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on November 30, 2010
This is a great dual port car charger.

Unlike a lot of dual USB chargers out there, it puts out a good 5v 2A current out of the top jack, and an above average 5v 1A current out of the bottom jack.

If you use a car dock (especially the Google/HTC Nexus One Car Dock) you can charge your phone and run your dock with a regular high quality Micro USB 2 cable. This saves a lot of headache if you are using a single Car DC jack for multiple devices. So, you can run a GPS Android Phone Dock, along with a standard iPod/iPhone USB 2 cable with no extra adapters or dongles. Mega space savings and clutter prevention.

The charger juts out about 1 1/2 inches from your standard sized DC jack surface. I can see why they needed to do this versus making it more flush to the car panel. The thing gets warm with full load and needs the extra space. I believe they made the Powerbolt Duo as small as they could for the price.

Speaking of price, this adapter uses high quality plastics and seems more expensive than its MSRP price. Although the metal contact pieces are not of a high conductivity metal, I expect that it would not corrode even with the occasional car style beverage spills and drips. The 30-pin Dock cable that comes with the unit is the standard Kensington iPod cable quality. The cable itself is flimsier, but it's reinforced where it counts. Apple cables usually become separated where the cable jacket meets the connector. The included Kensington cable will probably last a few months longer with heavy use because of its reinforced areas.

Here are my experiences:

2A Jack:
Fast Charge Barnes & Noble Nook
Fast Charge Nexus One (and probably all HTC devices)
Fast Charge and safely run Nexus One Car Dock using standard HTC or other premium Micro USB 2 cable
Fast Charge iPhone 4
Fast Charge iPad
Standard Charge iPhone/iPod (all)

1A Jack
Standard charge all devices, but not enough current to fast charge or run dock + phone combo by itself.

The only way this could be better if it were smaller, and both ports were 2A.

I highly recommend this adapter to all roadwarriors and mobile device users!

* UPDATE August 2011:

I am updating this review to give you an idea of the adapter longevity. I originally wrote this review in late 2010. It is now late-mid 2011 and the adapter is still running well. It has survived a soda spill with subsequent alcohol bath to clean it.

The Kensington 30-pin dock that I used it with has continued to serve its purpose well, unlike it's mate, an OEM (you know the fruit) cable that broke within 3 months.

I reiterate my positive review and I highly suggest purchasing this adapter.

New items tested working well with Adapter:

-Motorola Atrix Car Dock (2.1A & 1A)
-HP TouchPad (2.1A & 1A)

** UPDATE May 26 2012:

I am updating yet again to give you an idea of extreme longevity. I am still using the same adapter, and no faults yet.

I again reiterate my positive review and I have bought several of these adapters for friends and family. I think the only thing that it could do better is short the USB pins to simulate AC power.

New items tested working well with this adapter (works equally on both ports unless otherwise listed):

- Samsung Galaxy Nexus (GSM)
- Samsung Galaxy Nexus Car Dock (the one with the powered pins, works best on 2.1A)
- Light and Motion Solite 150
- "the New iPad" (fast charges on 2.1A)
- Nook SimpleTouch
- Nook Glowlight
- Nook Tablet
- Samsung Galaxy Tab 8.9
2626 comments| 435 people found this helpful. Was this review helpful to you?YesNoReport abuse
on January 28, 2012
A quick summary of this product before I get into the details:

Likely great for dedicated Apple device users that has all the power it claims (simultaneously 2.1 Amps on one port with 1 Amp on the other for a total of 3.1 Amps output combined, but under performs DRAMATICALLY for non-Apple devices due to protocol issues for USB chargers. It gets 3-stars because all it claims to support is Apple devices.

Now for more details...

A little background on USB charging for those who don't know:

The USB power spec is for 0.5 Amps at 5 Volts... or 2.5 Watts. This was great up until the last couple years when devices have gotten really power hungry, particularly smartphones and tablets and to a lesser extent dedicated GPS's. Some of these devices use over 2 Amps, particularly the tablets like the iPad (or in my case the HP Touchpad).

Manufacturers of these devices therefore had a dilemma. If they had their devices pull more than 0.5 Amps, they risked damaging the power source, which could be a computer, that was only prepared to source 0.5 Amps. Thus the manufacturers have used tricks to determine whether their device is connected to an unknown source, at which point they purposely only draw 0.5 Amps, or to the dedicated charger that was provided with the device, where they can draw all the power they need.

There seem to be two common tricks used. The first is to short the two data-wires together in the charger. This is what most non-Apple devices do. Since a computer or older device wouldn't have done this, the device can assume it is safe to draw all the power it needs.

Apple seems to have taken a different approach, one that I don't fully understand but know can be seen by the fact that the data lines are neither open nor shorted when the charger is plugged in, and is more sophisticated and probably superior, because I suspect it allows the device to know exactly how much power it can use.

While Apple taking a better approach might be nice in concept, it's created chaos in the USB charger product category. What is the non-specific charger to do? They can't support both.

Kensington chose to go the Apple route for the 2.1 Amp port. I don't own any high-power Apple devices, so I can't say for sure, but I suspect this unit performs well with Apple devices. Using electronic equipment I was able to draw 2.1 Amps when putting a fixed load on this USB charging port. However, when I connect any of the 3 high-power devices I have (HP Touchpad (2 Amps), Motorola Triumph Android phone (0.85 Amps) and the LG Optimus Slider (0.7 Amps)), none of them drew all the current they could have, because they were expecting a shorted set of data-lines.

The 1 Amp port on this device is a bit of a quandry however. It didn't have the signature on the data lines of either the Apple protocol or the shorted lines. It appeared to have them open... which was a surprise and I believe a mistake (although I can't be certain with Apple products). The results for my 3 devices however were identical to that of the 2.1 Amp port.

To highlight the positives, I can say this, I was able to draw all the power the product claims it can source using fixed loads. As my above explanation makes clear, it is the DEVICE, not the charger, that chooses not to make full use of the available current (Amps). So by using power resistors I could test the actual capacity of the device without dealing with the data-line issue.

As such, I was able to draw both 2.1 Amps from one port and 1 Amp from the other, simultaneously. I can not say the same for the other charger I have tried (and I have two in shipment to test).

Thus this device gets 3 stars because it only claims to support Apple devices and without any to test I have to assume it would work great for them. It also can deliver the current it claims. It is likely a 5-star product for sole apple users.

However, for non-Apple users, I STRONGLY encourage you to look elsewhere for your Car USB power needs. The other device I've tried is the "PowerGen Dual USB 2A Heavy Duty Ouput Car Charger" ( It has other problems (the 2A port doesn't have the data lines shorted and it only sources a TOTAL of 2A, not 2A on one port and 1A on the other), but at least one port (the 1A, which can really do 2A by itself, see my review over there for more details on that) on that has the data lines shorted to get the full power with non-Apple devices.

I've ordered two additional devices:
- "Ultra Compact High Output Dual USB Car Charger - 2.1A Output" (
- "Bracketron Universal Dual USB Car Adapter (UGC-298-BL)" (

Hopefully one of the two of them will be able to deliver to their specs for my devices.
1212 comments| 81 people found this helpful. Was this review helpful to you?YesNoReport abuse
on April 13, 2011
I second the other five-star reviews. This device outputs the power it states from both ports, and, consequently, can charge anything up to and including the iPad and iPad 2. It also runs cool even under load; it's a very well-engineered piece of gear.

Critically for Ford owners and other car owners whose cigarette lighter jacks are powered even when the ignition is off, this device has VERY low standby power draw. While this is not listed in the specs on the box, I asked Kensington tech support for the draw when the charger is plugged in but nothing is charging from either of the USB ports. The response: "We are sorry for the delay in the responce. We would like to inform you that the product(K33497US) draws approxmitely 5mA in stand by mode."

(I had another iPad charger that would drain my car battery in a few days when left plugged in but with nothing charging. The Kensington seems not to have the same problem.)

In short, of all the high-powered car chargers out there for iPads and similar devices, this is the one to get.
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on August 23, 2011
This charger is specifically for what it says in the title - iPhone 4, iPad 1 and 2.
With any other USB device you will get a 0.5A max current on both ports.
I bought this one for my Android phone thinking that USB charging specs are all standard. I was wrong...

From a review on another site:
"The 2.1A port implements *apple's* proprietary spec for high current charging which is necessary for that iPad, but the 1A port does not
implement the USB standard for high current charging above 500ma for smartphones and other devices. It may be rated at 1A on that second port but the required connection between pins 2 & 3 that tells your smartphone it can use >500ma is missing."

UPDATE 2011.12.06
I finally found a charger that will provide 2x1A for my phones.

There is a very useful comment on this item

(Due to censorship - see comments for details)

The one I've got had two pins in the middle soldered on one port but not the other. This way the soldered one was treated by the phone as an AC adapter, the other one as a USB port.
Soldering the other one made it look like an AC adapter as well. Now I have a fully functional 2x1A car changer :D

I believe the same applies to the "Kensington K33497US PowerBolt Duo Car Charger" - it simply has both ports not soldered and treated as USB devices by phones. And only Idevices can actually "talk to it" and figure out the proper current.
1212 comments| 142 people found this helpful. Was this review helpful to you?YesNoReport abuse
on November 1, 2011
I just purchased this charger for my new iPhone 4S. I tested it both my cars and it worked great. I'll try and update my review if I have any problems after longer use. If you want to be sure charger works with the 4s model of iPhone, this one really does.
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on November 30, 2011
Charges my iPhone 4S *and* my iPad2 simultaneously, exactly as advertised. LED is not super-bright so it doesn't distract when driving at night. The included cable is of good quality, and works for both charging and syncing.
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on January 3, 2012
The Kensington Powerbolt Duo Car Charger did not function out of the box, and I can confirm that since I ordered 3 identical products. I contacted Kensington through their customer care phone number, 1.650.572.2700, provided via their website ([...]). The customer care representative identified herself as "Ricky" and proceeded to tell me that I was using the item incorrectly or that the DC port in my car was broken. I had to tell her that not only could I confirm that my DC ports were working but that I had purchased and tested 2 identical chargers in 2 other cars as well as my own. Only then would she acknowledge that there could possibly be a problem with something Kensington sold.

The next step was telling me that Amazon should handle the replacement since they sold it and not Kensington. Amazon is the reseller and not the company that is backing the 2 year warranty. I had to repeatedly inquire about the Kensington's 2 year limited warranty and "The Kensington Promise (TM)" stated on the product package. She would not acknowledge that Kensington should be the first to replace the product even though they are the manufacturer. She said that I should return it to the store as it was their problem first not Kensington's. Only after 5 more minutes of asking about Kensington's warranty (since I do have 2 other chargers that may fail after Amazon's 30 day coverage) would she relent and begin the process for a warranty replacement. What would I have to do? Before she would give me the instructions she said that she needed my name, email, and phone number before sending me an email to give me directions for the process. Why does a call center in India, she acknowledged her location and that she was an employee of a call center not Kensington's, need a phone number when they are just sending an email not calling me back or following up on my warranty claim?

To begin filing a claim I first have to send a fax, not an email in 2012, to 650-249-0488 which may be another number routed to India never to be looked at by any actual Kensington employee. In addition before a replacement or refund the product would have to be shipped to Redwood Shores, CA "through any cheapest mail service". I suggest anybody returning an item to a company to always have a tracking number or some sort of delivery confirmation. Also if you only have a PO Box address or are international then you are out of luck. Per their email "We only ship to the U.S. and Canada. We cannot ship to P.O. Boxes. Delivery to APO/FPO addresses is not recommended and may experience delays." Good luck filing a warranty claim with Kensington, I know I will.

Oh and I was apparently talking to one Ricky Blossoms.
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on September 21, 2011
I did not purchase this for an ipad or iphone. I am using it for two Motorola Droids, which take huge amounts of power. This allows me to stream music, run gps navigation, charge the battery, and run my mobile hotspot all at the same time! If you go for the cheap chargers, you simply can't get the same amount of current. It's well worth the little bit of extra money for 3.1 amps across the two ports. Plus, the rebate (at the time I purchased this) made it an even better deal!

Definitely buy this if you need a good quality USB car charger. It will work for any device which charges through USB (you provide the cable if it's not an Apple product) and has one of the best current ratings on the market.
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on December 27, 2011
This product does not work with the iPhone 4S!! Unlike the claims the connector does not securely attach to an iPhone 4S. It will consistant stop charging because of movement in the car shakes the phone slightly. I have 5 people in the house with an iPhone 4S and all of them are experiencing the same issue when I connected them.

Definitely look for another product, I am returning it as soon as I get back home from the holidays.
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on August 8, 2011
This item works great for charging my iPhone4 and my iPad2 in my car. I'm thinking that some of the problems of reliability reported by others might be related to keeping the USB cable plugged in all the time, because I have had experience with this with other devices, and the USB part isn't that strong in ANY device, and should be unplugged when not actually charging an item.
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