To access the battery;
You must remove the two allen bolts, that hold the pole clamp to the rear of the pump.
You will the be able to remove the pole clamp and the rear half of the casing.
You will be able to see the battery, it is clamped in a cage like fixture, simpy loosen the allen bolts and the battery will slide out whilst observing the orientation of the platic plate on top of the battery, as this is what the pole clamp is fixed too.
When re-assembling be careful not to damage the black rubber case seal,which runs along a recess/groove in the case.
Kind Regards
Dom
