Questions concerning the warmech

[Viladin]

So, I'm running a game, and one of my players is running a warmech, and we've come to a disagreement in the wordings of the Backup Force Field Battery ability.

"Backup Force Field Battery (Su): At 3rd level, as an immediate action, the engineer can spend a repair usage to restart his force field if the temporary hit points of his force field drops to 0. The warmech’s force field reenergizes and grants him half of his normal temporary hit points granted by the force field."

When it says that it grants him half his normal temporary hit points, does that mean that the field recovers half of its hp, then starts regenerating back to full, or does it mean that it continues to work at half copacity, meaning its MAX hp is halved until the 24 hours charge up time happens?

It recovers of its hp.