Car Charging 101

[ka3yan]

Here's a repost of what I posted to the Motorola Owners Forum. I have yet to hear back from a Motorola employee but I did put in for warranty exchange.

Ok, so I decided to experiment a little. On my dirve home for lunch, I plugged the handset into the car dock and turned on Google Nav. I then switched to SetCPU where I could monitor both battery temp and charge level. My battery temp started at 47C and charge was 61%. Within 5 mins, the temp had dropped to 42C (I ran my A/C through my windshield defroster to keep cool air blowing on the car dock/handset), but the battery charge has also dropped to 60%. Clearly, the charge was running in the wrong direction. For the remainder of my 15 minute trip, the temp and charge remained the same.

When I made the 15 minute return trip, I had the exact same setup. My temp started out at 38C then immediately jumped to 44C and then as my A/C cooled the device, it dropped to 42C once again. The battery charge remained at 60% for the entire trip. I feel confident that the handset would've shown a discharge had my trip been longer. Also, this might disprove the theory that the battery discharge is due to the battery overheating.

It should be noted that the lightning bolt was on the battery indicator the entire time it was in the car dock. Also, from the unlock screen, the battery indicated "Charging."

 

[2leaponover1]

I have my exwife hold it while i'm charging it... she's a cold hearted icy beeeeutch

 

[s1mpd1ddy]

I have my exwife hold it while i'm charging it... she's a cold hearted icy beeeeutch

ZING!

nice way to start the morning! haha

 

[neer2005]

This made my day hahajahaahhaa

I have my exwife hold it while i'm charging it... she's a cold hearted icy beeeeutch

Sent from my MB860 using XDA App

 

[pilotboyshorty]

SOLUTION!!!

I believe all are correct in this thread


Yes. it is probably heat that causes the battery not to charge.
above a certain temperature it will not charge anymore and will discharge even though it says its charging(lightning bolt)

Yes. UV/IR light from the sun will play a large part in heating the device.
in my experience keeping it out of the sun is standard.

Yes. Your charger will have an effect but is usually not the primary culprit... i would recommend at least 650 MWh to charge while under load....

We are talking about a dual core computer with no fan or cooling of any kind (except the surface area of the phone ... i know)


AND THE FIX IS..........
SetCPU

1. Root your atrix (at your own risk)
2. scale the processor down to about 750MHz using SetCPU (or another scaling app)
3. ????????
4. Charging PROFIT??

It has really shown its worth for me... It doesn't slow the phone down that much, i can still use navigator, pandora and or phone calls without lag (dont go slower than 750 or you will get lag, but it will charge more quickly

hope this helps!

 

[jjwatmyself]

I believe all are correct in this thread


Yes. it is probably heat that causes the battery not to charge.
above a certain temperature it will not charge anymore and will discharge even though it says its charging(lightning bolt)

Yes. UV/IR light from the sun will play a large part in heating the device.
in my experience keeping it out of the sun is standard.

Yes. Your charger will have an effect but is usually not the primary culprit... i would recommend at least 650 MWh to charge while under load....

We are talking about a dual core computer with no fan or cooling of any kind (except the surface area of the phone ... i know)


AND THE FIX IS..........
SetCPU

1. Root your atrix (at your own risk)
2. scale the processor down to about 750MHz using SetCPU (or another scaling app)
3. ????????
4. Charging PROFIT??

It has really shown its worth for me... It doesn't slow the phone down that much, i can still use navigator, pandora and or phone calls without lag (dont go slower than 750 or you will get lag, but it will charge more quickly

hope this helps!

Good points. I am curious what operations would require a clock speed above 750 Mhz? Tegra 2 games perhaps? I would also add that one should only underclock if CPU heat is preventing you from charging. In my charge test on an idle phone, heat from the sun alone was enough to cause the temp of the phone to increase to the point that prevented the phone from being able to charge the battery. This is obviously a safety feature as charger creates heat and we don't want to burn anyone. The point is that underclocking can decrease the charge cycle time during heavy usage but will not solve the overheating due to direct sun exposure, which prevents the battery from charging. My guess is that you agree with all this. I'm explicitly stating this so that our readers address the root cause and don't think that undercloking will solve all of their dashboard charging problems.

Sent from my MB860 using Tapatalk

 

[rusreid]

If you don't keep it cool, it's not going to charge. It will not charge well if stuck to your windshield. I used the sticky disc to mount mine right beside a vent. With it there, or on the side window, with the a/c vent blowing on it, it will charge.

 

[zanzee]

The phone full out running navigation, music and charging will pull 800ma. So if you have something rated for 1amp keep in mind most chargers are good for 80% constant use and will over heat. Once they start to over heat they usually drop in voltage. This will cause the phone to pull more current and add to the bad. I run a 2amp charger with the data lines cut and bridged ment for an ipad and it works fine. I've ran this setup for 8hrs without issue. As has been mentioned heat is also an issue so take any protection case off.

Sent from my MB860 using XDA Premium App

 

[arachneon]

Hello all,
I just bought my Atrix one week ago and received the car dock yesterday. After viewing the issues that some had, I did a small test. I used Copilot for a 35min trip with a partially sunny weather. The battery was initially at 73% and at the end of the trip it was at 86% and the phone was quite hot. I don't how it would have behaved if the trip was longer and the phono hotter.
Well, it does show that the car charger is working (well, we knew that by now ^^ ) but with the power dissipation of the CPU and the lack of cooling, I don't know if this will be the case for a 5hours trip.

 

[jjwatmyself]

Atrix liquid cooling will be next! LOL

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