What Is C-Rate?

C-rate describes how fast a battery charges or discharges relative to its total capacity. A 1C rate means a battery fully charges or discharges in one hour; 0.5C means two hours; 2C means thirty minutes. It's a ratio, not a fixed amount of power, so it scales with battery size.

How to Read a C-Rate

A 100 kWh battery rated for 1C can sustain 100 kW of continuous charge or discharge. The same battery rated for 0.5C can only sustain 50 kW, half the power, over twice the duration.

Why C-Rate Matters for BESS Selection

Not every use case needs the same C-rate. A BESS covering brief, sharp peak shaving spikes needs a higher C-rate to deliver a lot of power quickly, even if that power is only needed for a few minutes. A system focused on longer-duration energy arbitrage, shifting energy across several hours, can use a lower C-rate battery, which is typically cheaper per kWh.

C-Rate and Battery Longevity

Running a battery consistently at a high C-rate generates more heat and stress on the cells than running it at a lower rate, which can shorten cycle life if sustained over years. Matching C-rate to the actual application, rather than over-specifying for headroom that's rarely used, is part of sizing a BESS correctly.

Neutron's Range

Our Energy Storage Systems are specified with C-rates matched to their intended use, from peak shaving-focused high-power configurations to longer-duration arbitrage and backup systems.

What C-rate does a BESS need for peak shaving?

It depends on how short and sharp the site's demand peaks are. A site with brief, very high spikes needs a higher C-rate battery that can discharge quickly, while a site with longer, more moderate peaks can use a lower C-rate system, which is often more cost-effective per kWh.

Does a higher C-rate mean a better battery?

Not necessarily, it depends on the application. A higher C-rate battery costs more per kWh and often has a shorter cycle life if run consistently at high rates. The right C-rate is whatever matches the actual power and duration profile of the job the battery needs to do.