[{"data":1,"prerenderedAt":511},["ShallowReactive",2],{"guide-en-jk-bms-wiring-diagram":3,"guides-en":377},{"id":4,"title":5,"body":6,"date":355,"description":356,"extension":357,"keywords":358,"meta":365,"navigation":366,"path":367,"related":368,"seo":373,"stem":374,"updated":375,"__hash__":376},"guides_en\u002Fguides\u002Fjk-bms-wiring-diagram.md","JK BMS Wiring Diagram: 8S and 16S Balance Leads and Connection Order",{"type":7,"value":8,"toc":335},"minimark",[9,13,18,47,51,117,126,130,133,148,151,154,159,162,171,175,178,181,184,188,201,209,213,278,282,293,297,301,304,308,311,315,318,322,329],[10,11,12],"p",{},"A JK BMS is wired with two thick leads and one balance harness. B- goes to the pack negative, P- goes to the negative of the load and the charger, and B+ feeds the board from the pack positive. In the balance harness, B0 sits on the pack negative and B1 to Bn sit on the positive of cell 1 to cell n. Connect the thick leads first and plug the balance harness into the BMS last, after you have measured every pin with a multimeter.",[14,15,17],"h2",{"id":16},"the-leads-on-a-jk-bms","The leads on a JK BMS",[19,20,21,29,35,41],"ul",{},[22,23,24,28],"li",{},[25,26,27],"strong",{},"B-"," connects to the total negative of the pack, the negative terminal of cell 1.",[22,30,31,34],{},[25,32,33],{},"P-"," (C- on some older boards) is the negative of the load and the charger. Charging and discharging share this port. The pack positive goes straight to the load and the charger, because the BMS switches the negative side.",[22,36,37,40],{},[25,38,39],{},"B+"," supplies the board. On B-series boards such as the JK-B2A8S20P it is the last pin of the balance plug, listed in the manual as the BMS power supply with a 10 to 40 V range. On inverter boards such as the JK-PB2A16S20P it is a separate cable (16 AWG in the kit) to the total positive of the pack.",[22,42,43,46],{},[25,44,45],{},"Balance leads"," carry each cell voltage to the board and the balance current back. B0 goes on the negative of cell 1, B1 on the positive of cell 1, B2 on the positive of cell 2, and so on. Each lead lands on the busbar between two cells, and the top lead on the pack positive.",[14,48,50],{"id":49},"board-type-and-inverter-type","Board type and inverter type",[52,53,54,69],"table",{},[55,56,57],"thead",{},[58,59,60,63,66],"tr",{},[61,62],"th",{},[61,64,65],{},"JK-B2A8S20P (board type)",[61,67,68],{},"JK-PB2A16S20P (inverter type)",[70,71,72,84,95,106],"tbody",{},[58,73,74,78,81],{},[75,76,77],"td",{},"Cells",[75,79,80],{},"4 to 8 LiFePO4 per the manual",[75,82,83],{},"16 per the manual",[58,85,86,89,92],{},[75,87,88],{},"Thick leads",[75,90,91],{},"B- and P-",[75,93,94],{},"B- and P-, plus a B+ cable",[58,96,97,100,103],{},[75,98,99],{},"Balance harness",[75,101,102],{},"One 10-pin plug: B0 to B8 and B+",[75,104,105],{},"Two 7-pin and two 6-pin cables: B0 to B16 and probe pins",[58,107,108,111,114],{},[75,109,110],{},"Switching on",[75,112,113],{},"A charger at least 5 V above the pack",[75,115,116],{},"A short press of the power button",[10,118,119,120,125],{},"The inverter type also has RS485 and CAN ports for the inverter. The ",[121,122,124],"a",{"href":123},"\u002Fguides\u002Fjk-bms-model-number-explained","model number guide"," decodes the names. Revisions differ, so check the manual that came with your unit.",[14,127,129],{"id":128},"the-connection-order-and-why-it-matters","The connection order and why it matters",[10,131,132],{},"The JK inverter BMS manual says the board has strict power-on sequence requirements:",[134,135,136,139,142,145],"ol",{},[22,137,138],{},"Connect B-, then P-, then B+ (and P+ where the board has one).",[22,140,141],{},"Plug in the balance connectors from low to high, the one with B0 and cell 1 first.",[22,143,144],{},"Press the button to activate the board.",[22,146,147],{},"Connect the load or the charger only after all wiring is in place.",[10,149,150],{},"To remove the BMS, reverse the order. The B-series manual says the same in other words: connect from the negative pole to the positive pole, check the balance leads again with a meter, and only then insert the plug.",[10,152,153],{},"The reason is protection of the measuring circuit. Each balance input is built for one cell voltage against its neighbour, with B- as the reference. Without that reference, or with a lead on the wrong busbar, an input can see several cells at once. That can damage the measuring or balancing circuit, and the board then reads wrong cells or does not start.",[155,156,158],"h3",{"id":157},"measure-before-you-plug-in","Measure before you plug in",[10,160,161],{},"With the harness fitted to the cells but not plugged into the BMS, put the black probe on B0 and touch every pin in turn. A LiFePO4 pack at rest climbs by about 3.3 V per pin: B1 about 3.3 V, B2 about 6.6 V, up to about 26.4 V on B8 of an 8S pack. A jump of two cells, the same value twice or a negative reading means a lead sits on the wrong busbar. Fix it before the plug goes in.",[10,163,164],{},[165,166],"img",{"alt":167,"height":168,"src":169,"width":170},"Wiring diagram of a JK BMS on an 8S pack: B- to the pack negative, P- to the load and charger negative, B+ to the pack positive, and balance leads B0 on the pack negative, then B1 to B8 on the positive of each cell",440,"\u002Fimages\u002Fguides\u002Fwiring-8s-en.svg",800,[14,172,174],{"id":173},"_8s-packs-and-spare-harness-wires","8S packs and spare harness wires",[10,176,177],{},"On an 8S board with eight cells every lead is used: B0 on the pack negative, B1 to B8 on the cells, and B+ on the pack positive together with B8.",[10,179,180],{},"When the harness has more leads than your pack has cells, for example an 8S board on 4 cells or a 24S board on 16 cells, JK draws a separate wiring diagram for every cell count. In the diagrams we checked, the spare leads are not stacked on the next cells: the 24S manual marks the unused middle leads as not connected, and the top lead goes to the pack positive with the last cell lead and B+. Copy the diagram for your exact model and cell count. Never leave the ends of spare leads bare: insulate each one on its own.",[10,182,183],{},"The JK-PB2A16S20P manual lists 16 as its supported cell count. For an 8S pack, choose a board that lists 8S, such as the JK-B2A8S20P, or check that your manual covers 8 cells.",[14,185,187],{"id":186},"cell-count-and-temperature-sensors","Cell count and temperature sensors",[10,189,190,191,195,196,200],{},"After the first start, set the cell count to your exact series count. The JK manual says the board will not work properly until it matches. Use the JK app or ",[121,192,194],{"href":193},"\u002F","JK Preset Studio"," in the browser, which reads the BMS over Bluetooth, applies a preset and writes it back with a check. The ",[121,197,199],{"href":198},"\u002Fguides\u002Fjk-bms-first-setup","first setup guide"," covers the rest.",[10,202,203,204,208],{},"Tape the temperature probes to the cells, not to a busbar or the BMS heatsink. The 8S board manual defines two probe sockets, and the inverter board has several NTC inputs, one of them in the balance harness. A missing or broken probe raises a temperature sensor alarm, see the ",[121,205,207],{"href":206},"\u002Fguides\u002Fjk-bms-alarms-list","alarm list",".",[14,210,212],{"id":211},"what-goes-wrong","What goes wrong",[52,214,215,228],{},[55,216,217],{},[58,218,219,222,225],{},[61,220,221],{},"Symptom",[61,223,224],{},"Likely cause",[61,226,227],{},"Fix",[70,229,230,241,252,267],{},[58,231,232,235,238],{},[75,233,234],{},"Cell count does not match the settings",[75,236,237],{},"Wrong cell count, or a loose or missing balance lead",[75,239,240],{},"Set the cell count, then measure every pin against B0",[58,242,243,246,249],{},[75,244,245],{},"One cell reads 0 V and the next reads double",[75,247,248],{},"Two leads swapped or one lead on the wrong busbar",[75,250,251],{},"Unplug the harness, find the lead with the meter, move it",[58,253,254,257,260],{},[75,255,256],{},"Wire resistance warning, balancing does not start",[75,258,259],{},"Poor crimp, loose lug or a wrong connection",[75,261,262,263],{},"Check that lead, see ",[121,264,266],{"href":265},"\u002Fguides\u002Fjk-bms-wire-resistance","wire resistance",[58,268,269,272,275],{},[75,270,271],{},"BMS does not start after plugging in",[75,273,274],{},"B+ missing, wrong order, or damage from a swapped lead",[75,276,277],{},"Check B+ and the order; do not keep replugging a suspect harness",[14,279,281],{"id":280},"safety","Safety",[19,283,284,287,290],{},[22,285,286],{},"Use insulated tools and take off rings and watches.",[22,288,289],{},"Connect one lead at a time and tape every loose lug until it is fastened.",[22,291,292],{},"Put a fuse or breaker in the positive lead close to the pack, rated for your cable and the BMS current.",[14,294,296],{"id":295},"faq","FAQ",[155,298,300],{"id":299},"in-which-order-do-you-connect-a-jk-bms","In which order do you connect a JK BMS?",[10,302,303],{},"Connect B- first, then P-, then B+, and plug the balance connectors in last, from low to high. Connect the load and the charger only after everything else is in place.",[155,305,307],{"id":306},"where-does-b0-go-on-a-jk-bms","Where does B0 go on a JK BMS?",[10,309,310],{},"B0 goes on the negative terminal of cell 1, which is the total negative of the pack. B1 then goes on the positive of cell 1, and each next lead goes one cell higher.",[155,312,314],{"id":313},"can-i-use-a-16s-jk-bms-on-an-8s-battery","Can I use a 16S JK BMS on an 8S battery?",[10,316,317],{},"Only if the manual of that model lists 8S. The JK-PB2A16S20P manual lists 16 cells, so an 8S pack usually takes an 8S board such as the JK-B2A8S20P.",[155,319,321],{"id":320},"how-do-i-connect-several-jk-bms-packs-in-parallel","How do I connect several JK BMS packs in parallel?",[10,323,324,325,208],{},"Each pack keeps its own BMS, and the packs meet on common busbars with a fuse per pack. See the ",[121,326,328],{"href":327},"\u002Fguides\u002Fjk-bms-parallel-batteries","parallel batteries guide",[10,330,331,334],{},[121,332,333],{"href":193},"Connect your BMS"," once it is wired and set the cell count, capacity and chemistry with a verified write.",{"title":336,"searchDepth":337,"depth":337,"links":338},"",3,[339,341,342,345,346,347,348,349],{"id":16,"depth":340,"text":17},2,{"id":49,"depth":340,"text":50},{"id":128,"depth":340,"text":129,"children":343},[344],{"id":157,"depth":337,"text":158},{"id":173,"depth":340,"text":174},{"id":186,"depth":340,"text":187},{"id":211,"depth":340,"text":212},{"id":280,"depth":340,"text":281},{"id":295,"depth":340,"text":296,"children":350},[351,352,353,354],{"id":299,"depth":337,"text":300},{"id":306,"depth":337,"text":307},{"id":313,"depth":337,"text":314},{"id":320,"depth":337,"text":321},"2026-10-19","How to wire a JK BMS on an 8S or 16S pack: the B-, P- and B+ leads, balance lead order from B0 up, spare harness wires and the connection order JK specifies.","md",[359,360,361,362,363,364],"jk bms wiring diagram","jk bms 8s wiring","jk bms balance wire order","jk bms connection order","jk-pb2a16s20p wiring","jk bms 16s wiring",{},true,"\u002Fguides\u002Fjk-bms-wiring-diagram",[369,370,371,372],"jk-bms-first-setup","jk-bms-wire-resistance","jk-bms-parallel-batteries","jk-bms-model-number-explained",{"title":5,"description":356},"guides\u002Fjk-bms-wiring-diagram",null,"FhSpFtiGnAi17EIeomfy5NAS9XSxORPXesznlRHSNT0",[378,379,384,388,392,396,400,403,407,411,415,419,423,427,431,434,437,441,446,451,456,460,464,468,472,476,480,484,488,492,496,500,504,508],{"path":367,"title":5,"description":356,"date":355,"updated":375},{"path":380,"title":381,"description":382,"date":383,"updated":375},"\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.","2026-10-14",{"path":385,"title":386,"description":387,"date":383,"updated":375},"\u002Fguides\u002Fjk-bms-bluetooth-not-connecting","JK BMS Not Connecting to Your Phone over Bluetooth: Fixes","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":389,"title":390,"description":391,"date":383,"updated":375},"\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":393,"title":394,"description":395,"date":383,"updated":375},"\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":397,"title":398,"description":399,"date":383,"updated":375},"\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":198,"title":401,"description":402,"date":383,"updated":375},"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":404,"title":405,"description":406,"date":383,"updated":375},"\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":408,"title":409,"description":410,"date":383,"updated":375},"\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":412,"title":413,"description":414,"date":383,"updated":375},"\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":416,"title":417,"description":418,"date":383,"updated":375},"\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":420,"title":421,"description":422,"date":383,"updated":375},"\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":206,"title":424,"description":425,"date":426,"updated":375},"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":428,"title":429,"description":430,"date":426,"updated":375},"\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":123,"title":432,"description":433,"date":426,"updated":375},"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":327,"title":435,"description":436,"date":426,"updated":375},"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":438,"title":439,"description":440,"date":426,"updated":375},"\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":442,"title":443,"description":444,"date":445,"updated":375},"\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":447,"title":448,"description":449,"date":450,"updated":375},"\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":452,"title":453,"description":454,"date":455,"updated":450},"\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":457,"title":458,"description":459,"date":455,"updated":355},"\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":461,"title":462,"description":463,"date":455,"updated":450},"\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":465,"title":466,"description":467,"date":455,"updated":450},"\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":469,"title":470,"description":471,"date":455,"updated":450},"\u002Fguides\u002Fjk-bms-lifepo4-settings","JK BMS Settings for LiFePO4: 8S and 16S, 280Ah and 314Ah","Tested JK BMS settings for LiFePO4: OVP 3.6 V, RCV 3.5 V, UVP 2.8 V per cell, plus balance, current and temperature values for 8S and 16S packs.",{"path":473,"title":474,"description":475,"date":455,"updated":375},"\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":477,"title":478,"description":479,"date":455,"updated":450},"\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":481,"title":482,"description":483,"date":455,"updated":450},"\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":485,"title":486,"description":487,"date":455,"updated":355},"\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":489,"title":490,"description":491,"date":455,"updated":355},"\u002Fguides\u002Fjk-bms-password","JK BMS Default Password (1234 \u002F 123456): Change and Reset","JK BMS default password: 1234 for Bluetooth, 123456 for settings. How to change both codes, fix a rejected password and reset a forgotten one via JK support.",{"path":493,"title":494,"description":495,"date":455,"updated":450},"\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":497,"title":498,"description":499,"date":455,"updated":450},"\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":501,"title":502,"description":503,"date":455,"updated":445},"\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":505,"title":506,"description":507,"date":455,"updated":375},"\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":265,"title":509,"description":510,"date":455,"updated":355},"JK BMS Balance Wire Resistance: Fix the Abnormal Resistance Alarm","JK BMS balance wire resistance (cell wire resistance): what the Abnormal resistance of the balance wire alarm means, normal values and how to fix a bad lead.",1792363763685]