I found this interesting accessory to charge up to 6 batteries lipo 2-6 elements connected in parallel, this accessory allows us to have multiple batteries in the robot and the charging charger all at once. Example: 4 batteries (3s) 5000mah in parallel = (3s) 20000mah (20A) The smart charger to charge a battery program 3s 5amp, each battery receives 1.25 amps, charging time approximately 4 hours. Make sure that the batteries are all the same, same number of elements, same capacity in amperes, and that all elements are in good shape. I found interesting to share with the community because every time we are but what we use lipo batteries. Even practical to incorporate smart charger robot and automatic coupling stations for charging lipos. There are several models of this accessory for various connectors of the batteries, some with fuse protection and different prices. In addition to the large 20 amp smart chargers, you could make the battery charge in the previous example in 1 hour (20 amp / 4 = 5 amps)

Board

Board with fuses and protection diodes

List of accessories