Dark Forces 2 - need power

Hi,
I have the Gog version of Jedi Knight and I use a walkthrough from Gamefaq to have a thorough gaming experience.
I have reached level 6 where there's a long swim underwater in a darkened pipe.
It's easily crossed with the nigth vision goggles but it say Goggles out of power.
I've tried a few cheat code but none seems to give full power.
So, I need to get full power for the goggles yet there's no batteries where I'm stuck.
What can I do please?

Would this be of any help?

If not, have you tried asking your question on the GOG forum for the game?

I've already a walkthrough - those of Gamefaq are the best btw - but my issue's simply too silly a situation to be solved. I got in this myself. I should feel ashame.
The only solution here is to restart the level and make sure to collect enough batteries for this passage.
Anyway thanks for the offer