You will probably find that your JP charger is a "smart" type. It commences to charge at what is often called a "bulk" rate, when a relatively high current is applied. Once the battery is almost fully-charged the charger automatically reverts to a much lower "float" charge-rate, sometimes called a "trickle" charge. At this low current you could leave the thing on charge more or less indefinitely without causing any damage. If your battery hasn't discharged much since the last charge then it may well go straight into float-charge mode.
SLA batteries dislike being left alone for long so it's a good idea to apply a top-up charge once every couple of months, even when you aren't using or planning to use them for a while. Once a SLA battery goes absolutely flat it's usually irrecoverable - although they do make handy weights or doorstops in the workshop!
Do make a note of the different units involved: a charge rate
is a current and indicated in A or mA (Amps or Milliamps) whereas the units of AH and mAH are battery capacity
in either Amp.Hours or Milliamp.Hours. The essential difference between charging a lead-acid battery and, say, a NiMH or LiPo, is that it is done at a constant voltage
, as opposed to a constant current
for the latter types.
So now you know!