Depth of discharge

<h2 id="occurrence">Occurrence</h2>
<p>During their use, secondary batteries are repeatedly charged and discharged within a certain range of state of charge. For many <a href="/facts/Battery_types/xhL4zfRu">battery types</a>, it is beneficial or even mandatory for safety reasons, to not encounter overcharging and/or deep discharge. To prevent adverse effects, a <a href="/facts/Battery_management_system/XNvWHEfp">battery management system</a> or battery charger may keep the battery from extreme levels regarding SoC, thereby limiting the SoC to a reduced range between 0 % and 100 % and decreasing <i>depth of discharge</i> below 100 % (see example below). This corresponds to the DoD in the sense of definition (1).
</p><p>For almost all known <a href="/facts/Rechargeable_battery/A6zUkPkW">rechargeable battery</a> technologies, such as <a href="/facts/Lead-acid_battery/84b8hALA">lead-acid batteries</a> of all kinds like <a href="/facts/Absorbent_glass_mat/fmPQ48sY">AGM</a>, there is a correlation between the depth of discharge and the <a href="/facts/Cycle_life/vMWrb3q9">cycle life</a> of the battery.<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a> For <a href="/facts/Lithium_iron_phosphate_battery/FQRNCjkl">LiFePO4 batteries</a>, for example, the state of charge is often limited to the range between 15 % and 85 % to greatly increase their cycle life, resulting in a DoD of 70 %.<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a>
</p><p>While the state of charge is usually expressed using percentage points (0 % = empty; 100 % = full), depth of discharge is either expressed using units of <a href="/facts/Ampere_hour/H8qKSLtk">Ah</a> (e.g. for a 50 Ah battery, 0 Ah is full and 50 Ah is empty) or percentage points (100 % is empty and 0 % is full). The capacity of a battery may also be higher than its nominal rating. Thus it is possible for the depth of discharge value to exceed the nominal value (e.g., 55 Ah for a 50 Ah battery, or 110 %).
</p>
<h2 id="sample-calculation">Sample calculation</h2>
<p>Using definition (2), the depth of discharge of a charged 90 Ah battery is discharged for 20 minutes at a constant current of 50 A is calculated by:
</p>

D
          o
          D
        
        =
        
          
            
              50
              
                 A
              
              ⋅
              
                
                  
                    20
                    
                       mins
                    
                  
                  
                    60
                    
                       mins
                    
                  
                
              
              
                 hours
              
            
            
              90
              
                 Ah
              
            
          
        
        ⋅
        100
        %
        =
        18.522
        %
        .
      
    
    {\displaystyle \mathrm {DoD} ={\frac {50{\text{ A}}\cdot {\frac {20{\text{ mins}}}{60{\text{ mins}}}}{\text{ hours}}}{90{\text{ Ah}}}}\cdot 100\%=18.522\%.}

<h2 id="deep-discharge">Deep discharge</h2>

<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Battery_balancing/sVYHED9l">Battery balancing</a></li>
<li><a href="/facts/Smart_battery/fRBufzRj">Smart battery</a></li>
<li><a href="/facts/Deep-cycle_battery/zhv4yGfN">Deep-cycle battery</a></li>
<li><a href="/facts/State_of_health/jJIkJ2uu">State of health</a></li>
<li><a href="/facts/Battery_management_system/XNvWHEfp">Battery management system</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Cheng, Yu-Shan; Liu, Yi-Hua; Hesse, Holger C.; Naumann, Maik; Truong, Cong Nam; Jossen, Andreas (2018). "A PSO-Optimized Fuzzy Logic Control-Based Charging Method for Individual Household Battery Storage Systems within a Community". Energies. 11 (2): 469. doi:10.3390/en11020469. ISSN 1996-1073. <a href="https://doi.org/10.3390%2Fen11020469" target="_blank">https://doi.org/10.3390%2Fen11020469</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Wikner, Evelina; Thiringer, Torbjörn (2018). "Extending Battery Lifetime by Avoiding High SOC". Applied Sciences. 8 (10): 1825. doi:10.3390/app8101825. ISSN 2076-3417. <a href="https://doi.org/10.3390%2Fapp8101825" target="_blank">https://doi.org/10.3390%2Fapp8101825</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>gwl-power. "lithium & solar power LiFePO4". lithium & solar power LiFePO4. Retrieved 2022-02-20. <a href="https://gwl-power.tumblr.com/post/26696964746/depth-of-discharge-dod-all-battery" target="_blank">https://gwl-power.tumblr.com/post/26696964746/depth-of-discharge-dod-all-battery</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>"Blog - LiFePO4 | shop.GWL.eu". shop.gwl.eu. Retrieved 2022-02-20. <a href="https://shop.gwl.eu/blog/LiFePO4/FAQ-LiFePO4-cycle-life-based-on-DOD.html" target="_blank">https://shop.gwl.eu/blog/LiFePO4/FAQ-LiFePO4-cycle-life-based-on-DOD.html</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>Bhadra, Shoham; Hertzberg, Benjamin J.; Hsieh, Andrew G.; Croft, Mark; Gallaway, Joshua W.; Van Tassell, Barry J.; Chamoun, Mylad; Erdonmez, Can; Zhong, Zhong; Sholklapper, Tal; Steingart, Daniel A. (2015). "The relationship between coefficient of restitution and state of charge of zinc alkaline primary LR6 batteries" (PDF). Journal of Materials Chemistry A. 3 (18): 9395–9400. doi:10.1039/C5TA01576F. OSTI 1183288. <a href="http://www.physics.rutgers.edu/~croft/papers/210-CoeffRest-2015.pdf" target="_blank">http://www.physics.rutgers.edu/~croft/papers/210-CoeffRest-2015.pdf</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
<li id="fn:6"><p>Wang, John; Liu, Ping; Hicks-Garner, Jocelyn; Sherman, Elena; Soukiazian, Souren; Verbrugge, Mark; Tataria, Harshad; Musser, James; Finamore, Peter (2011-04-15). "Cycle-life model for graphite-LiFePO4 cells". Journal of Power Sources. 196 (8): 3942–3948. Bibcode:2011JPS...196.3942W. doi:10.1016/j.jpowsour.2010.11.134. ISSN 0378-7753. <a href="https://www.sciencedirect.com/science/article/pii/S0378775310021269" target="_blank">https://www.sciencedirect.com/science/article/pii/S0378775310021269</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li>
<li id="fn:7"><p>Yamamoto, Takahiko; Ando, Tomohiro; Kawabe, Yusuke; Fukuma, Takeshi; Enomoto, Hiroshi; Nishijima, Yoshiaki; Matsui, Yoshihiko; Kanamura, Kiyoshi; Takahashi, Yasufumi (2021-11-02). "Characterization of the Depth of Discharge-Dependent Charge Transfer Resistance of a Single LiFePO4 Particle". Analytical Chemistry. 93 (43): 14448–14453. doi:10.1021/acs.analchem.1c02851. ISSN 0003-2700. PMID 34668693. <a href="https://doi.org/10.1021/acs.analchem.1c02851" target="_blank">https://doi.org/10.1021/acs.analchem.1c02851</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li>
<li id="fn:8"><p>Shim, Joongpyo; Striebel, Kathryn A. (2003-06-01). "Cycling performance of low-cost lithium ion batteries with natural graphite and LiFePO4". Journal of Power Sources. Selected papers presented at the 11th International Meeting on Lithium Batteries. 119–121: 955–958. Bibcode:2003JPS...119..955S. doi:10.1016/S0378-7753(03)00297-0. ISSN 0378-7753. S2CID 53992561. <a href="https://www.sciencedirect.com/science/article/pii/S0378775303002970" target="_blank">https://www.sciencedirect.com/science/article/pii/S0378775303002970</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li>
<li id="fn:9"><p>Anseán, D.; Viera, J. C.; González, M.; García, V. M.; Álvarez, J. C.; Antuña, J. L. (2013). "High power LiFePO4 cell evaluation: Fast charge, Depth of Discharge and Fast discharge dependency". World Electric Vehicle Journal. 6 (3): 653–662. doi:10.3390/wevj6030653. ISSN 2032-6653. <a href="https://doi.org/10.3390%2Fwevj6030653" target="_blank">https://doi.org/10.3390%2Fwevj6030653</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li>
<li id="fn:10"><p>support.rollsbattery.com:AGM discharge characteristics <a href="http://support.rollsbattery.com/support/solutions/articles/4346-agm-discharge-characteristics" target="_blank">http://support.rollsbattery.com/support/solutions/articles/4346-agm-discharge-characteristics</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li>
<li id="fn:11"><p>gwl-power. "lithium & solar power LiFePO4". lithium & solar power LiFePO4. Retrieved 2022-02-20. <a href="https://gwl-power.tumblr.com/post/26696964746/depth-of-discharge-dod-all-battery" target="_blank">https://gwl-power.tumblr.com/post/26696964746/depth-of-discharge-dod-all-battery</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li>
</ol>

Depth of discharge open-in-new

Depth of discharge