Questions tagged [bms]

A battery management system (BMS) is any electronic system that manages a rechargeable battery (cell or battery pack)

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30 views

Where is current sense on this 3S 40A BMS

I have recently purchased a BMS rated for 3S, 40A (still in transit). Following is pictures for this BMS: Now, according to seller, this has over-current, over-voltage, under-voltage and short-...
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29 views

Choosing bms for 3s system

I am attempting to build a bot project that runs off a 3s battery pack.in deciding on what BMS to choose based off its parameters.since I am a beginner I am wondering, do I choose a BMS that matches ...
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I want to design a Protection circuitry for ICR18650 Lithium-Ion cells

I am trying to design a protection circuitry for ICR 18650 Lithium-Ion cell (3.7V,2200mAH). I made a battery-pack by connecting 3 cells in series to get output voltage of 11.1V. During charging/...
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Designing BMS for 4S LiIon Pack

currently I'm working on 4S(2P) BMS mainly focused on TI's ICs. I'm stuck at the start - First, for now I want to use BQ2954 IC for charger, and BQ77915 IC for balancing and protection. Now, I'm not ...
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Would a BMS help discharge the 18650s individually at an equal rate when they are connected in series?

I'm wondering if I should add a BMS to my battery pack. I got 11x18650 with built protection in series, and have noticed that some of them get discharged quicker than others, and because of built in ...
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52 views

How to charge a 4S 18650 (16.8V) battery pack with a 5V USB input source?

I'm planning on building a 4s 18650 (16.8V) lithium-ion battery pack with a 4s BMS with balance function to replace an old built-in Ni-Mh battpack. I would like to charge the new lithium battpack via ...
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53 views

Different capacity lithium polymer batteries in parallel

Is there any problem if I put different capacity,from different manufacturer with different specification? This is my current configuration: DW01 Protection Bord is being used on both. But power bank ...
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46 views

18650 battery pack with “dead” cells, other cells still usable?

I have an 18650 battery pack (12p20s so 240cells) with 2 parallel groups which recently "died" (voltage is 0v or very close to 0v (0.09v for one of the packs 0.0v for other parallel group). ...
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38 views

How do I charge this odd 4S Li-ion circuit?

I am trying to make a battery pack that will power my electronics. I need to make +7V and -7V. The +7V needs to have a decent amount of capacity. I have proposed a 2S6P circuit for the +7V supply with ...
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16 views

Running NodeMCU ESP8266 on 3s 18650 battery pack powered by solar panel

I am making a circuit which controls a 12V analog mechanical device using microcontroller (NodeMCU ESP) GPIO. The Node MCU uses AMS 1117 to step down voltage to 5V (& another one to 3.3V), but ...
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27 views

BMS won't output voltage despite good LiPo Cells

I have an 20 cell LiPo battery pack that is healthy at 80V in total, the BMS uses 12 MOSFETs in parallel to switch the negative terminal and they all seem healthy but won't switch on, so I can't get a ...
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21 views

How to connect BMS board with balancing board to make a battery pack?

I’ve got BMS board without balancing feature and a balancing board. I want to know how to connect them to make a battery pack.
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LiFePO4 BMS purchase and wiring

I have 48 new CALB LiFePO4 batteries coming in. I want to build a 24V bank in a 8S6P configuration. I have enough room to build the 6 sets of 8P and connect the 6 sets together using the same bus ...
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90 views

2S BMS for Li-ion Battery not charging the batteries

I have been working on a small DIY project. Reference for this project is the following video from YouTube. DIY - 12V Mini UPS While I was able to put together everything and it works for most part, I ...
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Parallel BMSs with LiFePO4 Packs

I'm trying to design a BMS that allows for multiple larger packs to be connected together in parallel (say, multiple 4S LiFePO4 packs). Using an unconnected conventional BMS SOC there's obviously the ...
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1answer
112 views

Using Buck Converter as Solar Charge Controller ? (see pic)

Can I charge Li-Ion safely by connecting PV Panels to a CC CV Buck Converter then through BMS to a 3S3P batteries? This is basically a plan for a very small solar powered device that takes in solar ...
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49 views

How do I prevent my BMS from tripping when solenoid is connected?

I am working on a project that is effectively just a battery powered reticulation system. It is charged through a solar array and cheap MPPT charger, which connects into the battery via the BMS. The ...
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39 views

Is it possible to chain BMS modules?

Let's say i have two 6S Lithium BMS modules (basically protection and balancing) and i want to create a 12S battery pack. Is it possible to chain the power lines of said modules? Just curious
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18 views

Lifep4 BMS and control

Any Lithium battery experts here? My concern is that there is a lot of work and specialized chips on BMS systems that specialize in balancing battery cells for large batteries. Lets say I have a ...
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47 views

Individual cell balancing on multiple packs

UPDATED: I edited my question to clarify I'm building a 4s4p pack with 18650's. What is the best method to achieve on a per-cell balancing & protection if that makes sense? Most of the 4s BMS I ...
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Is it safe/possible to add a BMS board to a soft pack 3s1p LIPO for charging and discharging?

i would like to make a 12V battery pack from a soft pack LiPo which can supply 10A for my projects which i can charge from a 12.6V DC wall powersupply. I dont want to use an external big special BMS ...
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30 views

Cell balancing in BMS

I have questions with respect to cell balancing please help me 1.when this cell balancing will occur is it when charging the battery or when any cell goes more then rated voltage. 2.can you please ...
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37 views

Recharging 14v battery straight from 18v supply?

I am recharging a 14v LiFePo4 4s8p battery from a Phillips wall transformer from scrap. The phillips wall transformer is rated 13V 400ma on it, but it measured 18V on the multimeter. I put it on ...
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I want to make a power supply using two 18650 batteries in paralell with a TP 4056 module but im not sure how to balance the batteries

I am using a TP 4056 module, two 18650 batteries and some sort of BMS to balance the batteries before going to the charging module however I'm not sure whether I need a 2S BMS or a 1S BMS. Preferably ...
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25 views

How many cells can be practically connected to BMS

I have a 6S23P li-ion battery pack. I am thinking of split bigger battery pack into 3 packs 6S7P 6S8P and 6S8P for my application. Then parallel them to get total power. So basically I need 3BMS ...
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47 views

Can anyone help me identify this component? SMD P636

I damaged a BMS board by briefly shorting some connector leads. The only chips I see that appear physically damaged at the two marked by the red box in the image below. I can't seem to find those ...
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48 views

Help identifying pneumatically activated switch with possible BMS

Some decent googling has yielded me no results. Attached are pictures of a component that allows power from a 3-5v power supply to flow when positive pressure is applied to one side or negative ...
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26 views

Using only a part of Bms's balance leads

i was serching for a 100Amps bms and i saw one that said: 6S-28S and i was wondering if it's possible to use only a few balance leads and how to do it.Any other 10s bms is either not capable of ...
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266 views

Undervoltage protection strategy for Li-ion batteries

We are using a Li-ion battery with built-in safety PCM (Enix MGL9070), a gas gauge to monitor the battery voltage (STC3115A from ST) and a battery charger (bq24133 from TI). To protect the battery, ...
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145 views

what is maximum Input voltage for 2s bms

I am making UPS for my 12v broadband router. I am planing to use XL6009 boots converter to booter 8.4 volt to 12v. For charging 2s Li-ion battery with 2s BMS i don't have 8.4v charger. Can I use 12V ...
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55 views

DW01 for Lithium Non-Rechargeable Battery Protection

I'm thinking of using the DW01 IC to make a simple non rechargeable battery protection (over current, short circuit, over discharge). The sample schematic requires two Power fets, one to control ...
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50 views

What does this mean in datasheet : 2k: Ipgm/10 for term; Ipgm/5 for precharge

I was referencing the datasheet for BQ24040 Texas Instrument IC and could not understand the following statement and what does it actually mean. I am new to this. Can some one explain what does it ...
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265 views

Connecting to UART port on smart BMS

We are ordering batteries for powered wheelchairs from relatively big Chinese company specializing in large power banks (I am talking whole-house scale here). Our orders for them is just a side-...
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158 views

Why is my self built LiFePO4 battery pack not charging?

[NOTE] I understand that the adapter that I bought for my battery pack is not actually a charger. I also understand that it could be dangerous what I'm doing. I still wonder why there is no current ...
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69 views

How can I determine LI-ion battery charge while varying the load?

I'm building an autonomous boat which contains a li-ion battery pack and I want to know how much charge it still left in it. To do this I measure the voltage of the battery pack. I let it run for ...
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243 views

Battery management system circuit validation. Is my rough circuit design correct? Am I on the right path?

After referring to several pieces of literature, websites and several questions on Stack Exchange, I have designed the circuit of a battery management system and roughly sketched it for a 10s, 36 V, 2....
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38 views

BMS for multi cell batteries

I have several large LG multi-cell batteries. Images & description can be seen here: I'm wondering if I can use a 14S BMS for each of these batteries in order to keep every cell balanced and in ...
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E-bike battery-related questions

I am a beginner and I am learning to design and develop a Battery Management System for low voltage applications like E-Bike. I would like to build a 36 V, 10s, 2500 mAh battery pack. The knowledge ...
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184 views

How can I use 2 Tp4056 as protection circuit for diy 2s li ion battery?

Hi I want to use 2 Tp4056 modules as over-discharge protection circuit for my DIY 2s li ion battery pack. Those will not be used for charging! hence will not share input! The load is an arduino nano ...
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Will running a tab between the positive terminals interfere with a 4S BMS?

I have 3 12V, 64AH battery packs with a 50A MPPT solar charge controller and 3 50A balancing boards. The rest is theory because I'm still waiting for components to arrive but... Normally, the ...
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148 views

Side effects of using a motor with a greater current on a battery with a lower rated current

I'm looking to power a 33A brushless DC 2000w 48v motor. Ok so I have a lithium ion battery, and it's manufacturer states this: Specs: 48v 1000w 13s3p 28Ah Rated discharge current: greater than or ...
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66 views

BMS and Charger For LiFePO4 prismatic module

I just purchased a lithium battery module for an electric tractor project. I'm looking for advice on how to set up my BMS and charger. Here are the details of the module from the seller: "Prismatic ...
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Is a BMS supposed to be rated at your discharge current or the battery's?

So if I'm making a 13s2p 48v 16Ah battery out of these cells that are rated at 200A each, (3.7v 8Ah), and if I want to power a ~30Amp motor, do I need a 200Amp BMS or a 40amp (40 not 30 because 40 is ...
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357 views

Modifying an existing 3-cell BMS circuit to disconnect the pack at high temperature

There are a number of 3-cell protection boards available online for 18650 cells. None of which appear to disconnect the pack at high temperature. A schematic of one such board is shown below, along ...
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Charging 18650 3s5p

I am looking to build a 3s5p pack using LC18650 Samsung cells. The idea is to run my fiber/wifi router during power outages (south africa loadshedding +- 4h per day) directly from the pack and avoid ...
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234 views

How to use a (cheap) BMS for discharge only

I'm building a small robot (for the context, with a pi zero, a PCA9685 motor controller, 8 small servo motors a regulator and an Ubec) fully powered from a 2S 18650 battery. I've inserted a (cheap) ...
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147 views

ESP32 MOSFET Control with a Twist

Looking for some help with using an ESP32 (running Arduino IDE) to control a MOSFET. Currently, I have used the combo to control many things successfully by electronically "pressing buttons" by ...
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131 views

Identify chip on 2S BMS / Balance card

I picked up a bunch of Chinese-made 2S BMS / Balance boards. As is the norm with inexpensive Chinese boards, they came with essentially NO documentation aside from how to hook the board to the ...