During disk defragmentation on a D610 Latitude laptop, battery charging suddenly shuts down. At first it seemed like the dreaded "ID chip failure", a design fault in DELL AC adapters. but nothing like that. Read more about temperature issue's in DELL laptop series.
DELL D610 Latitude temperature sensors
The D610 system design and internal components are equipped with temperature sensors. First to protect it's owner from dangerous situations (like DELL batteries exploding) and secondly to protect the laptop from heat related problems. Some of the manufactured DELL latitude's (and related DELL laptop designs) are also known to have cooling issue's. Best known is a dust clogged CPU heatsink or a broken CPU fan. A nifty and free program to monitor internal temperatures and to force the CPU fan to blow is I8kfanGUI. However one could doubt the need for such a program for normal day to day use. Design should be good enough not to involve the user in cooling issues eh? Anyhow, for extreme laptop use it's good to keep an eye on internal temperatures specially if ambient temperatures reaches 50 degrees Celsius.
AC Power adapter heat protection tripped
In this case ambient temperature was nothing like that, just a regular summer day with temperatures hovering round 30 degrees Celsius in the shade. The D610 Latitude was not operating in full sun and it's DELL PA-10 family AC power adapter (PA-1900-02D2 ) was buried below a pillow and a few newspapers. After an hour or so during disk defragmentation and a bit of surfing screen intensity suddenly dropped and battery charging was shut down. The D610 was suddenly operating on it's battery. First thought was the dreaded "ID chip failure", a widely spread design fault in DELL AC adapters.
DELL D610 AC Power adapter cooling
The AC power adapter was below a pillow and was quite hot. In fact too hot to hold the charger in one hand. The green power-on LED was off, while AC mains was still there. It seemed like the AC power adapter had died because of excessive heat. The charger had to operate on maximum capacity while the battery needed charging, defragmentation was running while surfing the net. The DELL AC power Adapter draws close to 100 Watts AC under these conditions.
After an hour or so of cooling down the DELL AC charger switched on again and battery charging continued as before. Apparently the DELL AC Adapter is equipped with a temperature sensor to prevent it from heating up way to high. When it shut down it's temperature was well above 60 degrees Celsius.
Strangely, one could expect at least a warning on the AC power adapter to keep it in a place with a bit of air around it. With an ambient temperature of 21 degrees Celsius, the DELL AC Power adapter already heats up to about 46 degrees Celsius. And that's without battery charging during light text editing. For instance leaving the DELL AC Adapter in full sunshine could easily trip it's temperature protection.