# Aluminium, Carbon, Aluminium Sulphate battery. What's the reaction?

I made galvanic cells from the following items (while trying to do something else), and they give between 0.6 V and 1 V per cell.

Aluminium foil – negative terminal

Carbon (these work: charcoal sticks, graphite rods, carbon felt) – positive terminal.

Electrolyte – aluminium sulphate $$\ce{Al2(SO4)3}$$ in water.

With 9 cells – 3 series * 3 parallel – it lights a red LED. Left on overnight it gets very dim, but given some recovery time, it comes back bright again. So the current isn't high, but I wasn't expecting any.

I'm not observing any gas being evolved, or any change in the foil (yet). The battery has been running about a week.

I know the Al sulphate reacts with water to make sulphuric acid + Al hydroxide. Is that what's happening here? What happens next in the reaction? What's the final result?

Thanks for your help. It's a long time since school chemistry lessons.