Hi,
I lost the lithium charger for a cordless screw driver. The charger cost as much as the screw driver to replace. The charge specs shows 9V 100mA.
When I connect the screwdriver to a power supply and limit current to 100mA at 9V. The power supply shows it is only drawing 1 micro amp.
Any ideas? I should see some current under 100mA if it working?
Any reason why it would not work this way?
I lost the lithium charger for a cordless screw driver. The charger cost as much as the screw driver to replace. The charge specs shows 9V 100mA.
When I connect the screwdriver to a power supply and limit current to 100mA at 9V. The power supply shows it is only drawing 1 micro amp.
Any ideas? I should see some current under 100mA if it working?
Any reason why it would not work this way?
Are you limiting current and allowing voltage to run? That's "current limiting" and the voltage will run at whatever 100ma thru the battery requires.... should start off low and gradually rise as the charge increases. If you're limiting voltage "constant voltage" the current will run accordingly, initially high but dropping off to nil as charge accumulates in the battery. If so this is not the way. Use constant current but set an upper limit for voltage rise per spec. If the battery is fully charged,, at 9 volts you may get negligible current draw
The battery is almost depleted. It is set to current limit at 100mA. It does not seem to work since the current draw is extremely low.
Those wall adapters chargers have any special circuit in them? Or like it this case, just puts out 9V with mad 100mA.
It is this one:
https://www.amazon.com/Black-Decker...ix=black+decker+bdcs20+charger,aps,146&sr=8-5
Those wall adapters chargers have any special circuit in them? Or like it this case, just puts out 9V with mad 100mA.
It is this one:
https://www.amazon.com/Black-Decker...ix=black+decker+bdcs20+charger,aps,146&sr=8-5
Have you tried it both ways around? It's not clear from the picture if the polarity is shown looking at the charger or the drill. You could also put a multimeter on the drill's connector, there might be a few microamps of leakage current which will indicate the polarity.
Assuming the driver has a single cell (indicated by the "4V" on the "also bought" driver) then it'll have a built in converter/charge controller and 9 volts should be enough.
Assuming the driver has a single cell (indicated by the "4V" on the "also bought" driver) then it'll have a built in converter/charge controller and 9 volts should be enough.
I tried both ways, the power supply current limited. The correct way has, reads only 1uA. I tried to measure at the charging pins both ways but
I could not get a measurement, protection diode?
I agree with you, most of these devices have built in charging circuit and just plain DC brick adapter. I could try later, leave on longer and see what happens.
These black and deckers are 2 pins. The original adapter itself shows 2 pins. Why mention 3 pins?
Because it´s very common and you didn´t mention 2 pins or exact charger model.
If you want better answers then provide better data.
If you want better answers then provide better data.
looks like the actual current regulator is built into the drill, as it uses a 4V Li-ion battery. most likely a 18650 cell with 2.5Ah rating.
so there is a chance that the regulator circuitry is failing, or that the battery so much deplated that the regulator refuses to put charge in it . charging deeply discharged li-ion cells creates an explosion risk. so open upo the drill and check the cell voltage. worst case bring the cell contacts out and use a std 1A 4.2V li-ion charger
so there is a chance that the regulator circuitry is failing, or that the battery so much deplated that the regulator refuses to put charge in it . charging deeply discharged li-ion cells creates an explosion risk. so open upo the drill and check the cell voltage. worst case bring the cell contacts out and use a std 1A 4.2V li-ion charger
Hi Adason, no worries.
There is always a lot of info and we don’t always read through it. I‘m guilty of that. 🙂
Hi JMFahey,
If you look at my previous post, I sent the link of the actual charger. Not sure how that is not sufficient data.
Why waste your time to post. It just causes unnecessary bickering.
Thanks basreflex. Great idea.
There is always a lot of info and we don’t always read through it. I‘m guilty of that. 🙂
Hi JMFahey,
If you look at my previous post, I sent the link of the actual charger. Not sure how that is not sufficient data.
Why waste your time to post. It just causes unnecessary bickering.
Thanks basreflex. Great idea.
Charge the battery at constant current at 1C rate and go into voltage sourcing mode on the charger once the charge current drops off, usually below 100mA or the voltage across the cell is 4.1Vdc or so, whichever happens first. Checking with the battery's mfr. may also provide this sort of information, too.
My electric screwdriver died and the battery would no longer charge.
I did the usual trick of blasting the battery with 1 amp but it was still dead.
I read up a little on the batteries and they dont like being fully charged or full discharged.
I left mine for months flat so maybe not surprising it died.
I did the usual trick of blasting the battery with 1 amp but it was still dead.
I read up a little on the batteries and they dont like being fully charged or full discharged.
I left mine for months flat so maybe not surprising it died.
It looks like a 16550 battery. Most likely dead like yours. I will try the battery itself without the charging circuit.
For 16550 3.7V li-ion, what voltage is considered dead with no load?
For 16550 3.7V li-ion, what voltage is considered dead with no load?
if the batteries are nicad´s the blasting trick sometimes works. nicad can grow dendrites and create tiny shorts, dischargingt eh battery prematurely. quickly overcharging them with high current, (i´ve used a car battery for a few secs) may help, but explosion protective clothing can be advised.
If that 4V battery "looks open" and does not take charge even if fed from a higher voltage supply, then it´s dead, period.
if it´s below 2.5V don´t bother trying to charge it, it becomes explosive if charged at high current and low voltage, betwwen 2.5V and 3.2v charge at 0.05C or 100mA for a 18650 cell. above that charge at 0.5C or more if the specs allow it. limit the voltage at 4.2V. 4.1 if you like more cycle life and less capacity. above 3.95V li batteries start to deteriorate.
Even NMC does not always explode when charged from low voltage. However it is a risk, and that particular battery likely has a BMS that does not turn the circuit on unless it is ready for use. Find some Molicel P26A to rebuild the pack with if you can. You will need a resistance welder likely, so that is likely a pipe dream.
Douglas
Douglas