Having good Lithium cells are not enough.
The importance of a good LifePo4 Battery is often related to how the battery is constructed internally.
I was not paid by Meritsun to write this article nor did they provide the batteries free. The batteries were purchased from my own funds.
The image below shows the internal construction of the Meritsun 100Ah LifePo4 Battery. Unlike most Lithium battery suppliers the BMS (circuit-board) is designed and built by (or built for) Meritsun as well as the Meritsun bluetooth App. The BMS is shown below situated at the top of four LifePo4 cells which are linked together with sturdy Busbars (solid copper with nickel plate). Each 3.2 volt cell is individually monitored and if you look closely you can see the small black wire (NTC) in the centre of the battery, this is the temperature sensor. Lithium iron phosphate cells (LifePo4) are much more stable than Lithium-ion cells, they are less likely (almost impossible) to combust.
BMS: If you look carefully you will see a small PCB, its green coloured, this is the Bluetooth circuit-board (its quite small). At the bottom left hand corner there is a tiny gold button (you need to look carefully). This gold coloured button is the “re-set” button. The white plug at the very bottom are were the battery monitoring cables connect one from each cell plus the black NTC wire (temperature monitor).
What you cannot see: The cables bolts shown on this battery are made firm with silicone before final assembly. This is to prevent any bad connections later.
The LifePo4 Battery has its own Bluetooth App that shows the battery status as well as the staus of each cell.
Hidden Feature: (not visible on the app – shown below)
Hold your finger down on the Menu Page for about 10 seconds and slide to the left or right and it will reveal the Cell Voltage Display
Below: The batteries have arrived
You cannot be serious! You are going to cut a brand new LifePo4 battery open?
I want to see inside and the only way is to cut the battery open. Fortunately I have a brand new empty battery case with screw-on top so I will be able to build the battery and it will be like brand new again.
Below: The cutting begins
Below: Its very well sealed and not easy to open
I am finally inside the 100Ah Meritsun Battery: As you can see the construction is very well made. The blue flashing led is the Bluetooth/Power status (its switched on). I noticed the circuit board is a little different to the factory issue image above, it may have been upgraded. It looks like the separate green bluetooth PCB has been moved to another location on the PCB perhaps the BMS has been redesigned. Also each bolt or screw is sealed with white silicone to prevent them coming loose, a nice small feature. Another tiny feature is that Meritsun have even used clear heat proof tape on the NTC temperature sensor instead of normal tape. Cable ties have been placed around many of the cable groups and the cells sit inside a Plastic Framework which stops any movement and keeps them very secure. All Power Cables are a good thickness and sturdy.
Below: all the cells are factory balanced before shipping.
Removable Top Battery Case:
Another feature that is available from Meritsun is that you can specially order a LifePo4 Battery with a Battery Case that has a screw-on top and can be opened. Not everyone will want this but anyone with some electrical knowledge may want to access the inside of the case should there be a fault or problem. For example if a cell was to fail then it can be replaced.
Now its time to put the battery into a new case.
How good is the battery and the service?
The battery appears to be excellent although I haven’t had them long enough to fully say. Only after a year or two will I know. However, the service from Meritsun is also excellent. Placing the order and payment is easy either by transfer, credit card or Meritsun will invoice you via Alibaba (safe and secure). Shipping (at the time of writing) did take a little longer than expected, I had to wait for almost 3 weeks before the batteries were shipped using air freight (DHL). However the batteries were very well protected in the box and once they were on route everything went smoothly.
Fast Shipping door to door with no duty to pay on arrival. This doesn’t mean duty is free. Meritsun offer a prepaid duty service, actually is all processed by DHL which makes shipping very easy. You pay your country’s import duty when you pay Meritsun, its built into the shipping costs that you pay. For example I paid Meritsun only one payment for everything and they paid UK tax duties to DHL in China (Worldwide) on my behalf so that when the batteries arrived in the UK they were immediately shipped to me without delay. Very fast and very simple.
If you use Whatsapp then Meritsun will keep in close contact with you. This is an excellent service feature that keeps you informed day by day.
The Video below shows the factory where many of the components are manufactured including Battery Cells. Unlike many other battery suppliers Meritsun manufactures most of their own components themselves
Guangzhou Meritech Power Co.Ltd.
Address:Room B213, B215, Building 196-208, Xin Guangcong Rd., Guangcong 2nd Rd., Baiyun Dist, Guangzhou, Guangdong, China
Click this link for The Meritsun Website