i stucked on the chapter (barheim passage)

Well if you don't have any potions doesnt one of your team have cure? Set it up as a gambit if you have to.

What you needed to have done was to fight as much as you can in the waterways to collect gill and to collect loot to sell. Now you know why it's not best to sell your armour at the beginning of the game. I know it's difficult at the beginning as money is tight. If you can't kill the mimics then you are in trouble because soon there will be a boss battle. Now you need to buy a spell from the vender that is in the Barheim passage. It is blizzard if I remember rightly. Those battery mimics are weak to ice. So get back there and buy that spell and go get em!!
(if you don't have enough sell loot, fight if you have to and return and see the loot) Set up a gambit for one of your characters to steal. Stealing gets more loot and therefore more money. Hope this helps and good luck

Well, basically all you can do is train. I suggest you to do this: Go ahead, kill all the enemies you can and then go back and save the game again. The best actions you can perform are Cure and Steal. If you have Cure use it as a gambit and make your party leader first gambit to be Steal. This way you will gain lots of loot you can sell and buy all the armors you want.
About the charge, don't worry, it keeps coming to 0 because you have to kill the mimics. They are sucking the energy, so if you kill them all the energy will go to 100%. (Note: by opening the map with Select you can see their location)

Hope I helped

The only mimics you need to kill are the big ones that are draining the power, they are weak against ice so use that, you can also use cure to heal yourself. It would be a good idea to buy some potions from the Bangaa merchant at the start of the Barheim passage. Basch doesn't have a weapon yet at that point but when you get half way through he will get a sword and will be the most useful party in your party so keep him alive. You can't get the key for that gate until later in the game so don't worry about it for now.

You might only need to kill big mimics but I recomend getting the others cause you look like you need alot of training.i would recomend ovid big battles as balthier has a gambit to use first aid and as far as I am aware basch uses potions (he has infinite as he is a guest). Mimics main weakness is ice so keep casting blizard. If no one knows cure buy it form the merchant this is really helpfull. Train on anything you encounter as the boss "mimic queen" is @ the passage end.if you still struggle take em one by one thenr eturn to the save crystal heal and sell loot for more better arour weapons and most definate spells (especially cure and blizard). Once level 6+ advance on further (should no longer be hard) then when you reach you're nect crystal save and before the boss save again it will warn you that you cnt come back here so you know boss is up. The boss is easy when I re-started I used 1 mist abilty to drain over half it's health but just fight it with maigc as much as you can but save some for health

Hope this helps.

May I ask what level you are? Because you have to be level 40 or higher to have at least a chance of getting through. And you should equip the best weapons you can get.