[{"data":1,"prerenderedAt":374},["ShallowReactive",2],{"guide-en-jk-bms-first-setup":3,"guides-en":246},{"id":4,"title":5,"body":6,"date":224,"description":225,"extension":226,"keywords":227,"meta":234,"navigation":235,"path":236,"related":237,"seo":242,"stem":243,"updated":244,"__hash__":245},"guides_en\u002Fguides\u002Fjk-bms-first-setup.md","How to Set Up a New JK BMS: First Start Step by Step",{"type":7,"value":8,"toc":206},"minimark",[9,13,18,27,31,34,53,56,60,68,72,80,88,92,95,117,121,129,148,156,160,163,167,174,178,183,186,190,193,197,200],[10,11,12],"p",{},"To set up a new JK BMS, wire it in the documented order, activate it, connect over Bluetooth, set the cell count, capacity and chemistry, check the current limits against your BMS rating, and write the settings with a read-back check. Then charge the pack fully once so the state of charge starts from a known point. The whole job takes about half an hour, and most problems later come from skipping one of these steps.",[14,15,17],"h2",{"id":16},"step-1-check-the-model-and-plan-the-wiring","Step 1: Check the model and plan the wiring",[10,19,20,21,26],{},"Read the model on the label, for example JK-B2A24S20P or JK-PB2A16S20P. It tells you the supported cell counts, the balance current and the current rating. The ",[22,23,25],"a",{"href":24},"\u002Fguides\u002Fjk-bms-model-number-explained","model number guide"," decodes every part. Make sure the BMS supports your series count and that its continuous current covers your inverter or load.",[14,28,30],{"id":29},"step-2-wire-it-in-the-right-order","Step 2: Wire it in the right order",[10,32,33],{},"JK manuals describe a strict sequence:",[35,36,37,41,44,47,50],"ol",{},[38,39,40],"li",{},"Connect B- to the pack negative and P- (or C-) to the load and charger side. On boards with B+ and P+, connect them next.",[38,42,43],{},"Before plugging the balance connector, measure each pin against B- with a multimeter. Every step should add one cell voltage, with no jumps and no negative readings.",[38,45,46],{},"Plug the balance connectors from low to high, cell 1 first.",[38,48,49],{},"Fit the temperature sensors on the cells.",[38,51,52],{},"Connect the load and the charger only after everything else is in place.",[10,54,55],{},"The B2A manual adds: connect from the negative pole to the positive pole, check the balance wires again with a meter, then insert the plug into the BMS.",[14,57,59],{"id":58},"step-3-turn-it-on","Step 3: Turn it on",[10,61,62,63,67],{},"Boards without a button start when you connect a charger whose voltage is at least 5 V above the pack. PB inverter boards start with a short press of the power button. If nothing happens, see ",[22,64,66],{"href":65},"\u002Fguides\u002Fjk-bms-not-turning-on","JK BMS not turning on",".",[14,69,71],{"id":70},"step-4-connect-and-change-the-passwords","Step 4: Connect and change the passwords",[10,73,74,75,79],{},"Connect with the JK app, or open ",[22,76,78],{"href":77},"\u002F","JK Preset Studio"," in Chrome or Edge and press Connect BMS. The BMS shows up as a device whose name starts with JK. Only one connection works at a time, so close the phone app if you use the browser.",[10,81,82,83,87],{},"According to the JK manual, the default Bluetooth password is 1234 and the default settings password is 123456. Change them, especially if the battery is in a shared place. On PB boards a blinking ALM light on a new battery can simply mean the password is still the default. The ",[22,84,86],{"href":85},"\u002Fguides\u002Fjk-bms-password","password guide"," has the details.",[14,89,91],{"id":90},"step-5-set-the-basics","Step 5: Set the basics",[10,93,94],{},"These three settings must be right before anything else makes sense:",[96,97,98,105,111],"ul",{},[38,99,100,104],{},[101,102,103],"strong",{},"Cell count."," Exactly your series count. A wrong value disables protection for missing cells or causes a cell count alarm.",[38,106,107,110],{},[101,108,109],{},"Battery capacity."," The real capacity of the cells in Ah, all parallel cells added together. The BMS uses it to count the state of charge.",[38,112,113,116],{},[101,114,115],{},"Chemistry."," Pick LiFePO4, NMC or LTO so the voltage limits fit your cells.",[14,118,120],{"id":119},"step-6-apply-a-preset-and-check-the-limits","Step 6: Apply a preset and check the limits",[10,122,123,124,128],{},"Factory values are generic. A quick way to sane values is a ",[22,125,127],{"href":126},"\u002Fpresets","ready preset"," for your chemistry, in a hard, medium or gentle variant. The editor scales the currents to your BMS rating and checks every rule the firmware enforces, such as UVP below SOC-0% below UVP recovery. Then compare with your hardware:",[96,130,131,134,137,140],{},[38,132,133],{},"max charge current not above what your cells and charger allow;",[38,135,136],{},"max discharge current not above the BMS rating and your cable size;",[38,138,139],{},"cell OVP and UVP within your cell datasheet;",[38,141,142,143,147],{},"balancing starts above about 3.35 V for LiFePO4, as the ",[22,144,146],{"href":145},"\u002Fguides\u002Fjk-bms-balance-settings","balance guide"," explains.",[10,149,150,151,155],{},"The ",[22,152,154],{"href":153},"\u002Fguides\u002Fjk-bms-lifepo4-settings","LiFePO4 settings guide"," walks through every value.",[14,157,159],{"id":158},"step-7-write-and-verify","Step 7: Write and verify",[10,161,162],{},"Press Write to BMS. The editor shows a plan and offers to save the current settings as a backup file first. It writes one setting at a time in an order the firmware accepts, then reads the BMS back after every step. If a value is refused you see which one and why, instead of a bare Sending failure. Settings your model does not have are marked as missing, so they never cause a failed write.",[14,164,166],{"id":165},"step-8-first-full-charge","Step 8: First full charge",[10,168,169,170,67],{},"Charge the pack until the BMS reaches 100% and balancing settles. This gives the state of charge a known starting point, and the BMS learns the real capacity after a full cycle. If the SOC still drifts, read the ",[22,171,173],{"href":172},"\u002Fguides\u002Fjk-bms-soc-calibration","SOC calibration guide",[14,175,177],{"id":176},"faq","FAQ",[179,180,182],"h3",{"id":181},"what-is-the-default-password-of-a-jk-bms","What is the default password of a JK BMS?",[10,184,185],{},"The JK manual lists 1234 for the Bluetooth connection and 123456 for changing settings. Newer firmware and apps can differ, so change both after the first connection.",[179,187,189],{"id":188},"do-i-have-to-set-the-cell-count-on-a-new-jk-bms","Do I have to set the cell count on a new JK BMS?",[10,191,192],{},"Yes. The manual says the BMS will not work properly until the cell count matches the pack. It is the first setting to check after the first connection.",[179,194,196],{"id":195},"can-i-set-up-a-jk-bms-without-the-app","Can I set up a JK BMS without the app?",[10,198,199],{},"Yes. In Chrome or Edge on a computer or an Android phone you can connect over Bluetooth, apply a preset and write it, with no app. Only iPhone users need the JK app.",[10,201,202,205],{},[22,203,204],{"href":77},"Connect your BMS"," and finish the setup with a preset and a verified write.",{"title":207,"searchDepth":208,"depth":208,"links":209},"",3,[210,212,213,214,215,216,217,218,219],{"id":16,"depth":211,"text":17},2,{"id":29,"depth":211,"text":30},{"id":58,"depth":211,"text":59},{"id":70,"depth":211,"text":71},{"id":90,"depth":211,"text":91},{"id":119,"depth":211,"text":120},{"id":158,"depth":211,"text":159},{"id":165,"depth":211,"text":166},{"id":176,"depth":211,"text":177,"children":220},[221,222,223],{"id":181,"depth":208,"text":182},{"id":188,"depth":208,"text":189},{"id":195,"depth":208,"text":196},"2026-10-14","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.","md",[228,229,230,231,232,233],"jk bms setup","jk bms first setup","jk bms how to connect","jk bms installation","jk bms configuration","jk bms how to start",{},true,"\u002Fguides\u002Fjk-bms-first-setup",[238,239,240,241],"jk-bms-not-turning-on","jk-bms-lifepo4-settings","jk-bms-model-number-explained","jk-bms-soc-calibration",{"title":5,"description":225},"guides\u002Fjk-bms-first-setup",null,"qP2DL_cZiHykOT3yCdQUQZOGpmI7WGpWgY2sbihzgBc",[247,251,255,259,263,267,268,272,275,279,283,287,292,296,299,303,307,312,317,321,325,329,333,336,340,344,348,352,355,359,363,366,370],{"path":248,"title":249,"description":250,"date":224,"updated":244},"\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":252,"title":253,"description":254,"date":224,"updated":244},"\u002Fguides\u002Fjk-bms-bluetooth-not-connecting","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":256,"title":257,"description":258,"date":224,"updated":244},"\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":260,"title":261,"description":262,"date":224,"updated":244},"\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":264,"title":265,"description":266,"date":224,"updated":244},"\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":236,"title":5,"description":225,"date":224,"updated":244},{"path":269,"title":270,"description":271,"date":224,"updated":244},"\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":65,"title":273,"description":274,"date":224,"updated":244},"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":276,"title":277,"description":278,"date":224,"updated":244},"\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":280,"title":281,"description":282,"date":224,"updated":244},"\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":284,"title":285,"description":286,"date":224,"updated":244},"\u002Fguides\u002Fjk-bms-smart-sleep","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":288,"title":289,"description":290,"date":291,"updated":244},"\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":293,"title":294,"description":295,"date":291,"updated":244},"\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":24,"title":297,"description":298,"date":291,"updated":244},"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":300,"title":301,"description":302,"date":291,"updated":244},"\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":304,"title":305,"description":306,"date":291,"updated":244},"\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":308,"title":309,"description":310,"date":311,"updated":244},"\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":313,"title":314,"description":315,"date":316,"updated":244},"\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":145,"title":318,"description":319,"date":320,"updated":316},"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":322,"title":323,"description":324,"date":320,"updated":244},"\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":326,"title":327,"description":328,"date":320,"updated":316},"\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":330,"title":331,"description":332,"date":320,"updated":316},"\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":153,"title":334,"description":335,"date":320,"updated":316},"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":337,"title":338,"description":339,"date":320,"updated":244},"\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":341,"title":342,"description":343,"date":320,"updated":316},"\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":345,"title":346,"description":347,"date":320,"updated":316},"\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":349,"title":350,"description":351,"date":320,"updated":316},"\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":85,"title":353,"description":354,"date":320,"updated":316},"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":356,"title":357,"description":358,"date":320,"updated":316},"\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":360,"title":361,"description":362,"date":320,"updated":316},"\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":172,"title":364,"description":365,"date":320,"updated":311},"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":367,"title":368,"description":369,"date":320,"updated":244},"\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":371,"title":372,"description":373,"date":320,"updated":316},"\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.",1791980002130]