Wiring together 3 sla batteries

want to wire 3 x 12v sla batteries together for my robot, still want it to give 12volts mind. i know how to wire them together but do i just charge them individually and they will work ok. i was wondering if having them linked they might drain each other or something. and when the removeable link is removed in the robot, (so no power is going to the robot components), do i need to disconnect the 3 slas from each other? i will disconnect them when not in use for a while but wondered what would happen if i left them connected for about 6- 8 hours.

Its called being wired parallel.
if the batteries are of the same specs, and you have charged them seperatly to full charge, you can keep them connected for a long time, just treat them as if its 1 big battery.

Best bet is to give them seperatly a top up charge once a while.

If the batteries are 3 different sizes and/or with differences in quality/wear and tear, then its 1) not a good idea, 2) you need to remove and charge them seperatly

cheers mario, all batteries are identical (even the make is the same)