[{"data":1,"prerenderedAt":408},["ShallowReactive",2],{"guide-en-jk-bms-bluetooth-not-connecting":3,"guides-en":278},{"id":4,"title":5,"body":6,"date":256,"description":257,"extension":258,"keywords":259,"meta":266,"navigation":267,"path":268,"related":269,"seo":274,"stem":275,"updated":276,"__hash__":277},"guides_en\u002Fguides\u002Fjk-bms-bluetooth-not-connecting.md","JK BMS Not Connecting over Bluetooth: Fixes That Work",{"type":7,"value":8,"toc":235},"minimark",[9,13,18,21,38,41,45,50,59,62,66,69,72,76,87,90,94,97,101,104,108,120,123,149,156,159,163,166,196,200,204,207,211,214,218,221,225,228],[10,11,12],"p",{},"When a JK BMS is not connecting over Bluetooth, the cause is almost always one of five things: the BMS is asleep or off, another phone or app still holds the link, the phone lacks a permission, the distance is too large, or the browser or app cannot use Bluetooth at all. Check them in that order. Most people are connected again within a few minutes, and none of the fixes needs a reset.",[14,15,17],"h2",{"id":16},"how-a-jk-bms-bluetooth-link-works","How a JK BMS Bluetooth link works",[10,19,20],{},"A JK BMS does not pair like headphones. It advertises itself, and an app or browser connects to it directly for as long as it is open. Two consequences follow:",[22,23,24,32],"ul",{},[25,26,27,31],"li",{},[28,29,30],"strong",{},"You will not find it in the system Bluetooth settings,"," and you should not pair it there. If you paired it in the past, remove that entry: a stale pairing can block the app.",[25,33,34,37],{},[28,35,36],{},"Only one connection at a time."," While one phone, tablet, ESP32 or app is connected, the BMS stops advertising and nobody else can see it.",[10,39,40],{},"The name in the device list usually starts with JK, followed by the model, or it shows the device name you gave it in the app.",[14,42,44],{"id":43},"fix-a-jk-bms-that-is-not-connecting-step-by-step","Fix a JK BMS that is not connecting, step by step",[46,47,49],"h3",{"id":48},"_1-make-sure-the-bms-is-awake","1. Make sure the BMS is awake",[10,51,52,53,58],{},"A sleeping or powered-off BMS has no Bluetooth. Look at the board LED or the display. If it is dark, wake it with the power button, the display switch or by connecting a charger. If it falls asleep again after a day of standby, the cause is smart sleep: our ",[54,55,57],"a",{"href":56},"\u002Fguides\u002Fjk-bms-smart-sleep","smart sleep guide"," explains the setting and when to turn it off.",[10,60,61],{},"A BMS that shut down because a cell reached the power off voltage also looks dead. It needs a charger to start again.",[46,63,65],{"id":64},"_2-close-every-other-connection","2. Close every other connection",[10,67,68],{},"Fully close the JK app on every phone and tablet nearby, including apps running in the background. Stop any ESP32, Home Assistant bridge or Victron Bluetooth integration that talks to the same BMS. Then wait about ten seconds so the BMS starts advertising again.",[10,70,71],{},"This is the most common cause by far. If the BMS appears on one phone but not on another, something is still connected.",[46,73,75],{"id":74},"_3-grant-the-phone-permissions","3. Grant the phone permissions",[10,77,78,79,82,83,86],{},"On Android the JK app and the browser need two permissions to see Bluetooth devices: ",[28,80,81],{},"Nearby devices"," and, on many phones, ",[28,84,85],{},"Location",". Location services must also be switched on in the quick settings. Without them the scan simply finds nothing, with no error message.",[10,88,89],{},"On iPhone, check that the JK app is allowed to use Bluetooth in Settings, Privacy, Bluetooth.",[46,91,93],{"id":92},"_4-move-closer","4. Move closer",[10,95,96],{},"The Bluetooth module of a JK BMS has a short range, often only a few meters, and less through a metal battery box or a concrete wall. Stand next to the battery for the first connection. If the link drops while you edit settings, the distance is usually the reason.",[46,98,100],{"id":99},"_5-restart-bluetooth-and-the-bms","5. Restart Bluetooth and the BMS",[10,102,103],{},"Turn Bluetooth off and on in your phone or computer. If the BMS still does not show up, restart the BMS itself: switch it off with the button, or briefly disconnect the battery if you know how to do that safely. Several forum users fixed a frozen Bluetooth module this way.",[14,105,107],{"id":106},"jk-bms-not-connecting-in-the-browser","JK BMS not connecting in the browser",[10,109,110,114,115,119],{},[54,111,113],{"href":112},"\u002F","JK Preset Studio"," connects through Web Bluetooth, which needs Chrome or Edge on Windows, macOS, ChromeOS or Android. Firefox, Safari and every browser on iPhone and iPad have no Web Bluetooth, so the connect button will not work there. The ",[54,116,118],{"href":117},"\u002Fguides\u002Fjk-bms-app-alternative","app alternative guide"," compares the options for those devices.",[10,121,122],{},"When you press Connect BMS, the browser opens its own device list. Pick the entry that starts with JK. The messages you may see:",[22,124,125,131,137,143],{},[25,126,127,130],{},[28,128,129],{},"No BMS selected."," You closed the list without choosing. Try again and pick the BMS.",[25,132,133,136],{},[28,134,135],{},"Could not connect."," The BMS was found but refused the link, usually because the JK app is still connected. Close it, move closer and try again.",[25,138,139,142],{},[28,140,141],{},"The BMS did not answer in time."," The link opened but no data arrived. Move closer and reconnect.",[25,144,145,148],{},[28,146,147],{},"The Bluetooth connection dropped."," Range or interference. Press Reconnect; your edits are kept.",[10,150,151],{},[152,153],"img",{"alt":154,"src":155},"JK Preset Studio right after connecting to a JK BMS over Bluetooth: the link status bar on top and the settings read from the BMS below","\u002Fscreenshots\u002Fconnect.webp",[10,157,158],{},"On Windows, also check that the computer has Bluetooth Low Energy and that it is switched on. Some older USB dongles support only classic Bluetooth.",[14,160,162],{"id":161},"when-it-is-not-the-connection","When it is not the connection",[10,164,165],{},"Sometimes the link works, but writing fails. That is a different problem:",[22,167,168,179,190],{},[25,169,170,173,174,178],{},[28,171,172],{},"Sending failure in the JK app"," means the BMS refused a value. The ",[54,175,177],{"href":176},"\u002Fguides\u002Fjk-bms-sending-failure","Sending failure guide"," explains why.",[25,180,181,184,185,189],{},[28,182,183],{},"A password prompt"," that rejects your password is covered in the ",[54,186,188],{"href":187},"\u002Fguides\u002Fjk-bms-password","password guide",".",[25,191,192,195],{},[28,193,194],{},"Settings that do not exist on your model"," are detected right after connecting in the browser and shown as missing, instead of failing on write.",[14,197,199],{"id":198},"faq","FAQ",[46,201,203],{"id":202},"why-does-my-phone-not-see-the-jk-bms","Why does my phone not see the JK BMS?",[10,205,206],{},"Most often another device is still connected, the BMS is asleep, or the phone lacks the Nearby devices or Location permission. Close the JK app everywhere, wake the BMS and check the permissions, then scan again.",[46,208,210],{"id":209},"can-two-phones-connect-to-a-jk-bms-at-the-same-time","Can two phones connect to a JK BMS at the same time?",[10,212,213],{},"No. The BMS accepts one Bluetooth connection. Close the app on the first phone before connecting with the second, or with a browser.",[46,215,217],{"id":216},"do-i-have-to-pair-the-jk-bms-in-bluetooth-settings","Do I have to pair the JK BMS in Bluetooth settings?",[10,219,220],{},"No. Connect from the JK app or from the browser only. If the BMS is listed in your system Bluetooth settings, remove it, because a stale pairing can stop the app from connecting.",[46,222,224],{"id":223},"what-is-the-bluetooth-range-of-a-jk-bms","What is the Bluetooth range of a JK BMS?",[10,226,227],{},"Plan for a few meters with a clear view of the board. Metal enclosures and walls cut it further, so stay close while you change settings.",[10,229,230,231,234],{},"Once it shows up in the list, ",[54,232,233],{"href":112},"connect your BMS"," and read every setting in under a minute.",{"title":236,"searchDepth":237,"depth":237,"links":238},"",3,[239,241,248,249,250],{"id":16,"depth":240,"text":17},2,{"id":43,"depth":240,"text":44,"children":242},[243,244,245,246,247],{"id":48,"depth":237,"text":49},{"id":64,"depth":237,"text":65},{"id":74,"depth":237,"text":75},{"id":92,"depth":237,"text":93},{"id":99,"depth":237,"text":100},{"id":106,"depth":240,"text":107},{"id":161,"depth":240,"text":162},{"id":198,"depth":240,"text":199,"children":251},[252,253,254,255],{"id":202,"depth":237,"text":203},{"id":209,"depth":237,"text":210},{"id":216,"depth":237,"text":217},{"id":223,"depth":237,"text":224},"2026-10-14","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.","md",[260,261,262,263,264,265],"jk bms not connecting","jk bms not pairing","jk bms bluetooth not working","jk bms not showing in app","jk bms bluetooth connection","jk bms bluetooth range",{},true,"\u002Fguides\u002Fjk-bms-bluetooth-not-connecting",[270,271,272,273],"jk-bms-bluetooth-browser","jk-bms-app-alternative","jk-bms-smart-sleep","jk-bms-password",{"title":5,"description":257},"guides\u002Fjk-bms-bluetooth-not-connecting",null,"QCf1A4koPmOaN_x5ZICCUdEBefo--76qvMMTFsRGsFY",[279,282,283,287,291,295,299,303,307,311,315,318,323,327,331,335,339,344,349,354,358,362,366,370,374,378,382,386,389,393,396,400,404],{"path":117,"title":280,"description":281,"date":256,"updated":276},"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":268,"title":5,"description":257,"date":256,"updated":276},{"path":284,"title":285,"description":286,"date":256,"updated":276},"\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":288,"title":289,"description":290,"date":256,"updated":276},"\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":292,"title":293,"description":294,"date":256,"updated":276},"\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":296,"title":297,"description":298,"date":256,"updated":276},"\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":300,"title":301,"description":302,"date":256,"updated":276},"\u002Fguides\u002Fjk-bms-not-charging","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":304,"title":305,"description":306,"date":256,"updated":276},"\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":308,"title":309,"description":310,"date":256,"updated":276},"\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":312,"title":313,"description":314,"date":256,"updated":276},"\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":56,"title":316,"description":317,"date":256,"updated":276},"JK BMS Smart Sleep: What the Voltage and Time Settings Do","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.",{"path":319,"title":320,"description":321,"date":322,"updated":276},"\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":324,"title":325,"description":326,"date":322,"updated":276},"\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":328,"title":329,"description":330,"date":322,"updated":276},"\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":332,"title":333,"description":334,"date":322,"updated":276},"\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":336,"title":337,"description":338,"date":322,"updated":276},"\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. Why the -20 °C factory default is wrong for LiFePO4 and what to use instead.",{"path":340,"title":341,"description":342,"date":343,"updated":276},"\u002Fguides\u002Fjk-bms-soc-stuck-at-99","JK BMS SOC Stuck at 99%: Why It Never Reaches 100% and the Fix","JK BMS SOC stuck at 99% and never showing 100%? See what the BMS waits for at the end of charging, the six usual causes, and the settings that fix it.","2026-10-07",{"path":345,"title":346,"description":347,"date":348,"updated":276},"\u002Fguides\u002Fjk-bms-bluetooth-browser","Change JK BMS Settings over Bluetooth in Your Browser","Connect to a JK BMS from Chrome or Edge, read every setting, apply a preset and write it back in a safe order with read-back checks. No JK app needed.","2026-10-04",{"path":350,"title":351,"description":352,"date":353,"updated":348},"\u002Fguides\u002Fjk-bms-balance-settings","JK BMS Balance Settings: Start Voltage, Trigger, Current","JK BMS balance settings explained: start balance voltage, balance trigger voltage, max balance current and the Balancer switch, for LFP, NMC and LTO.","2026-10-02",{"path":355,"title":356,"description":357,"date":353,"updated":276},"\u002Fguides\u002Fjk-bms-cell-overcharge-protection-tripping","JK BMS Cell Over Charge Protection Keeps Tripping: Causes and Fix","JK BMS cell over charge protection tripping and releasing every minute? See why a charger set too high causes it, how to tell it from a weak cell, and how to fix it.",{"path":359,"title":360,"description":361,"date":353,"updated":348},"\u002Fguides\u002Fjk-bms-detail-log","How to export and read the JK-BMS Detail Log","What the JK-BMS Detail Log contains, how to export it from the app, how to read its events and what the log analysis page tells you about trips and faults.",{"path":363,"title":364,"description":365,"date":353,"updated":348},"\u002Fguides\u002Fjk-bms-export-import-settings","Export and Import JK BMS Settings: The .jkcfg File Guide","How to export and import JK BMS settings with the app, what the .jkcfg file contains, why hand edits break it, and how to edit it safely in your browser.",{"path":367,"title":368,"description":369,"date":353,"updated":348},"\u002Fguides\u002Fjk-bms-lifepo4-settings","JK BMS Settings for LiFePO4: 8S and 16S, 280Ah and 314Ah","JK BMS settings for LiFePO4 packs: per-cell voltage, balance, current and temperature values for 8S and 16S with 280Ah and 314Ah cells, in three wear levels.",{"path":371,"title":372,"description":373,"date":353,"updated":276},"\u002Fguides\u002Fjk-bms-log-messages-explained","JK BMS Log Messages Explained: Boot, Time calibration, Protections","What each JK BMS log message means: Boot, Time calibration, APP open charge, protection trips and releases, Discharge On Failed and Unknown Log Code [0].",{"path":375,"title":376,"description":377,"date":353,"updated":348},"\u002Fguides\u002Fjk-bms-nmc-lto-settings","JK BMS Settings for NMC and LTO: Safe Per-Cell Values","JK BMS settings for NMC and LTO packs: per-cell OVP, UVP, balance, temperature and C-rate values in three wear levels, plus how the editor detects chemistry.",{"path":379,"title":380,"description":381,"date":353,"updated":348},"\u002Fguides\u002Fjk-bms-ocp-scp-settings","JK BMS Overcurrent Protection Settings: OCP and SCP Guide","JK BMS overcurrent protection settings explained: charge and discharge OCP limits, delays, recovery times and SCP, with ranges and sizing for inverters.",{"path":383,"title":384,"description":385,"date":353,"updated":348},"\u002Fguides\u002Fjk-bms-parameters-explained","JK BMS Parameters Explained: Every Setting by Group","JK BMS parameters explained in one glossary: cell OVP, OVPR, UVP, UVPR, balance, SOC, RCV and RFV, current and temperature limits, with typical LFP ranges.",{"path":187,"title":387,"description":388,"date":353,"updated":348},"JK BMS Password: Default Codes, Change and Reset Guide","Your JK BMS password is really two codes: Bluetooth and settings. See factory defaults, how to change them, what to try if one fails, and what to do if lost.",{"path":390,"title":391,"description":392,"date":353,"updated":348},"\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":176,"title":394,"description":395,"date":353,"updated":348},"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":397,"title":398,"description":399,"date":353,"updated":343},"\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":401,"title":402,"description":403,"date":353,"updated":276},"\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":405,"title":406,"description":407,"date":353,"updated":348},"\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.",1791980001793]