Are 20V batteries interchangeable? (Are they universal?)

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Asking whether 20V batteries are interchangeable is really asking a couple of questions. Firstly, whether you can fit a battery designed for one type of device into another. The second question is whether you can use one 20-Volt battery technology in place of another. We are going to answer both of these questions here.

So, are 20-Volt batteries interchangeable? It depends on the situation. You can easily switch battery technologies. However, you may not be able to fit a battery designed for one device into another.

Throughout the rest of this page, we are going to help you to determine whether you can switch your 20-Volt batteries with another set.

Can You Switch Ni-CAD batteries for Lithium-Ion Batteries?

Yes, you can switch them!

As you may well know, Lithium-Ion batteries have a number of distinct advantages over Ni-CAD batteries. For example, they can last longer (they tend to have a higher AH), and they do not suffer from the memory effect.

As long as the Lithium-Ion battery has the same fitting as the Ni-CAD battery that you are replacing, then it is absolutely fine to do.

The thing that you are powering just wants power. It doesn’t really care where the power is coming from. In fact, the machine can’t tell the difference between a Ni-CAD and a Lithium-Ion battery. It just knows that it is getting power from a battery that has been plugged into it.

The only thing that you need to be aware of here is that battery chargers may not be compatible across the various battery technologies.

So, if you are going to be swapping out NI-CAD batteries for a Lithium-Ion battery, then you will want to double-check that the charger that you have is capable of charging your new batteries. However, if it has been purchased within the last few years, it probably will be. 

Are 20-Volt Batteries Interchangeable Between Devices?

For the most part, no. They could potentially be, but they are not.

Most 20-Volt batteries are used in power tools. Batteries are often the most expensive part of any cordless tool. As a result, power tool manufacturers only want you to purchase their batteries. They do not want you to purchase cheaper batteries from other battery suppliers. 

This means that even if the Voltage of the battery is going to be the same, the fitting won’t be the same. This means that you won’t be able to connect the battery to your tool.

As long as the battery has the same fitting as the one that you are going to replace, then you should be fine. 20-Volts is still 20-Volts. As we said in the previous section, the machine isn’t going to be particularly fussed about where the power is coming from. All it cares about is that it is getting the power that it needs to work.

Are 20-Volt Battery Cells Interchangeable?

We are going to say no, even though they potentially could be.

At the end of the day, a power cell in a 20-Volt battery is the same as a power cell in any other 20-Volt battery. In theory, you could open up a battery and switch the power cells around. However, it isn’t something that we would particularly recommend.

Batteries are a great deal more complicated than they were in the past. They have all sorts of electronics wired up inside of them, and battery chargers work in a very specific way.

There is a chance that if you swap the battery cells around, the new battery cell may not be compatible with the battery tech in the new battery. This means one of the cells won’t work. The battery may still be able to pump out a small amount of power, but it won’t be able to pump out all of the power that it needs.

Of course, it is also a huge amount of hassle swapping power cells around. It takes a lot of wiring, and you run the risk of doing something wrong. This could cause the battery to become damaged.

This is before you even factor in the fact that the new battery cell is going to be newer than the other battery cells. This means the new cell may hold more of a charge than the others inside of the battery.

So, while it is possible, don’t do it. It really isn’t going to benefit you in any way.

Can You Use 20-Volt Batteries As a Substitute For Another Voltage?

So, what about using a 20-Volt battery as a substitute for a battery of a lower Voltage?

Well, the same rules apply. If the fitting is the same, then it should work. However, in most cases, it isn’t really recommended.

If you swap an 18-Volt battery for a 20-Volt, this should be fine. The Voltage is close enough that it won’t be a massive problem.

If the battery you are replacing is 9 or 12-Volt, then don’t do it. The 20-Volt will be supplying too much power to the machine. This can drastically reduce the lifespan.

If you are looking to replace a battery larger than 20-Volts, then it may not work. This is because the 20-Volt battery won’t be able to supply enough power to keep the machine running properly. Again, you may find it works a little if the Voltages are similar (e.g. 20-Volt to 24-Volt), but if you were looking to replace a 40-Volt battery, you really have no chance.   


For the most part, 20-Volt batteries are not universal. They could be universal, however since selling batteries is highly profitable for companies, they want to ensure that only their batteries are compatible with their devices so you have no alternative but to buy their product.

As long as the battery fittings are the same, you will find that battery technology is universal. So, if you want to upgrade your batteries to a newer technology e.g. Lithium-Ion, then you should have absolutely no issues with the upgrade. However, you may want to check to see whether your charger is compatible.

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