The Best Car Phone Mounts: 5 Picks Compared for Vent, Dash and Windshield
Five real car phone mounts compared, from a clamp suction mount to a vent hook, a stick-on magnetic puck and a 15W wireless charging mount.
The mount that works brilliantly in your friend's car can be useless in yours, because the thing that decides it is not the mount, it is your dashboard and your vents. This guide compares five car phone mounts sold on Amazon in the United States and covers every common way of attaching one. The VANMASS Ultimate ships with a locking suction base and a steel vent clip together, so it fits the widest range of cars. The Qifutan does the same three jobs for under ten dollars. The Miracase is a pure vent mount with a hooked steel arm and no adhesive at all. The Kaistyle is a tiny magnetic puck that sticks down with VHB tape, which is the answer for textured dashboards where suction never seals. And the LISEN 15W charger adds wireless power for drivers who live on maps. We compared them on how they attach, what they hold, how far they adjust and where each one fails.
Table of contents
- Quick picks
- Comparison table
- Best Overall: VANMASS Ultimate Car Phone Mount with Suction Base and Vent Clip
- Best Value: Qifutan Car Phone Mount for Windshield, Dashboard and Air Vent
- Best Vent Mount: Miracase Air Vent Car Phone Holder with Metal Hook Clip
- Best Compact Option: Kaistyle Magnetic Dash Phone Mount with 20 Magnets
- Best for Wireless Charging: LISEN 15W MagSafe Car Mount Charger with Dash and Vent Bases
- How we chose
- What to consider before buying
- Vent mounts and heat
- Suction cups on textured dashboards
- Magnets, charging and your phone battery
- Windshield mounting and the law
- Final recommendation
- FAQ
Quick picks
Every pick wins a specific use case. Jump to the full review before you buy.
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Best Overall
VANMASS Ultimate Car Phone Mount with Suction Base and Vent Clip
A clamp mount that ships with both a suction base and a vent clip, so it can find a spot in almost any car.
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Best Value
Qifutan Car Phone Mount for Windshield, Dashboard and Air Vent
A ten dollar clamp mount that covers windshield, dashboard and vent mounting and holds phones up to 7.1 inches.
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Best Vent Mount
Miracase Air Vent Car Phone Holder with Metal Hook Clip
A simple hook-style vent holder for drivers who never want to deal with adhesive or a suction cup.
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Best Compact Option
Kaistyle Magnetic Dash Phone Mount with 20 Magnets
A tiny magnetic puck that sticks to the dash with adhesive and lets you snap the phone on with one hand.
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Best for Wireless Charging
LISEN 15W MagSafe Car Mount Charger with Dash and Vent Bases
A magnetic mount that also charges at 15W, with both a dashboard pad and a vent hook in the box.
Compare every pick
| Product | Award | Mounting type | Best for | Where to buy |
|---|---|---|---|---|
| VANMASS Ultimate Car Phone Mount with Suction Base and Vent Clip | Best Overall | Dashboard, windshield or air vent | Drivers who do not know yet whether their car suits a suction base or a vent clip and want both in one box. | Check price for VANMASS Ultimate Car Phone Mount with Suction Base and Vent Clip at Amazon (affiliate link) |
| Qifutan Car Phone Mount for Windshield, Dashboard and Air Vent | Best Value | Dashboard, windshield or air vent | Anyone who wants a second mount for a spare car, a work truck or a teenager's first car without spending much. | Check price for Qifutan Car Phone Mount for Windshield, Dashboard and Air Vent at Amazon (affiliate link) |
| Miracase Air Vent Car Phone Holder with Metal Hook Clip | Best Vent Mount | Air vent only | Drivers with horizontal or vertical vent slats who want a mount that leaves no marks on the car. | Check price for Miracase Air Vent Car Phone Holder with Metal Hook Clip at Amazon (affiliate link) |
| Kaistyle Magnetic Dash Phone Mount with 20 Magnets | Best Compact Option | Dashboard only | iPhone owners who want the smallest possible mount and have a flat spot on the dash to stick it to. | Check price for Kaistyle Magnetic Dash Phone Mount with 20 Magnets at Amazon (affiliate link) |
| LISEN 15W MagSafe Car Mount Charger with Dash and Vent Bases | Best for Wireless Charging | Dashboard or air vent | Rideshare and delivery drivers who run maps all day and want the phone to charge without touching a cable. | Check price for LISEN 15W MagSafe Car Mount Charger with Dash and Vent Bases at Amazon (affiliate link) |
Swipe sideways to compare every column.
Best Overall
VANMASS Ultimate Car Phone Mount with Suction Base and Vent Clip
by VANMASS
A clamp mount that ships with both a suction base and a vent clip, so it can find a spot in almost any car.
What we like
- Comes with a suction base and a steel vent clip, so you can try both without buying twice
- Suction cup is 2.8 inches across and rated to hold 85 pounds, which is far more than any phone weighs
- Telescopic arm extends from 5 to 7.5 inches, so the phone can reach closer to your eye line
- Cradle is 0.7 inches deep and the clamp opens to 3.8 inches, so thick cases still fit
What we don't
- VANMASS says the suction cup will not hold on leather or textured dashboards, which rules out a lot of newer cars
- The vent clip does not work with round, cross or diagonal vents
- VANMASS itself recommends switching to the vent clip above 113 degrees, so the suction base is not a summer answer everywhere
| Mounting type | Dashboard, windshield or air vent |
|---|---|
| Attachment style | 2.8 inch locking suction cup, plus a steel vent clip in the box |
| Adjustability | 360 degree ball joint with a telescopic arm from 5 to 7.5 inches |
| Max phone size | Clamp opens 2.2 to 3.8 inches, cradle is 0.7 inches deep |
| Price bracket | $ |
Most phone mount problems are fit problems. You buy a vent clip and your vents turn out to be round mesh, or you buy a suction mount and your dashboard is soft-touch plastic that nothing sticks to. The VANMASS answer is to put both bases in the box. That alone makes it the safest single order in this guide.
The suction cup is the part VANMASS talks about most. It measures 2.8 inches across, has a lock buckle that you close after pressing the cup down, and the listing rates it at over 85 pounds of hold. A phone weighs well under a pound, so that headroom is really about surviving heat cycles and bumps rather than raw weight. VANMASS includes a cleaning wipe because a clean surface is what actually makes a suction cup work.
The telescopic arm is the other reason this one sits at the top. It runs from 5 to 7.5 inches, which is long enough to bring the screen up out of the dashboard and closer to the road ahead. Shorter mounts leave the phone low, and looking down is exactly what you were trying to avoid.
The clamp is generous. It opens from 2.2 to 3.8 inches with a 0.7 inch deep cradle, so a large phone in a rugged case still drops in. The release button sits on the lower back of the cradle rather than the side, which means you push rather than pinch when you take the phone out.
The honest limits are written into the listing itself. VANMASS says the suction cup will not hold on leather or textured dashboards, and it tells you to use the vent clip when the cabin gets above 113 degrees. That is useful candour, but it also means owners of cars with soft or grained dash tops are really buying a vent mount here.
Research-based pick: this recommendation is based on product data, owner feedback and comparison with products we have tested, not on direct hands-on testing.
Buy it if: Drivers who do not know yet whether their car suits a suction base or a vent clip and want both in one box.
Skip it if: Your dashboard is leather or heavily textured and your vents are round, because neither included base will hold.
Best Value
Qifutan Car Phone Mount for Windshield, Dashboard and Air Vent
by Qifutan
A ten dollar clamp mount that covers windshield, dashboard and vent mounting and holds phones up to 7.1 inches.
What we like
- Under ten dollars and still includes both a suction cup and a vent hook
- Suction cup is heat-resistant TPU and can be rinsed with water to bring the grip back
- Fits phones from 4.0 to 7.1 inches and up to 14mm thick, so a big phone in a case is fine
- One-touch release means you can take the phone out with one hand
What we don't
- The extension arm only reaches 5.9 inches, so the phone sits lower than on the VANMASS
- The vent hook will not fit circular vents
- Qifutan publishes no suction hold figure, so there is nothing to compare against the mounts that do
| Mounting type | Dashboard, windshield or air vent |
|---|---|
| Attachment style | Double-locked heat-resistant TPU suction cup, plus a steel vent hook |
| Adjustability | 360 degree ball joint with an arm from 3.7 to 5.9 inches |
| Max phone size | Phones 4.0 to 7.1 inches, up to 14mm thick |
| Price bracket | $ |
Phone mounts are one of the few car accessories where the cheap option is genuinely fine. The Qifutan costs about a third of what a name brand asks and does the same three jobs. It sticks to a windshield, it sticks to a flat dash, and it hooks onto a vent blade.
The suction cup uses a double lock, which means you press the cup down and then turn a collar to pull the centre up and hold the vacuum. Qifutan makes it from heat-resistant TPU, and the listing says you can wash the sticky face with water and air dry it to bring the grip back. That last point matters more than it sounds. Suction cups mostly fail because they collect dust, not because they wear out.
Sizing is where this one quietly beats more expensive mounts. It takes phones from 4.0 to 7.1 inches and up to 14 millimetres thick, so a large phone in a chunky case still clamps in. The one-touch release lets you pop the phone out with the hand you are not steering with.
The extension arm runs from 3.7 to 5.9 inches. That is shorter than the VANMASS arm and it shows in where the phone ends up. On a low dash the screen sits below the vents, which means a longer glance down each time you check the map. If your dash is tall, that gap closes and the difference stops mattering.
What you do not get is data. Qifutan does not publish a suction weight rating or a temperature range for the cup, so you are trusting the material claim rather than a number. At this price that is a fair trade, but it is the reason this pick sits second rather than first.
Research-based pick: this recommendation is based on product data, owner feedback and comparison with products we have tested, not on direct hands-on testing.
Buy it if: Anyone who wants a second mount for a spare car, a work truck or a teenager's first car without spending much.
Skip it if: You want the phone high in your sight line, because the shorter arm keeps it down near the dash.
Best Vent Mount
Miracase Air Vent Car Phone Holder with Metal Hook Clip
by Miracase
A simple hook-style vent holder for drivers who never want to deal with adhesive or a suction cup.
What we like
- Steel hook catches a vent blade instead of squeezing it, so it does not pop off over bumps
- Silicone pad on the hook keeps the vent blade from getting scratched or marked
- Takes phones from 4.0 to 7.2 inches, the widest range of any pick here
- Nothing sticks to your car, so it moves between vehicles in seconds
What we don't
- Miracase states it will not fit round vents, and the hook needs a blade under 1.4 inches wide
- Hangs the phone in front of a vent, so you lose that air outlet or blow hot air at the phone
- No extension arm at all, so the phone sits wherever the vent is
| Mounting type | Air vent only |
|---|---|
| Attachment style | Steel hook up to 1.4 inches long with a silicone pad |
| Hold method | Spring clamp arms with a quick release button |
| Max phone size | Phones 4.0 to 7.2 inches, thicker cases fit |
| Price bracket | $ |
Vent mounts split people. Half of drivers love them because there is no adhesive, no suction and nothing left behind when the car goes back to the leasing company. The other half find their vents are the wrong shape and the mount goes in a drawer. The Miracase is the pick for the first group.
It uses a hook rather than a clamp. A steel arm reaches over the top of one vent blade and catches behind it, so the weight of the phone hangs on metal instead of on friction. Clamp-style vent grips work by pinching, and pinching is what lets go when the car hits a pothole. The hook is padded with silicone so the blade does not get scuffed.
Miracase quotes a maximum hook length of 1.4 inches, and that number is the compatibility test. If your vent blades are wider than about 1.4 inches, the hook cannot reach behind one. Round vents are ruled out entirely. Take thirty seconds to look at your own dash before ordering, because this is the single thing that decides whether the mount works.
The cradle handles phones from 4.0 to 7.2 inches, which is the widest range in this guide, and it accepts thicker cases. A quick release button opens the arms with one hand.
What you give up is placement. There is no arm and no adhesive base, so the phone sits exactly where the vent is. In cars where the vents are low and near the console, that is a worse position than a dash mount would give you. You also block one air outlet, and in winter that means warm air pointed straight at the back of your phone.
Research-based pick: this recommendation is based on product data, owner feedback and comparison with products we have tested, not on direct hands-on testing.
Buy it if: Drivers with horizontal or vertical vent slats who want a mount that leaves no marks on the car.
Skip it if: Your car has round vents, mesh vents, or vents low in the centre console below your sight line.
Best Compact Option
Kaistyle Magnetic Dash Phone Mount with 20 Magnets
by Kaistyle
A tiny magnetic puck that sticks to the dash with adhesive and lets you snap the phone on with one hand.
What we like
- Sticks on with VHB adhesive, which holds on textured dash plastic where a suction cup will not
- Twenty magnets grab a MagSafe iPhone directly, with no case adapter needed
- Small enough that it does not block any part of the windshield or a vent
- Sales rank near the very top of the category, so this is a heavily bought mount
What we don't
- The adhesive pad is a one-shot install, so a bad position means peeling it off and buying a new pad
- Android phones need the included stick-on metal ring, which then blocks wireless charging on that phone
- No arm and no height adjustment, so the phone sits flat where you stuck the base
| Mounting type | Dashboard only |
|---|---|
| Attachment style | VHB adhesive pad for any flat interior surface |
| Hold method | Magnetic, 20 magnets in the head |
| Magsafe compatible | Yes, and metal rings are included for other phones |
| Price bracket | $ |
This is the smallest mount in the guide by a long way. It is a magnetic head on a short ball joint with a VHB adhesive pad on the bottom. There is no arm, no clamp and no suction cup, which is the whole point.
Adhesive is the interesting choice. Suction cups need a flat, smooth, hard surface, and a lot of modern dashboards are soft-touch or grained plastic where suction simply will not seal. VHB tape does not care about texture in the same way. It bonds and stays bonded. That makes the Kaistyle the pick for cars where every suction mount has already failed.
The magnet side is straightforward. Twenty magnets in the head grab an iPhone 12 or newer directly, or any case with a MagSafe magnet ring. Kaistyle includes metal rings in the box for Android phones and non-magnetic cases. Those rings work, but they are permanent, and the ring sits right where a wireless charging pad needs to make contact, so you trade one convenience for another.
Because it is so small, it sits below your line of sight and out of the way of the windshield. There is no telescopic arm, so the viewing angle you get is whatever the ball joint gives you from the spot you chose. Choose that spot carefully. Adhesive comes off with heat and patience, but you will need a fresh pad afterwards.
At around ten dollars this is one of the cheapest mounts on Amazon, and its sales rank sits near the very top of the category, so plenty of people are buying it. That is a real signal, though it is a sales signal and not a durability one.
Research-based pick: this recommendation is based on product data, owner feedback and comparison with products we have tested, not on direct hands-on testing.
Buy it if: iPhone owners who want the smallest possible mount and have a flat spot on the dash to stick it to.
Skip it if: You swap between cars often or you are not sure exactly where you want the mount, because the pad only goes on once.
Best for Wireless Charging
LISEN 15W MagSafe Car Mount Charger with Dash and Vent Bases
by LISEN
A magnetic mount that also charges at 15W, with both a dashboard pad and a vent hook in the box.
What we like
- Charges wirelessly at 15W, so a long drive on maps does not drain the phone
- Ships with both a 3M dashboard pad and a metal vent hook, so it fits more cars than a single-base mount
- 24 N52 magnets rated up to 3800gf, one of the few hold figures published in this category
- Clamp-free design leaves the side buttons of the phone free
What we don't
- Only a USB cable is included, so you need to supply an 18W or stronger car adapter yourself
- LISEN says it will not work with thick non-magnetic cases, wallet cases or pop grips
- Wireless charging makes noticeably more heat than a cable, and heat is what ages a phone battery
| Mounting type | Dashboard or air vent |
|---|---|
| Wireless charging | 15W, needs an 18W or stronger car adapter |
| Hold method | Magnetic, 24 N52 magnets rated up to 3800gf |
| Magsafe compatible | Yes, Android phones need a MagSafe-compatible case |
| Price bracket | $ |
Everything else in this guide holds a phone. This one holds a phone and puts power into it. If your phone is your navigation, your music and your dispatch app all at once, that is the difference between arriving with 60 percent and arriving with 15.
LISEN builds it around 24 N52 magnets rated at up to 3800gf. Very few mounts publish a hold figure at all, so having a number is useful even if you cannot verify it. The magnetic head has no arms, which means the side buttons of the phone stay clear and you place the phone with one hand rather than prying clamps open.
Two bases come in the box. One is a dual-point 3M adhesive dashboard pad rated by LISEN from minus 40 to 194 degrees, and the other is a reinforced metal vent hook. Between them you should find a spot in most cars. An ice blue LED ring around the head makes it easy to find the mount at night.
Read the power note before you order. The package includes a 3.3 foot USB-A to USB-C cable but no car adapter, and LISEN says the charging needs at least 18W of input to work properly. Plugging it into an old 5W socket or a low-output USB port in the dash will leave you with a mount that charges very slowly or not at all.
The honest trade is heat. Wireless charging is less efficient than a cable, and the energy it loses turns into warmth against the back of the phone. A phone that runs warm all day loses battery capacity faster over the years. If your car already gives you a wired CarPlay connection, a plain holder is the kinder choice for the battery.
Research-based pick: this recommendation is based on product data, owner feedback and comparison with products we have tested, not on direct hands-on testing.
Buy it if: Rideshare and delivery drivers who run maps all day and want the phone to charge without touching a cable.
Skip it if: You already plug in for CarPlay or Android Auto, because then the charging coil only adds heat and cost.
How we chose#
This is a research-based comparison, not a hands-on driving test. We started with the phone mounts that sell in real volume on Amazon in the United States, then read each listing for the numbers that decide whether a mount works in your specific car. Clamp opening, cradle depth, arm length, hook length and suction cup diameter tell you more than any marketing line does.
We picked five different answers on purpose rather than five near-identical vent clips. That gives you a suction and vent combo, a budget version of the same thing, a pure vent hook, an adhesive magnetic puck and a wireless charging mount. Between them they cover every common way of attaching a phone to a car interior.
We also paid attention to what each brand admits. VANMASS says its suction cup will not hold on leather, Miracase says its hook will not fit round vents, and LISEN says thick cases will not work with its magnets. Those limits are the most useful sentences in any listing, and they are the ones the marketing images never show.
What to consider before buying#
Go and look at your car before you order anything. Open the door and check two things. Are your vent slats flat and horizontal or vertical, or are they round or mesh? Is the top of your dash hard, smooth plastic, or is it soft, grained or leather? Those two answers narrow this guide down to one or two picks and save you a return.
Think about where you want the phone to end up. A mount with a telescopic arm, like the VANMASS with its 5 to 7.5 inch reach, can bring the screen up near your normal sight line. A vent mount or a small magnetic puck puts the phone wherever the vent or the flat spot happens to be, and in some cars that is low and awkward.
Then decide whether you need charging at all. If your car does wired CarPlay or Android Auto, the cable is already there and a wireless coil adds nothing but heat. If you drive for a living and pick the phone up constantly, wireless charging earns its place.
Last, check your phone and case. Clamp mounts do not care what phone you have. Magnetic mounts care a lot, and a thick case with no magnet ring will let you down within a week.
Vent mounts and heat#
A vent mount puts your phone directly in the path of air coming out of the dash. In summer with the air conditioning on, that is genuinely helpful, because a cool phone charges faster and does not dim its own screen to protect itself.
In winter it works against you. Warm air blowing on the back of a phone that is already working hard on navigation pushes it toward its thermal limit. Phones respond by slowing down, dimming the display and pausing charging. If you run the heater hard on long drives, aim the blocked vent away from the phone or use a dash mount instead.
There is a second cost that is easy to forget. The vent you use for the mount is a vent you lose. In a car with only two centre vents, hanging a phone on one of them meaningfully changes how the cabin heats and cools. Cars with four vents rarely notice.
Suction cups on textured dashboards#
A suction cup holds because you push the air out from under it and the pressure outside presses it down. That only works if the cup can seal against the surface completely. Any grain, texture, stitching or seam in the dashboard leaves a tiny channel for air to creep back in, and the cup lets go hours later.
Modern dashboards are the problem. Soft-touch plastic, moulded grain and leather wraps are all common now, and none of them seal. This is why suction mounts often come with a stick-on plastic dash pad, which gives the cup an artificially smooth disc to grab. That works, but the pad is adhesive, so you are back to a permanent install.
Heat is the other failure mode. The dash under a windscreen in July gets far hotter than the outside air. The cup material softens, the trapped air expands, and the mount lands in the footwell. Keeping a windshield sun shade in the car helps more than any mount upgrade, because it keeps the whole dash surface cooler. VANMASS is unusually direct about this and tells owners to switch to the vent clip when the cabin passes 113 degrees.
Magnets, charging and your phone battery#
Magnetic mounts are the fastest to use. You bring the phone near, it snaps on, and you take it off with one hand. Nothing else here is that quick. The magnets themselves are safe for the phone, because flash storage cannot be erased by a magnet. Cards in a wallet case can be, and the phone compass can drift while it sits on a strong magnet.
The trade-off is grip. Magnetic pull drops off sharply with distance, so every millimetre of case between the magnets and the phone costs you hold. A MagSafe-rated case has its own magnet ring and works properly. A thick rugged case with no ring will slide off over the first big speed bump. On Android phones you usually need a stick-on metal ring, and that ring sits exactly where a wireless charging pad wants to be.
Wireless charging deserves a plain warning. It is slower than a cable and it makes more heat, because the energy that does not reach the battery leaves as warmth. Heat is the main thing that ages a lithium battery. A phone charging wirelessly on a sunlit dashboard on a summer afternoon is in the worst place it could be. The convenience is real, and so is the cost, so buy the LISEN charger because you hate cables, not because you think it is better for the phone. If you want to go deeper on magnet strength, Qi2 charging speeds and cooled mounts, our guide to the best MagSafe car mounts covers that category on its own.
Windshield mounting and the law#
Sticking a mount to the glass puts the screen closest to your eye line, which is why so many people do it. It is also the placement most likely to get you a ticket. Several states restrict objects attached to the windshield, and a few allow it only in a defined corner where the view is least affected. California and Minnesota come up most often in these discussions, and the rules do get updated.
The practical answer is simple. Check your own state vehicle code, and if you are not sure, mount on the dashboard or a vent instead. Neither position raises the question, and a mount with a long arm gets the phone almost as high anyway. The same thinking applies to anything else you attach to the glass, including a dash cam, which is usually tucked behind the mirror for exactly this reason.
Final recommendation#
Buy the VANMASS Ultimate if you want one order to cover you. It comes with a locking suction base and a steel vent clip, has the longest arm here at 7.5 inches, and clamps the biggest phones. Buy the Qifutan if you want the same flexibility for a third of the money and can live with the phone sitting lower. If your vents are the right shape and you refuse to put anything sticky in your car, the Miracase hook is the cleanest solution and moves between cars in seconds. If your dashboard is textured and every suction mount you have owned has fallen off, the Kaistyle magnetic puck sticks with VHB tape and takes up almost no space. And if you drive all day with maps running, the LISEN 15W charger keeps the battery up, as long as you supply a car adapter of 18W or more and accept that the phone will run warmer than it would on a cable.
Frequently asked questions
Vent, dashboard or windshield, which mounting style should I pick?
Start by looking at your car, not at the products. If your vents have horizontal or vertical slats that sit high in the dash, a vent mount like the Miracase is the neatest option and leaves no marks. If your dash top is hard, smooth plastic, a suction mount like the VANMASS or Qifutan gives you a higher, adjustable position. If your dash is soft-touch or grained plastic, suction will not seal at all and an adhesive base like the Kaistyle is the one that stays put.
Why do suction cup phone mounts fall off in summer?
Two things happen at once. Heat softens the cup material and makes the seal relax, and hot air trapped under the cup expands and pushes the edges open. A dashboard in direct sun gets far hotter than the air outside. VANMASS says outright that above 113 degrees you should use the vent clip instead of the suction base. If your car sits in the sun all day, plan on a vent mount or an adhesive mount rather than suction.
Do magnets in a car mount damage your phone?
No. Phone storage is solid state flash memory and magnets do not erase it. Credit cards and hotel key cards in a wallet case are a different matter, and those can be wiped. The other real effect is on the compass. A strong magnet next to the phone can throw off the compass heading that maps apps use to point your arrow. Most mounts shield the magnets to limit this, and recalibrating in the maps app usually fixes it.
Is a wireless charging mount worth it over a plain holder and a cable?
Only if you never want to touch a cable. Wireless charging is less efficient than a cable, so it is slower and it makes more heat against the back of the phone. Heat is what wears out a lithium battery over the years. The LISEN 15W is a good pick for rideshare and delivery drivers who mount and unmount the phone a dozen times a shift. If you already plug in for wired CarPlay, a plain holder is better for the battery and cheaper.
Can I legally stick a phone mount to my windshield?
It depends on your state, and the rules change. Several states restrict anything attached to the windshield, and others allow it only in a specific corner where it does not block the driver's view. California and Minnesota are the ones most often cited for having explicit placement rules. Check your own state code before you commit an adhesive or suction base to the glass, because a dashboard or vent position avoids the question entirely.
Will these mounts hold a big phone in a thick case?
The clamp mounts will. The VANMASS clamp opens from 2.2 to 3.8 inches with a cradle 0.7 inches deep, the Qifutan takes phones up to 7.1 inches and 14 millimetres thick, and the Miracase goes to 7.2 inches. Magnetic mounts are the ones to watch. Magnetic pull drops off quickly with distance, so a thick case without magnets in it weakens the grip badly. LISEN states plainly that thick non-magnetic cases, wallet cases and pop grips are not supported.