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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My 15S BMS of LiFePO4 battery stack outputs 15.9 V (the entire pack measures 48 V)

I have a LiFePO4 stack of 15S and 3P configuration. Everything was working fine until I broke the pack and divided it into two packs of 8S and 7S, and connected both via jumper wires. Now the pack ...
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45 views

Fast charging for battery management system

I want to implement fast charging for a BMS I am designing. I will be using BQ76940 for battery monitoring and balancing. As a companion controller I have opted for BQ78350 from TI. When I read the ...
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81 views

Why doesn't this LTC6803-4 battery controller work?

Our team is currently working on a Battery Management System with specifications as below: 12 x 3.3 V, 50 Ah LiFePO4 Batteries, connected in series LTC6803-4 Battery Controller Monitored via Arduino ...
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41 views

Battery Management System - Fast charging

I am using a TI BQ76940 battery management IC for a project. I want to implement fast charging in this system. How can I go about achieving it? Can I connect multiple high-side bidirectional MOSFETs ...
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39 views

MAX17320 factory Lock

I developed a bms based on max17320, but it has problems. The software for dev kit cannot record anything because the chip is blocked. I tried writing 0000 to 0x61 twice, it didn't give any result. ...
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40 views

EEPROM in battery management system

I am designing a battery management system. I am however unable to comprehend the way in which EEPROM can be accessed to feed OCD (Over Current Delay) values. I have attached the datasheet: https://...
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1answer
88 views

Battery management system

I am designing a battery management system for lithium ion batteries. I am referring a schematic that is already available. I do not understand the function of the two MOSFETs marked in the schematic.
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1answer
50 views

BMS adjusting charge current

I use this ready module for 3S battery group. Due to high charge rate (pull about 2-3A from power supply) a high current power supply also needs. I want to reduce charge rate up to 0.2C or 0.1C. No ...
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40 views

Charging a LiPo battery with load

I have built my own BMS (Battery Monitoring System) that can control the SOH (State of Health) and SOC (State of Charge) of a LiPo battery. It can control every cell voltage (with passive cell balance)...
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58 views

2S BMS shuts down by itself

I made a small 2 DC motor Arduino robot car which is powered by two 18650 cells. I am using a 2S BMS with a TP5100 to charge and protect my cells. I am using a DC-DC boost converter to make 9 V to ...
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356 views

Powering a RPI board with a 22V battery pack

I built a 22V battery pack with 6 18650 cells connected them to a 6s BMS. I will use this to power a portable audio amplifier. I also want to use the same battery pack to power a Raspberry Pi Zero W ...
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126 views

What can be possible reason for explosion and fire in battery pack built with 3S Li-Ios BMS

I recently made some 12v battery back using regular 3S Li-Ion BMS and 18650 cells. Unfortunately, 3 of them EXPLODED and one even caught fire on site. The BMS I used was almost exactly like this but ...
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59 views

Li-ion BMS 2S3P wiring to a 2S BMS

I'd like to seriously increase the capacity of my pack by adding more cells in parallel whist maintaining 8.4v from these 4.2v/3500mAh 18650 batteries. I'd like this scalable so I could potentially ...
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1answer
104 views

Is a battery pack connected parallelly or in series?

I have a circuit of a battery pack of 4 18650 and a 4S BMS. See the picture below. The question is: is my understanding correct that this circuit means that the batteries are connected in a series, so ...
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1answer
49 views

How to choose components to charge/discharge 18650 battery block for a robot

I want to build a battery for my robot, and I don't understand how to choose components to use after BMS to charge/discharge the battery. I have 4 pieces of 18650 batteries: 3.7 V, 6.7 A maximum. This ...
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3answers
236 views

Is an Ideal Diode necessary for BMS?

I'm designing a battery pack that's on the order of 10s5p. Each 10s stack has its own BMS, with high side driven FETs for charge and discharge. This is based on the Texas Instruments reference design, ...
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163 views

BMS charging voltage. Can I supply overvoltage?

Most decent battery management systems out there employ balancing, overdischarge protection, overcharge protection, etc. Almost universally they state that the charging voltage is just 4.2*N_cells. ...
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1answer
42 views

BMS 4S 40A Li-Ion balancer board problem

Trying to figure out how to use the BMS 4S 40A Li-Ion protecting balancer board that I got off Ebay. Revision 2.3, photo and schematic is attached. I am building a power bank. Got some new NCR18650b's....
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1answer
57 views

How can I follow the current in this DW01A circuit?

I try to understand the inner logic of this diagram, this a modified version of a schematic that I found online. I made the necessary calculations for my power MOSFETs and all but I have some ...
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1answer
151 views

DIY protection board for lithium-ion batteries. How to scale a schematic?

I need to build a DIY protection board for a university project. We are not allowed to buy one online so I have to construct it myself. I have found a variety of schematics accomplishing the same ...
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1answer
247 views

Smart BMS UART problems [closed]

I recently bought a Daly Smart BMS from China for an EV project. It works well but we can’t communicate with its UART port. I got the pinouts and protocol from manufacturer and connected it to an ...
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1answer
66 views

Power adapter 12V for charging LiFePo4 12V battery with BMS with passive balancing

I have a project where I need to charge an Enerpower LIFEPO4 Battery of 12V 12Ah with BMS with an integrated passive balancer, protection against overcharge, deep discharge, over-discharge (...
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50 views

Is a LiPo battery cut-off voltage open-circuit or under any conditions?

I'm working on battery management system firmware for a battery pack consisting of these cells. The battery pack powers a motor that, of course, when pulling current causes the voltage of the LiPo ...
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75 views

How to charge 8S battery pack with two 4S BMS circuits?

I recently made 8S battery pack out of 18650 cells (4.2V each) and I am worried about connecting it to BMS. Some time ago I asked what BMS should I get (well, I asked if i have to have some BMS at all ...
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57 views

Is it a good idea to charge multiple Li-Ion batteries using a single buck converter?

I am trying to implement a DIY MPPT into my solar tracker project and I wanted to know if it was possible to charge all of the three li-ion 3.7v batteries in series with just one feedback buck ...
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1answer
84 views

Can you just rely on battery BMS's undervoltage protection for normal use

Let's say you buy a lithium battery with BMS circuit included. The BMS protects against undervoltage (and other things) and only 2 wire-leads come out of the battery (so no seperate charging wire). eg....
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80 views

Are parallel wired BMS controlled batteries even necessary?

I've read many question on here about how to connect multiple BMS controlled batteries in parallel to step up amps. Is this necessary to step up amps as opposed to running all the cells in series and ...
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314 views

Undervolt protection circuit

I want to undervolt protect a series of 3 Li-ion cells. The load is a voltage booster with initial 5 amp usage for 5 seconds. Then power consumption is reduced to 5 watts. (It works ok on battery.) (A ...
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48 views

Can I use TP5100 2S Battery charger with 2S Bms

I want to use tp5100 2s battery Charing module with a 2s BMS. I posted questions before and found out that I can't use BMS only to charge. So can I use TP5100 as a charger and a BMS together ? ...
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114 views

Can I Charge 2 18650 with 2 TP4056 boards with single input

I found this video on youtube where they charges 2 18650 with 2 TP4056 modules with one input. below is the schematic he uses. Is it safe to do that?
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124 views

Can I charge 2s 18650 battery pack with a BMS and a 9V wall adapter

I have this cheap 2s BMS board that I want to use to charge a 2S 18650 battery pack (2 18650 in series). https://au-m.banggood.com/2S-3A-Li-ion-Lithium-Battery-Protection-Board-7_4v-8_4V-18650-Charger-...
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76 views

BMS for 12V Lead Acid Batteries (48V)

I'm thinking about creating a BMS for my Battery Bank. The bank consists of 12 VRLA Batteries connected in 4 series and 3 parallel configuration to get a 48V system. For this bank I wanted to monitor ...
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46 views

Problems with LiPo Volt buck boost for a LED

I need a little bit of help in understanding buck-boost converter. I have 4 LiPo 18650 batteries in series an BMS to charge and discharge the batteries properly. After that I added the buck-boost ...
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1answer
41 views

Building a 1S Li-ion battery pack with all the cells in parallel and using a DC to DC converter to get higher voltage

I want to build a 12 V battery for my Mac Mini and possibly a 36 V battery pack for a electric scooter I plan to make later using some old 18650 cells. I have read that a lot of battery management ...
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41 views

If I connect three different capacity lithium batteries in series with a 3S BMS board, When the BMS will stop giving output?

If three different capacity batteries are connected in series with a 3S BMS board, when the lowest capacity battery runs out and under voltage occurs of the battery then will the BMS continue giving ...
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46 views

What does 2.5-3.0V mean on BMS specs?

I'm looking at buying a cheap eBay BMS to prevent overdischarge of a Li-Ion battery, but I'm confused about the specs. Basically every BMS I can see lists the overdischarge cutoff voltage as "2.5-...
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53 views

In BMS if I connect li ion batteries of different capacities, how much mA will it provide in the output?

If I connect one 1200mah, one 2600 mah and one 800mah li ion battery with a 3S BMS board. How much mA will it provide at the output? And when the BMS will stop giving output? Thanks in advance for ...
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45 views

How to Design BMS in simulink?

I have designed a battery pack of li-ion batteries. At the initial stage I have given 0 at both constant blocks. This indicates there is no charging or discharging In the second fig I have applied ...
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41 views

Is a buck converter necessary for a 18V drill conversion? (NiCad to Li-Ion)

Im currently planning out my (first) conversion of an old 18V drill with dead NiCad cells to 18650 Li-Ion. I have enough cells that should support the high discharge rates and I'm putting them into a ...
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63 views

Multiple CC/CV charge controllers in parallel?

Can multiple cc/cv charge controllers (TS1052 for example, which is rated for 100mA drain current) in parallel configuration to achieve a higher drain current? (input signals also connected in ...
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1answer
132 views

How to supply limited power to a hungry BMS for li-ion charging

I am building a li-ion battery pack in a 7-series (3.6V) cell configuration. That gives 25.2V nominal voltage and 29.4V charging voltage. I have a BMS with balancing charging capabilities. This BMS ...
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49 views

Solution to prevent load from drawing the current from battery while it is charging and draw it from charger instead

I have the following problem: I have a 12.8V LiFePO4 Battery that powers the circuit and a lead acid charger with Intelligent MCU Control of 12V and 1.5 A to charge the battery. When the battery is ...
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47 views

Connecting 36V LiIon packs in series to get ~120VDC to run lawn mower

I'm converting my electric plugin lawnmower to battery power. I was able to get 3 used e-bike identical model 36V 5Ah packs (obviously not matched with respect to lifetime usage). Each pack has its ...
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121 views

How to go about testing which pins to short to turn on Daly BMS?

I have a 7S DALY BMS, but I forgot to buy the 'SOC (state of charge) display board', which has LEDs that display the state of charge, and crucially, a switch to turn on the battery itself. The board ...
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48 views

18650 Li Ion Questions

Good morning All, I'm obviously a complete novice as far as 18650 and Li-Ion or LiPo batteries is concerned although I do have a reasonable amount of knowledge as far as Electronics design goes, ...
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36 views

Could I get a second pair of eyes to check if this BMS can be used for charging?

I'm new to electric engineering and electronics in general, so as a first project I'm building a battery using 18650 cells (4S4P). I am aware of the risks when buying from Chinese suppliers on ...
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78 views

Connecting six protected 18650 cells 3S2p for close to 12V, suggestions?

I want to make a 12V range battery array with 2P 3S 18650 cells. The cells will be charged in an external charger NOT in the pack. They are removable in holders So I can pluck them out and charge ...
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1answer
544 views

Design a BMS (overdischarge protection)

I am tired of BMS that doesn't work the way I want, so I have decided to made my own BMS. Searching on internet I have found the schematic for a 4S BMS and I want to understand how it works before try ...
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63 views

Can LiFePO4 BMSes be connected in parallel without causing charge/discharge issues?

I have two LiFePO4 battery packs in 4S configuration: one with 2x4 cells (4S2P) and one with 3x4 (4S3P) cells. Each pack has a 4S BMS. Are there any potential issues with connecting those two in ...
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1answer
50 views

Different chemistry of batteries in operation

I had an idea of using different chemistry of batteries as shown in the schematic figure Is that possible to design a system in that way. According to the design, I am using all the evaluation boards....