In this article, We will introduce the battery characteristics, let us tell you a few basic advantages and disadvantages of parallel and series circuits;
We will talk about what is AGM battery ? what is GEL battery ? How to choose solar battery for solar power system ? What is the battery over-discharge ? What is the battery series connection ?
What is the battery parallel connection ? AGM or GEL ? How to choose solar battery for solar power system ?
VRLA AGM battery is valve-regulated lead-acid battery (VRLA ) + Absorbent Glass Mat (AGM) technology battery. This is one kind of lead-acid battery for energy storage.
The technical features of AGM battery technology :
VRLA AGM battery uses recombinant technology. The oxygen produced from the positive plates of the battery is absorbed by the negative plates. This suppresses the generation of hydrogen at the negative plates. The recombination of oxygen and hydrogen leads to Water, retaining the electrolyte amount within the battery. Water re-filling is never required.
Compared to flooded battery, the advantages of AGM battery are :
The advantage of AGM battery in application :
Maintenance free
When battery is charging, hydrogen would be absorbed and reversed to electrolyte by plates. It doesn't need to refill water and balanced charge, which makes maintenance free.
Flexible installation
AGM separator keep electrolyte absorbed in glass mat and still. Battery can be used or positioned in any orientation.
Extremely safe
When excessive gas production by inappropriate charging occurs, safety valves will automatically emit the gas to prevent battery cracked.
Long standby life, Better cycle performance Anti-corrosion lead-calcium alloy plate provides longer float charging life. AGM separator can trap electrolyte and prevent active materials on positive plate dropping at the same time. Moreover, it gives better deep discharge cycle performance.
Longer shelf life
Special lead-calcium alloy plates make lower self-discharge for longer shelf life.
High rate performance
Low inner resistance allows higher discharging and charging current for better performance in high rate application
VRLA GEL battery is valve-regulated lead-acid battery (VRLA ) + Gel electrolyte cell technology battery. This is one kind of lead-acid battery for energy storage.
Gel battery is using gel as electrolyte instead of liquid acid. Gel is usually produced by homogeneous dispersion of pyrogenic silica in diluted sulfuric acid. Pyrogenic silica is a kind of powder of very well dispersed SiO, which absorb more than 10 times of its weight acid liquid to produce gel. Because of the thixotropic property of gel, the agglomerates are connecting themselves together as a network which keeps the liquid inside and become gel structure after a certain gelling time. The Gel battery has no liquid inside, the electrolytes is in gel form and stand solid between positive and negative plate inside battery.
The technical features of Gel battery technology :
Compared to flooded battery, the advantages of Gel battery are :
The advantage of Gel battery in application :
Maintenance free
When battery is charging, hydrogen would be absorbed and reversed to electrolyte by plates. It doesn't need to refill water and balanced charge, which makes maintenance free.
Flexible installation
AGM separator keep electrolyte absorbed in glass mat and still. Battery can be used or positioned in any orientation.
Longer lifespan in extreme weather
Gel cell electrolyte prevent electrolyte being evaporated in high temperature or being frozen in low temperature, which keep battery in high performance in extreme weather.
Extremely safe
When excessive gas production by inappropriate charging occurs, safety valves will automatically emit the gas to prevent battery cracked.
Long standby life, Better cycle performance
Anti-corrosion lead-calcium alloy plate provides longer float charging life. AGM separator can trap electrolyte and prevent active materials on positive plate dropping at the same time. Moreover, it gives better deep discharge cycle performance.
Longer shelf life
Special lead-calcium alloy plates make lower self-discharge for longer shelf life.
High rate performance
Low inner resistance allows higher discharging and charging current for better performance in high rate application
Over discharge may cause difficulties in recharging the cell by increasing the battery’s internal resistance. Also, over discharging may cause lead to be precipitated in the separator and cause a short in the cell or between cells.
See the photo, this battery already dead and there is no way to discharge, so we open it, and We can find that the battery terminals have been oxidized, white crystals adhere to the terminals of the battery, It can be judged that after a long period of use, the battery does not have maintenance and supplemental power, and causes the battery to have a low battery voltage for a long time
We do not recommend using battery voltage lower than 10.5V, it will make battery over-discharge. For a low voltage battery, the battery should be stopped immediately, and the battery should be supplemented by electricity immediately. Proper maintenance can extend battery life.
a “series circuit” will share the voltage given from the supply evenly … however the current will remain the same across the entire circuit. When the battery is connected in series, the battery voltage increases, battery current does not change.
For example: 12V 100AH x4pcs in series connection:
The total capacity is 48V 100AH (12Volts + 12Volts + 12Volts + 12Volts = 48Volts)
When you connect the batteries in series, you are keeping the total capacity the same.
a "parallel circuit" in the same scenario will split the current evenly across all paths … however the voltage across the entire circuit and all paths will be same as supply.
When the battery is connected in parallel, the battery voltage does not change but battery capacity increases.
For example: 12V 100AH x4pcs in parallel connection:
The total capacity is 12V 400AH (100AH + 100AH + 100AH + 100AH = 400AH)
When you connect the batteries in parallel, you are keeping the total voltage the same.
We can easily understand the difference of AGM and GEL by the following chart :
AGM and GEL's deep cycle are suitable for solar However, if it is a more extreme climate or outdoor, Gel’s deep cycle will have a longer life span.
| ITEM | GEL／AGM | COMPARE | |
| Electrical performance | The pores of the gel structure are narrow, so the ions are more clogged, and the internal group of colloidal sealed lead acid batteries is larger than AGM. Therefore AGM's high-power discharge performance is better. | AGM is better | |
| Size | GEL electrolyte is 20% more than AGM, and it adopts flooded process, so AGM energy density is high | AGM is better | |
| Ventilation requirements | GEL is flooded battery, The cracks generated by the gel provide oxygen circulation. GEL must be well ventilated. AGM has 8% of the gap in the separator, and no electrolyte is filled. | AGM is better | |
| Thermal runaway | The AGM sealed lead-acid battery adopts a liquid-lean design. In the separator plate, 8% of the porosity must be maintained and the electrolyte is not allowed to enter. Therefore, the internal heat of the battery is poor, and the oxygen generated during charging reaches the negative electrode, which generates heat.If you can't dissipate heat immediately, the battery temperature will increase. | GEL is better | |
| Operating temperature | GEL working temperature adaptability is better than AGM | GEL is better | |
| Cycle Life | AGM battery cycle life is about 400 times; GEL battery cycle life is about 600 -800 times | GEL is better | |
| Standby Life | Both AGM and GEL can have a long life design. | Both are good | |
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