# Is running 4 18650 batteries in parallel too much current for a small RC circuit with the same voltage?

I built this small RC deadbolt lock and everything works great, however, I need to fix the issue of battery life before it is finished. Originally the circuit had a 3.7V, 800 mAh battery. I would like to hook up a total of of 3.7 V, 12000 mAh or so, my question is will the circuit only draw what it needs from the batteries or will this fry the circuit?

Sorry if this is a rookie question, my knowledge of this is not too extensive.

Thanks!

• Thought experiment: What does Ohm's law tell you? ($V = IR$.) – Transistor Apr 7 at 18:38
• You can't change capacity that much without checking out the charging circuit. Cutoff current is based on total capacity, so if you charge a 12 Ah bank to the cutoff current of a 0.8 Ah bank, you'll overcharge it and wear it out fast. – K H Apr 8 at 6:11