Note:  All of this applies to lithium-ion batteries in general and not just cordless drills.

We develop battery myths.  Generally these myths are based in truth and following them would be good, but we’re making different kinds of batteries with different characteristics now.

I wrote this post because I see many people whose li-ion batteries have died much sooner than they should and I think we haven’t spread the word on how to care for li-ion tools.  So let me set the record straight.

Lithium-ion batteries do not have “memory”

NiCad batteries can exhibit a “memory” effect, where consistently draining the battery to a certain point will cause the battery perform poorly past that point in the future.  So you want to completely drain a NiCad battery regularly.  But lithium-ion batteries do not have this problem.  In fact they have an opposite quality.

Completely draining a li-ion battery may damage it

That’s right.  Instead of trying to drain a li-ion battery you should try to charge it before it’s completely drained, the opposite of what you should do for a NiCad battery.

But I don’t want you to develop a complex where you’re scared to use your drill for more than 5 minutes. Li-ion batteries have circuitry to prevent them from completely draining.  So you can safely use your drill to close to exhaustion.  But

Never store your drill when it’s almost dead

Lithium-ion batteries have low self-discharge (the amount the battery drains when not in use).  But they still have some self-discharge.  And if you put your li-ion battery on the shelf almost dead and leave it there for 3 months, it’s likely to drain enough to cause damage.

The ideal charge state for long-term storage is around half capacity.  Leaving the battery in a completely charged state for long periods will slightly but permanently lower the capacity.  But since there is some self-discharge, if you put it away full after a month it won’t be full anymore.  Another minor point is that li-ion batteries are best store cool, but not freezing.

The takeaway here is it’s a bad idea to leave the battery charging all the time.  And it’s a bad idea to store the battery empty or almost empty.

Extreme temperatures degrade performance

If you want your battery to last to its full potential, then you should avoid temperatures, above 120 F and below freezing.  So you shouldn’t leave drill battery out in the truck in the summer or the winter.  If you want to store your spare battery for long periods, take it to half charge and put it in the refrigerator.  It will be safe for years in there.

Help spread the word

If you know people with lithium-ion tools point them to this article.  Share it on Facebook or Twitter or blog about it if you’re into that.  Friends don’t let friends abuse their li-ion tools.

I’m always interested in the unconventional things people do with cordless drills.  And it makes sense when you think about it.  Modern cordless drills provide a substantial amount of torque in a portable package.  There are a lot of applications.

And even though you really only need a motor and battery for most of these other applications, a cordless drill is the format most people will have that motor and battery in.

Enter the Cordless drill ice auger.  This is actually just a cool bit.  But like I said, it’s cool.  You can see one in use at this video on youtube.

I have specific criteria for a cordless drill for home use.  Versatility is most important.  You’re buying a drill to face as many situations as you can cover with one tool.

Power vs. Size

Having more power allows you to do more tasks.  But smaller size allows you into tighter spots.  I think it’s helpful to set a benchmark for power, a task you must be able to accomplish, and then we can consider the sizes of drills that allow you to do that.  My benchmark is driving several 3 inch screws into hard lumber.  Several years ago you would have needed an 18V (or at least 14.4V) cordless to handle that job.  But with the advent of lithium-ion batteries, manufacturers can pack more power into tighter packages.  Makita makes a 10.8V ultra-compact with 200 inch-pounds of torque that will easily handle the benchmark.

So you can have both (small) size and power in the context of home use if you go with a good drill.  Don’t expect a cheap compact drill to handle the job because you need a lithium-ion battery to fit that much power into the compact format.

Always at the ready

Another reason to go with a li-ion battery is the low self discharge.  Both NiCd and NiMH have high self-discharge rates (20%-30% per month).  If your drill has been setting for 2 months it would still be nice to pull it out and go right to work without having to charge the battery first.  Well, as long as you charged the battery after you used it last time (which you should always do with your li-ion batteries), your drill should be good to go because the self-discharge rate is 5%-10% per month.  source

Handy features

Having a built-in light on a cordless drill is about as handy as a pocket on a shirt.  It’s a major plus for a cordless drill used mainly at home.  A bit holder is also nice so you have a place to store your dual phillips/straight driver bit, the bit you’ll be using 90%+ of the time at home.  But since you’ll be using that bit the vast majority of the time a bit holder isn’t an essential feature.

The chuck

Among smaller drills the choice is between a 1/4 inch chuck and a 3/8 inch chuck.  Most of the time the quarter inch will do.  But there’s a good chance the smaller chuck will be a limiting factor for something you need to do.  Everything thing else the same, the 1/4″ drill will be smaller, but I don’t think that justifies the limited versatility.  And of course, a keyless chuck is absolutely required.

Unless you know you only need a 1/4″ chuck, go for the 3/8″.  As for 1/2″ chucks, I don’t consider that to be in the “home use” category.  If you think you need a 1/2 inch look at the 18V drill page.

My Choice

My recommendation for the best cordless drill for home use is the Makita 10.8V ultra-compact.  It has all of the essential features I mentioned and is surprisingly powerful.  Most importantly it is extremely versatile and represents the best package for all-around home use.

Check out the Makita 10.8-Volt Ultra Compact Cordless at Amazon

Unfortunately, rechargeable batteries don’t last forever.  There’s a good chance your Makita drill will outlast the battery or batteries that came with it. (Although, the newer Li-ion batteries are rated for thousands of cycles and our choice for best 18v cordless drill comes with two, and so should last for a decade even with regular use.)

If it’s time to replace your Makita cordless drill battery, here’s what you need to know.

Physical compatibility

Most drill manufacturers try not to change how the batteries physically connect to the drill and where the battery electrical leads connect to the drill. There are many benefits (both for the manufacturer and the consumer) to keep these the same.  But occasionally the manufacturer will see a greater benefit in making a change.  And Makita did just that when they moved to Lithium ion batteries.  It was a good time to make a change for reasons noted below.

But here’s what you need to know.  You either have the stick (or pod) model or the slide model.  Obviously, one doesn’t work with the other, but for the most part each type will work with all the various models.  If you purchase a non-Makita battery it may only fit certain model numbers, so make certain yours is listed.

Slide Model

Stick/Pod Model

Battery Chemistry

There are three types of rechargeable batteries: Nickel Cadmium (NiCd), Nickel Metal-Hydride (NiMH), and Lithium-ion (Li-ion).  That’s in order of oldest to newest and generally better.  There are subtle differences in how these batteries behave.  I did an article previously on the differences between NiCd and NiMH batteries.  Here’s the bottom line:

NiCd and NiMH batteries are close enough chemically to replace each other.  There are some electronics designed to work specifically with one or the other type, but Makita designed their tools to be compatible, specifically so you can upgrade from NiCd to NiMH.

Battery Capacity

The capacity of a battery is measured in amp-hours or Ah.  Amps are a measure of current, so amp-hours is measure of current over time.  A 3.0 Ah battery will deliver 1 amp for 3 hours or 3 amps for 1 hour.  Energy is amps * voltage.  So a 3.0 Ah 18V battery has more capacity than a 3.0 Ah 14.4V battery.

But among batteries of the same voltage, you can compare Ah like apples to apples.  A 3.0 Ah battery has twice the capacity of a 1.5 Ah battery.

My Recommendations:

* If you have a NiMH or NiCd 18V Makita model you should get a NiMH replacement like this one.  There are some other models on Amazon and other places, but this one fits all the NiMH and NiCd 18V models, it’s made by Makita, has received only positive reviews and is offered by Amazon at a great price.  There are 3.0 Ah models like this one, but it’s not made by Makita and currently has no reviews.

* If you have an 18V Li-ion Makita drill you have two options.  There’s the 1.5 Ah model and the 3.0 Ah model battery.  The 3.0 Ah model has twice the capacity for only about $14 more, so it’s got the value.  But it’s heavier.  One of the best features of the best 18V cordless drills is the light weight.  Since this is a replacement battery, you know how long the battery lasts and whether you need the extra capacity or could deal with half the capacity.  Make your decision accordingly.

My son turned two this week.  He received many gifts from from friends and family.  Thomas  the Tank Engine is one of his favorite characters and he got many “Poma” toys that he loves.  But he also got a toy tool set that ranks among his favorites and can you guess what his favorite tool in the set is?  That’s right, the cordless drill.

He can play with it for tens of minutes at a time (which at his age is like days and days).  This confirms my hunch that there’s something deep inside all of us that love cordless drills.

We have a category on our site for impact drivers.  There’s an explanation there for what an impact driver does.  Basically an impact driver uses a spring to store some of its energy and it delivers that energy in small bursts.  This is much more effective for tightening or loosening nuts and, to a lesser degree, for driving screws.

To put it in real terms, with an impact driver you can loosen a nut that would take a regular drill 3 times the size of the impact driver.  That’s the big win.  But here are the downsides.  An impact driver is noisier, heavier, and (slightly) more expensive than a comparable regular drill.

But the bottom line is if you need the maximum torque or if you plan on doing more driving (of screws) than drilling (with bolts) then you should be using an impact driver.

The cordless combo pack is a set of cordless tools from one manufacturer that all use the same battery.  This example is the Makita LXT702.  It includes 7 18V tools:

• hammer drill
• impact driver
• reciprocating saw
• circular saw
• angle grinder
• flashlight
• radio
• you also get two batteries and a handy bag

Most people won’t use all of those tools.  At least not very often.  And let’s face it, the flashlight and radio are throw in to pad the “tool” number.

The nice thing about a combo pack is that you get a discount.  The whole kit is a little over twice the price of the hammer drill.  Of course, if you bought separately you’d get more batteries, but two should be plenty since they are lithium-ion and rapid charge.

Here’s my recommendation.  If you’re considering a cordless tool, at least check out the combo packs available.  Consider the value proposition and whether you can afford the pack.  If you think you’ll use 3 out of the 7 tools then you should probably get the combo pack.