Owning a modern oral hygiene gadget from Xiaomi or a sub-brand Soocas is a great way to monitor dental health, but the life of lithium-ion batteries is not endless. Sooner or later, many users face a situation where the device stops holding the charge or only works a couple of cleanings, making it almost useless. At this point, the logical question arises about how to disassemble the Xiaomi Soocas brush to replace the battery or eliminate water from entering the case. This is not easy, because manufacturers specifically make the case sealed, but with the right tools and knowledge, it is quite solvable.
It is important to understand that opening the device automatically voids the official warranty, so the procedure should only begin if the warranty period has already expired. If the brush is new and is under warranty, the right solution is to contact an authorized service center, not self-repair. However, for devices that have been in use for more than a year, self-replacement of the battery is often the only economically viable option to extend the life of your favorite gadget.
In this article, we will take a closer look at the process of dismantling various Soocas brush models, including the popular X3, X3U and H3 series. You will learn what tools you will need to work, how to safely remove the old battery and how to properly assemble the device back, retaining its moisture protection. We will also discuss the typical problems that can be encountered in the process, and give practical tips for choosing a quality battery to replace.
Tools and workplace preparation required
Before disassembling an electronic device, you need to prepare a workplace and appropriate tools. Negligence in this matter can damage the plastic case or, worse, cause injury to the hands by sharp edges of tools. You need a clean, well-lit surface, preferably covered with a soft mat or fabric, so that small parts do not get lost and scratched.
Soocas' basic toolkit for disassembling brushes includes specific items, because standard cross screwdrivers won't help here. The design of the device is designed to minimize the possibility of unauthorized opening, so you'll have to use forceful but neat methods.
- 🛠️ Thin metal scalpel or special knife for opening electronics (spudger).
- 🔨 Small hammer (preferably rubber) for gently knocking out internal components.
- 🔥 A dryer or soldering station for softening the adhesive composition (optional, but useful).
- 🔋 soldering iron and solder for connecting a new battery (if the terminals do not match).
- 🧤 Safety glasses and gloves for safety when working with chemical elements.
Special attention should be paid to safety, as inside is a lithium battery that can ignite if the housing is damaged, work in a ventilated room and keep a sand container or fire extinguisher on hand in case of fire, and it will also be useful to prepare isopropyl alcohol to clean contacts and remove glue residues after work is completed.
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Use only high-quality isopropyl alcohol to clean the board, as plain water or vodka can cause short circuits or corrosion of the contacts.
Features of the design and sealing Soocas
Soocas brand devices, like most of Xiaomi’s ecosystem products, are renowned for their minimalist design and high level of water protection.The body of the brush, as a rule, has no visible screws or latches, which creates the illusion of monolithicity.All electronics, engine and battery packed in a sealed cylinder, filled with epoxy or tightly glued with a special composition.
The main challenge in disassembling the device is the bottom end of the device, where the charging connector is located, and through this compartment, the internal module is removed. In some models, such as the Soocas X3, the bottom cover can be glued, while in newer versions it is held by a tight fit and internal guides. Understanding how the locking mechanism works is critical for successful dismantling.
⚠️ Attention! Do not try to uncoil the body of the brush from the bristles or in the middle part, this will lead to irreversible destruction of the decorative coating and loss of leakage.
Inside the case, you'll find the main module, which is a control board, a vibrator and a battery, connected together, often with silicone pads or a compound to protect against vibration, and when you remove it, it's important not to damage the thin wires that connect the battery to the board, because repairing them will require soldering skills.
Why is it so hard to open?
Step-by-step instructions for dismantling the lower part
The opening process starts with the detachment of the bottom cap that hides the charging port, and you have to flip the brush up with the handle and look at the end carefully, and if you see a rubber cap, you have to gently tuck it in with a needle and remove it, and there may be a screw hiding underneath it, but in 90% of cases, Soocas models don't have screws, and the lid is held on glue or a tight fit.
If you don't have any screws, you take a scalpel, and you walk neatly, without fanaticism, around the perimeter of the bottom lid and the main body, and the goal is to break the adhesive layer or find a hook. Once the blade is in a couple of millimeters, you can use a thin plastic card or a mediator to widen the gap. You can act slowly so that you don't break the plastic fixtures.
- 🔍 Inspect the perimeter for hidden screws under decorative stickers.
- 🔪 Carefully cut the glue in a circle, holding the knife at a 45 degree angle.
- 🔄 Periodically twist the cover to evenly peel it off from all sides.
- 🧲 Use a magnetic screwdriver to avoid dropping small screws inside the case (if any).
When you remove the bottom cover, you'll have access to the insides, and in some cases, the inside module can sit very tightly, and this will be a very gentle knock-out method, which is to turn the brush down (plugged cloth) and tap a pen lightly on the table or use a rubber hammer, and the key is to keep the plastic glass of the engine intact.
☑️ Ready to disassemble
Removal of the battery and replacement of the battery
When the internal module is removed, you will see a cylindrical battery, which is most often the same size as standard batteries, but with welded contacts. Soocas brushes usually use 14500 elements or specific models with a protection controller. Before removing the old element, be sure to take a picture of the connection circuitry so that the new one does not confuse polarity.
The battery can be glued to the walls of the case or fixed with plastic holders. If it is glued, use a dryer for easy heating (don't overheat!) and gently tuck it with a plastic blade. Detaching the wires from the board requires caution: if they are on the connector, just unfasten it, if soldered, you will need a soldering iron. Try not to heat the board for long, so as not to peel off the tracks.
| Characteristics | Old battery | New battery (Recommended) |
|---|---|---|
| Type of element | Li-Ion (often unlabeled) | Li-Ion 14500 with protection |
| Tension. | 3.7 B (nominal) | 3.7 B - 3.85 B |
| Capacity | ~600-800 mAh (worn) | 800-1000 mAh (new) |
| Protection | Often absent | It is necessary to have a PCB-pay |
When installing a new cell, make sure it is securely fixed. If the dimensions of the new battery are slightly larger, do not force it to damage the body or the element itself. It is better to find a model exactly in size. After connecting the wires (observing plus and minus), conduct an initial health check without fully assembling the body.
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Use batteries with built-in protection board (PCB) only to avoid the risk of bloating or catching fire when recharging.
Assembly and restoration of leakage
After the battery is successfully replaced and the engine is tested, the assembly phase is as important as the disassembly process, because it depends on whether the brush will be waterproof again, all internal components must be cleaned of dust, pile and residues of old glue, wipe the inside of the case with an alcohol napkin.
To restore tightness, use a special electronics adhesive (e.g., B-7000 or T-7000) or double-sided waterproof tape. Apply a thin layer of sealant on the end of the body or on the inside of the bottom cover. Avoid getting glue on moving parts of the engine or on charging contacts.
- 🧪 Degrease surfaces before applying glue for better adhesion.
- 🕒 Let the sealant dry a little (2-3 minutes) before the final connection.
- 🔩 Tightly press the lid and fix the device with a rubber band or load for the time of drying.
- 🧼 Remove the excess glue immediately before it freezes.
The time to fully polymerize the adhesive is usually 12-24 hours. Don't rush to turn on the brush or wet it early. After drying, run a leakproofness test: lower the collected brush (without the nozzle) into the water for a few minutes and watch for air bubbles. If there are no bubbles, the assembly was successful.
Typical errors and troubleshooting
When you repair electrical appliances yourself, even experienced wizards can make mistakes. One of the most common problems is that the insulation of the wires is damaged when soldered, which leads to a short circuit immediately after switching on. Always check the integrity of the insulation and use shrinkage to protect the soldering sites.
Another common mistake is using the wrong battery: if you install a battery without a protection controller or with the wrong voltage, the brush control board may burn, and you should not ignore the condition of the vibrator: if it is worn out, replacing the battery will not return the device to its previous power.
⚠️ Attention! If the brush hums after assembly but doesn't vibrate, you may have mistook polarity when soldering or damaged the engine winding.
If the brush doesn't respond to charging after assembly, check the charging port contacts. They may have oxidized or shifted when disassembled. Clean them carefully with a blower or alcohol. If the problem is not solved, the control board itself may have failed, and repairs may not be cost-effective.