# Battery charging with boost converter topology

I'm designing a circuit for battery charging, which will make use of boost converter topology. I have determined the input/output voltage and current parameters for the circuit. If I put a resistor at the output with value of V_out/I_out, the simulation works just fine. My question is; how can I set the current, so that if I put a battery at the output when the circuit is built, the current would be same as the pre-defined output current value. Also, does the output current depend on the characteristic of the source? Like if the power value of source is constant but input current and voltage changable with PWM at the switch (like a pv panel), what would the output current depend on? Many thanks.

• What kind of batteries are you going to charge, and with what boost converter? If they are lithium batteries, and the converter is not intended to charge batteries, do not connect your circuit to lithium batteries. Commented Mar 26, 2021 at 18:07
• li-ion batteries. My problem is how to set the circuit to make it available for charging the battery. Commented Mar 26, 2021 at 18:12
• Is this a purpose-built lithium ion charger, or are you doing the CC-CV-cutoff logic yourself? If it's the latter, do you have a clear understanding of what you want the charge cycle to look like? Commented Mar 26, 2021 at 18:16
• What do you mean by setting the circuit to make what available for charging the battery? Provide all the details about the circuit. Charging lithium batteries wrong is dangerous as they can explode and burn down your house. If you don't get the circuit exaclty right with all the necessary safety features, it will be dangerous. Commented Mar 26, 2021 at 18:22
• Before you get disheartened, I'm just going to mention that there is an incredibly wide variety of lithium ion accessory boards available. The magic words you're looking for are "charger board" and "discharge protection" and if you have more than one battery in series you also need a "balancer board". If you know how to program and you're good at math and decent at electronics, you could build a microcontroller to perform all these functions. If you're good at calculus and logic, you can build one from discrete components, but that's really a task for someone in engineering.
– K H
Commented Mar 27, 2021 at 1:27