Conversion to Omax lithium batteries
Conversion to lithium rechargeable batteries Caliber
Conversion to lithium batteries Prorab
How to convert a Hitachi electric screwdriver to lithium batteries: process description
If the cans were sold without nickel electrodes, they are soldered. It is important to do this with great care, as overheating can permanently damage the battery, or even provoke an explosion. Before starting the process, it is useful to clean the soldered surfaces so that the likelihood of overheating decreases and the connection is strong.
The batteries are connected in series, the board is connected. The power wire is soldered to the microcircuit and the contact pad. Then, using a multimeter, the voltage readings are checked: for each battery, this figure should be about 1.3 V.
Upon completion of the test, all connections are carefully insulated. The assembled cassette is carefully placed into the case, the wire is laid without kinks and creases. The halves of the case are held together.
Preparation: selection of the necessary devices, elements
A battery pack that has lost its working qualities must be disassembled. The halves of the case can be fastened with glue and / or screws, clamps. To disconnect the glued seam, it is carefully tapped with a rubber hammer so that the halves of the plastic case separate from each other, but do not crack. The elements collected in a “cassette” are removed from the opened case. The contact pad is carefully separated, it will need to be fixed on new lithium batteries.
The new Li-Ion battery for the Hitachi electric screwdriver requires the purchase of additional accessories, while the following circumstances must be taken into account:
- New batteries must be similar in size and voltage to the old ones.
- It is more advisable to choose batteries that are already equipped with nickel plates so as not to waste time on soldering.
- The lithium-ion battery needs a BMS board (Battery Management System). It evenly distributes energy between the banks, protects the device from sudden power outages, turns it off if the charging time is exceeded, or the batteries are discharged to almost zero. To protect against overheating, a thermal detector is connected to the board.
- To connect the cassette to the contact pad, you need a power insulated wire of suitable thickness.
Conversion of the Hitachi electric screwdriver to lithium batteries
Nickel-cadmium batteries are inconvenient because of their “memory effect”, so switching to lithium-ion batteries is expedient and profitable.
The assembled lithium-ion battery pack must be put into working order. This is done so that new batteries do not wear out prematurely. The unit is fully charged and begins to be used intensively until the charge is depleted to zero and the device turns off. After that, it is recharged to 100% again, and work until it is completely discharged. This cycle can be repeated a third time. After this preparation, the battery module can be used normally.
You need to start charging the battery with lithium-ion banks when it is discharged to 20%, charging should always be done to 100%. It is forbidden to overexpose the device on recharging. as soon as the batteries are full, the charger must be disconnected.
Conversion of the Hitachi electric screwdriver to “lithium
Currently, there are a great many different batteries, protection boards, balancing boards, chargers, etc. It was necessary to select the right one and glue it together.
So, it was decided to supply high-current Li-Ion batteries. the current consumption of different screwdrivers can reach 30A and the batteries must be able to deliver such a current. Cheap “fingers” worth 80r apiece do not know how.
It was also decided to abandon the balancing BMS board, since all batteries were selected and were the same. By and large, at the beginning of operation it does not matter.
This pair of batteries in a collapsible case was subject to alteration:
It was necessary to collect a battery of 4 accumulators. The protection board was used on the basis of 4 batteries and 20A current. I do not specifically give the link, because very soon it will be inoperative. Search for a position by keywords
S 14.8V / 16.8V 20A peak li-ion BMS PCM battery protection board bms pcm
We assemble the battery with soldering of all contacts with an ordinary soldering iron. Please note: the connection of the assembled battery to the protection board MUST be carried out strictly in the following sequence: B-, B1, B2, B3, B:
You need to add a terminal for the charger to the case and you will get this final assembly:
Pay attention to the way of fixing the contact pad on the top of the battery. the self-tapping screw must be screwed in exactly in this place.
Here it is necessary to clarify. There are also protection boards with one contact group per charge and discharge. It is used here with separate connectors, so the charging terminal is taken out separately. I recommend to put it in the specified place.
Now with regard to charging such a battery. You can remake a native charger (this is not difficult and will be discussed in another article, perhaps), but I decided to sell my own charger, and use an extra power supply from a laptop with a voltage of 18 volts. At its output, a controller for the end of charging was made of this type (built into the case of the power supply):
After charging is complete, the LED will turn off reliably. In this case, the charge current was 1.5A and at the end of the charge before disconnection was about 1A. The full charging time of the battery was about 1.5 hours.
Budget: each set for one unit was 1000r and its service life will be unlike a regular nickel-cadmium battery.
Minus one: it is not advisable to use it in cold weather.
It is also necessary to take into account that in a more powerful electric screwdriver it is necessary to use protection boards with an operating current of 30A, otherwise, under difficult operating conditions, the protection board will go into protection and de-energize the electric screwdriver. In this electric screwdriver with this protection board, this problem has never been noted.
Nikolay (Friday, 07 September 2018 04:10)
Good day. I decided to read the articles on your site. Came across this one. Without going into the details of your alteration, I strongly disagree with your method of charging lithium. Firstly, balancing the cans is needed! Otherwise, after 10 charge cycles, your bank voltages will be different. As a consequence, undercharging some and overcharging as a rule of one can. Reducing the capacity of the entire battery as a whole. The risk of failure (overheating during charging) of the can that will be recharged. So put a separate balancing pad in the battery case or extend the balancing connector outside. The second is your charging method. Forgive me for being straightforward, but this is not how lithium is charged. In this case, the approach, the simpler, the better does not work. Lithium must be charged according to the scheme (constant current, constant voltage) and by the end of the charge, the voltage on your battery should be 16.8v. The current at the end of the charge should be no more than 0.1A. And you beat 18V instead of 16.8 and the current at the time of the BMS controller protection is 1.5A. Buy a current limited buck converter board. set it to 16.8v at the output and limit the current to 2A. There are indicators on this board that will show you that the charge is over. She stands on ALishka 100 rubles. and the can balancing fee is also a penny. Well, or if you have Imax on your farm, then charge it. Just by such a barbaric charge without balancing, you will very quickly kill your battery, and it costs money! Here are the links to the boards: https://en.aliexpress.com/store/product/CC-CV-5A-Lithium-Charger-Board-XL4015-Adjustable-6-38V-To-1-25-36V-DC-Step /3105031_32826721116.html?spm=a2g0v.12010615.8148356.21.44125425vlPYyw
RV9CX (Friday, 07 September 2018 07:43)
That’s right, Nicorlai. But let’s pay attention to where the batteries are operated. in an electric screwdriver! I understand if a device that is in operation around the clock was subjected to alteration, but in this case it is not. Secondly, I am skeptical about balancers. They are certainly needed, but not in such a performance. With a charging current in amperes and balancing of only 66mA, balancing cannot be achieved even with repeated charging. I conducted experiments: different batteries still do not equalize. Well, such a current is not enough for balancing. A few hundred mA at least. then yes.
As for CC / CV. same. for an electric screwdriver, there is no need to be pedantic about its batteries.
I completely agree with you. over, when using only the battery protection boards, they do not have time to gain their capacity, turning off when they reach 4.2V, but it would be necessary to hold them for a while at this voltage.
Cordless Drill Lithium Battery Conversion using 18650 Cells
Thus, when using only the protection board without BMS, the batteries will never overcharge. They won’t get the capacity, yes. But they won’t recharge. The imbalance is not terrible either. protection will operate on low voltage. But once in a certain time it is necessary to check the balance and align the batteries. Yes. For this, there are boards with external connectors. But there is no need to keep the balancer connected at all times, because with it, the charging time increases significantly, and with intensive work with an electric screwdriver, this is critical. However, for my second shura, I brought a board with a built-in balancer and a work current of 40A. I can’t deliver for half a year. not up to her.
This is the case for high charge-discharge currents. In my other designs, I still put a balancer. For example, in a battery for an echo sounder. there is an article next to it. The batteries there are not 18650, but flat, but this does not change the essence. The charge current is 200mA there and you can clearly see how the balancer works. It began to charge 3 times longer, but here I am just nowhere and in no hurry.
One more case. also next article. antenna analyzer. There, too, there is only protection without BMS, the charge current is about 1A. I have been using it for about 10 years already. At the same time, the batteries were disassembled from a dead laptop block, i.e. already unhealthy. And on DO is still in excellent condition. The difference on the banks is 0.1 volts. And do not care! Discharge current is typically 170mA, maximum 250mA when backlit. This is not 40A. It will be impatient. I will even out the tensions, but now that’s enough for me.
This is me to the fact that you need to take into account the operating conditions of batteries.
Nikolay (Friday, 07 September 2018 10:13)
Regarding charging, not CC \ CV. I disagree. Well, why risk overcharging and turn off charging when the protection board is triggered when 100 r. and all the cases. and control of current and LED indication! Beauty! Overcharging is quite possible. One of my acquaintances had it. And the picture is exactly like yours. electric screwdriver Makita, BMS without palancier, charging from the native unit with a current of 2.5A. As a result, the banks were unbalanced and one bank was gaining charge earlier than others. Shorter by the 1st 4.1 by the 2nd 4.1 by the 3rd 4.0 and by the 4th by 4.6. BMS disconnected charging when the total voltage was 14.8. result 1 can almost puffed, the temperature safety valve worked. The battery is dismantled, replacing the can, installing it inside the balancer board. Now more than a year has passed. all perfectly. Now about the work of the balancer. You are wrong that it balances the banks only at the moment of charging. It works on its own and evens out the stress on the cans by burning off the surplus of the more charged cans. so by the time of charging, your banks are all even and start charging more or less evenly. You can take the balancing jack outside and sometimes connect a balancer to it. I have several converted shura and one of the most successful I think is the one in which I did not put the bms board at all. She stupidly did not fit in there. But I remade my native charger for CC \ CV and put a balancer in it. so I plug in the battery and it charges and balances. And when I use it, there are no problems with the protection triggering. And in my opinion, only a fool can overdose the battery in an electric screwdriver. You feel that you started to twist weakly, changed the battery and this one for charging. It starts to twist weakly when the voltage on the battery is 10.10.5v.
RV9CX (Friday, 07 September 2018 19:57)
How to make Crappy Ni-Cad cordless tools useful again by converting them to Li-ion Power!!
Some kind of wrong protection board. In theory, it should stop charging after reaching the maximum voltage on at least one element! By the way, in the photo in the article, one of the two such boards was dead and turned off the voltage already when 4.5 volts was on the bank! Then they sent a new one, but the new batteries were already overheated, okay I saw ((