Hi all,

I have a few 18v Graco (same as DeWalt lithium ion) batteries for my paint sprayer which seem to charge well but then die very quickly. Once charged they show just over 20v on the multi meter. I have been doing some searching and come across people saying
1. Zap them with 36v - although this seems to be if they are not charging at all
2. Slowly drain them until tool doesn't work any more. Leave them and drain again. Repeat until completely dead and then charge.

Does anyone know if this works or is there a better option? For option 2, my sprayer only has one setting so will this have the same effect or do I need to find another way to discharge them eg somehow find a 18v ish bulb ?

Thanks in advance for your help

Lee.

On 22/09/2018 17:51, wrote:
Hi all,

I have a few 18v Graco (same as DeWalt lithium ion) batteries for my paint sprayer which seem to charge well but then die very quickly. Once charged they show just over 20v on the multi meter. I have been doing some searching and come across people saying
1. Zap them with 36v - although this seems to be if they are not charging at all
2. Slowly drain them until tool doesn't work any more. Leave them and drain again. Repeat until completely dead and then charge.

Does anyone know if this works or is there a better option? For option 2, my sprayer only has one setting so will this have the same effect or do I need to find another way to discharge them eg somehow find a 18v ish bulb ?

Thanks in advance for your help

Lee.

You could discharge them using two 12V bulbs in series, or indeed
anything intended for 18V or more. You could use an electric fire
element. But it won't work.

Bill

It is my understanding that Litium Ion batteries should not be fully discharged and usually contain circuits to prevent this happening. Some of your advice applies more to NiCads.

Richard

Yes I thought that and to some extent the older nickel metal hydride types
as well.

Lithium/ion ar a whole other animal indeed depending on their construction
several different animals. Some are like normal batteries some are like a
kind of thin set of electrodes squished up together... I know a technical
term!
One tends to have individual cell failure as with the older types and of
course because its being reverse charged by the others running the load it
is well knackered fast and turns into a resistor. The others can get very
hot and burst into flames hence the protection!

Brian

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"Tricky Dicky" wrote in message
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It is my understanding that Litium Ion batteries should not be fully
discharged and usually contain circuits to prevent this happening. Some of
your advice applies more to NiCads.

Richard

On 22/09/18 18:45, Tricky Dicky wrote:
It is my understanding that Litium Ion batteries should not be fully discharged and usually contain circuits to prevent this happening. Some of your advice applies more to NiCads.

Richard

Once lithyum are dead,they are dead.

No zombie jooz avaialable.



--
Microsoft : the best reason to go to Linux that ever existed.

On 22/09/2018 18:51, wrote:
Hi all,

I have a few 18v Graco (same as DeWalt lithium ion) batteries for my paint sprayer which seem to charge well but then die very quickly. Once charged they show just over 20v on the multi meter. I have been doing some searching and come across people saying
1. Zap them with 36v - although this seems to be if they are not charging at all
2. Slowly drain them until tool doesn't work any more. Leave them and drain again. Repeat until completely dead and then charge.

Does anyone know if this works or is there a better option? For option 2, my sprayer only has one setting so will this have the same effect or do I need to find another way to discharge them eg somehow find a 18v ish bulb ?

Thanks in advance for your help

Lee.


Those techniques are recommended by some for NiCd (and sometimes NiMH)
cells/batteries. I'd not try them on Li cells- especially the zapping
one.

Generally, if an Li cell is dead, it is done for.

--
Always smile when walking, you never know where there is a camera ;-)

Remarkable Coincidences:
The Stock Market Crashes of 1929 and 2008 happened on the same
date in October. In Oct 1907, a run on the Knickerbocker Trust
Company led to the Great Depression.

Well those batteries sound to me like they are knackered. One has to be
careful as often each cell has protection circuitry to stop them blowing up
or catching fire!
Brian

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----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
wrote in message
...
Hi all,

I have a few 18v Graco (same as DeWalt lithium ion) batteries for my paint
sprayer which seem to charge well but then die very quickly. Once charged
they show just over 20v on the multi meter. I have been doing some
searching and come across people saying
1. Zap them with 36v - although this seems to be if they are not charging
at all
2. Slowly drain them until tool doesn't work any more. Leave them and
drain again. Repeat until completely dead and then charge.

Does anyone know if this works or is there a better option? For option 2,
my sprayer only has one setting so will this have the same effect or do I
need to find another way to discharge them eg somehow find a 18v ish bulb
?

Thanks in advance for your help

Lee.

wrote:
Hi all,

I have a few 18v Graco (same as DeWalt lithium ion) batteries for my paint
sprayer which seem to charge well but then die very quickly. Once charged
they show just over 20v on the multi meter. I have been doing some
searching and come across people saying
1. Zap them with 36v - although this seems to be if they are not charging at all
2. Slowly drain them until tool doesn't work any more. Leave them and drain again. Repeat until completely dead and then charge.

Neither.

Charge them up, then take them apart and measure the voltages across each
cell as the battery is discharged (the car bulb suggestion is a good one).
You'll probably find one or more of the cells drops rapidly, which causes
the whole pack to cut out. A healthy Li-ion cell should be 4.2V when fully
charged, dropping to about 2.5V when empty (and the protection circuit
should cut in).

You can try replacing the dead 18650 cells (requires a tab welder or cells
with pre-welded tabs - or using a pack for donor cells). But it might be
easier to buy a new battery, which will last longer.

Theo