3.7v 500mah Lipo Battery with X4 Battery Charger for UDI U818A U817A U817 U818A-1 RC Drone Quadcopter 4PCS with X4 Battery Charger (Not Compatible for UDI U818A FPV)

Great back up batteries for my son’s drone. The batteries don’t last too long (none really do) but having 4 and the charger that can charge multiple batteries at once makes it possible to get some decent flying time.

I have to admit I wasn't expecting much from this purchase but things have gone very well. I am a high school teacher and I keep a few drones around to let my kids learn with. These batteries and the charger work perfectly. The charger charges all 4 batteries at once and gets it done pretty quickly. The flight times with the batteries are the same as you will get with any other battery.

I bought the charger and battereis as a replacement for the UDI RC 818a drone.This charger works better than the original - it charges 4 batteries at once, and the red status LEDs are less confusing than the original. It needs little adapter cables, which lets me think it's used more universally for this kind of batteries.The batteries - well, they are OK, but it would be better if they were a bit thicker. Without additional measures they are a bit too thin and can easily fall out of the drone's battery holder in flight.5 stars would have been with the batteries a bit thicker.

These are good quality replacement batteries. They hold a charge fine, and based on play time they seem to have the advertised capacity. It's also nice that it comes with a charger that can charge 4 batteries at once.TIP: The connector that fits the charger has to be pushed in VERY firmly, or it will not make a connection and you will get no charge at all. Once inserted firmly the charger works perfectly.

One of the four battery's was swelled when I received them. A Swelled battery is a fire hazard. The other three battery's would not take a charge. I tried two different chargers with these battery's with no luck. The battery's that came with the drone work great. I bought these battery's so I would have some extra time flying my drone. If you want battery's that don't work and may burn down your house down, these are the ones to buy. I decided not to send the battery's back because of the poor condition they were in. Unlike this company I care about people's homes and businesses and do not want to burn them down with these junk battery's. I hope this company takes pride in stealing peoples hard earned money for useless junk.

I used this product to replace a worn out battery and charger for a small RC helicopter. Product worked as advertised and the price made it a great deal.

I read a lot of reviews on this one before buying. Knowing I could get something that was really good or really bad I didn't have a whole lot of expectations. I wasn't delighted but I wasn't disappointed either. The batteries are a little short on life, which is one of the disappointments - but they're not that bad. The charger unit itself - I knew going in what to expect. And yes, like others have said, the plugs that go into the charger are a bit problematic. It's my plan to modify the charger and the cables that plug in. I'm going to remove the plugs and directly solder the cables to the board. That way I only have the battery to plug into each cable. That should improve performance.Performance is not bad. But as I said, it's those tiny little plugs that are problematic. When you get a good connection the charger does what it's supposed to do. At least the one I got does. So if you decide to go forward with this purchase know you are taking the chance you'll receive a good unit. Mine is OK. I'm not unhappy with it and won't seek to return it. But it certainly could have been better engineered.

Batteries work great, and nice to have a charger that charges all four simultaneously. Ordered this because I misplaced my one battery that came with the U818a. Given the short flight time of the U818a, it is so much nicer to be able to swap out for the next battery and keep going. We would have enjoyed the drone experience so much more had we had these extra batteries these last couple years. Recommended. Make sure the connectors are pressed in all the way for charging and flying.