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Home  resources bms_options
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.
Sophisticated digital technology, able to measure and report every cell voltage, and to calculate SOC
To see additional information, hover your cursor over the  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)
| Fan
drive
(11)
| Contac.
drive
(12)
| Displ.
(13)
| Case
(14)
| Price,
14-cell
[US$]
(15)
|
American Electric Vehicles
(no link: site not navigable)
| US
Colorado
| 
| Centralized
| ?
| Any
| -
| -
| ✓
| ✓
| CAN
| -
| ✓
| -
| Metal
| ?
|
| Black Sheep Technology
| US
No. Carolina
| 
| Central w/slaves
| 4~any
| Any
| ✓
| ✓
| ✓
| ✓
| Serial
| ✓
| ✓
| ✓
| Plastic /
metal
| 2600
|
| Elithion
| US
Colorado
| 
| Distrib.
| 1~255
| Sml cyl
Lrg cyl
Prism.
Pouch
| ✓
| ✓
| ✓
| ✓
| Wire
CAN
RS232
| ✓
| ✓
| Avail.
| -
| 485
|
n.a.
| 117
|
Genasun
Available from Battery Space
| US
Mass.
| 
|
Distrib.
| 1~24
|
64 mm
prism.
| ✓
| ✓
| -
| -
| Wire
RS232
| -
| ✓
| -
| -
| 1595
|
| Lithium Balance
| Denmark
| -
| Central.
| 4, 8, 12, 15, 19 or 23
| Any
| ✓
| ✓
| ✓
incl.
| ✓
| Wire /
simplex
RS232
| -
| -
| Incl.
| Metal
| 365
|
Ningbo Yangming
(no link: attack website)
Sold by Elite Power
| China
Zhe Jiang prov.
| 
| Central. w/slaves
| 10,20,
30...100
| Any
| -
| ✓
| ✓
| ✓
| ?
| ?
|
| Incl.
| Metal
| 1689
|
PackTrakr
from KJHall Motor Co
| US
Colorado
| 
|
Central. w/slaves
| 6~30
| Any
| -
| ✓
| ✓
| -
| RS232
| -
| -
| Incl.
| Plastic
| 290
|
| REAP systems
| UK
England
| 
|
Modular
| 4~168
| Any
| ✓
| ✓
| ✓: 2 inputs
| ✓
| Wire
CAN
RS232
RS485/
RS422
| -
| ✓: 2
| Avail.
| -
| 697
|
Company
(1)
| Location
| Picture
(2)
| Topology
(3)
| No of cells
(4)
| Cell shape
(5)
| Balan.
(6)
| Temper.
(7)
| Curr.
sense
(8)
| "Fuel
gauge"
(9)
| Comm.
(10)
| Fan
drive
(11)
| Contac.
drive
(12)
| Displ.
(13)
| Case
(14)
| Price,
14-cell
[US$]
(15)
|
Also:
Simple analog technology, just able to detect that some cell's voltage is too low or too high
To see additional information, hover your cursor over the icons.
- Company: 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.
- Picture:
• Click to see the complete picture (if available)
- Topology (more info):
• 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
- Number of cells: this is the acceptable range in the number of cells in series. The number of cells in parallel does not matter.
- 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
- 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.
- 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.)
- 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.
- "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.
- 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.
- Fan: The BMS is able to control or drive a cooling system
- 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.
- Display: Either the BMS includes a SOC display, or the company sells a display that is compatible with the BMS.
- 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.
- Price: from manufacturers' websites or discussion with them or their clients. Conversions into US $ based on rates effective at the time of writing. Quantity of 14 cell chosen because it is the highest number that all systems are able to support. Unless otherwise noted, prices are for small quantities.
Regulators (also called "equalizers") are sometimes used in Li-Ion packs as a simple protection against overcharging. A regulator is required across each cell.
What regulators do:
- Regulator can keep individual cells in a battery from overcharging, but that's all they do
- 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
What regulators don't do:
- 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:
- 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:
Companies that offer custom BMS designs:
- 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)
- Metric Mind, US - Oregon
- MPower / Axeon Power - UK - Scotland
- Energy CS - US - California
Some open source, DIY BMS projects:
List of available BMSs (not just Li-Ion)
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Commercially available, sophisticated digital BMS electronics
