It is that time of year when all those tools that we have used since the spring get a bit of TLC and put away for winter. But with all the portable powered tools we now have, do you pay enough attention to the batteries?
If you have a cordless strimmer, hedge clipper or similar outdoor tools, now is the time to consider how best to look after the batteries that power them. After all, come springtime you will not want to be dashing around because the battery will only power the device for a few minutes, and seemingly take forever to charge! If you are the type of person who does not get past the first page of the instruction manual, it is likely the only instruction you will have seen about the battery is ‘charge before use’, probably the most obvious thing to do with it! Beyond that though, there are instructions on how to treat the battery through the life of the device it is meant to power. To give as long, and as reliable, life possible.
It is most likely that the battery technology you have is going to be either a Nickel Metal Hydride (NiMH) or rechargeable lithium. Neither of these battery technologies respond well to being left fully discharged, and so the instruction manual should really read ‘charge before use, and afterwards too’. For optimum battery life there is a state of charge that is ideal (see an earlier blog on overfeeding your battery), but unless your device has a state of charge indicator, or a ‘pre storage’ charge setting on the battery charger, it is better to give the battery at least a partial charge.
Even though your batteries are going to have a few months ‘rest’, they will still be losing some of their charge. This will be through the natural ‘self discharge’ that occurs with all batteries, and through the small additional load resulting from protection and state of charge circuitry. Although very low, over four months this can add up to quite a bit of capacity loss. Leaving them fitted to the device they are intended to power can sometimes add an additional load. So make sure you remove the batteries from the equipment!
One method of slowing down self discharge is to store the batteries in a cool location, but not in a location that sees wide temperature fluctuations. So a cool and dry spot is best, but make sure that the battery terminals cannot short together.
The same advice can be applied to all cordless devices, power drills, powered screwdrivers and so on. When you want to do that refurbishment of the spare room you want all your tools to work perfectly, don’t get that sinking feeling when you hear the drill motor slowing down just as you have lined everything up!
Of course you should read the manual that came with the device and follow the instructions it contains, especially regarding safety issues.
So, when tidying up your shed / workshop this Autumn and packing your tools away, spend a little time on the batteries too – make sure they are at least partially charged, and store them in a cool and dry location. Replacement batteries are not cheap, and may even not be available. A little effort now can save you the hassle and inconvenience of not being able to use your cordless devices come the spring!