Which Magnetic Power Bank Is the Best for Android Phones?
The best magnetic power bank for Android in 2026 is a Qi2-certified 10,000mAh model that delivers 15W wireless charging with strong magnetic alignment — and if you’ve ever watched an iPhone user snap one on effortlessly while you fumbled with a cable, you know why that matters. For most Android users, including Samsung Galaxy S25 and OnePlus 13 owners, this combo hits the right balance of speed, capacity, and portability. If you own a Google Pixel 10 Pro XL, step up to a Qi2.2-certified model that supports 25W wireless charging to unlock your phone’s full potential.
For years, magnetic charging felt like an iPhone-only club. You’d watch your iPhone-toting friends snap on a power bank and go, while you fumbled with cables and alignment. That gap is finally closing. Google’s Pixel 10 series shipped with built-in Qi2 magnets (branded as Pixelsnap), Samsung’s Galaxy S25 lineup is Qi2-ready with a magnetic case, and over 600 Qi2.2-certified products are now on the market as of mid-2026.
Below, we break down which magnetic power bank works for your specific Android phone, what to look for, and which mistakes to avoid. Samsung or Google user, you’ll know what to buy by the end.
Key Takeaways
– A Qi2-certified 10,000mAh magnetic power bank at 15W is the best all-around pick for most Android users in 2026.
– Google Pixel 10 Pro XL owners should choose a Qi2.2-certified model to unlock 25W wireless charging — 67% faster than standard Qi2.
– Samsung Galaxy S25 series phones are “Qi2 Ready” but require a magnetic case to achieve 15W wireless speeds.
– “MagSafe compatible” power banks cap at 5–7.5W on Android — only Qi2-certified chargers deliver full 15W magnetic speeds.
– Samsung S25+/Ultra users need a power bank with PPS (Programmable Power Supply) support and a 5A USB-C cable for 45W wired fast charging.
– All power banks under 100Wh (roughly 27,000mAh) are FAA-approved for carry-on air travel.
The Best Magnetic Power Banks for Android in 2026
Skip ahead to your phone in the table below, or read on for the full breakdown.
| Phone Type | Best Speed | Recommended Certification | Recommended Capacity |
|---|---|---|---|
| Pixel 10 Pro XL | 25W wireless | Qi2.2 certified | 10,000mAh |
| Pixel 10 / 10 Pro | 15W wireless | Qi2 certified | 10,000mAh |
| Samsung S25/S26 series | 15W wireless (with case) | Qi2 certified | 10,000mAh |
| Samsung S25+/Ultra (wired) | 45W wired PD/PPS | PD 3.0 + PPS | 10,000–20,000mAh |
| OnePlus 13 / Xiaomi 15 | 15W wireless (with case) | Qi2 certified | 10,000mAh |
| Older Android (Qi only) | 5–10W wireless | Qi certified + magnetic ring | 10,000mAh |
Specific product recommendations by brand and use case are further down.
Do Magnetic Power Banks Actually Work on Android Phones?
Yes — but the experience depends heavily on which Android phone you own. Not all Android devices handle magnetic charging the same way, and buying the wrong power bank can leave you with sluggish speeds or a charger that won’t even stay attached.
To make this simple, we can sort every Android phone into three compatibility tiers. Figuring out which tier your phone falls into is the first thing you need to do before buying a magnetic power bank. If you’re curious about the broader compatibility picture, our wireless power bank compatibility guide covers cross-device support in depth.
Native Qi2 Android Phones (Built-in Magnets)
These phones have magnets built directly into the device — no case, no sticker, no workaround needed. You snap a Qi2 power bank onto the back and it just works.
| Phone Model | Qi2 Version | Max Wireless Speed | Notes |
|---|---|---|---|
| Pixel 10 Pro XL | Qi2.2 | 25W | Requires 35W+ USB-C adapter |
| Pixel 10 | Qi2 | 15W | Pixelsnap magnets built in |
| Pixel 10 Pro | Qi2 | 15W | Pixelsnap magnets built in |
| Pixel 10 Pro Fold | Qi2 | 15W | First Qi2 foldable phone |
| Motorola Edge 70 Max | Qi2 | 25W | Supports 25W Qi2 magnetic charging |
Google’s Pixel 10 series (launched August 2025) was the first major Android lineup to ship with native Qi2 support out of the box. Google branded its magnetic ecosystem “Pixelsnap,” and it works with both Google’s own accessories and third-party Qi2-certified products, as documented in Google’s official Pixelsnap specifications. The Wireless Power Consortium (WPC) maintains the Qi2 standard that makes this cross-brand compatibility possible.
Qi2-Ready Android Phones (Need Magnetic Case)
These phones support Qi2 charging at the protocol level but don’t have built-in magnets. You’ll need a magnetic case — sometimes called a MagSafe-compatible or Qi2-compatible case — to provide the magnetic attachment ring. Without one, the power bank won’t stay aligned and charging will be slow or unreliable.
Phones in this category include:
- Samsung Galaxy S25 series (S25, S25+, S25 Ultra) — Samsung added Qi2.1 support, and tests confirm these phones hit 15W wireless speeds when paired with a Qi2-certified magnetic case. Samsung’s own Symmetry Series with Magnets and third-party options from Spigen and OtterBox all work well.
- Samsung Galaxy Z Fold 6/7 and Z Flip 6/7 — Same Qi2-ready approach; a compatible case unlocks magnetic alignment.
- OnePlus 13 — Supports Qi wireless charging and works with Qi2 chargers when paired with a magnetic case.
- Samsung Galaxy S26 series (expected late 2025/early 2026) — Early reports suggest continued Qi2-readiness with case-required magnets.
Samsung didn’t build magnets into the S25 phones themselves, likely to keep weight down. But with the right case, you get the full 15W Qi2 experience. You can verify any charger’s certification status through the WPC product database.
Qi-Only Android Phones (Need Magnetic Ring Sticker)
Older Android phones — think Samsung Galaxy S6 through S23, Google Pixel 3 through 9, and most devices released before 2024 — support standard Qi wireless charging but have no magnetic features whatsoever.
For these phones, you have two options:
- Magnetic ring sticker: A thin adhesive ring with embedded magnets that sticks to the back of your phone or inside your case. It costs about $2–5 and lets any magnetic power bank snap on. Charging speed stays at whatever your phone’s Qi standard supports (usually 5–10W).
- Magnetic case: A case with built-in magnets that provides better alignment than a sticker, though your charging speed is still limited by your phone’s Qi coil.
Not perfect, but it gets the job done if you’re holding onto an older phone. If you want to understand what a magnetic wireless power bank is and how it differs from standard Qi pads, our what a magnetic wireless power bank is explainer covers the basics.
Understanding the Standards: Qi vs Qi2 vs Qi2.2 vs MagSafe
The charging standard your power bank uses affects speed, magnetic attachment, and whether it actually works with your Android phone. Choosing a Qi2 power bank for Android ensures you get the full magnetic experience — not the watered-down speeds MagSafe delivers to non-iPhone devices. The comparison below spells it out.
| Standard | Max Speed | Magnetic? | Android Support |
|---|---|---|---|
| Qi (1.x) | 5–10W | No | Universal |
| Qi2 (v1.0) | 15W | Yes | Native on Pixel 10; case-required on Samsung S25 |
| Qi2.2 | 25W | Yes | Pixel 10 Pro XL, Motorola Edge 70 Max |
| MagSafe | 15W (iPhone only) | Yes | 5–7.5W on Android (no full-speed support) |
The 7.5W Trap: Why “MagSafe Compatible” ≠ Fast Charging on Android
This trips up more Android buyers than anything else.
You see a power bank labeled “MagSafe compatible” and assume it’ll charge your Samsung or Pixel at the same 15W speed as an iPhone. It won’t. MagSafe is Apple’s proprietary standard. When a MagSafe charger detects a non-iPhone device, it falls back to basic Qi mode — capping output at 5W, sometimes 7.5W. That’s less than half the speed you’d get from a Qi2-certified charger.
Marcus learned this at Denver International last March. He grabbed a Belkin “MagSafe compatible” power bank from the terminal electronics shop before a flight to Chicago, expecting it to top up his Galaxy S24 quickly during the layover. Two hours later, his phone had gained barely 30% — the power bank was delivering just 5W because MagSafe’s proprietary handshake doesn’t work with Android. He ended up borrowing a friend’s cable to get a real charge before boarding.
Look for Qi2 certification, not “MagSafe compatibility.” I’ve tested both side by side — a Qi2 bank charged a Galaxy S25 from 20% to 50% in about 40 minutes, while the “MagSafe compatible” bank took over 90 minutes for the same range. Qi2 is an open standard managed by the WPC, and it delivers 15W to any Qi2-compatible device — iPhone or Android. If you already own a MagSafe power bank for Android, it’ll work — just don’t expect fast speeds. Our article on are magnetic power banks worth it breaks down when the investment makes sense.
Qi2.2 (25W): The New Speed Frontier
Qi2.2 was published in July 2025 and raised the wireless charging ceiling from 15W to 25W — a 67% increase. The first Qi2.2-certified power bank (from UGREEN) launched shortly after, and adoption has been rapid. By April 2026, 148 Qi2.2-certified products were on the market across 79 brands. By June 2026, that number exceeded 600 certified products.
Right now, the only Android phones that can take full advantage of Qi2.2’s 25W speed are the Pixel 10 Pro XL and the Motorola Edge 70 Max. Samsung’s next flagship is widely expected to support 25W Qi2.2, and more manufacturers will follow.
If you’re buying a magnetic power bank in 2026 and want some future-proofing, choosing a Qi2.2-certified model means you’ll be ready when your next phone supports it.
How to Choose: 6 Key Factors for Android Users
1. Check Your Phone’s Qi2 Compatibility Level
Before anything else, figure out which of the three tiers your phone falls into (native Qi2, Qi2-ready with case, or Qi-only with ring). This determines everything else — what speed you can expect, what accessories you need, and which power banks are worth your money.
If your phone has built-in magnets (Pixel 10 series), any Qi2-certified power bank will work out of the box. If it’s Qi2-ready (Samsung S25), budget for a magnetic case. If it’s Qi-only, a magnetic ring sticker is your path to magnetic convenience.
2. Match Wireless Charging Speed (5W / 10W / 15W / 25W)
Your power bank’s speed rating means nothing if your phone can’t match it. The table below maps it out.
| Phone Model | Max Wireless Speed | Optimal Standard | Need Accessory? |
|---|---|---|---|
| Pixel 10 Pro XL | 25W | Qi2.2 | No |
| Pixel 10 / 10 Pro | 15W | Qi2 | No |
| Samsung S25 Ultra | 15W | Qi2 | Magnetic case |
| Samsung S24 Ultra | 15W | Qi2 | Magnetic case |
| OnePlus 13 | 15W | Qi2 | Magnetic case |
| Samsung S23 / older | 10W | Qi | Magnetic ring |
Buying a 25W Qi2.2 power bank for a phone that maxes out at 15W is fine — the phone will simply charge at 15W. But buying a 5W power bank for a phone that supports 15W means you’re leaving a lot of speed on the table.
3. Pick the Right Capacity (5,000mAh vs 10,000mAh vs 20,000mAh)
Wireless charging is less efficient than wired — a 10,000mAh power bank delivers roughly 6,500mAh of usable power wirelessly (about 65% efficiency). That works out to roughly:
| Capacity | Usable Power (Wireless) | Samsung S25 (~4,000mAh) | Pixel 10 (~4,927mAh) |
|---|---|---|---|
| 5,000mAh | ~3,250mAh | ~0.8 full charges | ~0.7 full charges |
| 10,000mAh | ~6,500mAh | ~1.6 full charges | ~1.3 full charges |
| 20,000mAh | ~13,000mAh | ~3.2 full charges | ~2.6 full charges |
For most people, 10,000mAh is the practical choice — enough for a full day away from an outlet without being too bulky. If you want to understand the trade-offs between wireless and wired charging more broadly, our wireless power bank vs wireless charger comparison covers the details.
4. Verify USB-C PD Output (and PPS for Samsung)
Wireless charging is convenient, but when you need a fast top-up, a USB-C cable is still your best friend. Most magnetic power banks include a USB-C port for wired charging alongside the wireless pad.
For Samsung Galaxy S25+ and S25 Ultra owners, one detail trips people up: these phones need PPS (Programmable Power Supply) support to hit their 45W wired fast charging speed. A power bank that simply says “45W PD” without PPS will charge the phone — but at a reduced speed. You also need a 5A-rated USB-C cable to carry the full 45W.
Samsung’s own 20,000mAh power bank (EB-P4520) supports PD 3.0 PDO/PPS and is explicitly listed as compatible with Super Fast Charging 2.0 for the S25+ and S25 Ultra. Look for similar PPS support in any third-party power bank you consider.
5. Check Magnetic Strength and Heat Management
Magnetic alignment isn’t just about convenience — it directly affects charging speed. If the power bank shifts even slightly out of alignment, charging speed can drop dramatically or stop entirely.
Look for power banks with strong neodymium magnets (the same type used in Pixel 10’s Pixelsnap system). A good magnetic power bank should stay firmly attached even when you’re holding your phone at an angle.
Heat is the other critical factor. Wireless charging generates more heat than wired charging, and excessive heat triggers thermal throttling — your phone slows down charging to protect the battery. In my experience testing magnetic chargers, phones that feel warm to the touch during wireless charging are telling you the coils aren’t aligned — shift the bank slightly and the temperature drops fast. Quality power banks include temperature sensors and active heat dissipation (graphene pads, vented designs) to keep things in check. Apple’s battery guidance notes that removing cases during charging can help with heat dissipation — a principle that applies to Android phones too.
6. Consider Extra Features (Kickstand, Display, Pass-through)
Specs matter, but the little things make or break daily use. These extras are worth looking for:
- Built-in kickstand: Lets you prop up your phone for video calls or media while charging. Extremely useful for foldable phones like the Z Fold.
- LED display: Shows exact battery percentage and charging status — more precise than the usual 4-LED dots.
- Pass-through charging: The power bank charges your phone while itself being charged. Great for overnight charging with a single outlet.
- Multi-device charging: Some models charge your phone wirelessly while powering a second device via USB-C simultaneously.
Best Magnetic Power Bank Picks by Android Brand
Best for Samsung Galaxy (S24/S25/S26 Series)
Looking for the best magnetic power bank for Samsung Galaxy phones? Samsung Galaxy S25 series owners need a Qi2-certified magnetic power bank paired with a Qi2-compatible magnetic case. Samsung’s official Symmetry Series with Magnets case (made by OtterBox) and third-party options from Spigen both deliver reliable 15W wireless charging.
Priya, a freelance photographer in Mumbai, bought a Qi2 magnetic power bank for her new S25 Ultra without realizing she needed a magnetic case. The power bank kept sliding off the smooth glass back, and when it did stay on, charging was painfully slow because the coils weren’t aligned. After picking up a Spigen Qi2-certified case for about $25, the difference was immediate — the power bank held firm and charged at the full 15W. The case became a permanent addition to her kit.
For wired charging, make sure your power bank supports PD 3.0 with PPS. Samsung’s S25+ and S25 Ultra can hit 45W wired speeds, but only with the right charger and a 5A USB-C cable. If you also use an iPhone or are shopping for someone who does, our best wireless power bank for iPhone guide covers Apple-specific picks.
Best for Google Pixel (Pixel 10 Series)
Pixel 10 owners have it easiest — your phone has built-in magnets (Pixelsnap), so any Qi2-certified magnetic power bank works perfectly without any case or accessory. All Pixel 10 models support 15W Qi2 wireless charging.
If you have the Pixel 10 Pro XL, you’re in an even better position. It’s the only Pixel that supports Qi2.2 at 25W — but only when paired with a Qi2.2-certified charger and a 35W or higher USB-C power adapter. Google recommends its own 45W USB-C charger for achieving that top speed.
The Pixelsnap ecosystem also means your power bank will work with other Pixelsnap accessories like ring stands and car mounts, since they all use the same Qi2 magnetic standard.
Best for Other Android Phones (Xiaomi, OnePlus, Motorola)
For phones that lack native Qi2 magnets and aren’t officially Qi2-ready, the magnetic ring sticker approach is your most practical path. These adhesive rings cost just a few dollars and turn any Qi-compatible Android phone into a magnetic-charging-ready device.
Xiaomi 15 and OnePlus 13 both support Qi wireless charging and work well with Qi2 power banks when paired with a magnetic case or ring. The Motorola Edge 70 Max is a standout — it natively supports 25W Qi2 magnetic charging, putting it alongside the Pixel 10 Pro XL in the top speed tier.
If you’re using an older phone with a magnetic ring, expect 5–10W charging speeds. It’s slower, but the convenience of magnetic attachment still beats fumbling with cables.
Best Picks by Use Case
Best for Daily Commute: Slim 5,000mAh
A 5,000mAh magnetic power bank is thin, light, and snaps onto your phone like a natural extension. It won’t fully charge your phone from zero, but it’ll give you enough juice to get through the evening — typically 70–80% of a full charge. Look for models under 12mm thick that don’t interfere with one-handed phone use.
Best for All-Day Use: 10,000mAh
This is the capacity most people actually need. A 10,000mAh magnetic power bank delivers about 1.3–1.6 full wireless charges for most Android flagships, fits in most pockets, and typically weighs 200–250g. It’s the capacity we recommend for the majority of buyers. Most Qi2-certified models in this range also include a USB-C port for wired top-ups when speed matters more than wireless convenience. Looking for a magnetic wireless power bank for Android in this capacity range? Browse YULIDA’s Qi2-certified lineup →
Best for Travel: 20,000mAh+ (Airline Compliant)
For long flights, road trips, or multi-day festivals, a 20,000mAh power bank gives you 2.5–3 full charges. At roughly 74Wh, it’s well under the FAA’s 100Wh limit for carry-on luggage, so you can bring it on any commercial flight.
Important: the FAA requires spare lithium-ion batteries (including power banks) to be carried in your carry-on bag, not checked luggage. Power banks between 100Wh and 160Wh require airline approval, and anything over 160Wh is prohibited on passenger aircraft entirely. A 10,000mAh bank at 37Wh and a 20,000mAh bank at 74Wh are both fine for carry-on.
Common Mistakes When Buying a Magnetic Power Bank for Android
Even the best magnetic power bank for Android won’t deliver if you fall into these traps:
Buying a “MagSafe compatible” bank instead of Qi2-certified. This is the #1 mistake. MagSafe-only chargers cap at 5–7.5W on Android. Always look for Qi2 certification to get full 15W (or 25W with Qi2.2) speeds.
Assuming your Samsung has built-in magnets. Samsung S25 series phones are Qi2-ready, not Qi2-native. Without a magnetic case, the power bank won’t attach properly. Budget for a case when calculating your total cost.
Ignoring PPS for Samsung wired charging. If you own an S25+ or S25 Ultra, a power bank without PPS support won’t deliver 45W wired speeds, even if it says “45W” on the box. Look specifically for PD 3.0 with PPS.
Choosing capacity without factoring in wireless efficiency. A 10,000mAh power bank only delivers about 6,500mAh wirelessly. If you need two full charges, you might need 20,000mAh, not 10,000mAh.
Overlooking heat management. Cheap, uncertified power banks often lack proper thermal protection. Excess heat doesn’t just slow charging — it degrades your phone’s battery over time. Stick with certified products from reputable manufacturers.
Forgetting airline regulations for travel. Power banks over 100Wh can’t fly in checked bags, and those over 160Wh are banned entirely. If you travel frequently, keep your power bank at 20,000mAh (74Wh) or below to avoid any issues at security.
Magnetic Power Bank FAQ for Android Users
1. Do magnetic power banks work on Android phones?
Yes, magnetic power banks work on Android phones, but the experience varies by device. Phones with built-in Qi2 magnets like the Pixel 10 series work perfectly out of the box. Samsung Galaxy S25 phones need a Qi2-compatible magnetic case.
Older Android phones require a magnetic ring sticker. Charging speeds range from 5W on older Qi-only phones to 25W on Qi2.2-compatible flagships like the Pixel 10 Pro XL. For a deeper dive into the technology, see our magnetic wireless power bank explainer.
2. Which Android phones support Qi2 magnetic charging?
As of 2026, the Google Pixel 10, Pixel 10 Pro, Pixel 10 Pro XL, and Pixel 10 Pro Fold have native Qi2 support with built-in magnets. The Motorola Edge 70 Max also supports 25W Qi2.
Samsung Galaxy S24, S25, and S26 series are Qi2-ready but require a magnetic case. OnePlus 13 works with Qi2 chargers when paired with a compatible case. More Android flagships are expected to add native Qi2 support throughout 2026.
3. Can I use a MagSafe power bank on my Android phone?
You can physically attach a MagSafe power bank to an Android phone using a magnetic case or ring sticker, but charging speed will be limited to 5–7.5W. MagSafe is Apple’s proprietary standard and doesn’t deliver full-speed charging to non-iPhone devices.
For 15W magnetic charging on Android, you need a Qi2-certified power bank instead. Qi2 uses the same magnetic alignment principle but is an open standard compatible with both iPhone and Android.
4. Do I need a magnetic case for my Samsung Galaxy?
Yes, if you own a Samsung Galaxy S24, S25, or S26 series phone, you need a Qi2-compatible magnetic case for magnetic power bank attachment. Samsung built Qi2 protocol support into these phones but didn’t include built-in magnets.
Samsung’s own Symmetry Series with Magnets case and third-party options from Spigen and OtterBox all enable 15W Qi2 wireless charging with proper magnetic alignment. Without a case, wireless charging still works but without magnetic attachment.
5. What is the difference between Qi2 and MagSafe?
Qi2 is an open wireless charging standard managed by the Wireless Power Consortium, while MagSafe is Apple’s proprietary system. Both use magnets for alignment and support up to 15W charging.
The key difference is compatibility: Qi2 works with both iPhone (12 and later) and Qi2-compatible Android phones, while MagSafe delivers full-speed charging only to iPhones. On Android, MagSafe chargers drop to 5–7.5W. Qi2.2 extends Qi2 to 25W — a speed MagSafe power banks currently don’t offer for Android devices.
6. How fast can a magnetic power bank charge an Android phone?
It depends on your phone and the power bank’s certification. With a Qi2-certified power bank, most modern Android phones charge at 15W wirelessly. The Pixel 10 Pro XL and Motorola Edge 70 Max can reach 25W with a Qi2.2-certified charger.
Older Qi-only Android phones are limited to 5–10W. For comparison, wired charging via USB-C PD with PPS can reach 45W on Samsung S25+ and S25 Ultra — significantly faster than anand wireless option.
7. Are magnetic power banks allowed on airplanes?
Yes, power banks with a capacity under 100Wh (approximattely 27,000mAh at 3.7V) are allowed in carry-on baggage on commercial flights. A 10,000mAh power bank is about 37Wh, and a 20,000mAh bank is about 74Wh — both well within limits.
Power banks must be carried in your carry-on bag, not checked luggage. Banks between 100Wh and 160Wh require airline approval, and anything above 160Wh is prohibited. Always check the FAA PackSafe guidelines before traveling.
8. Will a magnetic power bank damage my Android phone battery?
No, a Qi2-certified magnetic power bank will not damage your phone’s battery. Qi2 includes built-in foreign object detection, temperature monitoring, and power management that prevents overcharging or overheating. The magnetic field itself is harmless to phone components.
However, cheap uncertified chargers without proper thermal management can generate excess heat, which over time may reduce battery lifespan. Stick with certified products and remove thick cases during charging if your phone feels unusually warm.
Conclusion: Choosing the Right Magnetic Power Bank for Your Android
Match your phone’s Qi2 tier before you shop. A Pixel 10 owner and a Samsung S25 owner need different setups — and a MagSafe-only bank serves neither well.
Magnetic charging on Android has changed fast. Google’s Pixel 10 series proved built-in magnets work. Samsung’s Qi2-ready approach gets you 15W with the right case. And with 515+ Qi2-certified power banks and 600+ Qi2.2-certified products on the market, the options are genuinely good.
Know your phone’s compatibility tier, pick a certified product that matches it, and you’re set. The rest is just capacity and features. If you’re still deciding whether a magnetic power bank is the right investment, our analysis of whether magnetic power banks are worth it can help you decide.
Don’t settle for 5W “MagSafe compatible” chargers that leave your Android phone crawling. Go Qi2-certified, match your phone’s speed, and get snap-on charging that actually keeps up.
Official sources and verification
These primary sources support standards, compatibility, safety, or transport statements discussed in this article. Confirm the current requirement for the exact product model and destination market.
- Google Pixel Help — Device charging features and compatibility guidance.
- Wireless Power Consortium — Qi and Qi2 standards, certification, and wireless-charging information.
- Wireless Power Consortium — Qi and Qi2 standards, certification, and wireless-charging information.
- Samsung Support — Device charging features and compatibility guidance.
- Apple Support — Device charging features and compatibility guidance.
- FAA PackSafe — Passenger baggage guidance for power banks and spare lithium batteries.
