Griffin PowerJolt

Overview

Griffin PowerJolt Box

I wanted a car charger for my iPhone 3G because it just needs juice more or less everyday to ensure it has power to last me the day. I had a car cigarette lighter extension which had a USB port for charging USB devices. It fit perfectly in a cubby hole under the stereo but Apple had changed the way the iPhone detects and charges.

iPod & iPhone Charging System

USB has for wires in the connector. They are (not necessary the correct order):

• +5v – Power line
• RX – Receive Data
• TX – Send Data
• GND – Ground

Normally for a USB device to charge using USB it uses the +5V and GND pins. This is the case for iPods. The iPhone however needs voltage to be applied in the RX and TX pins too even if it isn’t connected to a computer. The details can be found on Systm Episode 52 – Build a Must-Have iPod Accessory and DIY iPhone Charger.

Hacking My Cigarette Lighter Extension

Generic 3 Way Extension

I attempted to make the Cigarette Lighter USB socket compatible with the iPhone. I needed to add some resistors to bring the +5V power down to the 2-3v required for the TX and RX pins. I opened up the unit and found the data pins unconnected (and why should it?). It was possible to solder some wires on to the pins but it would be tight.

I took the unit to the car and a volt meter to see where the positive and negative voltages were. I ended up shortening the unit and to this day have not tested it to see if it still works.

This is when I found the Griffin PowerJolt.

Griffin PowerJolt

Box Content

I pre-ordered the unit and it had only come recently. It came with the lighter element which has a USB port on the top, a LED for power and a 2 amp fuse which can be easily removed on the side, a USB to iPod connector and a USB to mini USB. The Griffin PowerJolt comes in black and white.

Lighter Element

The lighter part is a different shape to the picture on Griffin’s website and it looks more like the Griffin PowerDuo.

Griffin And Apple iPod Connector

The website says it is compatible with the iPhone 3G but I got worried when the box did not stated. The two USB cables are about 1 metre long each.

In Car Use

Griffin PowerJolt With Griffin Connector

The charger fits into the cigarette lighter like any other device. The cable after the lighter element didn’t matter as I tried both Griffin and Apple cable for the iPhone.

I tried the mini USB cable and my Motorla A1200 didn’t pick up the charger. I also tried charging my iPod 5th Gen and it worked like a charm.

Systm Episode 52 – Build a Must-Have iPod Accessory
DIY iPhone Charger
Griffin PowerJolt

About Danny

I.T software professional always studying and applying the knowledge gained and one way of doing this is to blog. Danny also has participates in a part time project called Energy@Home [http://code.google.com/p/energyathome/] for monitoring energy usage on a premise. Dedicated to I.T since studying pure Information Technology since the age of 16, Danny Tsang working in the field that he has aimed for since leaving school. View all posts by Danny → This entry was posted in Mobile Phone, Review and tagged car charger, computer, DIY, griffin powerjolt, Hacking, iphone, mini usb, Systm, volt meter. Bookmark the permalink.

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