Product Description
Two at a time! The Dual Micro High Current Car Charger is made especially for power-hungry devices.
Now you can create a reliable power source for up to 2 power-hungry devices in your car simultaneously! You won't have to worry if you forget to charge your devices the night before; you can charge two devices at the same time with the Dual Micro High Current Car Charger while you're on the road!
Two USB ports allow for charging just about any device using your device's cable!
Product Details
- Amazon Sales Rank: #2861 in Cell Phone Accessories
- Size: Car Charger - Dual USB - 2.1A
- Color: Black
- Brand: BoxWave
- Dimensions: .3 pounds
Features
- Smooth glossy texture micro car charger safely rapid charge your device
- 2 USB port interface allows charging for a wide range of devices
- Full 2.1 Amp output made for up to two power-hungry devices charging simultaneously
- Intelligent chip prevents overcharging; Adaptive circuitry works with North American and International voltage standards
- Available in Black and White color
Most helpful customer reviews
270 of 276 people found the following review helpful.
Poor charger design
By Victor
I am an engineer and do hardware designs. I usually buy these cheap car chargers open and fix them before I use them to charge my phone. The 3.1 A current capability advertised for this car charger is not correct. I bought 3 car chargers from 3 different vendors on Amazon. Links provided bellow.
http://www.amazon.com/BoxWave-Dual-Micro-Current-Charger/dp/B000MGHXOI/ref=sr_1_1?ie=UTF8&qid=1367590298&sr=8-1&keywords=boxwave+car+charger
http://www.amazon.ca/niceEshop-Charger-Adapter-Iphone--White/dp/B00BMQ7STW/ref=sr_1_2?ie=UTF8&qid=1367331390&sr=8-2&keywords=3.1A+car+charger
The car charger I received from the second vendor had a brand name USAMS stamped on its side.
http://www.amazon.ca/gp/product/B0088YHEJK/ref=oh_details_o01_s00_i00?ie=UTF8&psc=1
The first 2 chargers claim 3.1A current capability. The circuit inside of both chargers is exactly the same. Both chargers use an IC chip MP1410 which is rated for 2A of output current. This chip could go into a current limiting mode at 2.4A, so there is no way it can support 3.1A of total charging current on the two USB output ports. It will simply go into current limiting mode or burn after a while.
Here is the link to the data sheet of the IC MP1410 used inside the car charger.
[...]
The capacitors used for the input and output are aluminum electrolytic, which is NOT GOOD. The charger puts out quite a bit of noise back into the 12V car system(0.7V pp voltage ripple when loaded with 1A). It is also extremely noisy at the 5V output. It has a voltage ripple(noise) of 0.84V pp when loaded with 1A of current. What that means is that the output voltage fluctuates between 5.42 and 4.58V at 420 kHz. It looks like a triangular wave. This is due to the poor filtering characteristics of the aluminum capacitor used at the output of the charger. It is easy to fix it, if you are an engineer. Just unsolder the input and output aluminum capacitors and replace the input one with 22uF/25V ceramic SMD capacitor. The output capacitor should be replaced with a 4.7uF/6.3V or 10V ceramic SMD capacitor. I also removed 4 resistors on one of the USB ports and shorted the D+/D- pins together. These resistors are needed for Apple users. They provide a special biasing voltage so the charger can charge Apple products on one of the USB ports. The second USB port had the D+/D- pins shorted already, so it was compatible with generic smart phone charging convention and it should appear to the smart phone as an AC charger. By shorting the d+/D- pins, I can use any of the two USB ports to charge my smart phone with full 1A of charging current. With the 4.7uF/6.3V capacitor, the output voltage ripple went down to 0.1V, which is really good. I measured the charging current on my Lumia 920. It does not matter that the charger is capable of delivering more than 1A (1.5A before the chip starts to get hot) of charging current after the fix. The phone was still charging with 1A of current.
With these changes made to the charger it will be able to supply a full 1A of current and will be able to slowly charge all smart phones even if the GPS is used and the phone plays MP3(I am using it with Nokia Lumia 920). In a 30 minute trip with GPS used and playing MP3 from the phone, the battery charge went up from 30% to 35%.
The third car charger I bought was made by Griffin and it has a very similar design( chip is XL1410 rated at 2A) and it also uses aluminum capacitors. I fixed it(changed capacitors and shorted the D+/D- pins) and it now supplies 1A of charging current to the smart phone.
In short, if you cannot open and fix the charger, you must spend the money and get an OEM charger( Nokia DC-17 rated at 1A, Motorola, Samsung dual USB rated at 2A or HTC). The OEM chargers have good input and output filtering circuits and usually provide the charging current they are advertised to provide.
The problem with the cheap chargers is that after a while (a few months of usage) the noise at the output of the charger(if not fixed) will increase and this will start to interfere with the charging circuit of your phone. The phone charging circuit is designed to accept charging voltages from 4.75V to 5.25V typically. With a ripple voltage(noise) of 0.84V, the output of the charger goes down to 4.58V already. You add some voltage drop loss in the USB cable itself and it already spells trouble.
I did some additional testing and it looks like the charger can sustain 1A of charging current for prolonged period of time(after the fix).
I hope that this information helps.
11 of 11 people found the following review helpful.
Decent replacement
By J Nicklaus
This Boxwave USB Wall Charger I purchased recently through Amazon works well. We lost the original one that came with our new Kindle Fire. It does seem to charge a bit slower than the original one, but the most important thing is it does recharge the unit in a reasonable amount of time, and did not seem to get too hot...
5 of 5 people found the following review helpful.
Good item
By 14eeee
The charger is as advertised and charges relatively quickly, though not super fast. The price was very good and with the free shipping and all it was a good purchase.
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