{"id":24,"date":"2013-04-17T08:55:41","date_gmt":"2013-04-17T15:55:41","guid":{"rendered":"http:\/\/pididu.com\/wordpress\/solarbike\/?p=24"},"modified":"2026-10-27T17:01:59","modified_gmt":"2026-10-28T00:01:59","slug":"monitoring-battery-voltage","status":"publish","type":"post","link":"http:\/\/pididu.com\/wordpress\/solarbike\/monitoring-battery-voltage\/","title":{"rendered":"Monitoring Battery Voltage"},"content":{"rendered":"<div class=\"wp-block-image\">\n<figure class=\"aligncenter\"><a href=\"http:\/\/pididu.com\/wordpress\/solarbike\/files\/2013\/04\/VoltageMonitor.jpg\"><img loading=\"lazy\" decoding=\"async\" width=\"480\" height=\"640\" src=\"http:\/\/pididu.com\/wordpress\/solarbike\/files\/2013\/04\/VoltageMonitor.jpg\" alt=\"DVM monitoring electric bike battery voltage\" class=\"wp-image-25\" srcset=\"http:\/\/pididu.com\/wordpress\/solarbike\/files\/2013\/04\/VoltageMonitor.jpg 480w, http:\/\/pididu.com\/wordpress\/solarbike\/files\/2013\/04\/VoltageMonitor-225x300.jpg 225w\" sizes=\"auto, (max-width: 480px) 100vw, 480px\" \/><\/a><figcaption class=\"wp-element-caption\">A voltmeter is clipped to the charging port to monitor the battery voltage under various conditions.<\/figcaption><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">A battery charger generally needs to know the voltage on the battery being charged, among other things. In order for my design to work right, I&#8217;ll need to know when the battery is full, when it needs current-limited charging, and when it needs a boost because the motor is running. So I strapped a $5 digital voltmeter to the headset to monitor the battery voltage under various conditions. &nbsp;Here is what I found.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><th>Condition<\/th><th>Voltage<\/th><\/tr><tr><td>Fully charged, with charger connected<\/td><td>31.8<\/td><\/tr><tr><td>Fully charged, charger just disconnected<\/td><td>26.8<\/td><\/tr><tr><td>Fully charged, after motor run just a little<\/td><td>25.8<\/td><\/tr><tr><td>Upon motor startup (high torque acceleration)<\/td><td>21.9<\/td><\/tr><tr><td>After 10-20 sec, motor running at terminal speed<\/td><td>23.5<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Those readings were taken with the old, weak batteries. I should redo the experiment now that fresh batteries have been installed. But this data gives me encouragement that my power transfer circuit can work by monitoring battery voltage alone.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A battery charger generally needs to know the voltage on the battery being charged, among other things. In order for my design to work right, I&#8217;ll need to know when the battery is full, when it needs current-limited charging, and when it needs a boost because the motor is running. So I strapped a $5 &hellip; <a href=\"http:\/\/pididu.com\/wordpress\/solarbike\/monitoring-battery-voltage\/\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Monitoring Battery Voltage<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":25,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-24","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-electrical"],"_links":{"self":[{"href":"http:\/\/pididu.com\/wordpress\/solarbike\/wp-json\/wp\/v2\/posts\/24","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/pididu.com\/wordpress\/solarbike\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/pididu.com\/wordpress\/solarbike\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/pididu.com\/wordpress\/solarbike\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/pididu.com\/wordpress\/solarbike\/wp-json\/wp\/v2\/comments?post=24"}],"version-history":[{"count":0,"href":"http:\/\/pididu.com\/wordpress\/solarbike\/wp-json\/wp\/v2\/posts\/24\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/pididu.com\/wordpress\/solarbike\/wp-json\/wp\/v2\/media\/25"}],"wp:attachment":[{"href":"http:\/\/pididu.com\/wordpress\/solarbike\/wp-json\/wp\/v2\/media?parent=24"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/pididu.com\/wordpress\/solarbike\/wp-json\/wp\/v2\/categories?post=24"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/pididu.com\/wordpress\/solarbike\/wp-json\/wp\/v2\/tags?post=24"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}