When using electrolysis / electrolytic rust removal, what susbtitutions can be made?

I’ll keep this straight and to the point:

I know that baking soda or lye can be used in place of washing soda.

So, what can be used in place of iron rebar, and most important of all:

WHAT CAN I USE IN PLACE OF A BATTERY CHARGER?

Thanks to any and all advice.

any low volt dc power source will work, like a car battery, cell phone charger, etc. Rebar is just scrap steel, so any scrap that is fairly clean should work.