Converting 18V Ni-Cd Charger for Use with 5Ah Li-Ion Battery: Feasibility and Process

Hello everyone :)

I have an 18V screwdriver powered by a Ni-Cd 1200 mAh battery.

I got a battery, also 18 V only 5 Ah and Li-Ion.

My question is, is it possible to convert my old charger to a new battery? I searched the forum and found several posts about the same conversion, but one says that it can be done without a problem, and in another that it is not possible. Besides, these are posts from 2015.

Below he adds some pictures which I hope you will find helpful.

Charger Pictures:








Picture of the current Ni-Cd battery



Photos of the new battery



Thanks a lot for any help.

If it is not possible to remake my charger, maybe it is possible to make one, e.g. from a laptop charger, which also has a Li-Ion battery.


I would like to add that I wanted to transfer the cells from this 5Ah battery to my old 1.2 Ah.


Edit:

The reason to change the battery is because my current battery is very poor. After full charge, it keeps about 5 minutes of continuous work and that's it. I think I know why it happened.
I just checked what current goes from the charger straight to the battery and it is NOTE 38V.
It's probably way too much. Does this mean the end of the charger?

Start with the charger ... can you use it (you don't need a special Li-Ion one) but you need to output about 21V
The second important thing, open a new purchase, there you will have an electronics board on the cells, take a photo and give it, it's about pins and markings, This is a discharge protection module and maybe a balance, because it will ultimately decide whether you will need a specialized charger or I can just charge what you have.
Yet there is another solution, but do it later, so don't be afraid of anything the solution will be found

Thanks for the answer.

I do not know about my charger, I do not see anything that could indicate its damage, and yet the current is 38v at the output.

I throw in the photo, but this plate is all stuck and you can't really see anything.



Added after 7 [minutes]:

kalkomania wrote:

Start with the charger ... can you use it (you don't need a special Li-Ion one) but you need to output about 21V
The second important thing, open a new purchase, there you will have an electronics board on the cells, take a photo and give it, it's about pins and markings, This is a discharge protection module and maybe a balance, because it will ultimately decide whether you will need a specialized charger or I can just charge what you have.
Yet there is another solution, but do it later, so don't be afraid of anything the solution will be found

As for the pin markings, please see the picture of the battery housing. There are various markings on the casing, but I don't know if that's what you mean.

Try to gently remove this cover, we need to see the module.
Unless someone from your colleagues unscrewed the battery and says about the pins.
A lot of these pins. You can see that the links were probably balanced from the outside. Chargers.
Big + and - this is the output. maybe it will also be possible to recharge after them

Unfortunately, after many attempts to remove this glue or whatever it is, it has not been possible to get rid of it. It was coming off piece by piece, but it did not break away from the plate itself, and I didn't want to try to do it with anything sharp.

I feel like I will be left with one good battery I am unable to charge and damaged original battery and charger

Calmly....
Are you sure that the battery is good and it's not about the cells themselves, but about electronics ...? check the voltage on pins (+, -), Check the voltage on individual cells there are 5 x2.
If the cells are good with charging, there is no problem, but in a moment ...

It may sound strange, but even the old battery (18v) has exactly the same voltage as the new one, 20.4 to be exact. All links are operational. I am just wondering why the old battery does not last even 5 minutes.

The new battery is good, before I got it it was used and charged Withstands several hours in mixed operation mode.

Ni-Cd, if you charge it to full capacity, does it keep the voltage or dropping /// after a few / several hours?
Check each cell separately, because there may be one or two weak ones, and they will blow your entire battery, and it may be that their end is close to no capacity and a flap, but it could be your charger blown out (38V is too much)
Coming back to Li-Ion, everything is OK.
Now the important thing is whether the battery electronics will allow you to charge through the pins (+, -), if so, then the matter is simple, you need to check it, discharge the battery a little, e.g. using a car bulb so that the voltage on the pins drops to say 19-20, then you need to have any power supply, even from a laptop, but on 21V 2-3A and try to charge through the same pins for several minutes and check whether it is charging or the module is not blocking you. Do you have any other power supply as long as it has 21V?

The old battery has not lost its voltage after a few hours, but after connecting it to the screwdriver and using it for about a minute without any resistance, the voltage is 18.9V.

I only have a laptop charger, but it's 19V. I will look for something in a moment, although I doubt that I will be able to find something like this at home.

Added after 5 [minutes]:

I also noticed that during charging, the voltage at the charger output varies between 19.8-20.02V.

20v is ok but on idle 38v something is wrong i would not trust her./
My old Ni-Cd charger also uses 18V, idle voltage 24V when charging the battery goes down to 18-19V.
If you have a power supply from a laptop and it is on 19V (but we're only talking about a charging attempt), then you need to discharge the battery below this voltage at least 1/2 V down.
The point is that we must be sure that the battery module will allow us to charge the cells.
If the result is positive, we will return to the issue of proper Li-Ion charging.
Are you able to fit those 10 levs in the old housing or is it just going to come in 5?

This in the picture in # 3 is it a new Li-ion battery, an old charger, or something else?

As for the battery, it should have some marking - maybe you can find a description on the manufacturer's website according to this?

The Li-ion cell itself should be charged to a voltage not greater than that specified by the manufacturer - they can be different, usually from 4.1V to 4.2V, and you have to watch it very carefully - exceeding the specified voltage generally damages the cell, and sometimes what is Near. This cell may contain a circuit that protects it against inappropriate charging and discharging - with this circuit it tolerates a slightly higher voltage.

The balancer ensures that the cells are charged evenly. It must be at the battery. If it is not there, the battery will probably not last long.

The plate in the battery is extremely small, I suspect that it is a normal charge / discharge protection. termiczne.balance is unlikely to be there.
But going back to charging, there is C + on the first left pin. (charge)
And 100% I would connect there (+) from charging, i.e. pins (C +, -)

The picture shows a li-ion battery for which I need a charger.

The model is bsl 1850, See you here

Well, you can get the charger for 100 and you're in trouble
Say, will these 10 cells go into the old housing?

will not enter, but it is so cool that I have a hitachi screwdriver So the topic of reworking the battery is basically outdated. So the only thing left is to buy the original?

That's great.
Because all this fun with DIY translation may not be bad, it will come out a bit cheaper, you will learn / learn something new, but will lose many hours of work.
And so you have a complete set, buy a second battery and it will last you for years.
Best regards.