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how to repair flashlight batteries

by Xinling Yang on 0 Comments

How to repair flashlight batteries


With the long-term use of flashlights, we have more and more garbage batteries on hand. Because of the large internal resistance, we can't use them. If we throw away the batteries, it will damage the environment. Many batteries are easy to use at the beginning. After charging for dozens of times, they gradually become more and more difficult to use. Finally, they are idle in the warehouse.

flshlight battery repair
flshlight battery repair

The principle of repairing batteries

I have tried small current charging, large current impact short circuit and other methods are not successful. Later, in several forums, I saw that someone poured water to repair the battery. The principle was very simple: when the Ni MH battery was charged, the battery would heat up, and the electrolyte would evaporate into gas and escape from the pressure relief hole. After a long time, the electrolyte dried up, resulting in the increase of internal resistance and scrapping of the battery. 


In particular, high current charging and even serious overcharging of the flashlight battery led to the faster drying of the electrolyte, while the electrolyte dried up, and the electrolyte was basically still in use In the battery, just add water to make the battery recover. There are many ways: drilling holes in the bottom of the battery, drilling holes in the top of the positive cap of the battery, and even steaming the battery in a pressure cooker, freezing it in the refrigerator, boiling it in water, pumping it in a mineral water bottle, and so on. For the method of hard damage to the battery structure such as drilling holes and drilling roof, many people use solder repair welding, the actual effect is not good, and many people can not master those difficult technologies, and damage the battery will affect the appearance, and the leakage will damage the electrical appliances in the future. It's very difficult to see the amount of water added by other methods of adding water. I don't know how much water is added. It's less important and more likely to leak. And there are some ways to make people afraid and uneasy. Is there a better and simpler way? I carefully learned from many experts' schemes, and I made some improvements in combination with the actual situation. I feel it's not bad. If you feel it's feasible, you can refer to it.

flshlight battery repair
flshlight battery repair

Let's take a look at my batteries first. There are more than ten Pinsheng batteries (all of them are 16 years old), two Shanzhai Samsung batteries (15 years old), three GP superba batteries (around 2010 or even before), and one BTY battery (actually, there are four batteries. The remaining three batteries were found a few days ago, and one has not been repaired. It's rubbish!) In 2013.


Let's talk about the results first: the success rate of more than 20 batteries is more than 90%, and 3 batteries are not repaired successfully. The only ones that can't be repaired are BTY's so-called garbage battery, one GP super bully, and one Pinsheng, which I used to do experiments. GP super Ba, which has been released for more than ten years, has three sections in total. Except for the one that hasn't been repaired, the short-circuit current of the remaining two sections has reached 3-4A after repair. I used a 35 yuan Shengli 830l digital meter to measure it. It's still not easy to install it in the camera, but it's already very good in the razor. All the remaining Pinsheng batteries, including two Shanzhai Samsung batteries, have been repaired. After they are fully charged, the use effect can be close to that of the new batteries, and the short-circuit current is mostly 5-6A. 


In the self discharge test, half a month after the battery is fully charged, 1 / 3 of the batteries are almost dead, 1 / 3 of the batteries are still full, and 1 / 3 of the batteries are low. Even if the battery is not fully charged on the day or the next day to use basically no effect, it should be said that the result is very satisfactory. I use the smart 936d charger to connect to the computer to see the discharge curve is not bad (not for smart advertising, I buy it is to see it can be online only). Although it's a little less than its 2300mah mark, even the new battery Pinsheng will be falsely marked, and there's not much less. Moreover, almost all Pinsheng in my hand use Jinpeng and haopeng batteries (ordinary Pinsheng is marked with letters and numbers beginning with JP, which should be manufactured by Jinpeng, while Teyi is marked with letters and numbers beginning with HP, which should be manufactured by haopeng), It seems that the battery cells of both of them are not so good.

Next: how to repair the flashlight betteries

Because the battery brand is different, the pressure relief hole structure is also different, Sanyo's battery pressure relief hole is very large, you can add water without drilling, repair is the most convenient! It's a pity that I only have 2 sections in my hand. I don't use it many times. It's still good. I don't need water. The others are difficult. They must be drilled with an electric drill. Some people use nails to drive them. I don't recommend it. The damage is too severe. Use the electric drill to drill the pressure relief hole larger, which will not affect the sealing. It is similar to Sanyo's pressure relief hole. This is the best way. The following is the type and structure diagram of several battery pressure relief holes for reference. After reading, I also have a specific feeling about the depth direction of the big needle. The green leather bag in my hand actually saw that there was no pressure relief hole, which made me marvel! I don't know how to design its pressure relief hole. If there is no pressure relief hole, how can the electrolyte dry up, and if there is no pressure relief hole, the charging and heating pressure will explode, which is abnormal.

Processing to recover flashlight batteries

 let's introduce the process, The Tools that i use:

  • surgical blade

  • small electric drill

  • medical pure water

  • syringe needle tube

  •  two pins

how to repaire battery
how to repaire battery
how to repaire battery
how to repaire battery
how to repaire battery
how to repaire battery

I don't spend money, and you can also basically spend no money:

A bottle of 500 ml medical pure water is only a few yuan. You can ask the nurse of the hospital for a waste needle tube, and then ask her to pump a tube of pure water for you;

You can also find aluminum alloy decoration without an electric drill The shop asks the man to drill for you. At most, it's just a good cigarette.;

First of all, cut the neck of the battery close to the positive electrode with a sharp knife, and remove the insulating sheet and the outer skin. (I had no experience at the beginning, so I used the method of peeling off all the batteries, and then came up with this move). 


Then, use an electric drill to drill a pressure relief hole at the positive electrode of the battery (Sanyo's does not need a drill, its pressure relief hole is relatively large and high). The electric drill just started to drill more holes than before It's troublesome. The battery cap is round and easy to slide. After you drill two holes, you can get hold of it. Expose the rubber valve inside. Clean the positive electrode with cotton swab and pure water. Use a pin (if it's difficult to absorb water at the back, you can use two pins to increase the gap of the pressure relief valve) to insert 3-5mm along the bottom to the center. Use a syringe to drop pure water into the positive electrode ring for 0.6-0.8ml (this amount is my test) It's only after several tests. Don't add more! More will leak! The effect of adding less is not good), and then put the battery into a water cup filled with hot water to heat for about 1 minute (I didn't experience it at first. I burned the bottom of the battery with a lighter to burn the battery skin out). You will find a lot of bubbles coming out. When there are no bubbles, take out the battery immediately, and then put it into another water cup filled with cold water (it's better to add some ice). At this time, the water will slow down Inhale into the battery (some batteries even suck up the water instantly!) Then put the battery cover and insulating sheet back to the original place, and glue it to the same place. If the condition is good, you can use transparent heat shrinkable cover to seal it better. If the cover is broken, you can also use colored heat shrinkable cover to seal it directly.

Finally, I put on a few more good photos. There are the shrink skin I bought, transparent. And inadvertently obtained battery skin, after the package is almost new battery! But one of the two German batteries I tried to pack is the test product. It is a little bit more water added and the liquid leaks. You can see that the positive pole is a bit wet. But now that all is done, I'm not ready to take any more photos. The battery skin is silver, and the flash reflects the color of the flash when taking photos.

My DIY battery

repair flashlight battery

Add a few extra words

Please use up the battery before adding water, otherwise the pin will be short circuited, which may cause scalding, and electrolysis will occur after adding water, which will affect the effect of adding water. Secondly, do not charge the battery immediately after adding water. Put the battery upright for a few hours and then charge it with a small current. After discharging, recharge it again. The best effect can be achieved by cycling about 3 times. I used it after adding water in July. It's been 4 months now, and I haven't found any problems. It can be seen that adding water is not useless at all as some guys say, unless the water is added incorrectly (actually not added), or the added water has too many impurities, resulting in serious self discharge, which is not as troublesome as some guys say. I think it's extremely simple. Now I can add water to a battery in less than 5 minutes, if Sanyo estimates that it won't take more than 3 minutes. In addition, the best charger is high precision, can automatically stop the full, otherwise still continue to charge after full, it is easy to charge bad in the future. The charging current of the charger is a little lower, and the battery with low heat is not easy to damage the battery. I didn't find that the online saying that the greater the charging current, the greater the discharge current is correct. I charged with 1A current, and the discharge current is almost the same as that after 100mA charging. 


I hope it is the individual difference of my battery brand. Some people use drinking water and even tap water, which may be no problem, but I still recommend pure water. I recommend medical water for injection. The water that can be used for people is much cleaner than the water you drink!

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