Hunan AUK New Energy Co., Ltd.
Hunan AUK New Energy Co., Ltd.
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1.What is the common port and separate port? what is the difference?
We take 13S48V16A BMS as an example, common port 16A means your charge cathode and discharge cathode are connected in the same point end(our P-), charge cathode and discharge cathode are used in the common connection port, so the charge current and discharge current are the same 16A. while the separate port is separately connected by charge cathode (C-) and discharge cathode (P-), so the charge current and discharge current are different, discharge current 16A, charge current 8A.
2.What is the balance function?
The working principle and function are as followings, when your one cell voltage is up to alarm voltage(Li-ion up to 4.18V, Life Po4 up to (3.6V), then the cell Balance starts to work, balance resistance starts discharge with 35ma(when balance discharge starts to work, BMS will starts a little heat up, which is the normal reflection), the cell is in both charging and discharging status, and others which are not reached to alarm voltage(Li-ion 4.18V, Life Po4 3.6V) are only in charging status, no discharging, when the fast cell voltage is reached to alarm voltage(Li-ion 4.25V, Life Po4 3.75V)BMS starts off power protection, all the other cells are all in stop of charging, this process will enable your battery charging in balance current, and your battery voltage are in balance status, but when your cell voltage difference are in a big range, then balance can not be functioning well .
3.The relationship between Battery capacity and BMS current?
There is no direct relationship between Battery capacity and BMS current, big capacity doesn’t mean a big battery, but rely on continue current, that is to say if your engine is powerful, your should choose high current of BMS, it is not relied on battery capacity.
4. What type of charger should I choose?
Lithium battery must choose specific charger, do not use Charger for Lead acid battery, for lead acid charger may have MOS with high pressure breakdown protection, which will not protect of BMS over charge.Life Po4 battery charger voltage=battery string No.X3.6V, while Li-ion battery charger voltage=Battery string No.X4.2V.
5. What current BMS should I choose ?
Take 10S36V as an example: what current BMS you choose is relied on your E-bicycle Motor power and current limitation of controller. eg., choose 16A for below 350W, 25A for below500W, 35A for below 800W, 60A for Below 1000W, higher than 1200W are contact with our service specialist for suggestions, one in all, continue current shall be higher than current limitation in Controller.
6. Whether my BMS damaged?
if you want to judge if the BMS is damaged, please take the following steps, to test if each cell voltage is the same with voltmeter? if the cell voltage difference is over 1.0V, the fault is displayed that it cannot run far, no power supply at the start range, short charge time, all these issues are almost caused by battery cells, if BMS damaged is displayed as no charge, no discharge, no discharge while the battery has voltage.
Attention When Connecting:
When we connect BMS with cells or disassemble BMS from battery pack, the following order and regulations must be complied with to avoid damage of components of BMS and problems of not protecting of cells.
In order to achieve the best performance of BMS and to run the longest distance, all the battery must be matched well (Each battery voltage difference less than 0.05V, IR difference less than 15 mΩ, capacity differenace less than 30mAh) to make sure the better consistency of the battery.
Cell must be connected in parallel first, after then connected in series.
(The BMS and parallel BMS modules must be used together and can't be mixed using. Wiring should be done according to the purchased parallel BMS module corresponding to the current.)
Method 1 (the BMS and the parallel BMS module wire are not connected): After the BMS is assembled, when the parallel BMS module is connected to the BMS, first connect the parallel BMS modules P-wire to the BMS (the common port is connected to the BMS P-wire, and the separate port is connected to the BMS C- wire), and then connect B- and B+ in turn . After the wire is connected, first plug the BMS and parallel BMS module ports, then the B+ port, and plug the control signal wire to the protection board finally;
Method 2 (BMS and parallel BMS module lines are connected): first plug the BMS and parallel BMS module ports, then plug into the B+ port, and finally plug into the control signal line to the BMS;
※Please strictly follow the above two methods for wiring, please operate in sequence if the wiring sequence is reversing, it will cause damage to the parallel BMS module .
NOTICE:
Protection (Current Sensor Anomaly)
This problem exists when the inverter is used, because the current direction is uncertain,
The alarm will be displayed. It does not affect the normal use of BMS.
This kind of alarm will appear when the sun is not big or small, because at this time,
the battery fluctuates frequently between charging and discharging,
and there are uncertain factors, so this problem occurs.
A pure sine wave inverter does not draw a constant current. The current from the battery follows a sine wave shape.
It ramps from zero current up to peak current in 1/4 of a cycle.
The peak current is actually about 40% more than the average current.
Then the current will ramp back down to zero at the 1/2 cycle time. At this point, the inverter reverses polarity,
and ramps the current back up again, hitting the peak at the 3/4 cycle time. The battery current is positive again,
and the inversion happens in the inverter circuit. The the current ramps down back to zero again at the end of the cycle.
The process them repeats for every cycle.
If you measure with an averaging meter, you will just see a fairly steady current that should be close to the true RMS current.
I use a True RMS Fluke meter, and it is able to give a vey accurate reading on this odd waveform.
The current reading in the BMS just measures the voltage across a shunt resistor. This reading is only taken periodically,
and it is not synced the the changing current from the inverter. It might take a reading at zero current, or at the peak current,
but most likely, it will fall somewhere in between.
Due to the shape of the wave, the reading tends to bounce a bit above and below the true RMS current.
It is not perfect, but over the long term, it is "good enough" for the BMS to calculate the amp hours charged in or discharged out of the battery.
This works because if you average the readings over a full hour, the high and low readings will average out.