Features for the 12V 4S BMS:
- Top Quality
(A-level) Protective Circuit IC
- Strong Load
Ability, Constant Discharge Current, High Voltage Resistance, Low Inner
Resistance Power Mosfet
- IC itself has
power balancing function. The circuit is simple and reliable.
- Extremely Low
Power Consumption. The consumption of the whole device is less than 50uA.
- The PCB uses
high anti-corrosion, high water resistance, and high impedance ESD
Specifications for the 4S BMS:
CHARGE PROTECTION VOLTAGE
DISCHARGE DETECT VOLTAGE
TEMP F (C)
First, Preparation before installation
Make sure the batteries are of a good consistency, the voltage
difference is no more than 0.05V, the inner resistance is no more than 5
milliohms, and the capacity difference is lower than 30mAh. Connect the
batteries in parallel first and then in series. The better the battery
consistency is, the higher the performance of the BMS.
Second, Wiring instructions
Attention: Please use our wires for our BMS. Don’t use other
factories’ wires because they don’t match up with our BMS.
Step 1, B-(blue thick wire): Connect to battery pack total negative
Step 2, Disconnect the wires for batteries from the BMS side.
Step 3, Connect the wires to batteries. Start from the thick black
wire to total negative pole (B1-), then connect the 2nd red
thin wire to the 1st battery positive pole (B1+) B2+, B3+, B4+
… till the last red thick wire.
Step 4, When you are finished connecting all the wires to each
battery, don’t plug into the BMS directly. We suggest you use a multimeter to
measure the voltage of two adjacent metal terminals (You can see the white
connector with silver metal pins on the BMS). If the voltage is 3.0~4.2V (LiNCM),
2.0~3.6V (LiFePO4), 1.5~2.75V (LTO), then the wiring is correct.
Step 5, Ensure the wires are connected to the batteries correctly
and the voltage is normal. Then you can plug the wires into the BMS.
Step 6, P-: Connect P-(black thick wire) to load – and charger –
(if you ordered “common port”).
Charger+ connect to C-(yellow wire) load+ connect to P-(black
(if you ordered “separate port”).
Step 7, charger+ and load+ connect to battery+. Please use thick
Third, Measure the total voltage of the pack and the output voltage
of the BMS. If the voltage is the same, it means the wiring is correct. You can
use the BMS now. Otherwise please check the wiring again according to the tips
Frequently Asked Questions about the BMS/PCB
1, Which current PCB should I use?
Take a 13S 48V pack as an example: Which PCB you should use
depends on the power of your motor or the current limitation of your
controller. Below 350W, you can use 16A. Below 500W, you can use 18A, Below
800W, you can use 35A, Below 1KW, you can use 60A. Above 1200W, the same. If
you are not sure, please contact us.
2, Can I use a bigger size of PCB than is indicated?
Suppose you need 60A PCB but you chose 80A, that will work.
80A allows for a higher current. A bit higher price is the only
But if you choose 50A, it will be too small. So you can use a
higher spec but not a lower one than it should be.
3, What kind of charger should I choose?
A Lithium Battery must be charged by a Lithium Battery Charger.
You can’t charge it with a lead acid battery charger because the lead acid
battery charger might damage the MOS pipe of the PCB.
4, if I have a PCB, do I need any balancers?
Yes if you add QNBBM balancers, that will be perfect.
The Main function of the PCB is to prevent batteries from over-charging
over-discharging, over-heating etc.
With balancers added, the batteries lifespan will be longer and
the capacity will get fully used.
5, How do I judge if my PCB is broken or not?
If you’d like to judge if the PCB is fine or not, please use a
multi-meter and see if the voltage of each cell is close to one other or not.
When the voltage difference is 1V, the battery will have this kind of
performance: the driving distance will be short, it will be cut off when
started, the charging time will be very short. Under such a situation, a
battery is defective. When the PCB is broken, the battery can’t be discharged.
When you measure the battery voltage, it will be normal.
* SHIPPING/PAYMENT OPTIONS *
There are 2 ways to get an exact quote for the base shipping for
your 12V 4S EV BMS (Battery Management System) order.
us at (801) 449-0681 9am-5pm Monday-Friday or email firstname.lastname@example.org
or go through our Contact Us
your order by clicking in the shopping pallet “Proceed To Checkout”
your information so we can get you a shipping quote
the “Shipping Method” of preference
the “Choose one payment method” has “Shipping Quote Request” selected
the “Check Out” button
receive a confirmation email of your request, as will we
We’ll research the exact shipping cost and send you an invoice
to your PayPal or email or you can add it to your pallet in $1 Shipping Increments for your 12V 4S EV BMS (Battery Management System) order.
discounts show in the “Shopping Pallet”.
We love to meet or beat any competitor’s price!
Higher volume discounts, price matching or questions?
Contact Carl, our resident specialist.
9am-9pm Mon-Sat MDT
or through our Contact