JKBMS Smart BMS 8S-24S 200A 2A Active Balance Built-in Bluetooth with RS485 PCB Battery Protection Board for Li-ion LiFePO4 LTO Battery Pack (JK-B2A24S20P)

This is a really nice piece of equipment. And it's small enough to go inside the battery case. The Bluetooth works amazingly well.

This BMS is truly awesome for the price. When I received the product, the assembly was fairly straight forward if you know what you are doing, if not many videos are available online. After setup they included a QR code for the app. The app is very easy to use and always opens on the page that displays your bank information. As far as initial setup it is very simple and straight forward as you only have to input the manufactures specs into the app and it instantly sets it and allows you to even lock the settings. It also allows for 2A of balancing which really helps to keep your cells balanced quickly. The Bluetooth connection range is also fairly good, as I can connect as I am walking to my car.

I would say overall this five stars it’s so much better than the Daly. I bought two of those and had to return them because they just didn’t work right out of the box. JKBMS is compact works well he can’t go wrong.

Update 2024-12-14: Actually looking like top balancing will recover 20% capacity. Heater puzzle solved. See below for info from JK BMS. The scene: After 6 years, converting two (24v) 8S 200Ah bottom balanced LFP cells to a single 16S 200Ah 52.1V battery. Installed BMS 6 days ago. The good: Super simple install. Connected to app immediately. Clear and easy to read manual (yes, really!) The great: Chugging away at top balancing the pack. At 2A, and as poorly balanced at the top these cells are, it’s made decent progress. Looking like I’ll be able to reclaim an easy 10% MORE capacity from these cells than I’ve ever had. The “Meh”: Can’t figure out WHEN the heater port will activate. CAN cable was missing. Only JK protocol supported CAN menu. Over All Grade: A+ Would I buy it again? Yep, as a matter I already have. If I figure out how to trigger the heater, I’ll update this. If I figure out how to get this to talk to my Victron gear, I’ll update this. I’ve played with pretty every setting. It works as documented. 2024-12-17 JK BMS sent info: Heating Function Activation Conditions: The heating function for charging will be activated when Condition 1 is met, along with Condition 2 or Condition 3. Condition 1: The battery temperature is below the charging low-temperature protection threshold. Condition 2: Heating is manually activated via the APP, without checking the charger status. Once the low-temperature condition is met, heating will begin, which will consume battery power. Condition 3: The charger is detected as being plugged in. This function is related to the hardware of the protection board and the charger, so please confirm the technical specifications before ordering. Heating Film Selection: Step 1: Determine the maximum battery pack voltage. For example, a 20-series LiFePO4 battery has a maximum voltage of 20 × 3.6V = 72V, while a 24-series LiFePO4 battery has a maximum voltage of 24 × 3.6V = 86.4V. Step 2: Calculate the resistance value of the heating film. The resistance value is calculated by dividing the maximum total voltage by the current: Resistance (Ω) = Maximum Total Voltage ÷ 3A. For example, 72V ÷ 3A = 24Ω. Based on this, select a heating film with a resistance close to this value. A suitable heating film specification would be 72V/24Ω/216W. Key Notes for Understanding: Condition 1 (Low-Temperature Protection): The heating function will only be triggered if the battery temperature drops below a certain threshold (often around 0°C to 5°C) to prevent damage to the battery and ensure it remains functional during cold weather conditions. Condition 2 (Manual Activation via APP): This condition allows the user to manually activate the heating function through an app, which will begin heating as soon as the low-temperature condition is met. However, this will drain battery power, which is important to consider in terms of overall efficiency. Condition 3 (Charger Detection): The heating function is also dependent on detecting whether the charger is plugged in. This ensures that the battery is being charged during the heating process, avoiding unnecessary power drain when not connected to a power source. Heating Film Specifications: The heating element (heating film) needs to be carefully selected based on the battery's total voltage and required current. The resistance of the heating film plays a key role in determining how efficiently the heat is generated without exceeding the system's power limits.

***MUST READ REVIEW**: First time using the JKBMS. I have used many other BMS from various other companies. I Was very excited to use this one because it is rated highly by people in the field. Anecdotally, there's good feedback. My experience with it otherwise was extremely awful. Here's the story: I had just got done designing and building a 35ah, 72v battery out of 18650 cells. 210 cells, 21s/10p. I am no stranger to building batteries, I have a battery business building custom batteries for people, and tons of experience in this field. Once the battery was completed. It was time to put the BMS on. I made sure everything was perfect. Every balance lead went to the correct cell group, and the B- and p- we're connected appropriately. I then connected the app. And input the correct parameters, and everything was perfect. I turned charging on, and connected my charger, and charged it up to its maximum. After the charge I enabled the active balance feature. And I monitored it while it balanced. Everything was going fine for a few minutes... Then literally all of the sudden out of nowhere I got a notification for cell grouping 10 and 11 saying there was an error. Then literally the two balance wires started turning red hot, melted through the heat shrink and continued to heat up and within seconds the whole battery was on fire! It almost burned down my whole house. My dining room table is burnt, my hardwood floors are burnt. I had to act fast so I had no choice but to pick up the flaming battery and run outside with it, and I extinguish the fire outside in the grass. Fast forward to the next morning, I go to check out the battery, I took what was left of the heat shrink off and all the other electrical insulation and tape I had had on for safety (thank God). I fully inspected the battery very thoroughly. And could not find any human error on my part that was evident or could be linked to why this fire broke out. It would seem, or I would guess -that the balance leads in theory would have had to have been arcing with something which would have made the glowing red hot wires that resulted in the fire - (my educated guess?) There was no human error. In conclusion this was a faulty BMS, and it almost burnt down my house. Now, I'm not one to leave bad reviews. But this is all just the facts and the truth of the matter and I feel it was necessary to share this. As an experienced professional in battery manufacturing, I can't say that I would recommend this product just based off my experience. I would like for the company to make it right. I would suggest for the creators of the JK BMS to establish better QC within their company. As this was clearly a faulty BMS with something wrong with it. I am out $1,000 for the battery cells alone. Not to mention all the time and work I put into this battery. I've tried reaching out to them with no answer. So I have explained it to Amazon customer service, and I have initiated a refund. I've sent it back, even in it's damaged State, as per Amazon's instructions and I hope at the very least I get my refund for this experience. I would be willing to try jkbms again based off of all the success lots of others have had with it. But I am hesitant. I'd be scared to get another faulty BMS from them. So I don't know what I'll do from here. Most likely get another BMS from a different company. I don't know. Anyways I just wanted everybody to hear this story and be cautious when using this BMS. I'm sure there are other faulty ones out there that are going to go out to customers and them have the same experience. I wish this on one! Be safe make sure to electrically insulate everything always.

i rely on the jkbms. i have used it on more than 7 battery packs. it is the best in its class. it has, however, DO MANY DEFICIENCIES and it is hard to comprehend why the manufacturer refuses to improve the design. the two 7awg cables for B- and two for P- are ridiculous. they are hard to find terminals for, and the wire is extremely fine, so not only is crimping a pain, the cable twists badly when bent. it is ridiculous. there are no fixture points on the unit for screws -- to attach the unit to anything, you must manufacture your own clamping material. the sensing wires terminate as raw wires, but almost everyone using these units needs to crimp on eyehole terminals -- JK vould easily prefit these but instead leaves the user an hour+ of tedious and inconsistent labor. the software has many quirks and god forbid you change the standard passwords (1234 and 123456) -- if you lose your bew password, the unit is bricked -- no DIY user requires this level of security, it is a huge annoyance. the datalogging is insane -- it cannot keep track of dates and cannot seem to output text files or track useful things while rejecting spam errors. on and on and on with this thing. but we have no better alternative. daly and overkill are jokes in comparison.

Came as expected. Contents of the box was the same as the one I ordered previously from China. If you need it quick this would be the best option.

Easy to install, app works nicely and is easy to program. Has been working great since 12-15-25