Einhell Screwdriver: Replacing NiCd with LiOn Cells & Compatibility with Original Charger

Question

Hello, I read a dozen or so threads about replacing cells in a screwdriver, I have a regular Einhell screwdriver and I would like to replace used NiCd batteries with LiOn, so I have a question whether using such a plate

can I use the original charger that I bought with the screwdriver to charge the battery?

Anonymous · Answer

You will need a 16.8V CC / CV charger, I don't know what the original voltage was, LiOn are very sensitive to overcharging. This BMS is a bit weak for a screwdriver, it can be seen by the current limiter.

radziok16 · Answer

Tomorrow I will check carefully but I suspect that there are no more than 14v batteries in the battery had a voltage of 1.2v and there were 10 pcs. So if the charger has less than 14v can I use it without any worries?

Anonymous · Answer

You can but you won't charge it for 100% of such a package.

radziok16 · Answer

I have one more question I have another boxer screwdriver with two batteries that I bought for a funny price after a year of use, the batteries went down, the charger claims that they are charged and the screwdriver is discharged (only the LED diode will flash for a moment - the flashlight function), they currently have voltage from 10 to 11v I understand that the circuit board is to blame, because by connecting the screwdriver for a short time the engine works, the battery looks like this;

In this case, I just need to convert the output and batteries to such a board?

https://m.es.aliexpress.com/item/32817897264....32817897264&shortkey=f6v6jEb6&addresstype=600

budro2 · Answer

It is not necessary to drop the plate in the Boxer because one battery can be dropped and the BMS PCM protection detects that under load its voltage drops below the minimum 2.5V and STOP !! limit.
The charger charges up to 3x4.2V = 12.6V (3s-1p package) and in the dead battery the voltage increases quickly and is supposed to be OK. After direct connection, the screwdriver properly spins on two links.
The proposed BMS PCM module is ok, has the right current and is up to 3s but as far as I know Italian there is no balancer (it is not necessary but advisable). And how to connect the original charger that has a third temperature contact, and if it is not connected, it will not move.

Returning to Einhel 10x1,2V = 12V but max is 10x1,45V = 14,5V. BMS shown is 4S, i.e. as I wrote below 4S (14.8Vmax16.8V) so the voltage is too high and can damage the screwdriver, I advise you to give 3S-1p or 2p and BMS 3S (11.1V-max 12.6V). As for the original charger, the voltage will be OK, but you need to examine what current it gives when the battery is discharged ~ 8V (for 3S-1p max 2A for 3S-2p max 4A) and whether it has a temperature contact (it is necessary to leave the thermostat because it will not start)

A FEW RULES FOR CONSTRUCTION OF PACKAGES FOR Li-Ion, Li-Po batteries 3.6-3.7V (max 4.2V)
1. The cells in the package should be identical (preferably do not mix old and new ones) - the package is marked 1S (3.7V max 4.2V) or 2S (7.4Vmax 8.4V) or 3S (11.1Vmax 12.6V) or 4S (14.8Vmax16.8V or 5S (18.5Vmax21V) or 6S (22.2Vmax25.2V .................. etc.) The cells in the package can be connected in parallel and the quantity cells are marked with the digit + p, i.e. the package as in the photo is 3S-1p (3 individual cells in series.) When converting Ni-Cd packets into Li-ion batteries, the voltage should be properly selected and if there is space, connect 2p, 3p ... in parallel for high capacity.
2. Cells should have proper continuous discharge current, i.e. laptops are NOT SUITABLE for power tools because they have ~~ 4A current and 10-30A high current are needed
3. Aku Li-Ion are very sensitive to overcharging above ~ 4.25V / cell and excessive discharge below 2.5-3V, as well as exceeding the permissible charging and discharging currents. Therefore, it is necessary to use BMS PCM min15A security modules preferably with a balancer (the balancer loads each Xp level of the series individually) and chargers with current limitation (BMS does not control it), temperature control is also recommended. CELL OVERHEATING MAY CAUSE EXPLOSION OR FIRE.

PRACTICAL ADVICE:
1. BMS module after soldering with the packet can give 0V output because it has spark protection. To activate the package, connect it to the charger !!!!! Battery packets without a balancer disintegrate after a long time and certain links are systematically undercharged, which means that the charger does not want to charge them, and often it is enough that late cells in a row are loaded individually to make the package OK (for some time!).
2. BMS modules, chargers with current-voltage limitation, voltmeters with 1-8S control can be bought cheaply in the network. And you have to make some effort to connect it all, build it up and run it.
3.You should buy ONLY high-current Sony, Panasonic, LG, Samsung, ... brand cells, if you can't afford new ones, they can be dismantled with a guarantee of almost nominal capacity in the range of 1.5-3Ah, for PLN 6-10 / pc.
4.When converting Ni-Cd to Li-Ion it is easier to buy a corpse screwdriver / Li-Ion wrench e.g. 18V Eubauer, Titan, Worx, Guild, JCP (compatible battery), break Ni-Cd cells into the trash and to blow out the original battery screw on the cut-off foot with the el. troupe. After purchasing complete Li-Ion batteries and a dedicated charger, you have slightly larger but lighter equipment of all kinds. If you already have other equipment on Li-Ion with similar voltage, it comes quite cheap. Having the adapter you can buy matching body tools both Li-Ion and much cheaper Ni-Cd. METHOD RECOMMENDED FOR DIY, NOT ELECTRONICS, because the work el. it is soldering two cables.
The example below is a vacuum cleaner - PLN 30 + PLN 18 (shipping), an Erbauer multifunction corpse with a charger and one battery is PLN 85 with shipping. So together 133 PLN !!! I skip that I still have a working engine, electronics and Erbauer bag, and that I have the opportunity to buy a whole range of Erbauer, Titan, JCB, Worx, Guild bodies ...

budro2 · Answer

And another NOTE !! When replacing the acu from Ni-Cd with Li-Ions, you need to protect the motor and the switch against overload because BMS is not always torobi and the efficiency of Li-Ions is very high. The dedicated Li-Ion devices have a special overload protection module, but it is difficult to access and expensive.
Therefore, I recommend using a series of erasable polymer fuse with properly selected current and voltage> max. Please note that the shutdown current is 2x rated current. The fuse is cheap (a few zlotys) and turns on when it cools down and looks like this:

kotton · Answer

As a non-electronics and DIY-combinator, I'm very happy to find your entry. And I'll be even happier if you help me with the project old tools on new batteries I have a few quite old but fully functional blue Bosh 14,4V tools with NiCd batteries that deign to die. Recently, I also have a charger and two Li-Ion batteries for newer tools from the same company .. The obvious thing is: you need to make an adapter. I decided to use the old battery plug armed with a homemade socket for the new one. However, I have serious doubts whether it is enough to connect the poles of the plug and socket .. As (almost) you can see here: in newer tools, several wires come out of the socket to the switch - in older tools only two +/- wires go. Is this the protection system for the switch and motor you wrote about? Whether is just an alternative to this security? If so, what should the system look like with this fuse? Best regards and thank you in advance for your help PS. The idea of replacing the cells in an old battery and reworking an equally old charger seems to me an unattractive and unnecessary complication.

budro2 · Answer

I don't know BOSCHA tools. The GSR 18V-2 LI screwdriver has a built-in protection module (overload and temperature) which communicates with the battery and can turn it on and off (the screwdriver has 4 contacts, including two middle ones - for communication). Check if the battery has voltage on the external, force contacts "+" and "-". If so, the easiest way is to use them to power an old screwdriver but I would still give an erasable polymer fuse in the screwdriver (the fuse trip current is 2x its rated current) and I would not discharge the ACU to the end because it is not known whether the discharge protection works and for Li-Ions , discharging to 0 is death for the cell (min is 2.5V per cell). I do not know what the communication procedure is and whether the BMS in the ACU has additional current protection, but rather not. VERY IMPORTANT THAT YOU WILL NOT CONFUSE THE "+" AND "-" POLARIZATION BECAUSE YOU WILL BURN THE SWITCH TRANSISTOR AND EVEN A BATTERY.
Service information and diagrams have only service technicians and maybe one of them will reveal the secret of operation and communication because if there is no voltage on the disconnected ACU, I don't know what to do.

kotton · Answer

I called Bosch and the battery recycling company and heard that:
- Bosch batteries have no cell protection inside - and I accepted, without looking inside, that they have
- what I took for protection of the switch / motor located in the tool is the battery protection module ..

So do you?

budro2 wrote:
protection module (overload and temperature) which communicates with the battery and can turn it on and off

is it ultimately a safeguard for a battery or a tool?

If I understood correctly and the module is a protection for the battery, it means that between the original Li-ion battery and the old Ni-cd screwdriver should be put BMS, right? Whereas the polymer fuse you are writing about is to be an additional protection for the switch / motor against excessive current?

pablo11z · Answer

Hello In this model of the battery falls power power resistor (in the photo you can see that it is swollen), replacing with another brings the batteries back to life. The links are probably OK. Proven in practice.

budro2 · Answer

As you can see on the photo, ACU BOSCH has 4 contacts and BMS 5S (18V) needs 6 connections, so the Robert Bosch battery should be built-in BMS maybe even with a balancer. Aku are protected in it against excessive discharge, overcharging and maybe short circuit. The BOSCH charger gives the right, limited current (because Li-Ions swallow / give away everyone EXPLOSION !!!!) and probably checks the temperature.
To sum up, if there is voltage on the ACU contacts marked "+" and "-", two cables are enough to connect the adapter with an old screwdriver and a polymer fuse is installed in the screwdriver (we disconnect / cut one wire and connect it again with polymer - irrelevant polarization).

It is different for BMS 4S (14,4V) because it needs 5 connectors, but the battery as seen above has 5 contacts so it can be different i.e. the same as I described above or the balancer in the charger but probably not because the chargers have 4 contacts. However, the battery is certainly not bare (without electronics) and should have at least excessive discharge / short circuit protection.

kotton · Answer

Well no. I am outside the home so I have no way to get to the battery and attach a photo but I will use the instructions found in the meantime to demolish the Bosch Li-ion 14,4V battery:

https://www.ifixit.com/Teardown/Bosch+GBA+Battery+14.4V+1.5Ah+Teardown/112253

1. "The PCB houses 5 spring jaws total, two on sides are GND and VCC, inner 3 are connected with resistors and are used to monitor battery temperature during workload and charging."

2. "There is no control board in the battery cell, which really improves the durability. The function of control board was moved into the charger and the drill."

So it turns out that Bosch, however, gave up electronics in the battery and placed it in the charger and the tool ..
I have twin batteries but 2.6Ah and most tools at 14.4V. It must somehow pair

budro2 · Answer

Well, Robert B saved. Acu has no BMS or balancer but only output for temperature control. The charger has a charge and temperature control and the screwdriver a current limiter and probably control of the entire ACU discharge below 11-12V.
I would not combine with the BMS building since you have the original AKU and charger. All you need is a polymer fuse and careful operation (discharge). If you fancy more checks, you can paste a voltmeter, diagnostic module in the ACU:
https://allegro.pl/oferta/woltomierz-tester-napiecia-ogniw-1-8s-li-ion-18650-7559247510

https://allegro.pl/oferta/woltomierz-tester-napiecia-ogniw-2-8s-bx100-7568579956
There may also be something like this in a screwdriver:

https://allegro.pl/oferta/wskaznik-naladowania-baterii-4s-16-8v-niebieski-fv-7557367317
You can also like this + fuse:
https://www.youtube.com/watch?v=7W3-M50uE8w
But it's better with BMS:
https://www.youtube.com/watch?v=Mlas6T-8E18

kotton · Answer

Not necessarily ... Maybe he came out with the assumption that simpler construction means less probability of malfunction Searching for info on the subject of Bosch batteries, however, I came across mainly posts about battery repair .. other manufacturers (some manufacturers put there systems like a computer motherboard Blue bosses from the previous line are quite durable tools and it's hard to get them. Listening is the battery still giving me somehow I do not lie .. Still in the screwdriver .. but in the angle, saw or jigsaw? It is better to focus on the blade / blade than on watching the state of the battery .. at least if you like your limbs. Generally, there are 3 systems in newer tools: ECP protects the battery, EMP protects the motor and ERC - protects the user. User protection is based on the accelerometer and I can forgive myself. But I would still like to know how to protect the engine and battery. If anyone has any idea, I invite you to a discussion.

budro2 · Answer

Motor protection against overload and short circuit battery is handled by a properly selected, cheap and simple erasable fuse - the cheapest solution.
Currently, as a colleague noted, batteries (even cheap brands) are electronically secured with BMSs.
Tools (especially for higher cuts over 10.8V) are protected by electronic modules to protect the device.
There are two types of such modules:
1. protection + speed control.
2. only protection !! (speed control in the switch with built-in power transistor - Mosfet)
Older devices have an adjustable rotation in the circuit breaker, oversized motors resistant to overloads up to the limit of low performance Ni-Cd batteries.
You can add a type2 module using efficient Li-Ions but it is difficult to access (can anyone know where to buy it cheap in Poland ????)
The small type2 module in cheap brands has "+" and "-" input and the third thermal contact probably to Aku, and "+" and "-" output, and often LED lighting output.

kotton · Answer

This is what I mean because the rotation regulator in old tools is integrated with the switch: And in newer tools, in fact, the regulator and protection (embedded in the plastic battery mounts) are separately: That's the problem - I called most of the warehouses with cells and electronics to them and ... lime. All available systems cut off the battery when the voltage drops below 2.7V for any of the cells and not when it drops to e.g. 10.8V for the entire 4s package. Instead, I found several protection systems for gel batteries, i.e. this one: but I don't know if I can use them or adapt them to protect my batteries - I await the seller's response. What do you think? As you can see Robert's batteries are bare: Despite the lack of balancing the links, they are probably quite good ... for batteries from 2009: - battery No. 1 - 4 cells 4.05V, 4 cells 4.06V - battery No. 2 - 6 cells 4.02V, 2 cells 3.96V. Perhaps the lack of balancing Robert B. compensated for the quality of the cells and charger? Ps. I came across one interesting statement from someone who actually worked (and did not twist one dresser from Ikea) on the old tool and new battery, but did not put any security. The author did not write anything about the battery but burned two switches in a row .. Conclusion: the fuse is key

budro2 · Answer

I think the modulator will be good because it is important that it will not allow Li-Ions to be discharged below 4x2.5V = 10V, and that's good, the type of cells does not matter. It is a pity that its dimensions are not given but judging by the screws it is small and can be stuffed in devices. The price could be lower but the battery is more expensive.
I found something cheaper but you have to solder a bit and replace the relay with a stronger one (12V, min 20A)
https://allegro.pl/oferta/avt1533-zabezpieczenie-akumulatora-zelowego-12v-7409752200
or if there is no space then something like 10A:
https://serwis.avt.pl/manuals/AVT772.pdf
It costs PLN 10 but the electronics (I'm not) should write what Mosfet to give 20A and whether the increased voltage in Li-Ions (4S-max 16.8V, gel max 14V) requires changing the value of resistors and other components. This also applies to all above modules.
And also a universal programmable 12-24V or 3S-6S, 68mm long but narrow 30mm:
https://allegro.pl/oferta/avt1748-zabezpieczenie-akumulatora-olowiowego-7438169945
The fuse is key but should be well chosen. The problem is that up to 9A are on 30V and larger only 16V. Aku 4S has a maximum of 16.8V. In the 24V Erbauer hammer drill, for which I made the 6S package, the 9A polymer turned out to be weak despite the fact that the shutdown is 2x9A = 18A and the switch is 20A. I gave a pair of 2 pieces in parallel x7A x2 = 28A and it works. In screwdrivers that have less power and 12A switches, one 9A should suffice, e.g.
https://allegro.pl/oferta/bezpiecznik-polimerowy-9a-2szt-7435282897

Fuses are cheap as borscht so you can do experiments, choose one that protects and gives you some work. And you should know that the polymer has a limited number of shutdowns ~ 100.

Arecuss · Answer

I'll join the topic. I have an old 14.4 Ni Cd screwdriver and a new AEG with AL1214g3 charger for 12v and 14.4v Li Ion batteries. If I add (or rather order from someone) a Li Ion cell pack, can it be charged with this charger? Does such a package require any electronics or the charger itself will do everything you need?

budro2 · Answer

The cooperation of the battery with the charger is a business secret and you need good electronics to decipher it. And you need a connector for the converted ACU. A simpler solution is to buy Aku AEG 14.4V and transfer the gutters and connectors to the old ACU. And it's best to buy a corpse, e.g. a screwdriver and use a foot with a connector as shown above, because you can use many original AEG batteries. Of course, we always give a fuse in the screwdriver. AEG is niche equipment and it is difficult to find parts. When buying power tools, I advise you to consider their quantity on ALLEGRO.

Einhell Screwdriver: Replacing NiCd with LiOn Cells & Compatibility with Original Charger

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