Happy Christmas all!
I've been given a Bosch GSB120-Li drill/driver as a pressie for Christmas with two 12v 1.5Ah Li-ion batteries. This is the first Li-ion battery tool I have had and have previously relied on my 50+ year old corded B&D for my occasional DIY use, but it's now on it's last legs.
I'm unsure how best to look after the batteries. How long can I leave a fully charged battery in the drill without use before the battery charge deteriorates? Can I leave a partially charged battery in the drill for long periods? How long will the alternative battery remain fully charged? Should I leave a battery in the charger, switched on, while not being used? Should I periodically recharge both batteries? Do I have to fully discharge the batteries before re-charge? The instruction manual is no use in answering these and many other questions I have so any advice would be appreciated.

Cheers
Pete

On 26/12/2020 23:33, petek wrote:

Happy Christmas all!

and to you...

I've been given a Bosch GSB120-Li drill/driver
as a pressie for Christmas with two 12v 1.5Ah Li-ion batteries. This
is the first Li-ion battery tool I have had and have previously
relied on my 50+ year old corded B&D for my occasional DIY use, but
it's now on it's last legs. I'm unsure how best to look after the
batteries.

LiIon batts are different beasts from the NiMh and NiCd batteries of the
past. They don't suffer so many of the drawbacks like high auto
discharge etc. They do however need careful management in use and when
charging and so typically contain battery management modules that do this.

How long can I leave a fully charged battery in the drill
without use before the battery charge deteriorates?

A significant time, and it will retain a charge. Might be worth giving
it a partial refresher charge once a year if not being used.

They are affected by temperature during storage. Prolonged periods over
55 deg C can ruin them, and below -15 can cause them to discharge.

Can I leave a
partially charged battery in the drill for long periods?

Yes

How long
will the alternative battery remain fully charged?

Similar amount of time or a bit more. There are some management
electronics in the battery that will take a tiny current even when not
in use.

Should I leave a
battery in the charger, switched on, while not being used?

You can - the chargers are smart and communicate with the battery. They
will only charge it until "done" and then stop.

Should I
periodically recharge both batteries?

Only if left a very long time. Bosch normally suggest not fully charging
before storage though since they are more "active" when fully charged
and that causes faster ageing.

Do I have to fully discharge
the batteries before re-charge?

No. Some of the less sophisticated systems may simply count the number
of times they are mounted on the charger as a "cycle". So frequent
partial charges may accelerate the point at which the battery management
system thinks the battery has reached end of life.

The instruction manual is no use in
answering these and many other questions I have so any advice would
be appreciated.



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 26/12/2020 23:33, petek wrote:
Happy Christmas all! I've been given a Bosch GSB120-Li drill/driver
as a pressie for Christmas with two 12v 1.5Ah Li-ion batteries. This
is the first Li-ion battery tool I have had and have previously
relied on my 50+ year old corded B&D for my occasional DIY use, but
it's now on it's last legs. I'm unsure how best to look after the
batteries. How long can I leave a fully charged battery in the drill
without use before the battery charge deteriorates?

More or less indefinitely. The ideal state to store li-ion is half
charged. But in reality that's pretty impractical. The rate of self
discharge is far far lower than any nickel chemistry.

If you are using them regularly keep them fully charged, If not well you
could always out them away in whatever state of charge they ended up I
suppose.

Can I leave a
partially charged battery in the drill for long periods?
See above. That is the ideal state.

How long
will the alternative battery remain fully charged?

I typically see maybe a 10% drop in charge over a year on my model
aircraft batteries - 5% over the winter.

Should I leave a
battery in the charger, switched on, while not being used?
Most chargers will switch off when the battery is charged. On my cheap
cordless an LED turns green...so there isn't much point in leaving the
batteries in..

Should I
periodically recharge both batteries?
No. Its pointless.
Do I have to fully discharge
the batteries before re-charge?
No. Its not that good for them although the drill circuitry would stop
over discharge

The instruction manual is no use in
answering these and many other questions I have so any advice would
be appreciated.

Cheers Pete



--
"Anyone who believes that the laws of physics are mere social
conventions is invited to try transgressing those conventions from the
windows of my apartment. (I live on the twenty-first floor.) "

Alan Sokal

John Rumm wrote:
LiIon batts are different beasts from the NiMh and NiCd batteries of the
past. They don't suffer so many of the drawbacks like high auto
discharge etc. They do however need careful management in use and when
charging and so typically contain battery management modules that do this.

Generally I'd suggest not overthinking things. The battery contains a
circuit to protect it from getting overdischarged, cooking itself, and the
charging system takes care of preventing it overcharging.

So just use it however you need. In general however there are a couple of
points to bear in mind for optimal life:

- batteries are happier if they're not 'full' or 'empty'. So if you need to
store for long periods, leave them somewhere in between. 40% is a typical
storage charge, although 80% is still fairly easy on the battery ( most
power tools don't have a gauge good enough to read this - you can use a
voltmeter if you need to, if you look up the lithium ion battery curves).

- when you use it under heavy loads, it gets warm. It's better to minimise
the warming (eg have a tea break, or swap to another battery), and to let
the battery cool before charging.


You can happily ignore these 'rules' and get many years life out of them -
they're more of a concern for big batteries that have to last for many years
of daily use, like those in electric cars. Unlike cars, power tools don't
have automatic ways of mitigating them (no liquid cooling in a drill).

Theo

On Sunday, December 27, 2020 at 12:45:40 PM UTC, Theo wrote:
John Rumm wrote:
LiIon batts are different beasts from the NiMh and NiCd batteries of the
past. They don't suffer so many of the drawbacks like high auto
discharge etc. They do however need careful management in use and when
charging and so typically contain battery management modules that do this.
Generally I'd suggest not overthinking things. The battery contains a
circuit to protect it from getting overdischarged, cooking itself, and the
charging system takes care of preventing it overcharging.

So just use it however you need. In general however there are a couple of
points to bear in mind for optimal life:

- batteries are happier if they're not 'full' or 'empty'. So if you need to
store for long periods, leave them somewhere in between. 40% is a typical
storage charge, although 80% is still fairly easy on the battery ( most
power tools don't have a gauge good enough to read this - you can use a
voltmeter if you need to, if you look up the lithium ion battery curves).

- when you use it under heavy loads, it gets warm. It's better to minimise
the warming (eg have a tea break, or swap to another battery), and to let
the battery cool before charging.


You can happily ignore these 'rules' and get many years life out of them -
they're more of a concern for big batteries that have to last for many years
of daily use, like those in electric cars. Unlike cars, power tools don't
have automatic ways of mitigating them (no liquid cooling in a drill).

Theo
Thanks to all three of you for the clear advice, which has set my mind at rest considerably.
All the best for the New Year - it can't be any worse than the last one!

On 27/12/2020 12:45, Theo wrote:
John Rumm wrote:
LiIon batts are different beasts from the NiMh and NiCd batteries of the
past. They don't suffer so many of the drawbacks like high auto
discharge etc. They do however need careful management in use and when
charging and so typically contain battery management modules that do this.

- when you use it under heavy loads, it gets warm. It's better to minimise
the warming (eg have a tea break, or swap to another battery), and to let
the battery cool before charging.

That was historically good advice, but these days runs counter to what
the makers suggest when they have cooling systems in the chargers. So
with the Makita for example, they say that hot batteries should be put
on charge ASAP. The chargers read the battery temperature and use the
built in cooling fan to pass air through the battery. They don't
actually start charging until the temperature has been brought down to
an appropriate level. They then fast charge (and cool), and continue to
cool after charge for a while.

You can happily ignore these 'rules' and get many years life out of them -
they're more of a concern for big batteries that have to last for many years
of daily use, like those in electric cars. Unlike cars, power tools don't
have automatic ways of mitigating them (no liquid cooling in a drill).

The battery management system will shut down the drill if the battery
gets too warm.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:
That was historically good advice, but these days runs counter to what
the makers suggest when they have cooling systems in the chargers. So
with the Makita for example, they say that hot batteries should be put
on charge ASAP. The chargers read the battery temperature and use the
built in cooling fan to pass air through the battery. They don't
actually start charging until the temperature has been brought down to
an appropriate level. They then fast charge (and cool), and continue to
cool after charge for a while.

That sounds a level beyond my cheapass Aldi tools

I have NiMH and 18650 chargers with a fan, but nothing else does - they're
just wallwarts with a battery cradle attached.

The battery management system will shut down the drill if the battery
gets too warm.

'too warm' meaning 'about to catch fire' rather than meaning 'will reduce
battery life by 25%', I suspect.

Theo

On 27/12/2020 13:19, petek wrote:

Thanks to all three of you for the clear advice, which has set my mind at rest considerably.
All the best for the New Year - it can't be any worse than the last one!


You may also find that you don't notice a drop off in performance of the
drill and then the protection circuits will just remove power from the
battery just before being discharged. You will not necessarily notice
the battery close to the end of charge before the drill cuts out completely.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 26/12/2020 23:33, petek wrote:
Happy Christmas all!
I've been given a Bosch GSB120-Li drill/driver as a pressie for Christmas with two 12v 1.5Ah Li-ion batteries.


Forget all this stuff about batteries..................

Who's bought you such nice presents and what DIY tasks do they want you
to do for them in return?

;-)







--
Adam

That model of drill has a battery gauge consisting of a row of LEDs and it's reasonably accurate so you could probably use it to estimate when the battery is half full for storage and also to get reassurance that next time you use it it's going to actually be able to function

On 27/12/2020 17:22, alan_m wrote:
You will not necessarily notice the battery close to the end of charge
before the drill cuts out completely.
Correct. I've run my cheapo cordless down several times. Just slows to a
crawl, and then refuses to start at all. Within seconds

--
€œA leader is best When people barely know he exists. Of a good leader,
who talks little,When his work is done, his aim fulfilled,They will say,
€œWe did this ourselves.€�

ۥ Lao Tzu, Tao Te Ching

In article ,
Theo wrote:
That sounds a level beyond my cheapass Aldi tools

I have NiMH and 18650 chargers with a fan, but nothing else does - they're
just wallwarts with a battery cradle attached.

With Lidl ones, the battery itself seems to contain a great deal of
electronics. Be interesting to see a block diagram of the entire unit -
drill battery and charger.

--
*Work like you don't need the money. Love like you've never been hurt.

Dave Plowman London SW
To e-mail, change noise into sound.