{"id":1542,"date":"2025-07-08T19:36:10","date_gmt":"2025-07-08T17:36:10","guid":{"rendered":"https:\/\/wp.stromer-tech.info\/?post_type=ht_kb&#038;p=1542"},"modified":"2026-07-05T21:44:15","modified_gmt":"2026-07-05T19:44:15","slug":"battery-does-not-deep-discharge","status":"publish","type":"ht_kb","link":"https:\/\/wp.stromer-tech.info\/en\/knowledge-base\/akku-laedt-nicht-tiefentladen\/","title":{"rendered":"Battery not charging - deep discharged?"},"content":{"rendered":"<p class=\"wp-block-paragraph\" id=\"843e33e2-ca6b-45ce-bfcf-dafd1ec77ab7\">If the battery can no longer be charged, the cause is sometimes a so-called deep discharge. This happens if the battery is sent into winter hibernation improperly, usually with too low a charge level, and\/or stored incorrectly. How this can be prevented is explained in the <a href=\"https:\/\/cdn.sanity.io\/files\/odfp6kjd\/production\/a09491ee3e3fb2a85d1a1f539a2cf9dad15ecdd2.pdf\">Safety instructions<\/a> to the battery, the <a href=\"https:\/\/www.stromerbike.com\/de\/support\/manuals\">Operating instructions<\/a>&nbsp;or under BATTERY \u2013&nbsp;<em><a href=\"https:\/\/wp.stromer-tech.info\/en\/knowledge-base\/mechanical-maintenance-in-operation-storage-safety\/\">'Care: Mechanical \/ in operation \/ storage \/ safety'<\/a><\/em><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Stromer writes the following regarding storage:<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1330\" height=\"1482\" src=\"https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Lagerung_des_Akkus.jpeg\" alt=\"\" class=\"wp-image-10567\" style=\"width:600px\" srcset=\"https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Lagerung_des_Akkus.jpeg 1330w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Lagerung_des_Akkus-269x300.jpeg 269w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Lagerung_des_Akkus-919x1024.jpeg 919w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Lagerung_des_Akkus-768x856.jpeg 768w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Lagerung_des_Akkus-45x50.jpeg 45w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Lagerung_des_Akkus-11x12.jpeg 11w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Lagerung_des_Akkus-54x60.jpeg 54w, https:\/\/wp.stromer-tech.info\/wp-content\/uploads\/2025\/07\/Stromer_Lagerung_des_Akkus-90x100.jpeg 90w\" sizes=\"auto, (max-width: 1330px) 100vw, 1330px\" \/><\/figure>\n<\/div>\n\n\n<h3 class=\"wp-block-heading\">Why does deep discharge happen, can it be prevented?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Self-discharge is a physiochemical process that <strong>fundamentally unstoppable<\/strong> Each individual cell in a Li-ion battery experiences self-discharge due to its chemistry. These processes occur even without any external circuitry \u2013 purely internally within the cell. This self-discharge is called calendar aging. It arises from several mechanisms:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Electrochemical side reactions at the electrodes (e.g., SEI layer growth)<\/li>\n\n\n\n<li>Ion diffusion through the separator<\/li>\n\n\n\n<li>Parasitic leakage currents within the cell itself<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">In a battery pack, several cells and the BMS are connected. Even a modern BMS consumes standby power, around 10\u201350 \u00b5A, so it's an additional consumer on top. It doesn't \u201esee\u201c the internal cell currents because they don't flow through external wires.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">When a lithium-ion battery <strong>stored long enough<\/strong> over time<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>The storage temperature is high (greatly accelerates self-discharge)<\/li>\n\n\n\n<li>The BMS itself draws power (typically 20\u2013100 \u00b5A)<\/li>\n\n\n\n<li>The cells are already aged<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\" id=\"4b9cc764-d59c-4bf3-8a27-601b1f081f74\">This leads to irreversible damage, loss of capacity, and a potential fire hazard due to internal short circuits.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A good BMS, correct handling, and storage can delay but not prevent deep discharge if no counter-measures are taken.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\" id=\"3557f348-ed0d-4a4a-8968-c0e4a34a65ca\">You can find more details on this in my compendium on Li-ion batteries under AKKU - <em><a href=\"https:\/\/wp.stromer-tech.info\/en\/knowledge-base\/theory-concept-compendium-on-the-li-ion-battery\/\" data-type=\"ht_kb\" data-id=\"2547\">'Theory &amp; terminology compendium for Li-ion batteries'<\/a><\/em> read more. <\/p>\n\n\n\n<p class=\"wp-block-ht-blocks-messages wp-block-hb-message wp-block-hb-message--withicon is-style-info\">The <a href=\"https:\/\/wp.stromer-tech.info\/en\/knowledge-base\/self-discharge-of-a-bq983-battery\/\" data-type=\"ht_kb\" data-id=\"783\">Self-detonation<\/a> A Stromer BQ983 battery has a lifespan when stored properly <strong>~1% per week<\/strong>&nbsp;or <strong>~4% per month<\/strong>.<\/p>\n\n\n\n<p class=\"wp-block-ht-blocks-messages wp-block-hb-message wp-block-hb-message--withicon is-style-danger\">On YouTube, videos are shown on how to revive a deeply discharged battery. Such a \u201ezombie battery\u201c is unstable, a fire hazard, and a safety risk. <strong>This is strongly discouraged<\/strong>!<\/p>\n\n\n\n<h3 id=\"62736601-761a-4ad1-8933-402496e8114c\" class=\"wp-block-heading\">What can you do with a Stromer if the battery can no longer be charged?<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\" id=\"99909a17-c0ea-4bd5-9594-94a093b6efae\">The following points can still be tried without security risks before a new battery becomes necessary.<\/p>\n\n\n\n<ul id=\"5e9e382e-09ce-402c-8386-e023b89ee6db\" class=\"wp-block-list\">\n<li>With a bit of luck, a battery may only appear to be deeply discharged, with the cell voltage still above the critical 2.5V but below 3.2V. Above 3.2V, a Li-ion cell is considered empty (0% capacity). This threshold is relevant for most chargers. They will not charge the battery for safety reasons if the voltage drops below 3.2V.<br><br>The Stromer charger CR245 (&amp; CR65) has a hidden capability. It can revive such a battery, if necessary. This is referred to as \u00abnurturing.\u00bb. <br><strong>Simply leave the battery connected to the charger for several days.<\/strong> and see what happens. With a bit of luck, the charger will begin the regular charging process after a certain waiting period. The newer CR246 does not have this \u00abtrickle charge function,\u00bb but it does offer a \u00abfloat charge.\u00bb.<\/li>\n\n\n\n<li>One can no further <strong>Send the battery to Stromer via the dealer<\/strong>. Stromer doesn't repair batteries, but they can reset the self-protection and reactivate the battery. The same applies here: if the cell voltage has dropped below 2.5 V, Stromer will no longer reactivate the battery.<\/li>\n\n\n\n<li>As <strong>last chance<\/strong> Is there still the <strong>Battery replacement<\/strong>. However, the respective company must offer the option to reset the SoH and charge cycle counter. And a reset is only possible with HTE batteries with 3 screws.<br>Further information can be found at AKKU -&nbsp;<em><a href=\"https:\/\/wp.stromer-tech.info\/en\/knowledge-base\/repair-new-refit-refurbishing-occasionen\/\">\u201aRepair \/ Battery Refurbishing \/ Used Items\u2018<\/a><\/em><\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Conclusion<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The typical self-discharge rate of a Li-ion battery at room temperature is about <strong>1\u20133 % pro Monat<\/strong> (Stromer = 4%, see above). At 20\u00b0C and with a properly stored battery, it therefore takes <strong>many months to years<\/strong>, until the critical cell voltage limit of 2.5 V is reached.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Tips for Long-Term Storage:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Charge level at ~40\u201360 %<\/strong> store (not full, not empty)<\/li>\n\n\n\n<li><strong>Store in a cool place<\/strong> (10\u201315\u00b0C ideal) \u2013 significantly slows down the chemistry<\/li>\n\n\n\n<li><strong>Battery management system with sleep mode<\/strong> choose one that reduces self-consumption to &lt;5 \u00b5A<\/li>\n\n\n\n<li><strong>Reload periodically<\/strong> (every 3\u20136 months) or use the CR246 with floating charge.<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-ht-blocks-messages wp-block-hb-message wp-block-hb-message--withicon is-style-info\">The BMS protects the cell from the <em>Damages<\/em> through deep discharge (by disconnecting the consumer in time), but cannot prevent the chemical-physical self-discharge of the cells. <br><br><strong>Anyone storing a battery for a very long time must therefore check and recharge it regularly.<\/strong><br><br>An alternative is to connect the battery to the CR65 or CR246 charger. Both models allow for float charging.<\/p>","protected":false},"excerpt":{"rendered":"<p>Wenn der Akku nicht mehr geladen werden kann ist die Ursache manchmal eine sog. Tiefentladung. Dies passiert, wenn der Akku unsachgem\u00e4ss, meist mit zu geringem Ladestand, in die Winterpause geschickt und\/oder falsch gelagert wird. Wie das verhindert werden kann steht in den Sicherheithinweisen zum Akku, der Bedienungsanleitung&nbsp;oder unter AKKU &#8211;&nbsp;&#8218;Pflege:&#8230;<\/p>","protected":false},"author":1,"comment_status":"open","ping_status":"closed","template":"","format":"standard","meta":{"footnotes":""},"ht-kb-category":[201],"ht-kb-tag":[],"class_list":["post-1542","ht_kb","type-ht_kb","status-publish","format-standard","hentry","ht_kb_category-p-akku-batterie"],"_links":{"self":[{"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/ht-kb\/1542","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/ht-kb"}],"about":[{"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/types\/ht_kb"}],"author":[{"embeddable":true,"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/comments?post=1542"}],"version-history":[{"count":58,"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/ht-kb\/1542\/revisions"}],"predecessor-version":[{"id":12145,"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/ht-kb\/1542\/revisions\/12145"}],"wp:attachment":[{"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/media?parent=1542"}],"wp:term":[{"taxonomy":"ht_kb_category","embeddable":true,"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/ht-kb-category?post=1542"},{"taxonomy":"ht_kb_tag","embeddable":true,"href":"https:\/\/wp.stromer-tech.info\/en\/wp-json\/wp\/v2\/ht-kb-tag?post=1542"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}