Balancing is one of the most important aspects of lithium-ion batteries. This is because lithium-ion battery packs contain multiple groups of cells in parallel and series. The parallel cells are able to transfer energy between each other and maintain a self-balance, but the series cells cannot do this.

This is why some sort of external balancing circuit is required. In an ideal scenario, you would not have to worry about balance because the cells are all the same anyway.

In reality, however, variations in the manufacturing process and other factors will make even batteries with perfectly matched cells eventually come out of balance.

Active balancing is able to redistribute energy between the series groups of a battery pack to ensure that they all have the same state of charge. This is done with a sophisticated circuit that is able to connect to the higher voltage cell group, take the excess energy from it,

connect to a lower voltage cell group, and then transfer the stored energy to them to bring them into balance. Because of this, active balancing is the more accurate and faster approach to battery balancing.

In contrast, passive balancing relies on Ohm’s Law and the natural cell and balance resistor characteristics to bring cells to the same state of charge. This method works by literally burning off the excess energy in the higher voltage cell groups,

which is wasteful. Because of this, passive balancing is generally less accurate and slower than active balancing and in cases where the cell groups are significantly imbalanced, the low and slow passive balance current may be totally unable to bring the battery to balance.

Technical Parameters

EnerKey BMS Active Balancer 5A 3S 4S 5S 6S 7S 8S 14S 16S 18S 19S 20S 21S LFP LTO LI-ION lifepo4 Balancer Capacitor Balancer
Product model	EK-C16S5A	EK-C17S5A	EK-C21S5A
Product strings	16S	17S	21S
Suitable strings	12-16S	13-17S	17-21S
Product Size(mm)	L125*W91*T16	L115*W102.5*T16	L145*W130*T18
Weight with box	0.32kg	0.33kg	0.39kg
Battery Type	NCM/LFP/LTO	NCM/LFP/LTO	NCM/LFP/LTO
Suitable capacity	30ah-300ah
Voltage equalization accuracy	5mV (typical value)
Balanced Cascading	Support balanced cascading for battery packs, for example , it can cascade for 11S , 24S ,36S , 48S....and so on
Single cell voltage collection range	NCM/LFP version : 2.7V-4.2V
	LTO version : 1.8-4.2V
Undervoltage protects sleep voltage	NCM/LFP version＜2.7V
	LTO version＜1.8V
Under voltage protection Start balancing voltage	NCM/LFP version: 2.835V
	LTO version: 1.89V
Equilibrium method	Patented (Patent No.: ZL 2019 1 1259513.3) balanced architecture Fit capacitor method, the entire battery pack is balanced at the same time. Connect to the battery pack for automatic balancing (default). You can add a switch to manually turn on or off balancing.
Equilibrium current	0.1V Differential pressure 1A Balanced current,
	the differential pressure is proportional to the balanced current,
	the maximum allowable operating current is 5.5A
External power supply	No need for an external power supply,
	relying on the internal energy transfer of the battery to achieve sdjacent equalization.
Quiescent operating current	7mA, the total string draws power
Sleep standby current	0.1mA(typical value)
Operating Temperature	-20℃ ~ +60℃

Packing List

Wire connect

A single EK-C21S5A supports the use of 17 and 18 and 19 and 20 and 21 string battery packs. The wiring method is as follows:

EK-C21S5A supports cascading battery packs. Fox exmple, 2pcs of 21s cascade to 41s, see below drawing:

NOTE:As shown in the figure above,there can be multiple common ends of energy exchangeso that the efficiency of equilibrium will be higher;It is also possible to use only one common end of theenergy exchange atthejunction of two modules.

The other free feet are suspended, and it is best todistribute the number of strings equally on each board.If you need the cascade diagram for more strings, Please contact our online service, Thanks.

FAQ

Q1. Why did we choose you?

* We can provide you with efficient after-sales service, with more than 10 years of strong technical support.

* Products have passed FCC, CE, ROHS and other international standards certification.

* We can provide you with factory price, Welcome you to visit our factory and production process.

Q2. What is your product range (type)?

*We mainly do battery management systems in the fields of power batteries, energy storage batteries and consumer batteries.

*Mainly used for LFP, Li-ino and LTO batteries.

Q3: How do I know which kind of material & type my battery is ?

*Please look the battery body, If the normal voltage of your battery shows 3.2V, The battery is LiFePo4.

*If the normal voltage of your battery shows 3.6V or 3.7V, the battery is Li-ion or Lto battery.

Q4. Do you have minimum order requirements?

Can it be customized? What is the lead time for samples and batches?

*Our minimum order quantity is 1 piece, ODM customization is available.

* 1~3 days delivery of existing samples, 3~10 days delivery of customized samples.

Q5: What if i can't use it?

*Regular products have instructional videos, We can also support online video call guidance from engineers.

Q6. What are your terms of payment?

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Q7. How do you guarantee the quality?

* All our products are subjected to professional laboratory 100% testing, as well as repeated aging tests.

* Obtained FCC, CE, ROHS and other international standard certification.

* Provide 3 years after-sales warranty service. Free spare units for replace in 3 years.

Q8. How to choose a BMS suitable for our battery?

*Depending on the voltage and current that matches your battery, you can consult our customer service and we will provide it for you equipped with the most suitable battery management system.

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*We have 7x24 hours online service, Please leave us a message online.

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