I finally am making the switch to battery tools. Looking to buy some kits and bare tools as well. I have the option of getting two 1.5AH batteries or a single 2AH battery. In theory this should be pretty straighforward, 2 x 1.5 = 3AH. However, I feel like it might not be that simple in reality.

I've watched videos where larger batteries do things like drilling faster. I also read that smaller batteries will overheat quicker for tougher jobs. And heat is a big waste of electricity, so I would guess that it isn't simple 1.5 plus 1.5 in the end.

Of course the smaller ones also have the benefit of being physically smaller and lighter. Definitely a plus when working in cramped spaces or when drilling above your head for a long time.

What does everyone recommend when choosing between multiple small vs single large batteries?

For me specifically, I'll be using impact driver, impact wrench, hammer drill driver, grinder, maybe an oscillating tool, and not much else. I'll probably never have a circular saw (I still love my corded one). Additionally, these will all be Ridgid because the lifetime warranty is very attractive to me.

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    This is likely to be closed as primarily opinion based. But, with the two smaller batteries, you have the advantage of letting one charge while using the other. Sep 13, 2021 at 20:10
  • a smaller battery would also cool down faster than a large one, the amount of heat generated by a given operation wouldn't vary according to capacity. Larger batteries with more cells could indeed provide more current (though that's not a given), which multiplied by the same volts is more power (aka drilling faster), so you need to compare current capabilities as well as capacity.
    – dandavis
    Sep 13, 2021 at 22:39
  • Not quite duplicate, but probably of interest: electronics.stackexchange.com/q/20701/210485
    – Z4-tier
    Sep 14, 2021 at 2:55
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    Might be worth noting that some tools simply will not work properly on the lower 1.5AH and 2AH batteries. Stuff like Impact wrenches or saws can be iffy on the lower batteries since the power draw is smaller. I would recommend at least 1 4AH battery or higher for this purpose.
    – GamerGypps
    Sep 14, 2021 at 8:09
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    @isherwood I dont have any data to show but from personal experience and what ive been told by friends/colleagues /others have shown this to be true. I cant explain why that would be the case as im not an electrician. On my tools using a 2AH battery on one of my drills definitely makes it less powerful and you can hear the difference as well as feel it when using it. Not to mention my wood saw sometimes cuts out completely when using a 1.5AH battery despite the fact its still got charge, but when using a 4AH battery it does not do this.
    – GamerGypps
    Sep 15, 2021 at 13:18

6 Answers 6


If you are getting 'x' tools, where x > 1, and 'y' batteries, 'y' should be at least 2. Very simple - you will have times where you are using two tools at once. Maybe with a helper. Or maybe just switching back and forth between two tools by yourself. Not having to switch batteries every 5 minutes will make a big difference.

Plus using two batteries has the big advantage that you can use battery one until it gets low and then charge it while using the other battery.

There is a point of diminishing returns. Clearly, for most people, if you have 5 tools you don't need 5 batteries (unless you are working all day in a place where you can't charge). But 2 batteries definitely makes sense with 2 or more tools.

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    Thanks. Those are good points. I will end up with multiple batteries regardless because of a promo right now that certain tools come with a free battery. The point of the question is really just in general, comparing two 1.5ah vs a 2.0ah battery
    – mhost
    Sep 13, 2021 at 19:07
  • Mmmm.. I dunno about having vastly fewer batteries than tools; if I was doing a job that was simplified by having e.g. one drill, one driver and one cutter it would drive me more nuts having to swap the batteries than it does having to swap a drill bit for a screw bit. I;d rather just have a battery per tool then a job that needs N tools at the same time doesn't require swapping batteries
    – Caius Jard
    Sep 14, 2021 at 7:12
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    @CaiusJard Each person's situation will be a little different. But I think many people end up with more tools than they typically use in a particular task. For example, circular saw won't necessarily be needed at the same time as drill/driver. I have many power tools (not all battery powered, because I don't get new tools that often - the new ones are usually battery powered) that only get used "once in a while" where the main drill/driver gets used frequently. 2-at-a-time, sure. 3-at-a-time, maybe. But if I was likely to use 3 at once I'd probably have another 3 I'm not using that day at all. Sep 14, 2021 at 15:47

Two 1.5AH batteries is definitely better than one 2AH one for equal money if they are the same brand and chemistry.

Yes you are getting 50% more capacity. You can question the precision and behavior but that won't undo a 50% increase.

You can charge one while you use the other. Your tools will be lighter and easier to use. If one fails, you still have the other and the failed one is cheaper to replace.

My suggestion if you're buying your first battery tool is to buy a kit with the two or three tools you use the most and two batteries. Don't go with a very expensive brand because then when you want to buy more tools that are compatible with your batteries, tools that you don't use as frequently, it will be harder to justify the premium price. Pick a brand where you are comfortable with the price of eventually buying 8 tools and 3 batteries, even if you won't do that right away.

  • Great points! I would address mhost's concern about larger batteries being better: it can definitely be true for very power hungry tools but the difference between 1.5 and 2 is not much. If you ever hit that problem, you will want 4AH or 6AH.
    – Olivier
    Sep 13, 2021 at 20:16
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    The point that you are choosing a brand is a very good one. All the brands seem to have starter kits that are quite inexpensive for what you get, hoping to get you set on their batteries and brand. As we never know what the future holds, it is hard. Sep 14, 2021 at 2:39
  • from what I've seen, tools usually come with at least one battery anyway...? So it may not matter whether the tools you use infrequently use the same battery type or not. Sep 14, 2021 at 11:17
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    @user253751 most tools in most lines I've seen are sold with or without a battery with a meaningful difference in price. Once you have enough batteries for your needs you buy more tools without them.
    – jay613
    Sep 14, 2021 at 11:26
  • @jay613 okay, could be a regional or store or price level difference. Still, I don't think the batteries are that expensive compared to the tools... so don't waste money now buying the wrong tool just so you'll save a battery later! Sep 14, 2021 at 11:32

I wouldn't consider a 1.5AH battery small and a 2.0AH battery large. I'd go with the 2- 1.5AH setup. It's more bang for your buck and it's also a backup if one goes bad. Stick with a reliable brand so you'll always be able to get replacement batteries and watch out for counterfeits (Amazon).


Get two battery packs even if the capacity is lower. Why? Because one always runs out halfway a job and and a second one allows you to charge it while using the first. Nothing as frustrating as having to wait for your jour battery to charge befor you can get on with the job.

As for 'power' or rotational speed/torq of the tool, that is dependent on the voltage of the battery (usually in the 12V-18V range), which for both battry types will be equal as the tools will be designed for only one voltage.

That leaves you with only a difference in the amount of batteries or the charge they hold. The charge difference of a larger battery is insignificant to the quality of life of having multiples.


When we talk about the modern li-ion power tools with detachable batteries, there is an important distinction:

There are high-current 1.5Ah cells and there are relatively lower-current 2.0Ah cells.

Both come in 18650 size and the battery pack may contain 3,4,5,6,8 or 10 of them (or other number) in order to get 12, 16, 20V packs of once or twice the cell Ah value (some manufacturers state the voltages slightly different, but they are not really different because they are not constant in the first place).

The difference between 1.5 and 2.0 element is in the trade-off between the "active mass" (the substance that makes the electricity) and the wires or foils (that carry the electricity out of the active mass).

Both things have to be put inside the limited volume of the cell and you either get a high-current, lower capacity cell or low-current, higher-capacity cell.

A power-hungry tool like an angle grinder will run longer off an 1.5Ah high-current battery pack because it will heat less.

On the other hand, a less-demanding tool like an impact driver will be able to get more from the 2.0Ah pack.

Different tools and different usage patterns (active use vs rest time) make one or the other kind of battery better.


Different tools have different power requirements. And different projects have different needs for how long you need the tools, as well as how you use the tools. So the answer is: it depends.

I have several cordless power tools from the same brand and also have 2 different sizes of battery packs. The circular saw will barely cut with the smaller battery pack, even though it's the same voltage as the drill. The oscillating tool works well with the smaller pack, but is apparently invincible with the larger one.

In my case, the smaller battery is 2Ah/36W and the larger is 4Ah/72W. Because of these differences, and the fact that some of the batteries came with the tools, I have 4 of the smaller packs and 2 of the larger ones. This allows me to use any number of combinations of battery and tool for what I need.

I can put the large pack in my drill for extended use or to get some extra power, or I can use the smaller pack if I'm going to be holding it over my head for long periods and want to reduce the weight. (The 4Ah weighs 4.4lbs and the 2Ah weighs 1.8lbs, so that's a significant difference for someone who is a software developer by day.)

I can also switch out the 2 large packs in my circular saw or oscillating tool when they drain, to recharge them and not have to wait as much. Or I can have 2 VSR drills and 2 impact drivers all ready with different drills and screw bits, and still have 2 packs for swapping out.*

As far as the battery heating up during drilling, that's not as likely as the motor heating up, and that's more likely to happen if you underpower the drill for the application. There's also the wear and tear of the bearings if you have to do 2x-3x the rotations to make the hole because a drill doesn't have the power to do the cutting (but a sharp drill bit affect that, too). And that doesn't even consider the power needed to screw in something, or remove the screw. From my own experience, I've seen cordless drills (including a DeWalt) that couldn't touch a screw that my corded drill (nameless brand) didn't have any problems removing.

On the flip side to power is length of use. Are you going to be drilling a lot of holes or putting screws into soft materials? If yes, then going with the 2 pack option might be right for you. It'll help prevent downtime as you can switch out packs while one is charging.

If you are using it for hard materials or a tool that needs the power (likely the grinder), then you probably need the single pack with more power.

If you simply are looking at it from an economic point of view, how much more is the 2Ah battery vs. the 2x 1.5Ah battery? Can you afford to get both? Should you find a way to afford both? Is there an option to get 1 of each? Generally, it's less expensive to get a battery with the tool, since it also includes a charger. Buying them separately generally costs about as much as the original tool kit, IME, including cheaper tools from places like Harbor Freight.

Unfortunately, we can't tell you the absolute answer to your question. Not only do we not know how you intend to use the tools right, but we also don't know how you are going to use them in the future, which might change the answer.

*I ended up with so many batteries because of the kits I chose, as well as I think I bought 1-2 batteries separately. I also have probably at least 10 tools from this brand. I'm also highly annoyed by having to switch out battery packs for every different tool I use, as well as having to switch between different drills and screw bits constantly.

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