[{"data":1,"prerenderedAt":451},["ShallowReactive",2],{"guide-en-jk-bms-smart-sleep":3,"guides-en":320},{"id":4,"title":5,"body":6,"date":298,"description":299,"extension":300,"keywords":301,"meta":308,"navigation":309,"path":310,"related":311,"seo":316,"stem":317,"updated":318,"__hash__":319},"guides_en\u002Fguides\u002Fjk-bms-smart-sleep.md","JK BMS Smart Sleep: What the Voltage and Time Settings Do",{"type":7,"value":8,"toc":276},"minimark",[9,22,27,83,104,108,115,122,129,132,135,139,142,164,177,181,185,188,192,195,199,202,206,238,242,246,249,253,256,260,263,267,270],[10,11,12,13,17,18,21],"p",{},"Smart sleep lets a JK BMS switch itself off when the battery sits idle, so the board stops drawing power from the cells. It goes to sleep when the cell voltage is below the ",[14,15,16],"strong",{},"smart sleep voltage"," and the current stays under about 1 A for the ",[14,19,20],{},"smart sleep time",", 24 hours by default. A sleeping BMS has no output and no Bluetooth until you wake it with the power button, the display switch or a charger. If your battery has no way to wake it, turn smart sleep off.",[23,24,26],"h2",{"id":25},"the-three-smart-sleep-settings","The three smart sleep settings",[28,29,30,46],"table",{},[31,32,33],"thead",{},[34,35,36,40,43],"tr",{},[37,38,39],"th",{},"Setting",[37,41,42],{},"What it does",[37,44,45],{},"Default",[47,48,49,61,72],"tbody",{},[34,50,51,55,58],{},[52,53,54],"td",{},"Smart sleep",[52,56,57],{},"Turns the feature on or off",[52,59,60],{},"Depends on the model",[34,62,63,66,69],{},[52,64,65],{},"Smart sleep voltage",[52,67,68],{},"The cell voltage below which the BMS may sleep",[52,70,71],{},"3.5 V on many LFP boards",[34,73,74,77,80],{},[52,75,76],{},"Smart sleep time",[52,78,79],{},"How long the pack must stay idle before it sleeps",[52,81,82],{},"24 h; 0 h disables sleep",[10,84,85,86,89,90,93,94,97,98,103],{},"All three have to agree before anything happens. The voltage decides ",[14,87,88],{},"when"," the pack counts as low enough, the time decides ",[14,91,92],{},"how long"," it must stay idle, and the switch decides ",[14,95,96],{},"whether"," the feature runs at all. Not every model has all three: when you connect in ",[99,100,102],"a",{"href":101},"\u002F","JK Preset Studio",", the editor checks which ones your board supports and marks the others as missing.",[105,106,65],"h3",{"id":107},"smart-sleep-voltage",[10,109,110,111,114],{},"This is the setting people misread most often. A ",[14,112,113],{},"higher"," voltage makes the BMS sleep more readily. On LiFePO4, most of the useful capacity sits on a flat plateau around 3.2 to 3.3 V per cell, so a smart sleep voltage of 3.35 or 3.5 V means that an idle pack at almost any charge level will go to sleep after the timer runs out.",[10,116,117,118,121],{},"A ",[14,119,120],{},"lower"," voltage makes sleep a last line of defence: the BMS only sleeps when the pack is nearly empty and idle, which protects it from being drained to zero by its own consumption.",[10,123,124,125,128],{},"The parameter reference lists recommended ranges per chemistry for the ",[99,126,16],{"href":127},"\u002Fparameters#smartSleepVoltage",".",[105,130,76],{"id":131},"smart-sleep-time",[10,133,134],{},"The hours of idle time before sleep. \"Idle\" means the current stays below about 1 A in both directions. A trickle from a small standby load can keep the current under that limit, so a pack that powers only a router or an alarm system at night can still fall asleep. Setting the time to 0 hours disables sleeping, which JK recommends for batteries without a wake wire or button.",[23,136,138],{"id":137},"how-to-wake-a-sleeping-jk-bms","How to wake a sleeping JK BMS",[10,140,141],{},"A sleeping BMS looks dead: no LED, no display, no Bluetooth, no output. Wake it in one of these ways:",[143,144,145,152,158],"ol",{},[146,147,148,151],"li",{},[14,149,150],{},"Press the power button"," on the board, if your model has one.",[146,153,154,157],{},[14,155,156],{},"Use the display or activation switch."," This is the most convenient option and the reason JK recommends fitting one.",[146,159,160,163],{},[14,161,162],{},"Connect a charger."," Charging voltage at the terminals wakes the BMS. If the pack is already full, the charger must supply a voltage clearly above the battery voltage.",[10,165,166,167,171,172,176],{},"If none of these work, the BMS may have shut down at the power off voltage instead, which needs a charger to recover. The ",[99,168,170],{"href":169},"\u002Fguides\u002Fjk-bms-not-charging","not charging or discharging guide"," covers the other reasons the output can be off, and the ",[99,173,175],{"href":174},"\u002Fguides\u002Fjk-bms-bluetooth-not-connecting","Bluetooth guide"," the reasons it will not connect.",[23,178,180],{"id":179},"recommended-smart-sleep-settings","Recommended smart sleep settings",[105,182,184],{"id":183},"home-storage-with-an-inverter","Home storage with an inverter",[10,186,187],{},"An always-on inverter system should not sleep, because nobody may be there to wake it. Turn smart sleep off, or set the time to 0 hours. If you want a safety net against a total drain during a long outage, leave it on with a low voltage close to UVP and a long time, and make sure the pack has a button or display you can reach.",[105,189,191],{"id":190},"camper-boat-or-seasonal-storage","Camper, boat or seasonal storage",[10,193,194],{},"Here smart sleep earns its place. A pack that stands unused for weeks loses charge to the BMS itself, plus anything left connected. With smart sleep on, a voltage in the recommended range and the default 24 hours, the BMS shuts down after a day of rest and the pack keeps its charge much longer. Fit an activation switch so waking it is one press.",[105,196,198],{"id":197},"small-packs","Small packs",[10,200,201],{},"The BMS consumption matters most on small batteries. A board that draws, for example, 30 mA while awake uses about 22 Ah a month. That is little for a 280 Ah pack, but it empties a 20 Ah pack in under a month. For small packs, smart sleep is worth enabling.",[23,203,205],{"id":204},"common-mistakes","Common mistakes",[207,208,209,215,221,227],"ul",{},[146,210,211,214],{},[14,212,213],{},"Smart sleep on, no wake button."," The pack goes idle overnight, the BMS sleeps, and the inverter cannot restart it. Disable sleep or fit a switch.",[146,216,217,220],{},[14,218,219],{},"Reading the voltage backwards."," A higher smart sleep voltage means more sleep, not less.",[146,222,223,226],{},[14,224,225],{},"Expecting a load to keep it awake."," A load under about 1 A counts as idle.",[146,228,229,232,233,237],{},[14,230,231],{},"Copying another chemistry's value."," LFP, NMC and LTO cells have very different voltages. Use the range for your cells, as the ",[99,234,236],{"href":235},"\u002Fguides\u002Fjk-bms-lifepo4-settings","LiFePO4 settings guide"," does for LFP.",[23,239,241],{"id":240},"faq","FAQ",[105,243,245],{"id":244},"should-i-enable-smart-sleep-on-my-jk-bms","Should I enable smart sleep on my JK BMS?",[10,247,248],{},"Enable it on batteries that stand unused for days and have a button, display or charger to wake them. Disable it on always-on inverter systems where nobody can wake the BMS quickly.",[105,250,252],{"id":251},"how-do-i-turn-off-smart-sleep","How do I turn off smart sleep?",[10,254,255],{},"Switch Smart sleep off in the settings, or set the smart sleep time to 0 hours. Both stop the BMS from sleeping. Write the change and read it back to check it was applied.",[105,257,259],{"id":258},"how-much-current-does-a-jk-bms-draw","How much current does a JK BMS draw?",[10,261,262],{},"It depends on the model and on what is active, such as Bluetooth, the display and balancing. Check the datasheet of your board. Even a few tens of milliamps add up to many ampere-hours over a month, which is why sleep matters for stored packs.",[105,264,266],{"id":265},"why-does-my-jk-bms-turn-off-by-itself","Why does my JK BMS turn off by itself?",[10,268,269],{},"If it happens after a long idle period, smart sleep is the usual cause. If it happens when the cells are low, the power off voltage was reached. The Detail Log tells the two apart.",[10,271,272,275],{},[99,273,274],{"href":101},"Connect your BMS"," to see its smart sleep settings and change them in one place.",{"title":277,"searchDepth":278,"depth":278,"links":279},"",3,[280,285,286,291,292],{"id":25,"depth":281,"text":26,"children":282},2,[283,284],{"id":107,"depth":278,"text":65},{"id":131,"depth":278,"text":76},{"id":137,"depth":281,"text":138},{"id":179,"depth":281,"text":180,"children":287},[288,289,290],{"id":183,"depth":278,"text":184},{"id":190,"depth":278,"text":191},{"id":197,"depth":278,"text":198},{"id":204,"depth":281,"text":205},{"id":240,"depth":281,"text":241,"children":293},[294,295,296,297],{"id":244,"depth":278,"text":245},{"id":251,"depth":278,"text":252},{"id":258,"depth":278,"text":259},{"id":265,"depth":278,"text":266},"2026-10-14","What JK BMS smart sleep does, how the smart sleep voltage and time work together, how to wake a sleeping BMS and which values to use for home storage or a camper.","md",[302,303,304,305,306,307],"jk bms smart sleep","jk bms smart sleep voltage","jk bms sleep mode","jk bms time smart sleep","jk bms how to wake up","jk bms current consumption",{},true,"\u002Fguides\u002Fjk-bms-smart-sleep",[312,313,314,315],"jk-bms-parameters-explained","jk-bms-lifepo4-settings","jk-bms-bluetooth-not-connecting","jk-bms-not-charging",{"title":5,"description":299},"guides\u002Fjk-bms-smart-sleep",null,"PUju5FDj1CO2VxIRbRh3rTBDIg_YhR0Lb9X5bzCdE38",[321,325,328,332,336,340,344,347,351,355,359,360,365,369,373,377,381,386,391,396,400,404,408,411,415,419,423,427,431,435,439,443,447],{"path":322,"title":323,"description":324,"date":298,"updated":318},"\u002Fguides\u002Fjk-bms-app-alternative","JK BMS App Alternative: Change Settings from Your PC or Browser","Looking for a JK BMS app alternative? Compare the JK app, the PC monitor software, ESPHome and a browser editor that reads and writes settings over Bluetooth.",{"path":174,"title":326,"description":327,"date":298,"updated":318},"JK BMS Not Connecting over Bluetooth: Fixes That Work","JK BMS not connecting or not pairing over Bluetooth? Work through the causes in order: sleep, another app holding the link, permissions, range and the browser.",{"path":329,"title":330,"description":331,"date":298,"updated":318},"\u002Fguides\u002Fjk-bms-calibration","JK BMS Voltage and Current Calibration: How to Do It Right","How to calibrate JK BMS voltage and current: what to measure, which value to enter, why calibration ends in Sending failure, and when to leave it alone.",{"path":333,"title":334,"description":335,"date":298,"updated":318},"\u002Fguides\u002Fjk-bms-error-codes","JK BMS Error Codes: What the Display and LEDs Are Telling You","JK BMS error codes explained: what the Err numbers, the ALM light and the app alarms mean, which codes users have matched to real faults, and how to find the cause.",{"path":337,"title":338,"description":339,"date":298,"updated":318},"\u002Fguides\u002Fjk-bms-firmware","JK BMS Firmware: V15 vs V19 and How to Update Safely","JK BMS firmware explained: how to read your hardware and software version, what changed from V11 to V15 and V19, and how to update without bricking the BMS.",{"path":341,"title":342,"description":343,"date":298,"updated":318},"\u002Fguides\u002Fjk-bms-first-setup","How to Set Up a New JK BMS: First Start Step by Step","Set up a new JK BMS the right way: wiring order, first power-on, passwords, cell count, a chemistry preset, current limits and a verified write over Bluetooth.",{"path":169,"title":345,"description":346,"date":298,"updated":318},"JK BMS Not Charging or Discharging: Why the MOSFET Is Off","JK BMS not charging or not discharging? Find which protection or switch turned the MOSFET off, how to tell the causes apart and which setting fixes each one.",{"path":348,"title":349,"description":350,"date":298,"updated":318},"\u002Fguides\u002Fjk-bms-not-turning-on","JK BMS Not Turning On: How to Start and Wake It Up","JK BMS not turning on? Learn how to activate a new board with a charger or the button, wake it from sleep, and find the wiring faults that keep it dark.",{"path":352,"title":353,"description":354,"date":298,"updated":318},"\u002Fguides\u002Fjk-bms-precharge","JK BMS Precharge: Stop Sparks and SCP Trips on Inverter Start","What JK BMS precharge does, why inverter capacitors trip short circuit protection, how to set the precharge time and when you still need a precharge resistor.",{"path":356,"title":357,"description":358,"date":298,"updated":318},"\u002Fguides\u002Fjk-bms-reset","How to Reset a JK BMS: SOC, Capacity, Alarms and Settings","How to reset a JK BMS: reset the SOC, the capacity, a stuck alarm or all settings, what the cycle count really is, and why you should back up before any reset.",{"path":310,"title":5,"description":299,"date":298,"updated":318},{"path":361,"title":362,"description":363,"date":364,"updated":318},"\u002Fguides\u002Fjk-bms-alarms-list","JK BMS Alarms List: Every Alarm, Its Cause and the Fix","All JK BMS alarms in one table: what each one means, what usually triggers it and which setting governs it, from cell OVP and MOS OTP to wire resistance.","2026-10-12",{"path":366,"title":367,"description":368,"date":364,"updated":318},"\u002Fguides\u002Fjk-bms-inverter-communication","JK Inverter BMS Communication: Deye, Victron and Growatt Setup","Connect a JK inverter BMS to Deye, Victron or Growatt over CAN or RS485: protocol number, port mode, DIP address, cable pinout and the inverter-side settings.",{"path":370,"title":371,"description":372,"date":364,"updated":318},"\u002Fguides\u002Fjk-bms-model-number-explained","JK BMS Model Numbers Explained: B2A8S20P, PB2A16S20P and More","Decode any JK BMS model name: series, balance current, cell count and current rating, plus the -H, -HC and -R suffixes and what they mean for heating, CAN and RS485.",{"path":374,"title":375,"description":376,"date":364,"updated":318},"\u002Fguides\u002Fjk-bms-parallel-batteries","JK BMS Parallel Batteries: Wiring, DIP Addresses and Settings","Connect several JK inverter BMS packs in parallel: busbar wiring, the RS485-2 link, DIP switch addresses, the master pack, matching settings and current limits.",{"path":378,"title":379,"description":380,"date":364,"updated":318},"\u002Fguides\u002Fjk-bms-temperature-heating-settings","JK BMS Temperature and Heating Settings: Safe Values for LiFePO4","Set JK BMS charge and discharge temperature limits, MOS OTP and the heating function. 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See factory defaults, how to change them, what to try if one fails, and what to do if lost.",{"path":432,"title":433,"description":434,"date":395,"updated":390},"\u002Fguides\u002Fjk-bms-reboots-power-events","JK BMS Reboots and Charge MOS Off: Reading Power Events in the Log","JK BMS reboots or the charge MOS switched off by itself? Learn to read Boot rows and MOS state in the Detail Log and tell expected restarts from real faults.",{"path":436,"title":437,"description":438,"date":395,"updated":390},"\u002Fguides\u002Fjk-bms-sending-failure","JK BMS Sending failure: Causes and Step-by-Step Fix","JK BMS Sending failure on import? See why the firmware rejects settings (voltage chains, write order, SCP delay) and how to fix it step by step.",{"path":440,"title":441,"description":442,"date":395,"updated":385},"\u002Fguides\u002Fjk-bms-soc-calibration","JK BMS SOC Calibration: Fix SOC Drift, Jumps and Reset","JK BMS SOC calibration explained: why SOC drifts or jumps, what the SOC-100% voltage and SOC-0% voltage do, and how to set them and recalibrate the pack.",{"path":444,"title":445,"description":446,"date":395,"updated":318},"\u002Fguides\u002Fjk-bms-weak-cell-log","Find a Weak Cell with the JK BMS Log: Trips, Spread and Balance","Find a weak cell in the JK BMS Detail Log: which cell trips first, how wide the spread is at the trip, and whether it is balance drift or a bad cell.",{"path":448,"title":449,"description":450,"date":395,"updated":390},"\u002Fguides\u002Fjk-bms-wire-resistance","JK BMS Wire Resistance: Fix Abnormal Balance Wire Alarm","JK BMS wire resistance explained: what the abnormal resistance of the balance wire warning means, normal values, common causes and how to fix a bad lead.",1791980002975]