Review on Biswaye 2-Pack 4.0Ah 20V Lithium Battery LBXR20 Compatible With Black And Decker 20V MAX Battery LBXR2520 LBXR2020 LB2X3020 LBX20 LB2X4020 LBX4020 And LST522 LHT2220 LST300 20V Max Tools by Dang Reid

Bought two, and I use these on a BLACK+DECKER LST300 trimmer, but after the first and subsequent charges, I only get 10 to 11 minutes (max) in constant use for each, in medium to heavy crab grass and weeds. You can a a few more seconds of use if you let the unit rest, but that is not recommend. The 2.0 Ah LBXR2020 battery that came with the LST300 trimmer is heaver in weight, still provides about 10-12 minutes of the same manner of use. It actually does not seem to matter much how heavy the weeds you can cutting.That said, you can get a good amount of work done in 30-35 minutes, using the two batteries plus the 2.0 Ah LBXR2020 that came with the unit, and which constitutes about half the price. Buy your own trimmer line (like Greenworks .065-Inch 240-Foot) and wind it yourself to save money.