A few years ago, if you had told me I would buy a battery operated circular saw, I would have laughed in your face.
I mean, come on – what use would someone have for a battery operated circular saw? As it turns out, I now have a battery operated circular saw and its convenience and portability is unprecedented.
These days you can buy battery powered drills, drivers, impact drivers, routers, jig saws, portable planers, circular saws, reciprocating saws and chop saws. So let’s see how to get the most from these tools.Batteries
Lets stop for a moment and look at batteries that power these units. Most power packs that drive these tools are a series of small rechargeable batteries all wired together to give the optimum power. These rechargeable batteries are very similar to the flashlight batteries that you buy for your TV clicker and garage door opener and various other home products.
The difference is that the rechargeables have higher quality shells and consist of slightly different components to make them safe to recharge. The rechargeable batteries that are wired together were initially nickel cadmium (nicad) or nickel-metal-hydride (Ni-MH) batteries.
When they are wired together in series, as more batteries are added, the voltage increases – from 9.6 volts, to 14.4 and so on. That is how more power is generated, more little batteries, more power, and of course, more weight. Modern manufacturers are now using Lithium Ion or Lithium Polymer technology in their rechargeable batteries, making them more powerful and longer-lasting.
The more batteries that are wired together, the greater the torque (or twisting power) of the tool. Torque is created by a combination of horse power and speed, and high speed does not necessarily mean high power. Conversely, high power does not necessarily come with high speed.Enemies of batteries
As woodworkers, we all know one thing, HEAT is our greatest enemy. When saw blades get too hot they lose their tensility and become dull. Screws that are driven into hardwoods can snap because of the high heat created by friction and heat can burn out the electric motors of our tools if we are not careful. Heat is also the enemy of batteries. All batteries heat up when they are being recharged. The larger battery packs such as 18 volts and larger tend to heat up even more because there are so many batteries in the packs and they don’t have the same heat dispersion characteristics as smaller packs because there are so many batteries next to one another. Batteries tend not to take a charge when they are hot, so keeping the ambient temperature normal to cool is a benefit.
On the flip side, batteries do not do well in the cold either. Once the temperature drops below 14 degrees Fahrenheit ( minus 10 Celsius) batteries do not perform well (if at all). Most batteries will lose their power when the temperature gets this low.
The recharging of batteries is a bit of a mystery to many people. The tendency is to keep batteries fully charged all the time. In truth, batteries need to be exercised in order to keep them in top shape. This means they should be fully discharged every few months, then fully re-charged. Topping up battery charges will make the batteries lose their effectiveness, and after a time they will only take a partial charge because that is what they have become accustomed to. This means they will lose their ability to use the full charge. Sometimes you can rejuvenate an older battery by charging and FULLY discharging it several times.
My experience with battery operated tools
I once had a 14.4V Craftsman cordless drill that I got several years of heavy use from. However, after a while it got to the point that the NiCad batteries would not hold a charge. So, I looked into buying replacement batteries. I soon found that a replacement battery pack would cost more than replacing the drill.
So, I went looking for a replacement. I soon found a Ryobi kit, containing a drill, a circular saw, a sawz-all and a light, plus two batteries and a charger for just a little more than a battery for my Craftsman drill would have cost.
It turns out the Ryobi kit also used NiCad batteries. So, after a couple of years they wore out too and wouldn’t hold a charge either. This time, however, I was in luck.
Over the previous couple of years Lithium technology had progressed to the point where Ryobi was now making direct replacement Lithium batteries for its older NiCad powered tools. I was able to pick up a couple of Lithium batteries for half the cost of what the NiCads would have cost. They’ve now lasted two years without a sign of slowing down.
Now, if I need a replacement, I simply drive to the big box hardware store and pick up a new one. Ryobi, in particular, seems to have made a commitment where one battery fits all tools. They’ve definitely earned my repeat business.Do you have experience with battery operated tools? Like one brand over another? Tell us about it in the comments below.