read them and finish the charging process on its own. It moat definitely works and I've been able to salvage some of the batteries, but not all. That wasn't the fault of this booster though. They were just beyond repair. Be cautious though, especially with Lithium batteries as they can explode violently if they are too far discharged or are faulty. You will need additional parts as well if you want to use this booster for that reason though, such as power wire and an old laptop charger. You can find videos all over the internet for what you need. The output voltage is adjustable to meet the needs for different voltage batteries, but you need to adjust it manually.

Was exactly what I needed initially, but stopped working after two weeks. The output is equal to the input no matter how you adjust it. The LCD screen stopped working at the same time. Sent them a message, they responded that they were looking into it, but nothing seems to be happening.

Nice product! I purchased this to boost 12 volt (DC)-5 amp to 35 volts to bring a Ryobi battery back to life. It worked too. I charged the battery up to 35.2 volts (DC), it took about 25 hours. When I was done, I reattached the battery cover and placed in the charger to finish charging. I liked it so much, I bought 2 spares.

Works as advertised, which says a lot.