Hello, i wanted to place some accumulaors inside a factory, but those dont charge here. is it a bug or am I doing someshing wrong?

No, you're doing everything right. Unfortunately, what you're trying to do is impossible, since the inside of a factory is powered by a tertiary priority energy source (an accumulator) and accumulators don't charge each other. There's no better solution, unfortunately, because there's a tradeoff involved. You'll have to put your accumulators outside with your solar panels.

There is no need to have accumulators inside because the factory itself can save 100 GW ^^

3.3 GJ*

3.3 GJ, thanks for the number. I want some acc inside, because 3.3 GJ is not enough