How to Replace JBL Charge 4 Battery?
By Robert Jones · 2021-07-17
Your trusty JBL Charge 4's given up the ghost, eh? Losing its spark halfway through a tune? Don't bin it just yet! I'll walk you through swapping out that dead battery, saving you a few quid and bringing your portable speaker back to life. It's a bit fiddly, but totally doable if you're careful.
Your trusty JBL Charge 4 has started playing up, hasn't it? Not holding its charge, dying on you halfway through "Bohemian Rhapsody" at the garden party. Frustrating, I know. But before you chuck it in the bin and splash out on a new one, hold your horses. That battery can be replaced, and I'm here to tell you exactly how. I've had countless bits of kit come through my workshop over the years, and one common culprit for speakers getting binned prematurely is a knackered battery. Manufacturers aren't always keen on making things easy to repair, but with a bit of patience and the right tools, you can often give your gear a second lease of life. The JBL Charge 4 is a prime example. Good speaker, solid sound for its size, but those batteries do eventually give up the ghost. > **Quick Verdict: Give your JBL Charge 4 a new lease of life with a bit of DIY – it's fiddly but worth it to save a decent speaker from the scrap heap.** ### Why Bother Replacing the Battery? Look, I get it. We live in a throwaway society. Something breaks, you just buy a new one. But think about it for a minute. A new JBL Charge 4 will set you back probably £130-£150, maybe more depending on where you look. A replacement battery? You're talking £15-£30, tops. Plus, you get the satisfaction of fixing something yourself. It's good for your wallet, and honestly, it's better for the planet too. Fewer electronics ending up in landfill, eh? I've seen plenty of these speakers come in with what folks think are terminal faults, only to find out it's just a tired battery. The Charge 4 is a decent bit of kit for its price point. It's rugged, sounds good for a portable, and it's waterproof. Why bin all that functionality just because the battery's had it?  *How to Replace JBL Charge 4 Battery? — tested in the SpeakersMag workshop.* ## So, What Do You Need? Right, before we get stuck in, let's gather our bits and bobs. You don't want to be halfway through and realise you're missing a crucial piece. Trust me, I've made that mistake more times than I care to admit. Nothing worse than having a speaker in pieces and having to stop. * **A new JBL Charge 4 battery:** This is a given, obviously. Make sure you get the right one. Most common ones are 3.7V, 7500mAh or 7800mAh. Double-check the model number on your existing battery if you can. Often they're marked as "MLP387796". You'll find these on Amazon or eBay. Be wary of super-cheap ones; you don't want something that'll pack up after a month. * **Small Phillips Head Screwdriver (PH0 or PH00):** You'll need this for a few screws. Precision is key here. Those tiny screws strip easily. * **Plastic Prying Tools (Spudgers):** Absolute essential. Don't even think about using a metal screwdriver to pry things open. You'll scratch, dent, and generally mess up the plastic housing. Plastic tools are gentle and won't short anything out. * **Tweezers:** Handy for fiddly connectors and tiny bits of wire. Sometimes those connectors are a nightmare to get a grip of with fingers. * **Small, Sharp Knife or Razor Blade:** For carefully cutting adhesive or rubber seals. Be very, very careful with this. Your fingers are important. * **Heat Gun or Hairdryer:** Useful for softening adhesive, especially around the fabric cover. Don't go mad with the heat; a little bit goes a long way. * **Thin Plectrum or Guitar Pick:** Another good option for prying if you don't have dedicated plastic spudgers. They're thin but firm. * **Double-Sided Adhesive Tape (thin):** Useful if any existing adhesive gets damaged, especially when putting the end caps back on. Not essential, but good to have. * **Small Container or Magnetic Mat:** For keeping track of all those tiny screws. Losing one of these is infuriating. * **Good Lighting:** You'll be working with small components. Don't try this in a dimly lit shed, unless you've got hawk eyes. * **Patience:** Probably the most important tool on the list. This isn't a race. Take your time, don't force anything. ## Disassembly: Taking the Charge 4 Apart Right, deep breaths. This is where the magic (or the mayhem, if you're not careful) happens. Follow these steps methodically. Don't rush it. ### Step 1: Remove the End Caps This is usually the trickiest bit to get started. The Charge 4 has those rubberised end caps, one covering the ports, the other a passive radiator. They're held on with a strong adhesive and a few hidden screws. 1. **Heat it up:** Grab your hairdryer or heat gun. Gently warm up the edges of one of the end caps. This softens the adhesive. Don't hold it in one spot for too long, keep it moving. You're not trying to melt the plastic, just loosen the glue. 2. **Pry it open:** Once warm, take your plastic prying tool or plectrum. Carefully insert it into the seam between the end cap and the fabric body. Work your way around slowly, applying gentle pressure. You'll hear some satisfying (or terrifying, depending on your outlook) cracking sounds as the adhesive gives way. Don't pull too hard, you might damage the wires underneath the port-side cap. 3. **Locate the Screws:** Once the cap is loose, you'll see a few small Phillips head screws underneath. Typically, there are four on each end. Unscrew them all and put them in your little container. These are usually pretty tiny, so don't lose them. 4. **Repeat for the other end cap:** Go through the same process for the second end cap. Be even more careful with the port-side one, as there are ribbon cables for the USB-C port and the aux jack that you *really* don't want to damage. *Robert's Tip:* I've often found that the passive radiator side is a good place to start. Less chance of accidentally yanking a crucial cable early on. Just focus on getting the screws out, don't worry about completely removing the cap at this stage, just let it hang if it's still partially attached by adhesive. ### Step 2: Peel Back the Fabric Cover Now that the end caps are off and their screws are out, you need to get to the main chassis. This means peeling back the fabric cover. It's glued on, so again, a bit of heat helps. 1. **Warm the fabric:** Gently warm the fabric around the seam where it meets the plastic chassis. This loosens the glue. 2. **Peel carefully:** Start at one end. With your plastic tool, gently separate the fabric from the main body. It's usually pretty stretchy and resilient, but you don't want to tear it. Work slowly, peeling it back until you expose the main screw casing underneath. You don't need to completely remove the fabric, just peel it enough to expose the screws holding the internal assembly. ### Step 3: Remove the Main Chassis Screws With the fabric peeled back, you'll see a series of larger Phillips head screws running along the length of the speaker. These hold the internal guts in place. 1. **Unscrew them all:** There are usually around 8-10 of these. Take them out and keep them separate from the end cap screws, as they might be a different size. Again, magnetic mat for the win here. ### Step 4: Access the Internals Once all those screws are out, the internal assembly should slide out from one end. This is where you'll see the main circuit board and, crucially, the battery. 1. **Slide out the core:** Gently pull the internal assembly out from one end of the speaker housing. It should slide relatively freely now that the screws are gone. Be mindful of any remaining wires or adhesive. You'll see the two main drivers, the passive radiators, the circuit board, and the battery pack, usually wrapped in a blue or black plastic heat-shrink material. ## The Battery Swap Alright, you're almost there. The battery is usually pretty obvious once you have the internals out. It's the biggest blocky thing that isn't a speaker driver. ### Step 5: Disconnect the Old Battery 1. **Locate the connector:** The battery will be connected to the main circuit board via a small, usually white or black, two-pin or three-pin connector. It's often quite stiff. 2. **Gently pry it off:** Use your plastic prying tool or tweezers to *very carefully* disconnect this plug from the circuit board. Do not pull on the wires themselves, always try to push/pull on the connector housing. Yanking wires can damage the connection to the battery or, worse, the circuit board. 3. **Remove the battery:** The old battery is often lightly adhered to the chassis or internal housing. Gently pry it up with your plastic tool. It might be a bit stubborn, but it will come free. *Robert's Warning:* Be careful not to puncture or severely bend the old battery. Lithium-ion batteries can be temperamental if damaged. Dispose of it responsibly at an electronics recycling point, don't just chuck it in the household bin. ### Step 6: Install the New Battery 1. **Position the new battery:** Place your brand-spanking-new battery in the same spot where the old one sat. If it has a sticky pad on one side, peel off the backing and secure it. 2. **Connect it up:** This is the reverse of disconnecting. Carefully align the new battery's connector plug with the socket on the circuit board. Push it firmly until it clicks into place. Make sure it's seated properly. You don't want it wiggling loose. *Robert's Tip:* Before you put everything back together, it's a good idea to quickly test it. Plug in the charging cable and see if the charging light comes on. If it does, you're probably good to go. If not, double-check your connection. ## Reassembly: Putting It All Back Together Now, reassembly is essentially the reverse of disassembly. Just be methodical and don't leave any screws out! ### Step 7: Slide the Internals Back In 1. **Carefully slide:** Gently guide the internal assembly back into the speaker housing. Make sure it's oriented correctly, with the ports lining up where they should be. ### Step 8: Replace Main Chassis Screws 1. **Screw them in:** Put all those main chassis screws back in. Don't overtighten them, just snug them up. You don't want to strip the plastic. ### Step 9: Re-apply Fabric Cover 1. **Smooth it down:** Carefully smooth the fabric cover back over the chassis. Press it firmly into place. If the old adhesive isn't holding well, you can use a tiny bit of spray adhesive (very sparingly!) or thin double-sided tape on the chassis, not the fabric itself. Make sure it's neat and tidy. ### Step 10: Reattach the End Caps 1. **Secure the screws:** Place the end caps back onto their respective ends. Screw in the smaller Phillips head screws you removed earlier. Again, don't overtighten. 2. **Press and seal:** Once the screws are in, press the end caps firmly around the edges to re-engage the adhesive. If the original adhesive is completely gone, a thin bead of B-7000 glue (the sort phone repair shops use) can work wonders, but give it plenty of time to cure before getting it wet. Or, as mentioned, thin double-sided tape can help. Just ensure a good seal if you want to maintain its water resistance. I've found that if you're careful with the initial removal, often enough of the old adhesive remains to get a decent seal, especially once those screws are holding it tight. ## Testing Your "New" Charge 4 Right, everything's back together. The moment of truth. Plug it in. Does the charging light come on? Leave it for a bit to get some juice in that new cell. Once it's charged up a bit, power it on. Connect your phone. Play some music. Does it sound like it used to? Does it hold its charge? Fantastic! You've just saved yourself a good chunk of cash and gained some valuable repair experience. Give yourself a pat on the back. ## Who This Repair Is For: * **The Budget-Conscious:** You don't want to shell out for a brand new speaker when a £20 part can fix yours. * **The DIY Enthusiast:** You enjoy tinkering and fixing things. That satisfaction of a job well done, eh? * **The Environmentally Minded:** You prefer repairing over replacing to reduce electronic waste. * **Owners of an otherwise perfectly good speaker:** If your Charge 4 sounds great but just won't hold a charge, this is for you. ## Who Should Skip This Repair: * **Those without patience:** If the thought of tiny screws and fiddly cables makes you rage, pay someone else to do it or buy new. * **Anyone clumsy with tools:** If you're prone to stripping screws, snapping plastic, or cutting yourself, this might not be the best project. * **If your speaker has other issues:** If the drivers are blown, the ports are damaged, or it's been completely waterlogged and isn't powering on at all, a new battery won't magically fix those problems. * **Those who need guaranteed water resistance:** While you can re-seal it, achieving factory-level water resistance can be tricky. If you regularly submerge your speaker, buying a new one might offer more peace of mind regarding its IP rating. ## Troubleshooting Common Issues Even with the best instructions, sometimes things don't go quite to plan. I've been there, staring at a dead speaker wondering what went wrong. Here are a few things to check if your Charge 4 isn't springing back to life. * **No Power After Replacement:** * **Battery Connector:** Did you plug the new battery in properly? Is it seated all the way? Sometimes they need a firm push. Don't force it, but make sure it's snug. * **Charge It:** Sounds daft, but did you actually try charging it? New batteries often come with very little charge. Give it a good hour or two on the charger. * **Old Battery Fault?** Is there a chance the old battery wasn't the *only* problem? If you're unlucky, there might be a deeper issue with the main board. This is rare for just charging problems, but it happens. * **Wrong Battery:** Did you definitely get the right voltage and connector type? Some aftermarket batteries can be slightly off. * **Loose Connections/Rattles:** * **Screws:** Did you put all the screws back in? Double-check both the end cap screws and the main chassis screws. Even one loose screw can cause a rattle. * **End Caps:** Are the end caps fully seated and properly adhered? Give them a firm press all around the edges. If they feel loose, you might need to re-apply some adhesive. * **Passive Radiators:** Ensure the passive radiators on the end are not obstructed or rubbing against anything. They're quite delicate. * **Reduced Water Resistance:** * **Seal Integrity:** This is the big one. If you're worried about taking your Charge 4 for a dip after this repair, I'd advise against it. The original factory seal is very precise. While you can re-glue the end caps, it's difficult to replicate that original IPX7 rating perfectly. If water resistance is paramount, a new speaker is the only guaranteed way. ## Maintaining Your JBL Charge 4 Battery Once you've got a fresh battery in there, you want to make it last, don't you? A bit of care can go a long way. These are general tips for lithium-ion batteries, but they definitely apply here. * **Avoid Extreme Temperatures:** Don't leave your Charge 4 baking in the sun on a hot day or in a freezing car overnight. Heat and extreme cold are enemies of battery life. * **Don't Deep Cycle Constantly:** Try not to constantly run the battery down to absolute zero and then fully charge it. Keeping it between 20% and 80% charge is often cited as the sweet spot for longevity. Obviously, you'll use it as you use it, but try not to make a habit of draining it completely every time. * **Use the Right Charger:** Stick to the original JBL charger or a reputable third-party one. Using an underpowered or over-powered charger can degrade the battery over time. * **Store Partially Charged:** If you're going to store the speaker for an extended period (say, a few months), try to leave it with about 50-60% charge, rather than full or empty. ## JBL Charge 4 Battery vs. Charge 5 Battery Now, a quick comparison, because I know some of you might be wondering about the newer model. The JBL Charge 5 uses a different battery, usually a 27 Wh (watt-hour) capacity, which translates to roughly 7500 mAh at 3.6V or 3.7V, similar to the Charge 4 but physically it