Lead UPS Battery 12V 9Ah (151 x 65 x 93 mm) - Ultracell

VRLA Lead Acid Battery
Maintenance free
Closed construction for optimal security
Faston 187 connectors
12 volts
Capacity 8.6 Ah
Life cycles 200 - 1200 cycles (depending on discharge)
Maximum charging current 2.55 A
Cabinet: ABS

Observation:

Don't deep discharge batteries. The more empty they get, the faster they deteriorate. Ideally, charge 6V batteries before they drop below 6V and 12V before they drop below 12V. Deep cycles can be discharged a little further, 5.8V and 11.6V. Recharge a battery as soon as possible if it starts to get noticeably less full.

Store batteries full.

If they are not used for a long time, disconnect at least one pole of the battery so that they do not discharge through the device, and recharge them after half a year and charge them before use.