Warm Tips for Connections: 

1. To connect in series or /and parallel, batteries should meet the below charging/ discharging voltage). As there are subtle differences in the conditions: 

a). identical batteries with the same battery capacity (Ah) and BMS (A);

b). from the same brand (as lithium battery from different brands has their
special BMS) 

c. purchased in near time (within one month).

2.Restriction for parallel and series connection:

Up to 3 identical batteries for serial connection up to 72 V and no limit for parallel connections.

3.Two necessary steps before connecting:These two steps are necessary to reduce the voltage difference between batteries, and through these, the battery system can provide the best of it in series and/or parallel.
Step 1: Fully Charge the batteries separately.
Step 2: Connect the batteries one by one in parallel and leave them together for 12-24h. And then you can connect your batteries in series and/or parallel.

4.Or if you need to load and unload them together, the following steps should be taken:
A: Fully recharge the batteries separately before the first connections.
B: Disconnect the connections among the batteries and recharge the batteries separately once a month.

C:If there is slight voltage difference among batteries during series use, please read page 38 of the manual.