Building a working battery | Treatment Plant Walkthrough Resident Evil Zero HD Guide
Last update: 02 February 2017
Keep playing as Rebecca. In the control room (M6,20) where you start you will find new supplies, but the most important interactive object in the location is a lever. Turning it will lower the water level and unlock passage through the platform on the lower floor of the facility (later Billy will use this path). Select a good weapon for Rebecca (for example, shotgun) and use the door leading to the neighboring room (M6,21).
Use a good weapon (for example the suggested shotgun) to kill at least one giant insect just after you reach the new room. Once the battles are over you can explore the area. Most of all, there is a blue tank there - interact with it and confirm that you want to take Blue Chemical. It will automatically mix with the previously obtained red chemicals and you will receive Sulfuric Acid. Additionally, take the Industrial Water from the left table. Open inventory and combine the water with sulfuric acid. You will receive Battery Fluid.
Now you can unlock the northern door from this side, but don't use them yet (unless you want to travel a long road to the typing machine and save your progress). Instead of that, take interest in the stairs and use them to reach the lower floor (M6,22). Once you get to the new room, take interest in the battery lying on the currently unavailable upper ledge. Remain as Rebecca in that place and switch to Billy (M6,17). Use the small elevator to reach as Billy the room in which you recently fought Proto Tyrant (M6,18).
Pick the left door which you ignored during your previous visit to this room (M6,23). They will lead you to the outside balconies at the dam. Before you move ahead equip Billy with shotgun or rocket launcher. Walk down the ladder and try going left. Lurker should soon jump from the water and you must QUICKLY act if you don't want Billy to die. Don't run and don't wait too long with the attacks so that the toad won't capture Billy - Rebecca won't be able to save him. Go as far to the left as possible after killing the toad. You will reach a new ladder and then door (M6,24).
Watch out for zombies that you must kill in that room. Once the battle is over, search the room. You will obtain some supplies. Then unlock the northern door from this side (M6,22). Behind them you will find Rebecca, so you can now join her. Walk as Billy to the previously mentioned upper ledge with the battery. Position him in the place shown on the picture, press the interaction button and confirm (Yes option) lifting Rebecca (first make sure that she has at least one free slot in her inventory). Now you can take the Empty Battery.
Prepare yourself as at least two new giant insects will appear in the room after you obtain the battery. Quickly get rid of them (preferably with a shotgun). Once it is done, open Rebecca's inventory. You must combine the newly obtained Empty Battery with the previously created Battery Fluid (it replaced the Mixing Set). You will receive the fully loaded Hi-Power Battery by doing so.