![]() ![]() Two 100Ah deep-cycle batteries joined in parallel would provide 200Ah of 12V power, three would provide 300Ah of 12V power, and so on. Running two deep-cycle batteries in parallel means they are connected to each other in order to increase the capacity of the 12V system, in amps, without affecting the voltage – i.e., 12V DC energy remains available to power the system. Otherwise when connecting in parallel, very high inrush currents will flow, leading to possible sparks or even damage.If your caravan was fitted out by its manufacturer with numerous 12V appliances, from wireless phone chargers to a compressor fridge, there’s a good chance it was also fitted with two house batteries joined in parallel.īut what does this mean, exactly? And can you create your own parallel battery ‘bank’ PARALLEL UNIVERSE Installation tip #īefore connecting cells or banks parallel, always make sure the voltage of each cell of bank is about the same as the others. ![]() Conclusion #įor safety reasons, always add a power relay to each bank in parallel. This ensures that if one BMS shuts down the bank, for example because of an overvoltage, the other bank can continue to operate. The power relay per bank is also needed for redundancy. That is why you need to give each bank it’s own power relay: to give the BMS the option to disconnect itself from the other banks, preventing overcharging of the healthy cells. This means that the 13.2V of bank 2 is distributed over the 3 working cells in bank 1, charging each healthy cell to over 4.2V! However because a second bank (bank 2) is in parallel, this bank will directly start to charge bank 1 to keep it to the same voltage as it’s own bank. If cell 2 in bank 1 would ever go bad and drop to a very low voltage (0.5V), the total bank voltage would drop. Under normal conditions, the bank voltage is about 3.3V x 4 cells = 13.2V. Let’s take as example two banks with each 4 cells in series. That is why you need a BMS per bank.īesides a BMS, each bank also needs a power relay to fully protect the bank. In example: in you have two banks parallel, it can be that the voltage of cell 1 in bank 1 is quite different from the voltage of cell 1 in bank 2, even though the bank voltage is the same. When multiple banks are parallel, the voltage of each cell in a bank is not the same as the voltage of the same cell number in a different bank. In this case, each battery bank needs it’s own BMS. Multiple banks in parallel #Įven though placing cells in parallel cuts in BMS cost, sometimes multiple banks in parallel are required. ![]() This means that you need 8 cells in total: each 2 cells are parallel, then this parallel branch in series with the next parallel branch.Įxample of 2P4S with the 123\SmartBMS. For example: when you want a 12V battery with a capacity of 200Ah and you want to build this from 100Ah cells (3.3V), then configure the battery as 2P4S. The capacity of a string of cells parallel is the sum of the indivual capacities. This means that you do not have to monitor each cell in parallel, but only the voltage of the whole parallel branch. The voltage on each cell is always the same. The big advantage of cells parallel is that the cells keep each other balanced. Each situation has advantages and disadvantages and, of course, things to look out for. To increase capacity, multiple cells can be connected in parallel or you can place multiple battery banks in parallel. For example, because you want to increase the capacity of an existing battery, or perhaps because the desired cell capacity is not available in one battery package. Placing multiple battery banks or cells in parallel increases capacity. ![]()
0 Comments
Leave a Reply. |