CBB 3.7V 550mAh Lipo Battery for Wltoys V930 V977 V988 E50S E50 JJRC H37 XK K110 RC Helicopter Drone Spare Parts 5 Pack with 5-in-1 Smart Charger

You have to remove the bumps that hold the stock battery in place. I removed the landing gear/battery compartment then took a scalpel and heated it with a lighter then cut the bumps off. Fits perfectly now. Picture shows where the bumps were.

Most are good and last as long as the origional ones that came with the copters. I have a couple that are a little thicker (out of the package) and won't fit but for a few dollars each it's worth a couple non starters. Beside the couple not fitting I wish I didn't have to buy the charger with each order. They do only have that tiny Losi connector and that is all they with work in. I bought a aftermarket charging board to go with my multi chemistry chargers that charges more than ten at a time which I prefer to use so they don't get overcharged. We all know how particular lipos are with keeping voltage between 3.7 and 4.2 volts per cell. The supplied charger does overcharge some, which will decrease the life of the batteries. I will buy again but use my charger.

Don't fit xk220s Reheated shrink wrap Nothing helped Did battery compartment update (removed tabs) Still won't fit

in the blast with a little mod it fits perfect longer run time

Batteries work right like they should very satisfied with my purchase

The batteries are working fine, but the charger is flaky. Works some time but can't always get the batteries plugged tight enough to charge them.

Came packeded well, longer battery life then oe battery.

The batteries are fine, but the included charger is dead on arrival. The LED on the charger is always on regardless if any battery is connected or if the battery is charged or discharged.

Tight fit in the XK110 with a small mod (two "bump" cut). They work great, longer flight times than stock 450mAh.