Car Dock Charger, Sun, and Battery Temperature Rise Stops Charging other Dangers

[Gnatman1102]

I purchased the Vz car dock charger thinking how cool this product would be for my new Droid X. I am beginning to think that using it can be dangerous, at least for the battery.

I have also been reading thru the different posts concerning the car dock and battery charge problems. I am no expert on this subject, but I have a theory on the battery charging problems with the car dock.

Lithium-ion batterys have a safety feature, essentially a switch, that shuts off charging if the battery temperature gets too hot or the voltage gets outside of a prescribed safety range. The battery also discharges much more quickly at higher temperatures. I do live in the hot southeast USA.

My Droid X has a battery widget which displays the battery health items temperature and voltage. Although I do not know the accuracy of the health display, I do feel that the values vary properly according to the operating conditions.

The other day I decided to test the navigation feature on my way home from work. It was around 2:00 pm, and the sun was high in the sky. Within 5 minutes of placing in the charger, the battery charge level dropped from 80% to 70%. The widget displayed the status as "Overheating" and a temperature of 135 degrees F, which is quite high for this battery. I removed the phone from the dock, and found the back very hot.

I suspect the sun shining on the dock which transferred this energy/heat to the phone, which also blocks ability to vent the heat, caused the battery to get too hot. Therefore, my guess is the charging stopped to prevent damage to the battery, or worse a fire. I did not look at the voltage display. I also wonder if this could cause a short circuit in one of the battery cells permanently damaging the battery?

And yes, I did have my car A/C on full blast, and it was comfortable in my car.

Therefore, I plan to return this charging unit, explaining to Vz my concern.

If anyone else has a theory on the problem or has a contrary viewpoint, please chime in on this subject.

Thanks and have a great day!

 

[cjbear10]

based on my experience, the heat is coming from the sun, not from your unit. Suspect that we are in full agreement on that front. I relocated my mount from the windshield to the dash early on and have had no such issues since. My method was to graft the DroidX mount to my Garmin Nuvi mount after realizing the swivel ball on both mounts is exactly the same size. I am located in the Southeastern US and have enjoyed 100 degree F days over the last few weeks with no ongoing issues.

if you are sold completely on the windshield mount, you might consider shaping a heat shield ahead of your phone and see if that helps. A quick cardboard test unit should not take long to fabricate and could later be improved upon if the theory holds true. I would certainly be interested in your results. Also, any insight you would share into your car type would be interesting. I am of the opinion that large steeply sloping windshields (like say -- minivans) will lead to more findings of your described issues.

best regards,
Bear

 

[Gnatman1102]

Hello Bear! Thanks for the reply!

I may experiment with some form of heat shield as long as I don't alter the dock or phone. Gotta think warranty! Right now, it has been fairly cloudy and may stay that way for a few days. So, I may wait for a bright sunny/hot day

I agree the heat energy is coming from the sun. Inside, the battery temperature rarely gets above 105 deg under very hard use. However, the unit does not have ability to help dissapate that heat effectively while in the dock (back is covered). I am curious if left in the dock exposed to the sun, would or could the battery suffer a thermal runaway? This means the battery would increase in temperature faster than it can dissapate the heat energy. That is believed to be cause of some of the battery exploding/fire cases. At a minimum, could it damage the battery and/or the phone? I took my phone out of the dock before I could find out, which is probably a good thing.

Here is a link on the subject of thermal runaway:

Thermal runaway - Wikipedia, the free encyclopedia

It is noted that lithium-ion batteries are "expecially prone to thermal runaway."

One thing I failed to mention. When I removed the phone from the dock, I reconnected the charger and moved the phone to a shaded area in the car. From the battery widget, I noticed the displayed temperature dropped to 120 deg in about 5 to 10 minutes. At that point, I noticed it began charging again.

I looked through the provided instructions/warranty information and found nothing about caution when using it in higher temperatures or full sun. I don't know if Motorola has evaluated thermal issues with their dock. Apparently no since I could not find any information in the literature. Perhaps the battery/charging system have enough failsafe features to prevent catastrophic results. However, if someone uses the dock and the battery and/or phone is damaged as a result, the person should be able to make a succesful reimbursement/replacement claim. I sure hope no fire occurrs as a result, or Motorola or Vz could be responsible for more damages.

Call me overly cautious about this issue if you want. I just don't like the idea of my phone's battery increasing approximately 35 degrees in less than five minutes due to sun exposure, especially while on a charger hoping the failsafe systems work.

 

[impostor71]

I have the same problem. I ended up getting a vent mount to get my DX out of the sun. The AC vent helps too. Not sure what I'm going to do comes winter time. Maybe start using the Moto windshield mount again...

 

[Needly]

Car Dock issue

I have had a similar issue with my DX. I live in Michigan, it was 53 and dark when I went to work this morning and had the same overheating issue. The sun was not part of the equation. On the way home this afternoon my unit locked up and then shut down. I also have had trouble with consistent gps reception while in the car doc. I wonder if the doc is interfering with the satellites.

 

[FunN4Lo]

I use GPS everyday. GPS + charging = overheating has been a common thread discussed many times. My experiences is that the sun certainly does effect the scenario using a windshield mount, it does not matter as much as the charger.

For me the VZW charger has been the quickest to overheat and shut down charging regardless of position in the car. I have tried several other chargers with varying results. Currently I use a Bracketron mount that fits directly into the cig lighter. The mount has another 12v cig lighter type receptacle and a USB port. Using the USB port gives me the longest period without overheating, but on long trips it will shut down

 

[Akita]

Can you guys not position the mount above your air vents? I did this on a trip today(2 hrs) and had no issues with my phone overheating

 

[FunN4Lo]

Can you guys not position the mount above your air vents? I did this on a trip today(2 hrs) and had no issues with my phone overheating

I get about 4 hours on my current set up, so it works good for everything except long trips. I don't think mounting over a vent is prudent in a high humidity environment (my environment) . Have you ever stepped out of the A/C and had your sun glass instantly fog over? That kind of condensation can not be good for electronics.

 

[Akita]

Can you guys not position the mount above your air vents? I did this on a trip today(2 hrs) and had no issues with my phone overheating

I get about 4 hours on my current set up, so it works good for everything except long trips. I don't think mounting over a vent is prudent in a high humidity environment (my environment) . Have you ever stepped out of the A/C and had your sun glass instantly fog over? That kind of condensation can not be good for electronics.

Good call. Would this still be an issue if you have a silicone case over the phone?