Do batteries last longer in Series or Parallel?

Although, batteries connected in Series versus Parallel will offer roughly the same amount of runtime.

It often noticed that series connections provide a higher voltage, which is slightly more efficient for home uses. This simply means that batteries wired in series can last marginally longer than batteries wired in parallel.

But a parallel connected battery will offer you marginally more backup, as capacity gets double when you add the second battery. The only limitation is you cannot run high-end machines, as heating issues will make it inefficient compared to batteries connected in series connection.

Series
Parallel

Let’s understand the case with an example:

Here we took 12 Volts 150 Ah at C10 inverter batteries to test this down.

Series connection:

In a series connection, you’ll get a total of 24 Volts and 150 Ah of capacity.

If you put a 360 watt load on it, the system will run for 10 hours.

Watt Hours = (12 V × 150 AH) × 2 Units = 1800 × 2 = 3600 Watt Hours.
Backup Time = 3600 Watt Hours / 360 Watts = 10 Hours.
  • Series connected batteries do not overheat easily.
  • Series connection are easy to learn and to make, higher voltage is good for all kind of setups.
  • We can add more load devices, they have a higher output in terms of voltage.
  • It’s the single point of failure, if any battery stops working.
  • Suitable for large setup with heavy load.

Parallel connection:

In a Parallel connection, you’ll get a total of 12 Volts and 300 Ah of capacity.

If you put a 360 watt load on it, the system will run for 10 hours.

Watt Hours = (12 V × 150 AH) + (12 V × 150 AH) = 1800 + 1800 = 3600 Watt Hours.
Backup Time = 3600 Watt Hours / 360 Watts = 10 Hours.
  • Series connected batteries do overheat easily, if you assign more load on it.
  • Parallel connection is easy to learn and to make, but higher amps are dangerous to manage.
  • We cannot add more load devices, because voltage remains the same.
  • If one battery stops working, the setup will work with half backup.
  • Suitable for small setup with low load.

In conclusion, there is no such big difference unless you define a load that eliminates one system. Until there is any bottleneck or heating issues, you won’t notice any difference. But for big loads, I’ll recommend series connection.

Published by AtulHost

Creator of AtulHost. An ardent Linux user. Comes from a business management background. Loves to do research on modern business insights and enterprise solutions like career, education, finance, investments ideas, marketing strategies, and productivity skills; technological trends like automation, artificial intelligence, cloud and edge computing, computer hardware and networking, data science, and the internet of things.

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