So until about 3 months ago, foot pedals pedaled by a normal human were providing about 15 HP, and you could attach a stack of alternators with 1 HP, 2 HP, and 3 HP of load and merrily pedal away.
Then some code monkey with delusions of grandeur decided to go “oh realizm!” and cut the power output of foot pedal to a more reasonable 2 HP, of which you can use about 0.75 HP without a huge amount of effort. So now a normal human can’t run an alternator stack, and mostly can only power a single motorbike alternator or possibly a single car alternator if your character is pretty strong.
There’s now a bicycle alternator that only requires 0.1 HP, so you can attach that, but it also only produces 36W (compared to ~400W for a motorbike alternator). You can find them on electric bicycles and sometimes in bike shops.
