{"id":93785,"key":"What_is_a_C-rate_for_batteries","title":"What is a C-rate for batteries","latest":{"id":744354,"timestamp":"2023-06-09T20:03:23Z"},"content_model":"wikitext","license":{"url":"https://www.appropedia.org/Appropedia:Copyrights","title":"CC-BY-SA-4.0"},"source":"{{To Catch the Sun}}\n\n'''C-rates''' are useful in determining which battery is best for your operation, e.g. [[Table of battery comparison]], especially in conjunction with the battery capacity.\n\n'''Battery capacity''' is the Amp-hr (Ah) rating of a battery and describes how long a battery can provide a certain current (A). For example, a 100Ah battery can provide 100 Amps to a system for 1 hour (100A x 1hr = 100Ah), or 50 A for 2 hours (50A * 2hr = 100 Ah), or 10A for 10 hours (10A * 10hr = 100 Ah).\n\n'''C-Rate''' is a measure of that battery capacity rating. A battery that is rated to discharge its total capacity (Ah) in 1 hour would be rated at 1C, or in 2 hours would be rated at .5C, or in 4 hours would be rated at .25C, or, in the faster direction, in 30 minutes would be rated at 2C. See Table 1 for some examples.\n\nBecause of internal resistance loss and battery chemistry, a battery rarely delivers nameplate rated capacity in only one hour (1C) and typically maximum capacity is found at a lower C-rates. Plus, faster charging and/or discharging (aka at a higher C-rate) typically reduces the total capacity and lifespan of a battery.<ref>https://en.wikipedia.org/wiki/Electric_battery#C_rate</ref><ref>Battery University - What is a C-Rate</ref>\n\n{| class=\"wikitable\"\n|+ Table 1: C-Rate with Average Current and Charge Time for a 50 Ah battery\n! C-Rate\n! Rated Capacity (Ah)\n! Average Current (A)\n! Charge (or discharge) Time\n|-\n| 5C\n| 50 Ah\n| 250 A\n| 12 min\n|-\n| 2C\n| 50 Ah\n| 100 A\n| 30 min\n|-\n! 1C\n! 50 Ah\n! 50 A\n! 1 hour\n|-\n| .5C (aka C/2)\n| 50 Ah\n| 25 A\n| 2 hours\n|-\n| .25C (aka C/4)\n| 50 Ah\n| 12.5 A\n| 4 hours\n|-\n| .1C (aka C/10)\n| 50 Ah\n| 5 A\n| 10 hours\n|}\n\nBattery manufacturers often publish datasheets with graphs showing capacity versus C-rate curves. The C-rate is also used as a rating on batteries to indicate the maximum current that a battery can safely deliver in a circuit. So a battery rated at 1C on the battery, indicates that it can safely discharge its full storage in 1 hour. Some batteries, e.g. Lead Acid Absorbent Glass Mat (AGM), typically have a low C-rate of about 0.25C (safe and efficient charging or discharging of the rated storage over a 4 hour span), where as other batteries, e.g. Lithium Iron Phosphate (LiFePO4), can have a high C-rate of over 3C (safe and efficient charging or discharging of the rated storage in just 20 minutes!).\n\n== See more ==\n\n* [[Table of battery comparison]]\n* [[Battery temperature to capacity tables]]\n* https://www.engineeringforchange.org/webinar/battery-fundamentals-off-grid-electrification/\n\n== References ==\n\n<references />\n\n{{Page data}}\n\n[[Category:Photovoltaics]]\n[[Category:Electricity]]"}