84V 3A Charger 84V Lithium Battery Charger for 20S 72V 74V Li-ion Battery with Cooling Fan

Be very careful. The polarity on mine was reversed. I plugged it into the battery, and it blew the fuse. I replaced the fuse, checked it with the multimeter, and saw that it was wired backward. I cut off the plug and reverse the leads. Now it seems to be working properly.