Project Description
7.4v 8.8Ah 8800mah li-ion battery pack for solar pump kit
This battery pack with nominal voltage 7.4v. And when it is fully charged, the voltages goes up to 8.4v. Also, the battery charger for this pack should be 8.4v as well. This 8.8ah 7.4v battery pack made by 2S4P 18650 rechargeable li-ion battery cells. With built in BMS protections. CMX factory supply this 8800mah battery pack for OEM order in bulk quantity. Welcome send your design for quotation.
7.4 volt 8800mah li-ion battery
Specifications
7.4v Li-ion 18650 battery pack 8800mah
The 7.4v 8800mah li ion battery pack apply with high-quality 2s Lithium ion battery cells, Battery pack with PCM/BMS protections. The charging voltage is 8.4 volt. Can be install to any small applications. When you place order, you can contact with our sales to get required capacity. 8000mah, 8800mah and 10000mah all available. We can use different cell to get different capacity without change dimensions of the pack.
7.4 volt 8.8ah structure.
The battery system build by 2S PCM. can effectively charge and discharge the battery pack . The PCM prevent any battery overcharge, over discharge caused by damage, And can control the battery charge, discharge current，Ensure that the battery pack and applications are not damaged；To ensure that in the event of a short circuit failure when the output off and automatic balance of the application of the battery pack at any time in the best condition. The 7.4v 8800mah lithium battery packed with Blue PVC. Provide protection from any physical damage.
Safety and economical
7.4v with Newest ICR18650 cells. Battery cell is tested before assemble. It does not have toxic chemicals and offers four times the power density at a third of the volume compared to lead acid. For these reasons it’s safe for household use.
Excellent discharge characteristics
7.4 v 8.8ah or 8000mah With low internal resistance and high, flat voltage characteristics during strong current discharge, which ensures a wider application field. POS machines.
Long cycle life
8ah 7.4 volt battery pack Provide long storage life with few limiting conditions. It offers problem-free charge after long storage, permitting to use in a wide range of applications.
Safty Test:
- Over-charge test
- Over-discharge test
- Short-circuit test
- High-temperature test
- Fire test
- Squezzing test
- Pin-Prick test
- Fall down test
- Water immersion test
- Shooting test
7.4v 2S li ion PCM protection
Overcharge protection: When the battery is under the charging state, the voltage keeps going up. When the protection board detects that the voltage of any cell is higher than the overcharge protection value, the protection board will start timing immediately. When the time reaches the overcharge protection delay, the protection board will turn off the charging MOS tube, at that time, it cannot be charged.
Overcharge protection recovery: After the overvoltage protection appears on the protection board, the battery voltage will going down under the static or discharge state of the battery. When the protection board detects that each voltage is lower than the recovery voltage of the overcharge protection, the protection board will output a signal and turn on the charging MOS tube to charge.
Over-discharge protection: When the battery is under the discharge state, the voltage keeps going down. When the protection board detects that the voltage of any cell is lower than the overcharge protection value, the protection board will start timing immediately. When the time reaches the over discharge protection delay, the output signal of the protection board will turn off the discharge MOS tube, the load lock circuit will work, but, it cannot discharge at this time.
Over discharge protection recovery: After the over discharge protection appears on the protection board, the battery voltage will going up under the static or discharge state of the battery. When the protection board detects that each voltage is higher than the recovery voltage of the over discharge protection. At this time, disconnect the load or charge, the protection board will output a signal and turn on the charging MOS tube to charge.
Overcurrent protection: When the battery is under the static or discharge state, the current suddenly increases. When the protection board detects that the current reaches the overcurrent protection value, the protection board will start timing at that time. When the current duration in the circuit reaches the overcurrent protection delay time, the output signal of the protection board will turn off the discharge MOS tube, and the load lock circuit will work. At this time, the discharge cannot be conducted.
Overcurrent protection recovery: After the discharge overcurrent protection appears on the protection board, the discharge MOS tube is turned off, and the current in the loop becomes 0. At this time, the load is disconnected or charged, the output signal of the protection board will turn on the discharge MOS tube to discharge.
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name |
7.4 volt 8000mah, 8800mah li-ion battery pack | |||
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Nominal Voltage |
7.4 volt |
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Nominal Capacity |
8ah, 8.8ah, 10000mah (can be customised) |
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Charge End-off Voltage |
8.4v |
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Discharge End-off Voltage |
6V |
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Charging Method |
CC-CV |
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Initial Charging Current |
Standard Charge |
0.2C |
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Max. Charge |
>10℃ |
1.0C |
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0~10℃ |
0.2C |
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Max continious discharge current |
5A (can be customised) |
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peak discharge current |
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10 A (can be customised) |
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Weight |
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390g |
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Main Protection Function |
Over Charge, Over Discharge, Over current, Short Circuit |
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Operating temperature |
charge -10-50℃ |
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discharge -20-60℃ |
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Storage temperature |
1 month:-20-45°C |
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3 months:-20-35°C |
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6 months: -20-25°C |
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What would cause a battery or battery pack not to take a charge?
- Zero voltage battery or zero voltage battery in the battery pack;
Lithium ion battery like polymer or 18650 li ion. They are very sensitive on low voltage. Normally, the battery or battery pack come with BMS, it has the function prevent over discharge. However, the bms circuit could be damaged for some reason. And battery cell fully discharged to 0. In this situation. The battery cell could be damaged permanently.
- Battery pack connection error, internal electronic components, protection circuit abnormal;
- Charging equipment failure, no output current;
- External factors cause charging efficiency to be too low (e.g. very low or very high temperature).
What to do when the battery pack does not charge
Step 1. Check the connections.
It may seem improbable, but the stability of any power connection is limited by its weakest link. Check the contacts and terminals for dirt, oils, corrosion, excessive wear or anything that can hamper a good, stable connection. This includes the battery contacts with application, in the charger, and on the battery itself.
Step 2. Reseat the battery in the devices.
It seems unlikely, but it happens. Some application require a tight fit with the battery and may seem attached when they are not fully locked in place. Make sure the battery is seated properly and the battery pack locks firmly in place when attaching it.
Step 3. Verify you are using the correct battery charger.
Using the wrong charger can not only prevent your battery from charging properly, it could damage your equipment. It can also be potentially dangerous.
Step 4. Check to be sure the charger is plugged in and turned on.
Sound silly, doesn’t it? Well, it isn’t really, because it does happen. It’s one of the easiest mistakes to make when charging a fleet of batteries and one of the simplest to resolve.
Step 5. Reseat the battery in the charger.
Battery seems like it’s connected to the charger when it’s not making contact at all. If it is a drop-in or desktop charger with a pocket or tray, the radio and/or battery may be able to sit in the tray without actually touching the contacts. If it is a plug-in type of charger, the plug may not be fully inserted. Be sure the radio/battery is properly seated or fully connected and the charging indicator light is on.
Step 6. Charge another battery of the same make and model in the charger.
Determine if the issue is really with the battery pack.
Step 7. Swap out the charger.
Sometimes a dead battery is the result of a dead charger.
Step 8. Charge the battery again.
Just to be sure, give it another chance.
Every battery has a limited life span determined by a number of different factors, including but not limited to how and where it is used, how much it is used and under what conditions. There is no set time table before a battery “kicks the bucket”. If your battery has reached its End of Life, it’s time to purchase a new one.
What are the main factors affecting battery life? 3 things you must know.
There are different reason affecting battery cycle life. Here we peak up some Main reasons to explain. So you can have a better understanding and how to take care of your batteries.
Charge the battery:
When selecting a charger, it is best to use a charger with the correct termination charging device (e.g. anti-overcharge, negative voltage differential (-dV) cut-off charging and anti-overheating sensing) to prevent the battery shorten circle-life due to overcharge. In general, slow charging extends battery life more than faster charging. So, we suggest charging a battery with small current go gain longer life cycles.
Discharge:
The depth of discharge is the main factor affecting battery life cycles, and the higher the depth of discharge, the shorter the battery life. In other words, reducing the depth of discharge can significantly extend the battery life. Because
For this reason, we should avoid over-setting the battery to very low voltages.
- When the battery is discharged at high temperatures, it shortens the life of the battery.
- If the design of electronic equipment can not completely stop all current, if the equipment is put on hold for a long time, without removing the battery, its residual current will sometimes cause the battery to be excessively consumed, resulting in excessive discharge of the battery.
- When a battery with different electrical capacity, chemical structure or different charging levels is mixed, and a battery of different ages and sizes, the battery will also discharge too much, and may even cause anti-polar charging.
Storage:
If the battery is stored at high temperatures for a long time, it will attenuate its electrode activity and shorten its service life.
How to charge a 12 volt lithium ion battery
First check what kind of lithium battery you have. There are major 2 type of lithium battery in the market. 3.7v cell and 3.2v cell. And find out the full charge voltage. If the cell is 3.7v. Nomally full charge voltage is 12.6v( 3S lithium ion battery. when fully charged, each cell 4.2 volt). While if it is 3.2v cell. When it fully charged, the voltage is 3.65 volt. 12 volt lithium battery pack fully charged is 14.6 volt.( 4S 3.2 v cell). Make sure your charger voltage is compatable with the 12v lithium battery.
Please note that not all Li-ion batteries charge to the voltage threshold of 4.20V/cell. Lithium iron phosphate typically charges to the cut-off voltage of 3.65V/cell and lithium-titanate to 2.85V/cell. Some Energy Cells may accept 4.30V/cell and higher. It is important to observe these voltage limits.
Important to Lithium battery chargers
Lithium cells (18650, lipos, LiFePo4 etc.) which require the charging cycle CC-CV (constant current, constant voltage). The battery system may work for other types for batteries as well, as long as they wants to be charged with CCCV.
CC-CV varies the voltage to constantly deliver the current set by you. When the voltage reaches the battery’s maximum charge voltage, the current is gradually decreased so that the voltage does not exceed the set value.
3.2v LiFePo4 cells
3.7v Lithium ion cells
Lithium battery Charger guide List
| Nominal Voltage | Battery type | series | Charging voltage |
| 12v | 3.7v lithium ion | 3 | 12.6v |
| 3.2v LiFePo4 | 4 | 14.6v | |
| 24v | 3.7v lithium ion | 7 | 29.4v |
| 3.2v LiFePo4 | 8 | 29.2v | |
| 36v | 3.7v lithium ion | 10 | 42v |
| 3.7v lithium ion | 11 | 46.2v | |
| 3.2v LiFePo4 | 11 | 40.15v | |
| 3.2v LiFePo4 | 12 | 43.8v | |
| 48v | 3.7v lithium ion | 13 | 54.6v |
| 3.7v lithium ion | 14 | 58.8v | |
| 3.2v LiFePo4 | 15 | 54.8v | |
| 3.2v LiFePo4 | 16 | 58.4v | |
| 60v | 3.7v lithium ion | 17 | 71.4v |
| 3.2v LiFePo4 | 20 | 73v | |
| 72v | 3.7v lithium ion | 20 | 84v |
| 3.2v LiFePo4 | 24 | 87.6v |
