Dear Lifehacker, Like many other Lifehacker readers, I have the usual collection of cordless power tools that don’t get used quite as often as they should or I’d like. I’ve read that keeping the battery pack constantly charging is no good for the battery. Can you recommend a strategy for ensuring the cordless power tools have the power when you need them but maintaining the battery life? Thanks, Cordless and Powerless
Picture by Douglas Muth
Dear C&P,
There’s no denying the convenience of cordless tools — but there’s also no denying that if you don’t use them regularly, chances are they’ll be entirely out of power when you want to use them. I often find myself thinking “OK, now I need the drill” and then having to hold off while the battery charges up.
If you regularly plan to use your cordless tools, the obvious solution is to leave the batteries plugged into the charger all the time. Assuming you have the space in your garage and shed, this means they’ll always be available for use. But is it a good idea? Many of us vaguely recall the warnings over battery memory that applied to notebooks and mobile phones, and worry that taking this approach will actually reduce the life of the devices.
As we’ve pointed out before in the context of PCs, with modern lithium ion batteries, it’s not true that constantly charging them will reduce battery life. And this is also true for newer power tools, which are designed to charge the battery more intelligently. Here’s what it says in the manual for a Bosch PSR 18 cordless drill which I’m currently testing:
Due to the intelligent charging method, the charging condition of the battery is automatically detected and the battery is charged with the optimum charging current, depending on battery temperature and voltage. This gives longer life to the battery and always leaves it fully charged when kept in the charger for storage.
This won’t necessarily apply if your cordless tools are older, or you have purchased them from a brand-name supplier. But if you have new modern tools, keeping the batteries in their chargers plugged in and ready to go will make it easier to engage in a spot of DIY when the mood takes you.
Cheers
Lifehacker
Lifehacker’s weekly Reno 101 column covers the basics of renovation and DIY. Got your own question you want to put to Lifehacker? Send an email to tips@lifehacker.com.au, and include ‘Ask Lifehacker’ in the subject line.
Sam
Friday, June 10, 2011 at 2:38 PMThe above is fine if you already have a new drill/tool that “intelligently” charges, but going out and buying such hardware kind of defeats the purpose. If you’re going to do that, you may as well leave your batteries plugged in permanently (albeit at a shorter service life) then go and buy a new tool when your existing one carks it.
As a cheap stop-gap method of preventing constant charging, whilst still keeping the battery relatively fully charged – duck into Bunnings (or any hardware store) and buy yourself a 24-hour mains timer. People often use them for lamps or heaters, and you can get a cheap HPM branded one from upwards of $5. Run a power board off the timer, and plug in your various tool chargers from there. Depending on the frequency of use of your tools, you can set your batteries to receive a daily charge anywhere upwards from 15mins per day, in 15 minute increments. As a bonus, if you have a smart meter in your meter box, set your batteries to charge in the middle of the night so you can take advantage of the off-peak tariff. If plugging your depleted battery in after use, most timers also have an over-ride switch to keep the power permanently on until you manually disable it.
Obviously this probably isn’t as great as using an intelligent charger, but at least you’re minimising constant charge, and allowing up to 23-hours-and-45-minutes downtime for your batteries to naturally discharge throughout the day before it receives another top up.
Jesse
Friday, June 10, 2011 at 3:23 PMSam, you should work for lifehacker. Freaken brilliant idea.
Sam
Friday, June 10, 2011 at 3:54 PMShh, don’t say that, Gus will start blocking my comments! :P
k
Friday, June 10, 2011 at 4:50 PMthumbs up
Tom
Friday, June 10, 2011 at 3:38 PMmy one year old drill is useless even when left on charger all the time. so this advice isnt 100% true (ryobi)
Ben
Saturday, June 11, 2011 at 12:03 AMLike Dale mentioned, you get what you pay for. Ryobi are in the bottom imo.
Im a carpenter aswell and i see so many people mistreating tools.
To save juice, adjust your cordless drill settings. Read the manual and learn the settings. I think alot of the ones these days have 3 speed, screw/hammer/drill features.
I found the new lithium makita batteries charge up very quick.
Quality seems to be down on makita tools aswell. Made in china, not made in japan anymore.
Dale
Friday, June 10, 2011 at 9:39 PMAs a carpenter, cordless power tools are something i deal with every day, i have a total of 11 cordless power tools in my van at all times and quite often im using 3 or 4 of them at a time. I was taught from a very early age in my apprenticeship to not skimp on tools, infact my boss told me “if you pay for a $4 haircut you are going to get a $4 haircut”. over the many years i have seen power tools come and go but the Lithium Ion batteries have changed the way i work for the better. Battery memory used to be the biggest pain in the ass to deal with.
Another tip, if your thinking of investing in some cordless power tools, buy all your tools THE SAME BRAND, more specifically the same model line and voltage if you can. This ensures that you can swap batteries between all of your different tools. For your drill invest in some quality bits and make sure they stay sharp, there is no need to put excessive strain on your power tool because the bit is blunt. Its unsafe and it decreases battery charge a fair bit. And the last point, KEEP YOUR TOOLS CLEAN. i cant stress this enough to apprentices, those shiny new power tools are bloody expensive and you want to make sure you get the best out of them, stray bits of dirt and wood chips can reek havoc on a power tool, keep dirt and sand and other small particles away from the vent slots, more than often a few of those vent slots are for air intake and you can be damn sure that a few small grains of sand will completely fuck the motor in your new tool, also dont cover the vents while using the tool, motors, need air too.
Ian Mackereth
Saturday, June 11, 2011 at 3:07 AMIt depends mainly on the chemistry of the batteries.
If they’re NiCd types, then leaving them charged will shorten their life considerably, and they should be left as close to fully discharged as possible and only charged up when you’re about to use them. (Yes, that can be a hassle, but they usually charge to a usable level pretty quickly for small jobs.)
Lithium batteries (of whatever type) are best kept charged, and Sam’s timer idea sounds like a good one if the charger’s not specifically marketed as being an intelligent one.
If they’re not used often, then a short re-charge once a week is probably enough, given that Lithium cells don’t self-discharge much.
NiMHs are like lithium except that they typically self-discharge more quickly, so might need a more frequent top-up.
JR
Sunday, June 12, 2011 at 2:50 PMBuy lithium batteries, or get your nicad/nimh converted by a battery shop.
One hour of charging gets you four hours of use (compared to 4 hours of charging to get you one hour of use with nimh), and the charge will last 6 months without recharging.
Problem solved.
Alex
Thursday, June 30, 2011 at 5:17 PMGreat idea, Sam. Very interesting topic I’ve often considered the most efficient way to keep a charge.
Filon
Friday, August 5, 2011 at 6:04 PMI have been searching the internet for sam’s idea and ended up here. I had the same idea based on the tickle feature of my AA charger. Has anyone tried this idea? Would 15 minutes a day be enough to keep the batteries charged?
Filon
Friday, August 5, 2011 at 6:05 PMAnyway I just want to add that this sort of idea should hit LH’s top stories… well done sam!