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Parallel Batteries-Introduction, Effect, And Connection

Jan 28, 2021   Pageview:42

Nowadays, batteries play a major role in our lives. Nearly every electronic gadget we use in our everyday life is connected to us. This is because most computers have been made portable, and a battery is the portable power source that powers all the gadgets.

Most gadgets use batteries in either series or parallel connections, so people are interested in knowing the effects of connecting batteries differently. Here is a descriptive guide on the batteries' parallel connection and its consequence in various aspects.

What is a parallel battery?

In parallel connections, batteries of similar voltages and capacities are connected to improve the overall assembly power. The positive terminals of all batteries or common conductors are connected together. All negative terminals are also connected in the same manner. As long as assembly power remains the capacity of each battery of this connection, the final voltage will remain unchanged. These combinations are also referred to as parallel batteries.

Reasons for parallel battery connection

  • To get the desired capacity in the factories.

  • To maximize the charge.

  • For better serviceability and longer battery life

  • For better battery redundancy in the field

Advantages of parallel connection

The advantage would be that suppose it is a light bulb and that are the output devices connected in parallel. If one bulb broke, the others would continue to go. Therefore, the brightness of the bulbs will be greater than the brightness of the bulbs in a series.

Additional key advantages:

  • Cells in parallel will last longer.

  • All circuit elements are regulated by one component.

  • The remaining bulbs will not be harmed if one of the bulbs is burned.

  • In a parallel connection, the voltage does not increase or decrease.

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What happens when you connect batteries in parallel?

It is the most commonly asked question about connecting the batteries in parallel. Many people asking for these types of connections are either working on fixing their devices or working on a project themselves.

So if you are thinking about connecting batteries in parallel, then there are two different situations, i.e., connecting different batteries or the same batteries. Let's dive into each of them in detail:

Connecting different batteries in parallel

So, if you're thinking of connecting two separate batteries in parallel, the answer is no. This is because the most crucial rule for connecting the batteries in parallel is that they must be the same in terms of their voltage and power. This is because if you follow this very significant rule, you will end up facing some consequences.

Consequences of using two separate batteries in parallel.

When you connect two separate batteries, one will have more voltage than the other. In this case, the better battery is going to start charging a battery that isn't that good. This is going to create more problems than you can think of. The issue that you will have to face with two separate batteries is:

Decreasing the efficiency of the batteries.

As one of the batteries will charge the other, this will reduce the efficiency of the batteries. This is because with the intended use, the better battery will never be able to provide all the energy, and the low battery or low-capacity battery will also use the better battery's power to charge itself.

Not only will the individual efficiency of the batteries decrease, but the efficiency of the entire device will also decrease.

Connecting the same batteries in parallel

While connecting two separate batteries can leave you in some serious trouble, doing so with the same batteries can give you impressively productive results. Here we're going to talk about what happens when you connect the batteries in parallel and how things get productive by doing that.

If the two batteries are connected in parallel, the current capacity doubles, and the output voltage stays the same as a single battery when the batteries are connected in parallel.

For example, suppose two batteries with the same rating, i.e., 1800 mAh, 12 V, are connected parallel. The output voltage of the parallel circuit remains 12 V, but the current capacity becomes 3600 mAh. If you connect more similar batteries in parallel, the output voltage will stay the same, but the current capacity will continue to be added.

The battery increases the output power with a parallel combination. In short, the total output voltages remain the same if the batteries are connected in parallel, but the output capacity is increased.

Hope that you understand the same battery parallel combination benefits. Still, if the parallel batteries are not similar, it will not function as we discussed above.

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Can you connect batteries in parallel with different amp hours?

Yes, you can attach the batteries of different Ah-in parallel with the diodes. In parallel, you can use diodes to connect your batteries to the UPS. The diodes prevent one battery from charging or discharging another battery.

But it is essential to note some potential issues:

  • Check your battery chemistries: Sealed lead-acid batteries, for example, have different charging points than flooded lead-acid systems. This means that if the two are recharged together, certain batteries would never be fully charged. The consequence here will be the sulfation of those who never enter a full state of charge, which would shorten their lifetime.

  • Double-check voltages: The voltages will likely be different (even though the specified voltage on the labels matches) if you are using batteries with different amp-hour power. Check this with a voltmeter, or you will face issues (covered in the above parallel relation of batteries with varying voltages).


So here, we have addressed some of the key points about connecting batteries in parallel. Now you can quickly address all the issues regarding the parallel batteries.


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