Help! I have problems with my car/USB charger! It just doesn't charge!

http://www.pocketpcthoughts.com/forums/viewtopic.php?p=372738

Q: Help! I have problems with my car charger! It just doesn't charge! It used to charge in the first few days but it doesn't do it any more. What now? A: This question is a very complicated one. 1. most (cheap) car chargers only deliver 1 Amper (or even less), which isn't enough for charging a PDA if its battery is (deeply) depleted and particularly if it's switched on. Then, typically, the needed current is well over 1 Amper - around 1.5-1.7 Ampers with most current PDA's (no wonder the official HP/ Fujitsu-Siemens chargers are all 5V/2A, while the Dell Axim x50(v)/Asus 730(w) chargers are even 2.4A!). For example, here is a real-world example of the Fujitsu-Siemens PL720's Amperage requirements during (re)charging – pretty instructive if you want to know why for example USB/cheapo car chargers don't work with (deeply) discharged PDA's. 2. the more the power consumption, the less the voltage with all voltage converters/regulators, including car chargers. I really recommend this thread for some examples of this effect in practice. Don't be afraid of its being Mac-specific - the voltage measurements it contains are first-class and generic. That is, if the charger is forced to produce, say, 1A, its voltage may decrease to, say, 4.6-4.8 (or even less) Volts. Under a certain voltage threshold (about 4.8V for a 5V device like iPAQ's - unlike Dell Axims, which require 5.4V unless they're in the USB charge mode where they're charged with 5V only - see this blog entry), they will simply not charge. 3. the symptom you've described may be caused by two things: a, something in the charger is dead/doesn't work as good as it used to. This is highly probable, especially with cheaper ones – after all, during regulating (converting 12V DC to 5V DC) a LOT of heat is made and wear/tear done, which really pushes the regulator chip to its capabilities' end. No wonder some of them just burns out (one of them has also burned on me.) b, the charge level of your iPAQ battery is considerably lower than in the first few days and this is why it's not more charged, unlike earlier. If this is the case, you're lucky. Then, all you need to do is charging the PDA up in a wall charger or switch it off while it's on the char charger, it will top up and then, you won't have problems any more. The most generic solution: get a car charger that has higher amperage output. (See the above-linked Dell blog entry for some Dell-specific examples.) (Please note that the same stands for USB-based charging as well. The (same) problems with USB charging are even more known because USB hosts are only meant for providing 0.5 Ampers at 5V, which is barely enough for a PDA that is switched on and/or more than slightly depleted.)