When I reviewed the ESR CryoBoost Foldable 3-in-1 in June, I was using an iPhone 12 Pro. I said I wanted to rerun the charging tests after upgrading. I now use an iPhone 17 Pro, and after several months with the same charger, I have finally done that.
The results are considerably better with my current phone, especially with the fan turned off. Wired charging still wins on speed, but the fan-on wireless result is now close enough that I am happy to trade those few minutes for the convenience.
ESR originally sent me this charger for testing. This is the same review unit from my original review, and the measurements and opinions below are my own.
Charging with the iPhone 17 Pro
I tested wireless charging with my Pitaka case on. That is how I normally use the phone, so it is the setup I wanted to test.
My charging times from 0 to 80% were 46 minutes with USB-C, 55 minutes with CryoBoost and the fan on, and 67 minutes with the fan off.
The recorded checkpoints also give a useful direct comparison with the fan-off run. After 30 minutes, the phone was at 57% with the fan on versus 42% with it off, a difference of 15 percentage points. After an hour, it was at 83% versus 75%, an 8 percentage point gap.
Turning the fan on still made a clear difference to charging speed. The fan-off run reached 80% at 67 minutes, while the fan-on time was 12 minutes shorter. USB-C was the quickest option at 46 minutes, but the fan-on wireless result was only nine minutes behind it.
Test conditions: These are individual charging runs with my own iPhone 17 Pro and the same CryoBoost review unit. Room temperature and starting battery temperature were not recorded or controlled, and I did not repeat each run. The results describe my setup; they do not measure peak wattage or predict every phone and case. The “6m to 80%” text in the desk photo is the phone’s remaining-time prediction at that moment.
Does CryoBoost work with a case?
Yes, with the thin PITAKA case I use on my iPhone 17 Pro. My fan-on run was 55 minutes from 0 to 80% with the case fitted, compared with 51 minutes without it. That four-minute difference was small enough that I kept the case on for everyday charging.
| Elapsed time | PITAKA case fitted | No case |
|---|---|---|
| 10 minutes | 22% | 20% |
| 20 minutes | 38% | 39% |
| 30 minutes | 57% | 59% |
| 40 minutes | Not logged | 73% |
| 50 minutes | Not logged | 79% |
| 51 minutes | Not logged | 80% |
The case run also has a recorded 60-minute reading of 83%; the chart stops at 80%. At the first three shared checkpoints, the difference between the two runs was only one or two percentage points. I have not tested a range of thicker cases, so I would not generalise this to every MagSafe case.
ESR’s Foldable CryoBoost product page lists magnetic cases up to 2 mm thick. Its model 2C590 support page also says to remove metal accessories, wallets, stands and grips from between the phone and charging pad.
You can see the case, fit and charging comparison in my PITAKA Argyle case review.
From the iPhone 12 Pro to the iPhone 17 Pro
Moving from the 12 Pro to the 17 Pro made a surprisingly large difference in my charging results, especially with the fan turned off.
In my original test, fan-off charging took 120 minutes to reach 80%. With the 17 Pro, it took 67 minutes. That is a much more usable charging time for my current setup.
With the fan enabled, the result changed from 79 minutes to 55 minutes. Wired charging also improved, from 62 to 46 minutes.
The gap between fan-on wireless and wired charging has narrowed from 17 minutes in the old test to nine minutes now. I have not changed the CryoBoost unit; these are the results from using the same charger with my previous phone and my current one.
Several months later
I have used this charger daily since May and have taken it traveling too. My first review was written after about a week of use, so I can now say more about how the hardware has held up.
I do not fold and unfold it very often. In my use, the hinges have not changed, and I have not noticed any visible wear. The Apple Watch arm was looser than the main hinge when I first reviewed it, and that difference is still there.
The fan remains quiet. That was one of my pleasant surprises in the original review, and several months later it still has not become an annoyance in everyday use.
What I would still change
The AirPods charging area is still the part I would change. I wanted magnetic positioning in my first review, and I miss it even more after using the charger for longer.
If I do not place the AirPods case quite precisely, charging sometimes switches on and off, and the case beeps. That makes positioning more fiddly than I would like. A charging pad that helped the case settle into the right place would be a welcome improvement.
This is a more concrete annoyance than the wishlist item I mentioned in June. It does not change my phone charging results, but it is part of living with the charger every day.
Fan, Apple Watch and AirPods questions
Does the fan keep the phone cool?
With the fan running, my iPhone feels cooler to the touch when I lift it off the stand than after charging it by cable. That is the same experience I described in the follow-up discussion. I did not record temperatures, so I cannot put a degree value on the difference.
Can I turn the fan off?
Yes. The switch next to the USB-C port turns CryoBoost off. ESR’s 2C590 instructions say this switches off both the fan and light. The phone still charged in my fan-off run, but it took 67 minutes to reach 80%, versus 55 minutes with the fan on.
How does Apple Watch charging compare with the Apple puck?
In my original Series 10 test, the Watch reached 80% in 38 minutes on the ESR stand and 30 minutes on its original Apple charger. I have not rerun that Watch comparison for this follow-up. Those results should not be applied to newer Watch models.
ESR advertises the foldable model as Made for Apple Watch certified. For its fastest current charging, Apple recommends the cable supplied with your particular Watch and a dedicated USB-C Power Delivery charger. The charging time comparison above is more useful here than treating a wattage label as a promise of equal speed.
What should I check if AirPods charging is inconsistent?
ESR says to centre a wireless-capable AirPods case on the pad. Apple says to close the lid and keep the status light facing up. The light normally goes out after about eight seconds, and a single charging-start sound is normal on AirPods Pro 2. Repeated start sounds and the intermittent charging I see when placement is off are the annoyance here, rather than the light simply going dark.
Has the newer phone changed my opinion?
Yes, positively. The iPhone 17 Pro results make me like this charger more. Fan-off charging is much more usable than it was with my 12 Pro, and with the fan enabled, wireless charging gets much closer to the cable.
For me, the convenience of putting the phone on the stand is worth the nine-minute difference between my fan-on wireless result and the wired result. I would still choose USB-C if charging time alone were the priority, but that small advantage is not enough to outweigh wireless convenience in my everyday use.
Several months of daily use have also left me with quiet fan operation, unchanged hinges and no visible wear. The AirPods positioning issue is the main thing I would still improve. Overall, the newer phone has made the same CryoBoost charger a better fit for how I use it.
The original Reddit review includes my first impressions and earlier charging results.
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Check the ESR CryoBoost on Amazon ↗Check the exact foldable model, included adapter, current price and availability. The linked listing is marketed as Qi2.2 25W; these charging times do not measure peak wattage.
Join the follow-up discussion on r/MagSafe or r/ESR_official.