[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-seo-568793-105":3,"detail-sidebar-cat-1-en-105":81,"doc-detail-568793-en":127},{"code":4,"msg":5,"data":6},0,"ok",{"site_id":7,"language":8,"slug":9,"title":10,"keywords":11,"description":12,"schema_data":13,"social_meta":74,"head_meta":76,"extra_data":78,"updated_unix":80},105,"en","state-of-charge-12-volt-standard-batteries-guide","State of charge 12 volt Standard Batteries - Guide","","Battery state of charge for 12 volt standard batteries is determined using terminal voltage or the specific gravity of the sulphuric acid electrolyte in a lead-acid battery. Specific gravity is measured with a hydrometer, which cannot be used with sealed, AGM, or gel cell batteries. Voltage meters can be used, but voltage varies through the day due to charging and discharging, so experience helps interpret readings. The document also provides a percentage-to-voltage and specific gravity table and highlights common technical mistakes and precautions.",{"@graph":14,"@context":73},[15,34,56],{"@type":16,"itemListElement":17},"BreadcrumbList",[18,23,27,31],{"item":19,"name":20,"@type":21,"position":22},"https://docshare.wps.com","Home","ListItem",1,{"item":24,"name":25,"@type":21,"position":26},"https://docshare.wps.com/template/","Template",2,{"item":28,"name":29,"@type":21,"position":30},"https://docshare.wps.com/template/general/","General",3,{"item":32,"name":10,"@type":21,"position":33},"https://docshare.wps.com/template/state-of-charge-12-volt-standard-batteries-guide/568793/",4,{"url":32,"name":10,"@type":35,"image":36,"author":41,"headline":10,"publisher":44,"fileFormat":47,"inLanguage":8,"description":12,"dateModified":48,"datePublished":49,"encodingFormat":47,"isAccessibleForFree":50,"interactionStatistic":51},"DigitalDocument",{"url":37,"@type":38,"width":39,"height":40},"https://docshare.wps.com/thumbnails/state-of-charge-12-volt-standard-batteries-guide/568793.png","ImageObject",442,249,{"name":42,"@type":43},"Sarah ","Person",{"url":19,"name":45,"@type":46},"DocShare","Organization","application/pdf","2026-10-23","2026-10-13",true,{"@type":52,"interactionType":53,"userInteractionCount":55},"InteractionCounter",{"@type":54},"ViewAction",8,{"@type":57,"mainEntity":58},"FAQPage",[59,65,69],{"name":60,"@type":61,"acceptedAnswer":62},"How can the state of charge of a 12 volt lead-acid battery be determined?","Question",{"text":63,"@type":64},"By reading either the terminal voltage or the specific gravity of the sulphuric acid electrolyte. Specific gravity is measured with a hydrometer.","Answer",{"name":66,"@type":61,"acceptedAnswer":67},"Why can’t a hydrometer be used on some batteries?",{"text":68,"@type":64},"Because hydrometer readings cannot be used with sealed, AGM, or gel cell batteries.",{"name":70,"@type":61,"acceptedAnswer":71},"What are the common technical mistakes when installing batteries?",{"text":72,"@type":64},"Common mistakes include using insufficient capacity, incorrect charging (especially overcharging AGM batteries), flattening batteries, and undersized wiring or corroded/loose connections.","https://schema.org",{"og:url":32,"og:type":75,"og:title":10,"og:site_name":45,"og:description":12},"article",{"robots":77,"canonical":32},"index,follow",{"doc_id":79,"site_id":7},568793,1792088577,{"code":4,"msg":82,"data":83},"success",[84,89,94,99,104,109,114,119,124],{"id":85,"doc_module":22,"doc_module_name":25,"category_name":86,"show_sort_weight":87,"slug":88},11,"Presentations",90,"presentations",{"id":90,"doc_module":22,"doc_module_name":25,"category_name":91,"show_sort_weight":92,"slug":93},12,"Resumes",80,"resumes",{"id":95,"doc_module":22,"doc_module_name":25,"category_name":96,"show_sort_weight":97,"slug":98},14,"Invoices",70,"invoices",{"id":100,"doc_module":22,"doc_module_name":25,"category_name":101,"show_sort_weight":102,"slug":103},15,"Posters",60,"posters",{"id":105,"doc_module":22,"doc_module_name":25,"category_name":106,"show_sort_weight":107,"slug":108},16,"Social Media",50,"social-media",{"id":110,"doc_module":22,"doc_module_name":25,"category_name":111,"show_sort_weight":112,"slug":113},17,"Forms",40,"forms",{"id":115,"doc_module":22,"doc_module_name":25,"category_name":116,"show_sort_weight":117,"slug":118},18,"Letters",30,"letters",{"id":120,"doc_module":22,"doc_module_name":25,"category_name":121,"show_sort_weight":122,"slug":123},21,"Paper Templates",5,"papers-templates",{"id":125,"doc_module":22,"doc_module_name":25,"category_name":29,"show_sort_weight":4,"slug":126},158,"general-158",{"code":4,"msg":82,"data":128},{"doc_id":79,"user_id":129,"nickname":42,"user_avatar":130,"doc_module":22,"category_id":125,"category_name":29,"doc_title":10,"doc_description":12,"doc_content":131,"file_id":132,"file_url":133,"file_type":134,"file_size":135,"view_count":55,"is_deleted":4,"is_public":22,"is_downloadable":22,"audit_status":22,"page_count":26,"language":136,"language_code":8,"site_id":7,"html_lang":8,"table_of_contents":137,"faqs":138,"seo_title":139,"seo_description":12,"update_tm":140,"read_time":22},962085320529,"https://ap-avatar.wpscdn.com/davatar_9964176cb1d06d4a9deccf72a44ae3dc","Balmain Battery Discount Store  \n16 Mansfield Street, Rozelle NSW 2039  \n(02) 9555 9444 – 0425 286 700  \nState of charge 12 volt Standard Batteries  \nBattery state of charge is determined by reading either terminal voltage or the specific gravity of the electrolyte. The density or specific gravity of the sulphuric acid electrolyte of a lead-acid battery varies with the state of charge (see table below) . Specific gravity is read with a hydrometer. A hydrometer reading will tell the exact state of charge. A hydrometer cannot be used with sealed, AGM or gel cell batteries.  \nVoltage meters are also used to indicate battery state of charge. Digital voltmeters provide the accuracy to read the voltage in hundredths and are relatively inexpensive and easy to use. The main problem with relying on voltage reading is the high degree of battery voltage variation through out the day. Battery voltage reacts highly to charging and discharging. As a battery is charged the indicated voltage increases and, as discharging occurs, the indicated voltage decreases. With experience, one can accurately determine state of charge using a voltmeter.  \n\n| Percentage of Charge\u003Cbr>| 12 Volt Battery Voltage | Specific Gravity |\n| --- | --- | --- |\n| 100 | 12.70 | 1.265 |\n| 95 | 12.64 | 1.257 |\n| 90 | 12.58 | 1.249 |\n| 85 | 12.52 | 1.241 |\n| 80 | 12.46 | 1.233 |\n| 75 | 12.40 | 1.225 |\n| 70 | 12.36 | 1.218 |\n| 65 | 12.32 | 1.211 |\n| 60 | 12.28 | 1.204 |\n| 55 | 12.24 | 1.197 |\n| 50 | 12.20 | 1.190 |\n| 45 | 12.16 | 1.183 |\n| 40 | 12.12 | 1.176 |\n| 35 | 12.08 | 1.169 |\n| 30\u003Cbr>| 12.04 | 1.162 |\n| 25\u003Cbr>| 12.00 | 1.155 |\n| 20 | 11.98 | 1.148 |\n| 15 | 11.96 | 1.141 |\n| 10 | 11.94 | 1.134 |\n| 5 | 11.92 | 1.127 |\n| \u003Cbr>Discharged | 11.90 | 1.120 |\n\nTechnical Support  \nMaking the correct choice of battery for your application is no laughing matter and ensuring that your investment is protected requires careful planning.  \nCommon mistakes made with battery installations include:  \nNot enough capacity  \nSkimping on battery capacity is a mugs game. The simple fact is that if you are using 120 Ah per day in your application and you have only 200Ah of battery capacity, you are going to repeatedly damage your batteries. You should never plan to draw down on more than 50% of your battery capacity, and size your system to support that.  \nIncorrect charging  \nAGM batteries, as with all batteries require a specific charging to avoid damage.  \nOver charging, or punching in too much voltage or amperage will cause runaway chemical reactions outside the design of the battery. ALWAYS use a battery charger designed for charging AGM's. We recommend CTEK battery chargers for the task, or ensure that your installation has a smart charging system with a program for AGM's  \nFlattening batteries  \nFlattening a battery on the camping trip because the beer MUST be kept cold is going to cost you more than a hangover. All batteries are damaged when flattened, and taken too far will destroy them in one outing. Ensure that the appliances drawing the power, or the circuit has low voltage protection. The humble flood light or cheap car fridge has the ability to takedown your investment in one night.  \nOver charging  \nAGM's while charging create Hydrogen and Oxygen just like most other technologies. Thesemi sealed, pressurised environment helps contain the H's and the O2's inside the unit, but if the battery is charged too fast, or overcharged the valves will trigger releasing gases and changing the balance of chemicals and once escaped, there will be no topping up, the battery will eventually be useless.  \nUndersized wiring  \nAGM's typically have good cranking ability, with the Absorbed Power range having excellent cranking characteristics. Engines not starting or under voltage buzzers sounding, this is typically found to be a corroded connection, loose connection, under sized wiring or wiring runs too long. Ensure that your installation takes full account of these issues.  \nThe simple answer t","cbCaijQXz4S3ODKp","https://ap.wps.com/l/cbCaijQXz4S3ODKp","pdf",143721,"English","# Battery state of charge methods\n## Hydrometer vs sealed batteries\n## Voltage meter considerations\n# Charge level reference table\n# Technical support and common mistakes\n## Capacity planning\n## Charging and overcharging\n## Battery flattening and protection\n## Wiring and connection issues","[{\"question\":\"How can the state of charge of a 12 volt lead-acid battery be determined?\",\"answer\":\"By reading either the terminal voltage or the specific gravity of the sulphuric acid electrolyte. Specific gravity is measured with a hydrometer.\"},{\"question\":\"Why can’t a hydrometer be used on some batteries?\",\"answer\":\"Because hydrometer readings cannot be used with sealed, AGM, or gel cell batteries.\"},{\"question\":\"What are the common technical mistakes when installing batteries?\",\"answer\":\"Common mistakes include using insufficient capacity, incorrect charging (especially overcharging AGM batteries), flattening batteries, and undersized wiring or corroded/loose connections.\"}]","State of charge 12 volt Standard Batteries - Guide | PDF",1791872392]