What is the difference between an 18v and 40v battery and which do you need in your tools? The obvious answer is that 40v is more powerful so that’s the best option, but it isn’t that simple. This article will explain the differences between the two batteries and help you decide which is right for your specific needs.
What’s the Difference Between an 18v and a 40v Battery?
A 40v battery has more power cells than an 18v battery, giving it a higher voltage. What that means is that it uses power more efficiently and, in practice, makes the tools you use more powerful. When using large garden tools, a 40v battery could give you the additional power you need for tough jobs, and the battery life will be longer too.
There is a physical difference between the batteries too. A 40v battery will be larger and heavier, which is something you should consider if you are using tools all day long.
Can You Use a 40v Battery on an 18v Tool?
No, the 40v batteries are much larger than the 18v ones and have a different mechanism for fixing onto the tools, so they won’t be interchangeable. Even if you could put a 40v battery into an 18v tool, you would most likely do some damage to it, so it would be best avoided anyway.
Can You Use a 18v Battery on a 40v Tool?
No, it doesn’t work this way around either because the batteries are a different size and shape. You can get dual chargers that will charge both types of battery, but they are not interchangeable in tools.
The only exception to this is with some Dewalt tools. They have some tools that will let you use both batteries, but only on the new models.
Will a 40v or an 18v Tool Have More Power?
A 40v tool will usually have a lot more power than an 18v tool. You have more power cells, so the current being put into the tool is used more efficiently. However, this is only true if the tool itself has the capability to utilize that extra power. If the motor in a hedge trimmer, for example, is already working at full capacity with an 18v battery, a 40v version wouldn’t give you more power. But if a more powerful motor was combined with the larger battery, you can expect to see a higher output. So, it is largely down to the battery but the quality of the tool itself needs to be up to scratch too.
Does an 18v or 40v Battery Take Longer to Charge?
An 18v battery is roughly half the size of a 40v battery, so you’d expect it to take half the time to charge, but that isn’t the case. An 18v battery does charge a bit faster, but there isn’t a huge difference between the two. The Makita battery charger, for example, will charge the 40 battery in around 45 minutes. The 18v battery takes just under 40 minutes on the same charger.
Will an 18v or a 40v Battery Drain Faster?
The battery life is not only affected by voltage, it is more determined by the amps. To determine the average battery life, you multiple the amp hours by the voltage. So, if you have an 18v battery and a 40v battery that both have the same amps, the 40v battery will give you much longer run time. However, that is not always the case if the amp hours are different. So, make sure that you check both if you want an idea of run time.
Can You Charge an 18v Battery with a 40v Charger?
If you have a standard 40v charger, you won’t be able to fit a normal 18v battery in it, in most cases. However, many tool companies now provide chargers that are compatible with both batteries. So, if you have a newer model, you may be able to use a dual charger, but older models are more limited.
Can You Charge a 40v Battery with an 18v Charger?
No, if you are using an older battery that is not compatible with dual chargers, you will have to use a 40v charger.
Which Batteries are More Affordable Between 18v and 40v?
The price difference between the two batteries is not that big. If you compare these 18v and 40v batteries, both compatible with Ryobi tools, you will see that the 40v is slightly more expensive, but not by much. So, if you are deciding between the two, the price isn’t a major factor.
Are 18v Batteries Heavier in Weight than a 40v Battery?
No, an 18v battery has roughly half the amount of power cells that a 40v one does, so the 40v is bigger and heavier. It should still be manageable, but if you’re using tools in a tight space and mobility is a priority, you may prefer a smaller 18v battery.
Can You Buy a 40v and 18v Adapter Kit?
Yes, you can buy a 40v and 18v adapter kit for your charger. This allows you to use one charger to charge both batteries. However, there is not an adapter option that allows you to use the batteries interchangeably on tools. There are details online about how people have made their own, but this is not advisable if you don’t know what you are doing as it could be dangerous.
What’s the Difference Between a 40v and 18v Drill?
A 40v drill gives you more power and a longer run time than an 18v drill, but do you really need one? The 40v drill will cost you more, and the batteries will be more expensive too. It will also be a larger, heavier tool to handle. In most cases, an 18v drill is more than adequate for general DIY jobs, while the 40v drill is used for professional jobs.
Specific Brand Comparisons
Ryobi 18v vs 40v?
Ryobi is considered an entry-level tool brand but both their 18v and 40v lines are excellent quality, especially considering the price. When it comes to choosing between the 2, it depends what you are looking for.
The 18v line has more options and the batteries are more affordable. For general household tools like drills and impact drivers, the 18v battery is excellent. The 40v line is best for garden tools. You can get some great cordless string trimmers and leaf blowers that give you the same power as a gas powered alternative, without any of the noise.
However, the 40v batteries are quite a bit more expensive. You can save a bit of money if you buy tools and batteries in bundles, but the cost still adds up. So, if you are just doing a few odd jobs around the house, there is no sense buying the 40v range. But if you do a lot of heavy yard work, the 40v range is excellent.
When it comes to run time, both the 18v and 40v are not as good as other options. Make sure that you check the amp hours and go for the higher option (though this will be more expensive) if run time is a priority for you. The 6.0 Ah 40v battery will give you the longest possible work time.
Makita 18v vs 40v?
Makita tools are known for their reliability and you can be sure that you’ll get great performance regardless of whether you buy the 18v or the 40v option. Makita currently has more tools available for their 18v batteries, so it’s the better choice if you need a wide range of tools. However, they are giving more support to the 40v range and there are still a lot of excellent options available.
Just like the Ryobi range, there is really no need for the average DIYer to invest in the 40v range because the batteries are more expensive and you probably don’t need that much power anyway. Yard tools are perhaps the only exception to this. Even large tools like their circular saws and grinders give you great performance with an 18v battery.
Dewalt 18v vs 40v?
The Dewalt 18v range is good for simple jobs but many of the yard tools don’t hold up well when faced with tougher tasks. Take the weed strimmer, for example; it works well on the low setting if you are cutting back a bit of an overgrown garden but it won’t go through woody plants. You can turn it up to the high setting but you will soon burn through the battery.
You’ll have the same issue with a lot of the 18v tools and you may want to go for the 40v alternatives if you have a lot of heavy yard work to tackle. The 40v Ego lawn mower is also far superior to the lower voltage options because you need the excess power for the bigger tools.
Having said that, Dewalt does an excellent job of maximizing the power that their tools get from an 18v battery. Their circular saws, for example, make use of brushless motors to give a nice power increase, making the 18v option more than powerful enough for everyday use. So, you can save a lot of money without making too many sacrifices on performance by opting for the 18v range.
The Verdict – Which One Should I Choose?
You may assume that 40v batteries are better because they’re more powerful, but do you really need it? In most cases, an 18v tool is more than powerful enough for your needs. If you are a professional and you need heavy duty tools that can handle tough jobs for extended periods, you may want to invest in the 40v ranges. Otherwise, the 18v batteries are cheaper and they are more than capable of handling everything you can throw at them, especially with improved tool technology.
Read our related battery article:
- 18v vs 20v Battery | What’s the Difference?
- 12v vs 18v Battery | What’s the Difference?
- Can You Use a 40v Battery in a 20v Tool?
- What Is the Difference Between a 2.0Ah Battery and a 4.0Ah Battery?
Jamie is the Founder of My Home Dwelling. He is a homeowner and enjoys sharing his homeowner tips with others. He has real estate experience working as a new home construction Realtor. Jamie has worked on numerous residential construction sites helping with interior and exterior renovations. He loves refinishing furniture, DIY home projects, and sharing his knowledge online.