Bosch battery charger (for a drill)
 

I have been given a Bosch battery charger (along with a battery) for a
fairly chunky looking battery powered drill.

The problem apparently is that the charger does not charge batteries. The
battery appears to have about 15vdc (marked as 24v 1.2Ah). I have popped
the covered off the charger, and there is about 35vdc across the charging
terminals.

However when I attach the battery, the voltage drops to about 15vdc - as if
the charge has no current supply.

I have had a quick look at the circuit board and it looks ok. There is also
an LED attached to the board which briefly flickers when the battery is
attached and then goes out again.

I was lead to believe the LED is meant to flash until the battery is charged
and then remain on to show 'fully charged'.

The details I have for the unit a Typ 1617 224 006 (then 820 in an
ellipse)
prim: 240vac, 50/60Hz, 30w
sek: 24vdc, 0.6a, 15va

Any suggestions?!

Cheers,
Matt

ps. device is apparently a bit over a year old, but has not had much use.

Bosch battery charger (for a drill)
 

Matthew Ames wrote:
I have been given a Bosch battery charger (along with a battery) for a
fairly chunky looking battery powered drill.

The problem apparently is that the charger does not charge batteries.
The battery appears to have about 15vdc (marked as 24v 1.2Ah). I
have popped the covered off the charger, and there is about 35vdc
across the charging terminals.

However when I attach the battery, the voltage drops to about 15vdc -
as if the charge has no current supply.

I have had a quick look at the circuit board and it looks ok. There
is also an LED attached to the board which briefly flickers when the
battery is attached and then goes out again.

I was lead to believe the LED is meant to flash until the battery is
charged and then remain on to show 'fully charged'.

The details I have for the unit a Typ 1617 224 006 (then 820 in an
ellipse)
prim: 240vac, 50/60Hz, 30w
sek: 24vdc, 0.6a, 15va

Any suggestions?!

Cheers,
Matt

ps. device is apparently a bit over a year old, but has not had much
use.

This charger is the same as mine, which is for my GBH24 VRE 24Volt Hammer
Drill. I doubt that there is anything wrong with the charger itself, rather,
the battery is knacked. This is precisely the same effect I had with my
original battery which went the same way.

Bosch battery charger (for a drill)
 

"b_white" wrote in message
...
This charger is the same as mine, which is for my GBH24 VRE 24Volt Hammer
Drill. I doubt that there is anything wrong with the charger itself,
rather,
the battery is knacked. This is precisely the same effect I had with my
original battery which went the same way.

There was a second battery in the box with the drill, and we tried that -
same result - the LED just flickered once and that was it.

what sort of life would you expect to see from the batteries?

Bosch battery charger (for a drill)
 

"b_white" wrote in message
...
This charger is the same as mine, which is for my GBH24 VRE 24Volt Hammer
Drill. I doubt that there is anything wrong with the charger itself,
rather,
the battery is knacked. This is precisely the same effect I had with my
original battery which went the same way.

Just put an amp meter inline with the battery and it appears to be charging
at about 100ma

Bosch battery charger (for a drill)
 

In article ,
Matthew Ames wrote:
The problem apparently is that the charger does not charge batteries.
The battery appears to have about 15vdc (marked as 24v 1.2Ah). I have
popped the covered off the charger, and there is about 35vdc across the
charging terminals.

However when I attach the battery, the voltage drops to about 15vdc - as
if the charge has no current supply.

A Ni-Cad charger - assuming a non intelligent one - will (or should) be
constant current, so the voltage will vary a lot according to the
condition of the battery and what the charge rate is set at (hours). So
you really need to measure the current going into the battery, and know
how long it's meant to take to charge. A simple overnight charger would
deliver *about* 200 milliamps.

--
*Seen it all, done it all, can't remember most of it.

Dave Plowman London SW 12
RIP Acorn

Bosch battery charger (for a drill)
 

"Matthew Ames" wrote in message
...
"b_white" wrote in message
...
This charger is the same as mine, which is for my GBH24 VRE 24Volt
Hammer
Drill. I doubt that there is anything wrong with the charger itself,
rather,
the battery is knacked. This is precisely the same effect I had with my
original battery which went the same way.

Just put an amp meter inline with the battery and it appears to be
charging
at about 100ma



How long are you leaving the batteries in the charger ? The batteries won't
charge in five minutes if they've been left discharged for any length of
time or are new. New batteries should be left on charge for at least eight
hours before being used, and if the batteries have been left for months
without charge, then they'll probably need the same treatment.


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Bosch battery charger (for a drill)
 

"BigWallop" wrote in message
...
How long are you leaving the batteries in the charger ? The batteries
won't
charge in five minutes if they've been left discharged for any length of
time or are new. New batteries should be left on charge for at least
eight
hours before being used, and if the batteries have been left for months
without charge, then they'll probably need the same treatment.

So far, not very long. I'll leave one in over night and see what happens.
If I can fix this, then I can get a free riding lesson :-) I will report
back tomorrow. My only concern was that the LED did not seem to function as
I was told (by the owner) it would... but there again!

Bosch battery charger (for a drill)
 

In article ,
Matthew Ames wrote:
Just put an amp meter inline with the battery and it appears to be
charging at about 100ma

Right. Sub C cells are usually between about 1500 and 2500 mAh capacity,
and the safe basic charge rate is 1/10th of the capacity for 14 hours. So
100mA sounds rather low - unless the system is old when batteries *may*
have had a lower capacity than today. Also, you said earlier the charger
was marked as 0.6 amp which seems a bit generous if it's only charging at
100mA.

However, if things aren't overheating etc, I'd leave it on overnight and
check the current again in the morning.

I'd be willing to bet though that it's simply the battery that's
knackered.

--
*Virtual reality is its own reward *

Dave Plowman London SW 12
RIP Acorn

Bosch battery charger (for a drill)
 

Dave Plowman wrote:
In article ,
Matthew Ames wrote:
Just put an amp meter inline with the battery and it appears to be
charging at about 100ma

Right. Sub C cells are usually between about 1500 and 2500 mAh
capacity, and the safe basic charge rate is 1/10th of the capacity
for 14 hours. So 100mA sounds rather low - unless the system is old
when batteries *may* have had a lower capacity than today. Also, you
said earlier the charger was marked as 0.6 amp which seems a bit
generous if it's only charging at 100mA.

However, if things aren't overheating etc, I'd leave it on overnight
and check the current again in the morning.

I'd be willing to bet though that it's simply the battery that's
knackered.

I would too. Some of the cells will have grown internal whiskers that will
have shorted them out.
This often happens with NiCads that are left for months discharged.
Sometimes I've fixed them by blasting a current into each cell from a
controlled power supply, but you have to get at each cell to do this..