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Hello all,

I've been exploring solar charge controllers on Robu's website, but I need clarification regarding their support for lithium-ion or lithium polymer batteries. The descriptions primarily mention lead-acid batteries, which raises concerns about compatibility. Since I require controllers specifically for my lithium-ion battery, I would greatly appreciate your assistance in clarifying this.

You can consider using SmartElex Solar Lithium Ion/Poly charger -BQ24074 https://robu.in/product/smartelex-solar ... r-bq24074/
This charger is specifically designed for lithium-ion and lithium polymer batteries. It supports multiple input sources, including USB Type-C, DC, and solar, and offers features like smart load sharing and voltage protection.

What kind of battery configuration do you plan to use? (i.e., number of cells in series (𝑥S) and parallel (𝑥P) and the capacity of each cell?)
For now, I will assume that you plan to use a single-cell (1S) setup (or multiple in parallel but still 1S).

In my opinion, the BQ24074-based Smartelex module might be unnecessarily expensive for your use case, as it costs ₹1100 but lacks MPPT and is a linear charger. While relatively efficient for a linear regulator (since it’s from Texas Instruments), its only significant advantage is dynamic power management, which allows it to seamlessly switch between battery and input power. However, it does not have buck or boost conversion, meaning the output voltage is tied to the battery voltage.

For a more cost-effective alternative, I would recommend one of the following CN𝑥𝑥𝑥𝑥-based modules, depending on your budget and requirements:

• CN3065 (₹108): This is the cheapest option and uses linear charging (not PWM). It lacks MPPT and is best suited for 1S Li-ion or Lipo batteries with a max charge current of 1A. It does have dynamic power adjustment for solar panels, but it is the least efficient.
• CN3791 (₹242): This is a PWM-based switch-mode charger with MPPT, designed for 1S Li-ion/Lipo batteries. If you need MPPT and higher efficiency, this is the best choice for single-cell setups.
• CN3795 (₹324): This charger supports adjustable CC and CV, meaning it can charge Li-ion, LiFePO4, or even multi-cell configurations. If you need a charger that can handle multiple cells in series, this is the best option according to the datasheet.