Over the years I've purchased many, many battery operated power tools which suffered the same fate; owner used (or never used...) for a bit, neglected to care for the battery, then when it no longer works, threw it out.
It seems most of these were designed for the active construction worker, who uses the tool daily and expects good performance. In reality, many such tools get used a few times every few months for some odd job. In between these times, the battery doesnt know what to do with itself, so it rolls over and dies.
I'm of the latter camp. I want my tool at the ready, whenever I happen to need it, which could be at an interval in weeks of time. What's the best practice for maintaining the battery in good condition?
A fellow at work (also an audiophile) once said that he stores NiCd - or was it NiMh - shorted with a resistor. Then charges when needed. I notice none of the commercial tools do this; you dont get a "shorting cap" as an accessory. So I'm skeptical, even though the guy may have been right.
Thoughts?
It seems most of these were designed for the active construction worker, who uses the tool daily and expects good performance. In reality, many such tools get used a few times every few months for some odd job. In between these times, the battery doesnt know what to do with itself, so it rolls over and dies.
I'm of the latter camp. I want my tool at the ready, whenever I happen to need it, which could be at an interval in weeks of time. What's the best practice for maintaining the battery in good condition?
A fellow at work (also an audiophile) once said that he stores NiCd - or was it NiMh - shorted with a resistor. Then charges when needed. I notice none of the commercial tools do this; you dont get a "shorting cap" as an accessory. So I'm skeptical, even though the guy may have been right.
Thoughts?
From everything I remember, storage at/around 80% total capacity of the battery is the best place for almost all chemistries. Draining them is a great way to get reactions and kill most cells. I think NiCd like deep cycling, but not *storage* under stored condition.
So periodic charging of your batteries if you haven't used them for a while is probably a decent bet. Things like electric vehicles/industrial-scale battery systems tend to run their capacity in a much smaller range to aid with life versus consumer products, which squeeze every last drop out their battery capacity.
So periodic charging of your batteries if you haven't used them for a while is probably a decent bet. Things like electric vehicles/industrial-scale battery systems tend to run their capacity in a much smaller range to aid with life versus consumer products, which squeeze every last drop out their battery capacity.
Depends on the battery chemistry, seeing most power tools these days are using Li-ion batteries the general recommendation is if the battery is not going to be used for a long period of time then don't store it with a full charge.
Some general reading and info - Tips for extending the lifetime of lithium-ion batteries and Battery University BU-702: How to Store Batteries
Li-ion Battery packs normally have built-in electronics to prevent overcharging and over discharging.
That's not such a good idea as the battery at some point will be invariably damaged to being in a semi-permanent discharged state. I guess he was trying to reduce the "memory effect" of Nicad batteries. A few cycles of full discharge and charge every now and again can remedy this. Nicad's and NiMh are considered discharged at between 1.0 and 1.1 volt per cell.
You do not need a shorting connection for a nicad. First they will self discharge at a pretty quick clip (months). And if they discharge too far they tend to self destruct.
Best practice (and this from owning an early hybrid with 100's of d cell nicads in series in its pack) is to charge the batteries to 80 % of full charge every few weeks if they are just sitting. Do not discharge below 20%. You should get more than 500 cycles. The original battery pack on my car made it 16 years and 250K miles so it seems that plan works pretty well.
Decent quality cells do not suffer from memory effect any more.
Same general model for NiMH and LI.
Best practice (and this from owning an early hybrid with 100's of d cell nicads in series in its pack) is to charge the batteries to 80 % of full charge every few weeks if they are just sitting. Do not discharge below 20%. You should get more than 500 cycles. The original battery pack on my car made it 16 years and 250K miles so it seems that plan works pretty well.
Decent quality cells do not suffer from memory effect any more.
Same general model for NiMH and LI.
I've had a Bosch cordless drill since 2006. As far as I can tell both batteries that came with it work about as well as they did when new.
I use it a few times/year. I'll use whatever battery is in the drill with whatever charge is left in it until it's dead. I'll then put it in the charger and switch to the other battery. Once the first battery is fully charged, I'll remove it from the charger and put it in the storage case. Repeat cycle as necessary.
If I have a project coming up that I know will require a fully charged battery, I'll top off both batteries the day before.
Tom
I use it a few times/year. I'll use whatever battery is in the drill with whatever charge is left in it until it's dead. I'll then put it in the charger and switch to the other battery. Once the first battery is fully charged, I'll remove it from the charger and put it in the storage case. Repeat cycle as necessary.
If I have a project coming up that I know will require a fully charged battery, I'll top off both batteries the day before.
Tom
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For lithium-ion, the best is to keep them about half charged (according to the lithium-ion battery datasheets I've read and the user manual of my partner's electric bicycle).
Like Indiglo already wrote, it is not necessary to discharge NiCad cells each and every cycle if you want to prevent memory effect, and in fact their lifetime goes down a lot when you do. Besides, when you have a battery consisting of several NiCad cells in series, discharging the whole battery too far may lead to the cell with the smallest capacity getting charged with reverse polarity, which is very harmful.
Like Indiglo already wrote, it is not necessary to discharge NiCad cells each and every cycle if you want to prevent memory effect, and in fact their lifetime goes down a lot when you do. Besides, when you have a battery consisting of several NiCad cells in series, discharging the whole battery too far may lead to the cell with the smallest capacity getting charged with reverse polarity, which is very harmful.