By Petra PaulsonConnecting two SLA Batteries in series will double voltage output while keeping the battery capacity (Ah) the same.For example, if you have two UltraTech UT640 batteries, each battery has 6 volts and a 4 Ah capacity. Wiring them in series will double the voltage to 12v, but keep the current draw the same, at 4 Ah. This is a common wiring configuration for electric scooters, battery-powered children's vehicles, and other similar devices. Before wiring, make sure the batteries you're connecting are of the same voltage, capacity, or chemistry (battery type). Consult your device's manual beforehand to make sure it supports the new voltage output of the batteries you're connecting in series. You will need jumper wire to make these connections.
To connect batteries in series:
Connect the negative terminal of Battery 1 to the positive terminal of Battery 2
Connect the positive terminal of Battery 1 to the corresponding positive terminal on the device
Connect the negative terminal of Battery 2 to corresponding negative terminal on the device
Click here for instructions on how to connect SLA batteries in parallel.
EnerSys Genuine NP4-6 SLA Battery
Yuasa NP4-6 SLA Battery