Dual battery converter with wide DC input 24V -72V. 
Output: DC 24V -72V, max 40A current. 
Input with Anderson connector; output with Anderson connector. 
Xt90 connectors can handle up to 80a. 
If you have two batteries(24V-72V) with different voltages or the same voltage, you want to use the two batteries with one ebike, then you can connect the two batteries with the dual battery converter.  
When you are going to charge the battery, please switch one of the batteries first before charging because the dual battery converter only protect the two batteries discharging; it has no protection for simultaneous charging.
Note that this can be dangerous if left unattended, user assumes all responsibility.