Fenix 5 heats up during charging

Hello everyone,

I've experienced several non-permanent issues during last battery charges. See below the list:

The device is not recognized by Windows when I connect the Fenix 5 to my laptop through USB, only battery charging is started. Few weeks ago this worked properly. Garmin Express was paired with the device and I was able to see the different files and folders inside Fenix 5 storage through Windows Explorer.

Sometimes, when I connect the charging cable to the PC or wall socket, the Fenix 5 starts to heats up. This can be checked by means of the temperature widget and also by putting your finger in the rear side of the clock (you can feel the heat). When this occurs the battery level percentage remains at the same value, it seems the clock is not charging.

Other times, when I connect the charging cable to the PC or wall socket the charging process is working fine.

Has anyone seen a similar behavior?

Sure I'll send the watch to Garmin, but I'm afraid because of as it's not a permanent issue might be they're not able to reproduce the behavior I've seen.

0 m.fisac over 6 years ago

Any comment?

0 TrippyZ over 6 years ago

Return device due to fire risk

0 m.fisac over 6 years ago

Thanks TrippyZ for your suggestion. I already had that in mind.

I'd like to capture the issue during charging in order to send some photo to Garmin Support Team.

0 mcalista over 6 years ago

In terms of capturing the issue for garmin Support, the watch has an onboard temperature sensor.

I'd recommend installing the Temperature Widget (which includes a graph). Take it off your wrist, and let it establish a clear baseline of room temperature (prob 30 minutes), then take a screenshot (you may need to edit your hotkeys for this) showing the clear rise in temperature once it has been plugged in. Perhaps a couple of external shots as well with your phone and timestamps showing the graph and it not plugged in, and the graph with it plugged in.

You may also want to test that this still happens when plugged in to a different USB power source, just to eliminate an out-of-spec USB power source as a possible cause.

0 Former Member over 6 years ago

I would suspect your charger(s) before I suspected the watch. I know that some wall chargers have terrible output regulation (super-cheap electronics) and will fry some devices that don't require much current to charge. It is possible a cheap charger fried your Fenix 5 charging circuit.

As an example, I had an inexpensive wall charger at work I was using to run a USB hub. The hub was really misbehaving sometimes, so I looked at the output of the charger on a scope. It averaged 5.5V with more than 1V pk/pk of noise at 100kHz without a load. That means peaks were at 6.5V, and valleys at 4.5V. When I plugged in the hub without any devices, it got slightly better. When I plugged in a device that provided a load, the voltage went to 5.3V and maybe 0.1V of ripple, much better but still not good. The dang power supply was unstable with light loads.

Lesson of the story: Buy good, name brand USB chargers and pay a little extra for them. After all, you tend to plug in some pretty expensive gear into them, why take the risk to save a few bucks.

If you are able to get it repaired or replaced, order a charger from Garmin and chuck out the other AC adapter version. The PC should be fine.

0 m.fisac over 6 years ago

Regarding the charger, since I bought the watch I used a Samsung EP-TA20EWE charger. The only concern I see right now is this charger has fast charging capability and maybe the Fenix "doesn't like" this kind of technology.

Since I realized the issue I use the USB laptop ports for charging the device, just in case...

0 m.fisac over 6 years ago

Regarding the issue, finally I was able to reproduce it after several and take some photos. Finally I reproduced the issue by using the USB laptop port.

When I connected the Fenix to the laptop the battery level was frozen at 12%. By the way, Garmin Express is not able to recognize the watch although it's connected.

After several minutes, as you can see in the pictures I sent through Google Drive link (I don't know why but I cannot upload the picture in Garmin Forum), the temperature achieves 40°C. At that time I decided to disconnect the watch from the laptop, for safety reasons.

Once the Fenix was disconnected and after few minutes, the temperature is decreased until room temperature.

Afterwards I connected one more time the watch to the laptop, and the temperature increases again.

In the last picture you can see the test screen. Temperature = 45!!!! and Charge state = suspend (during normal charging the typical message is "constant current" or something like that).

PS: I share the picture through this link, I'm getting an error when I try to upload the pictures.

0 Former Member over 6 years ago

Hard to believe, but it sounds like the laptop USB power is no good. Sometimes laptops will limit USB power when running off of battery only, and you will only get full power if it is actively charging from AC and the battery is somewhat full. Otherwise it is also possible the USB signal integrity of the laptop is poor, and it is causing the Garmin software to crash or go bezerk. It may just be pushing the CPU really hard and it runs hot.

0 m.fisac over 6 years ago

Hello LiquidSquid,

The issue occurs equally with laptop USB and wall charger, but my understanding is that the watch was damaged when I used the wall charger.

I already contacted Garmin Support, I'm waiting for news from them.

0 m.fisac over 6 years ago

Another point I'd like to highlight is the charging cable. I'm using always the original cable, but I'm not sure if could be something wrong in the cable that could damage the watch.

What about the cheap cables can be found in Amazon or eBay? The original one costs around 30€, and the low-cost version around 10€.