Weak current College】 【photovoltaic power generation batteries parallel use considerations.

<br> <br> <br> ---- Over a long period of time, from antiquity to the present, whether domestic or foreign, or whether communication systems or the UPS systems, people are accustomed to using two batteries parallel up and .a UPS or a communications device. Do not know because habits forces or other reasons, this parallel using way became designers and users' one must adhere to the principle, but in my view, it is not, as long as the user can follow the .battery manufacturer's instruction manual for battery maintenance, only one set of batteries is sufficient, not only sufficient, but this set of batteries use effect (eg battery of stability, reliability, balance, especially the battery life, etc) rather than using two sets of .batteries used in parallel. Especially for VRLA battery, especially so. So, why are active advocates the author (or even not in favour) should not use the battery pack in parallel, parallel use of tradeoffs? <br> <br> First, .let's review some of the characteristics of a parallel circuit. In a parallel circuit, the total voltage is equal to the voltage of the tap. In other words, plus the two groups in parallel the battery in each group on the battery charge voltage and charging .voltage equal, ie U total = U1 = U2. Also according to the I = U / R formula, you can tell the result calculation, I1 ¡ .ù I2 (because the internal resistance of the two sets of batteries is definitely not the same, namely, R1, R2 ¡ù U1 = U2, sure that results of I1 ¡ù I2). This means that, in the same amount of charging .voltage, two sets of parallel use of the battery pack, each group of the charging current is not the same, the internal resistance of the charging current is small, the internal resistance is smaller, the charging current. This can cause a charging current of .the battery charging current is less than the State, with the passage of time, this set of batteries may be long-term lack of electricity and sulphate more intensified its internal resistance, its internal resistance, the larger the charging current is smaller, because such .a vicious circle which leads this group battery life significantly shortened. But only one set of batteries is not the case. In this connection, it is sufficient to show use of a single set of batteries by far better than parallel use. Therefore, it is .recommended that the user can use a set of batteries you can meet the needs of the device, never use two sets of batteries parallel use, both will shorten the battery life, increase the use of cost, and reduces the battery's performance, should not do .such a waste of resources. <br> <br> If the device's power, with two sets of batteries parallel still does not meet the requirements of device power, with 2 groups above, such as group 3, group 4, or even more sets .of batteries parallel use, it would be unnecessary, two sets of batteries parallel use has brought many adverse, more sets of batteries parallel use becomes even more complex, more negative. In this case, be sure to choose to meet your equipment needs of the .bulk power models of battery, if there is no 12V series battery capacity specifications, you can choose the 2V series battery, 2V series battery, various large capacity, you can say you need and how much you can do much, as far as I know ., currently existing 2V series battery maximum achievable 6000Ah, our largest can provide to 300Ah. <br> <br> Of course, designers and users from the standby power supply reliability this point to consider is also understandable that fear if the AC power failure, .the two groups of cells in a group cannot power can also have a different set of batteries to ensure that even the stem is wasteful of anything of value. If it is from this point of view and consider adopting battery parallel use, I also only support .a maximum of two sets of batteries in parallel, if more than 2 group is absolutely parallel the unhelpful. If non-2 battery shunt is unavailable, requests the members should also observe the following principles: first, the parallel use of the battery must be .the same manufacturer, and is the same model, same specifications battery; the second is the parallel use of the battery must be consistent with the new and old state; the third is the same lot number at the factory; the fourth is also installed at .the same time. <br>.