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Li-Ion BMS options

A comparison of commercially available Li-Ion BMSs

These tables compare Li-Ion BMSs available on the market today.
This information does not constitute an endorsement of any of these companies and products.
While the information presented here is believed to be accurate, Elithion takes no responsibility for any errors.
Please send us comments, corrections and additions.

back to topBMS types

This table explains the difference between digital and analog BMSs, and between Protectors, Balancers, Monitors, Displays and Regulators.
Reports individual cell voltages Balances the battery Requests that battery be switched off Includes switch to turn off battery
Digital Protector
Balancer
Monitor
Display
Analog Protector
Balancer
Monitor
Regulator

back to topPrices
Digital BMSs anchor
Price vs number of cells
Protectors (thick dotted line), Balancers (thick line), Monitors and displays (thin dotted line).
Note: log scales. Sources: (15)
Analog BMSs anchor
Price vs number of cells
Protectors (thin line), Balancers (thick line).
Note: log scales. Sources: (15)
back to topDigital Protectors

Sophisticated digital technology, able to measure and report every cell voltage, to calculate SOC, to balance the battery pack, and to cut-off the battery current.

To see additional information, hover your cursor over the more info icons.
Company
(1)
Location Picture
(2)
Model Topology
(3)
No of cells
(4)
Cell shape
(5)
Temper.
(7)
Curr.
sense
(8)
"Fuel
gauge"
(9)
Comm.
(10)
Fan
drive
(11)
Contac.
drive
(12)
Displ.
(13)
Case
(14)
All New Energy
Distributed by Lithium Batteries Australia (LBA) / Battery Manufacturer's International (BMI) / LifeBatt
Taiwan. Click to see the BMS VMS / GBTS Modular 1~24
more info
Any - - Wire
serial
more info
- - -
more info
-
more info
Genasun US
Mass.
Click to see the BMS GLD Distributed
more info
1~24 64 mm
prism.
more info
- - Wire
RS232
more info
-
more info
-
more info
-
Lithium Balance Denmark
more info
Click to see the BMS 'C' series Master / slave
more info
4, 8, 12, 15, 19 or 23
more info
Any
more info

more info

incl.
Wire /
simplex
RS232
more info
- - Incl. Metal
Lithium Start US - CA
San Francisco
Click to see the BMS BluFlex Centralized
more info
4 Any - - -
more info
- - - -
Company
(1)
Location Picture
(2)
Model Topology
(3)
No of cells
(4)
Cell shape
(5)
Temper.
(7)
Curr.
sense
(8)
"Fuel
gauge"
(9)
Comm.
(10)
Fan
drive
(11)
Contac.
drive
(12)
Displ.
(13)
Case
(14)

back to topDigital Balancers

Sophisticated digital technology, able to measure and report every cell voltage, to calculate SOC, to balance the battery pack, and to request that the battery current be shut off to protect it. Does not include a switch to cut off the battery current.

To see additional information, hover your cursor over the more info icons.
Company
(1)
Location Picture
(2)
Model Topology
(3)
No of cells
(4)
Cell shape
(5)
Temper.
(7)
Curr.
sense
(8)
"Fuel
gauge"
(9)
Comm.
(10)
Fan
drive
(11)
Contac.
drive
(12)
Displ.
(13)
Case
(14)
American Electric Vehicles
(no link: site not navigable)
US
Colorado
Click to see the BMS - Centralized 1~150 Any CAN
Serial
- Metal
Black Sheep Technology US
No. Carolina
Click to see the BMS Stack V1 Master / slave 1~32
more info
Any Serial -
more info
Cage V2 1~48
more info
Serial
Mini V3 Any
more info
Serial
BMS Auto V4 Any
more info
Serial Automotive
grade
Convert the future
Resold by Jungle Motors
US
CA
Click to see the BMS Flex BMS48 Centralized 48 Any Internal Bus - Plastic
Company
(1)
Location Picture
(2)
Model Topology
(3)
No of cells
(4)
Cell shape
(5)
Temper.
(7)
Curr.
sense
(8)
"Fuel
gauge"
(9)
Comm.
(10)
Fan
drive
(11)
Contac.
drive
(12)
Displ.
(13)
Case
(14)
Elithion US
Colorado
Click to see the BMS Lithiumate™ Distributed 1~255 Sml cyl
Lrg cyl
Prism.
Pouch

more info
Wire
CAN
RS232
Avail. -
more info
EVST China
Guangzhou
Click to see the BMS BMS-4 Master / slave ??? ??? CAN
RS485
- - Metal
Peter Perkins
more info
UK Click to see the BMS - Distributed 1~255
more info
Prismatic Wire
RS232
- - Included -
more info
REAP systems UK
England
Click to see the BMS - Modular
more info
4~168
more info
Any ✓: 2 inputs Wire
CAN
RS232
RS485/
RS422
more info
- ✓: 2
more info
Avail. -
more info
Company
(1)
Location Picture
(2)
Model Topology
(3)
No of cells
(4)
Cell shape
(5)
Temper.
(7)
Curr.
sense
(8)
"Fuel
gauge"
(9)
Comm.
(10)
Fan
drive
(11)
Contac.
drive
(12)
Displ.
(13)
Case
(14)

back to topDigital Monitors

Sophisticated digital technology, able to measure and report every cell voltage, to calculate SOC, and to request that the battery current be shut off to protect it. Not able to balance the battery pack.

To see additional information, hover your cursor over the more info icons.
Company
(1)
Location Picture
(2)
Model Topology
(3)
No of cells
(4)
Cell shape
(5)
Temper.
(7)
Curr.
sense
(8)
"Fuel
gauge"
(9)
Comm.
(10)
Fan
drive
(11)
Contac.
drive
(12)
Displ.
(13)
Case
(14)
Guantou China
Heilongjiang
Click to see the BMS GTBMS005A-MC8 Master / slave 100
more info
Any Wire - -
more info
Click to see the BMS GTBMS005A-MC11 Wire, CAN, USB
more info
Click to see the BMS GTBMS005A-MC16
Click to see the BMS GTBMS005A-MC17
Lithium Start US - CA
San Francisco
Click to see the BMS BluFlex Distributed
more info
Any 26650 small cyl. - - Wire
more info
- - - -
Company
(1)
Location Picture
(2)
Model Topology
(3)
No of cells
(4)
Cell shape
(5)
Temper.
(7)
Curr.
sense
(8)
"Fuel
gauge"
(9)
Comm.
(10)
Fan
drive
(11)
Contac.
drive
(12)
Displ.
(13)
Case
(14)
KJHall Motor Co US
Colorado
Click to see the BMS PackTrakr Master / slave
more info
6~30 Any
more info

more info
- RS232 - - Incl. Plastic
Worley Parsons
Rebranded by Leo industries,
Singapore
UK Click to see the BMS LBSU-4-100 Centralized
more info
4~28
more info
Any LiPo
more info
- - Wire /
simplex
RS232
more info
-
more info
- -
Ningbo Yangming
(no link: attack website)
Sold by Elite Power
China
Zhe Jiang prov.
Click to see the BMS BMS40 Master / slave 10,20,
30...100
Any
more info
? ? Incl.
more info
Metal
Unknown Manuf.
Rebranded by Richard Edminston / RCEV products / Pensacola FLA (no website)
China Click to see the BMS - Master / slave At least 32
more info
Any
more info
CAN Incl.
more info
Metal
Company
(1)
Location Picture
(2)
Model Topology
(3)
No of cells
(4)
Cell shape
(5)
Temper.
(7)
Curr.
sense
(8)
"Fuel
gauge"
(9)
Comm.
(10)
Fan
drive
(11)
Contac.
drive
(12)
Displ.
(13)
Case
(14)

back to topDigital Displays

Sophisticated digital technology, able to measure and report every cell voltage, and to calculate SOC. Not able to balance the battery pack; does not protect the battery (does not request that the battery current be shut off).

To see additional information, hover your cursor over the more info icons.
Company
(1)
Location Picture
(2)
Model Topology
(3)
No of cells
(4)
Cell shape
(5)
Temper.
(7)
Curr.
sense
(8)
"Fuel
gauge"
(9)
Comm.
(10)
Fan
drive
(11)
Contac.
drive
(12)
Displ.
(13)
Case
(14)
CasaDelGato US
Washington
Click to see the BMS - Master/Slave 10
more info
Any
more info
- - - - -
more info
Plastic
Electric Blue Motors US
Arizona
Click to see the BMS Blue View Distributed 1~255
more info
Any - - -
more info
Metal

back to topAnalog protectors

  • A protection circuit is a BMS that also includes a way to interrupt the battery current to protect the battery (unlike a protection circuit, a standard BMS must rely on external devices (charger, motor controller, contactors) to reduce or stop the battery current when the BMS tells them to)
  • Protection circuits usually are meant for small batteries (cell phones, laptops) as they can usually only handle a few Amps of battery current

Sources of commercially available circuit protectors for small Li-Ion batteries:

back to topAnalog Balancers

Simple analog technology, just able to detect that some cell's voltage is too low or too high, but unable to report which one. Able to balance the battery.

To see additional information, hover your cursor over the more info icons.
Company
(1)
Location Picture
(2)
Topology
(3)
No of cells
(4)
Cell shape
(5)
Balan.
(6)
Temper.
(7)
Curr.
sense
(8)
"Fuel
gauge"
(9)
Comm.
(10)
Displ.
(13)
Case
(14)
Price,
14-cell
[US$]
(15)
Agni motors
Stybrook Ltd
Cedric Lynch
India / Britain Click to see the BMS Distributed 1~200 Prismatic - - - Wire - - 261
Black Sheep Technology US
No. Carolina
Click to see the BMS Distributed 1~any Prismatic
more info
-
more info
-
more info
-
more info
-
more info
-
more info
- 560
Blade Electric Vehicles Australia
VIC
Click to see the BMS Distributed ? Prismatic ? ? ? ? ? ? ?
Clean Power US
Florida
Click to see the BMS Distriduted
more info
Any Prismatic
more info

more info
- - - Wire - - 198
Company
(1)
Location Picture
(2)
Topology
(3)
No of cells
(4)
Cell shape
(5)
Balan.
(6)
Temper.
(7)
Curr.
sense
(8)
"Fuel
gauge"
(9)
Comm.
(10)
Displ.
(13)
Case
(14)
Price,
14-cell
[US$]
(15)
Elithion US
Colorado
Click to see the BMS Centralized 8~24 Any Wire
RS232

more info
-
more info
204
more info
EV power
Distributed by EV Works
Australia
W. Aus.
Click to see the BMS Distributed 1~any Prismatic - - - Wire -
more info
Metal
more info
186
High Tech Systems
more info
US
Colorado
- Distributed
more info
1~any
more info
Sml cyl.
Lrg cyl.
more info

more info
- - Wire
more info
Incl.
more info
-
more info
480
Shenzhen Soopower Technology China
Shenzhen
- Centralized 10 Any - Wire - ? ?
Company
(1)
Location Picture
(2)
Topology
(3)
No of cells
(4)
Cell shape
(5)
Balan.
(6)
Temper.
(7)
Curr.
sense
(8)
"Fuel
gauge"
(9)
Comm.
(10)
Displ.
(13)
Case
(14)
Price,
14-cell
[US$]
(15)

back to topAnalog Monitors

Simple analog technology, just able to detect that some cell's voltage is too low or too high, but unable to report which one. Does not balance the battery.

To see additional information, hover your cursor over the more info icons.
Company
(1)
Location Picture
(2)
Topology
(3)
No of cells
(4)
Cell shape
(5)
Balan.
(6)
Temper.
(7)
Curr.
sense
(8)
"Fuel
gauge"
(9)
Comm.
(10)
Displ.
(13)
Case
(14)
Price,
14-cell
[US$]
(15)
Belktronix
Bryan Belk
US
California
Click to see the BMS Distributed 1~44 Any - - - - Wire - - ?
 

back to topRegulators / Equalizers / Balancers

Regulators (also called "equalizers" or "balancers") are sometimes used in Li-Ion packs as a simple protection against overcharging. A regulator is required across each cell.

A regulator performs balancing during charging by bypassing charging current from the fully charged cells, so that other cells in the battery can finish charging.

balance on cell
Elite Power Solutions Battery Balancer.

What regulators do:

  • Regulator remove excess energy from cells whose voltage is above a certain threshold, but that's all they do

What regulators don't do:

  • Regulator can't keep individual cells in a battery from overcharging
  • Regulator don't monitor the entire battery, and don't report on its status
  • Regulators do not protect a pack from undercharging
  • Regulators are not able to tell the charger to stop charging: a human has to keep an eye on the regulators (which usually have LEDs) and shut down the charger
  • Regulators cannot not tell external devices to slow down or stop charging or discharging; therefore, a pack with regulators can still be under-charged, and overcharging may damage the regulators
  • Regulators can't protect themselves from overheat: they will be damaged if a CCCV charger's end current is higher than the regulators can bypass

Sources of commercially available regulators for Li-Ion cells:

back to topNotes
  1. Company: Trade names are the property of their respective owners. A few other companies are getting ready to offer Li-Ion BMSs, but are not yet ready to be listed here (for example, Evie Systems). Some cell manufacturers (most notably Valence) offer proprietary BMS for their cells, only available as part of a complete battery.
  2. Picture:
    • Click to see the complete picture (if available)
  3. Topology (more info):
    • BMS: does not include a switch to cut off the battery current
    • Protector: includes a switch to cut off the battery current
    • Centralized ("spaghetti"): single BMS controller with n+1 wires going to n cells
    • Centralized with slaves: single BMS controller connected to a few slave boards, each with n+1 wires going to n cells
    • Modular: single BMS controller with n+1 wires going to n cells; expanded by adding more, identical BMS controllers
    • Distributed: small board mounted on each cell; BMS controller connected just to the 2 cells at either end of a battery
  4. Number of cells: this is the acceptable range in the number of cells in series. The number of cells in parallel does not matter.
  5. Cell shape:
    • Small cylindrical: cylindrical cells to be welded, such as the 18650 or the 26650 sizes
    • Large cylindrical: cylindrical cells with screw terminations at either end
    • Prismatic: boxy cells with screw terminations on top, such as Thundersky
    • Pouch: soft bags with tabs on one end, such as Kokam
    • Any: there are no electronics on the cells, so the BMS works with all the above, using wires
  6. Balance: The BMS is able to remove energy just from the most charged cells, to allow the other cells to reach the same level of charge. A balanced pack will have the maximum possible capacity. This is not as important for Hybrid Electric Vehicles.
  7. Temperature: The BMS is able to measure and report individual cells' temperature. (The 'more info' tells you if the temperature measurement is not for every cell.)
  8. Current sense: The BMS includes a current sensor or at least an input for a current sensor, to measure battery current. This enables the BMS to react to excessive current, and to calculate the SOS or DOD.
  9. "Fuel gauge": a.k.a.: "Gas Gauge". The BMS calculates the SOC (State Of Charge) or DOD (Depth Of Discharge), by integrating the battery current. Devices that simply use the voltage to estimate SOC are not included here.
  10. Communications: In general, the BMS must communicate with the rest of the system, to report the status of the pack, and be able to limit charging and discharging of the pack, in order to protect it.
    • Wire: separate wires are used, each with a single, specific function, such as to turn on the charger relay.
    • CAN: CAN bus, common in vehicles and European industrial equipment.
    • RS232: serial point-to-point communication, usually used only for initial set-up and testing, but some time also available for communication during operation.
  11. Fan: The BMS is able to control or drive a cooling system
  12. Contactors: The BMS is able to control or drive a set of contactors between the battery pack and the load, including a precharge relay. Many motor controllers already have this function built in, so BMS controller that includes this function is not required.
  13. Display: Either the BMS includes a SOC display, or the company sells a display that is compatible with the BMS.
  14. Case: Whether the BMS controller is enclosed (metal or plastic case), or it is an open PCB assembly. Unless otherwise noted, any cell-mounted boards are assumed to be open PCB assemblies.
  15. Price: from manufacturers' websites or discussion with them or their clients. Conversions into US $ based on rates effective at the time of writing. Unless otherwise noted, prices are for small quantities.
back to topCustom BMSs

Companies that offer custom BMS designs:

  • Axeon Power - UK - Scotland
  • Black Sheep Technology - US, No Carolina
  • Boundless - US - Colorado:
    • Producing packs and standalones with integrated BMS to OEM customers
    • For Cobalt Oxide, Iron Phosphate and Titanate cells
    • "Fancy" BMS, distributed topology, master-slave set-up with no sense wires (uses fiber optic cables)
    • Current Sense, Fan Drive, Contactor Drive, Display optional
    • Comm: RS232, CAN, I2C, TTL
    • Two product lines: standalone and pack
      • standalone: Com wires between cell BMS
      • pack: Com wires between modules (24v multiples in the pack architecture)
  • Energy CS - US - California
  • Metric Mind, US - Oregon
  • MPower (Axeon Power) - UK - Scotland
  • REAP - UK
  • BMS, from ITI Energy, for which they invested 1.5 million pounds!
  • Generic BMS, from Ricardo: central with slaves (up to 16 cells / slave), very high measuremeny accuracy.
back to topDIY BMSs

Some open source, DIY BMS projects:

List of available BMSs (not just Li-Ion)
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