Project image
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$2,860
pledged of 35.000 $pledged of 35.000 $ goal
56
backers
Funding Canceled
Funding for this project was canceled by the project creator on Aug 26 2014
Last updated December 6, 2016

PWRLNK - The Versatile Power Converter (Canceled)

Get the 5 Volt power your devices crave from just about any source: solar panels, batteries, laptop bricks, wall adapters.

PWRLNK - The Versatile Power Converter (Canceled)

Get the 5 Volt power your devices crave from just about any source: solar panels, batteries, laptop bricks, wall adapters.

$2,860
pledged of 35.000 $pledged of 35.000 $ goal
56
backers
Funding Canceled
Funding for this project was canceled by the project creator on Aug 26 2014
Last updated December 6, 2016

About

PWRLNK - Power is the Missing Link

Most interesting electronics these days - whether your own special creations, Arduino, Beagle Bone, Raspberry Pi, or cell phones and tablets - run on 5 Volts, some directly and others through USB ports. And while there are lots of power sources and chargers you can plug into the wall or your car, things get less convenient when you go portable, or want to use unconventional sources.

There are many choices depending on what you're trying to do and most of them are not quite right. Linear regulators are simple and cheap, but they waste a lot of power. Solar panels are a great idea for outdoor projects, crawlers, robots, and recharging at the beach. There are lots of inexpensive surplus panels available, but they rarely come in the voltage you want.

It works, but it's neither convenient nor efficient
It works, but it's neither convenient nor efficient

The PWRLNK-55

We have a design for a small power converter, the PWRLNK-55, that can take any input from 7 to 28 Volts DC or 7 to 18 Volts AC and provide up to 5 Amps of power at 5 Volts. It can tame batteries and solar panels, reuse old laptop power bricks and AC adapters and efficiently convert them to the 5 Volt DC that your devices need.

Some of our prototypes. Variable output on the right (stretch goal?)
Some of our prototypes. Variable output on the right (stretch goal?)
This should be the final design, with two USB charge ports!
This should be the final design, with two USB charge ports!
Batteries from 7 to 28 Volts
Batteries from 7 to 28 Volts

Efficient Conversion

Like most modern power supplies, this is a switching regulator, where the power is actually converted to a different voltage. So even though the input voltage must be at least 2 volts higher than the output, there is very little wasted energy - 85% to 97% efficient at loads above 1 Amp. Note that all power supplies can get hot in normal operation, so it's best to let them have some breathing room or shade when outdoors.

Wikipedia has an extensive article about DC-to-DC Step Down converters (warning: detailed math ahead) http://en.wikipedia.org/wiki/Buck_converter

Reduce, REUSE, Recycle

Do you have any old laptop power bricks or those little "wall wart" plug-in transformers? They still work. Getting rid of them feels like a waste, and they are not easy to recycle. So we keep them around, just in case, for some day.

Saving some of these for a rainy day?
Saving some of these for a rainy day?

The 5.5mm / 2.1mm barrel connector is one of the most common connectors, even though they may have quite different outputs. Be sure to read the label to avoid surprises. With a PWRLNK-55 they can be productively reused to safely power new projects or recharge USB devices. A 5.5/2.1 barrel connector jack will be included with every PWRLNK-55.

Don't feed your Arduino more than 12 Volts!
Don't feed your Arduino more than 12 Volts!

Polarity and Over-voltage Protection

PWRLNK-55 has a full wave bridge at the input, which means it can take AC voltages as well as DC, and the input is protected against incorrect polarity. It doesn't matter which input terminal you hook up with the positive and negative wires - either way works fine. And a TVS diode knocks out spikes on noisy lines that might otherwise cause damage.

This little Nexus 7 really gets around!
This little Nexus 7 really gets around!

What Else Can It Do?

Suppose you've built a homebrew bicycle charger or a wind or water mill, and you get a strange output like 8 VAC that's too weird for your USB devices and not enough to charge a 12 V battery. It would be a tragedy to waste that hard earned power with a linear regulator, which just turns excess voltage into heat. With a PWRLNK-55, you can convert it to a useable voltage with up to 97% efficiency!

Builders of robots and lighting systems can do distribution with unregulated supplies and put voltage regulators near the point of load. This makes wiring harnesses lighter and less expensive, since they don't have to use long runs of large wires to avoid voltage drops.

Watch the video to see a tablet charging off "dead" batteries.

Specifications

PHYSICAL DIMENSIONS: 1.8" x 1.9" (45.7mm x 48.2mm)
    4 mounting holes near the corners for #4-40 and M3 etc

INPUT: 7-28 VDC or 7-18 VAC 
    Screw terminals 14-22 AWG 
    Universal polarity AC/DC input
    Over-voltage protected

OUTPUT:  5V up to 5 Amps combined over 3 outputs 
    Screw terminals 14-22 AWG up to 5 Amps 
    USB Direct Charging Port (DCP), up to 1.5 Amps 
    USB Direct Charging Port (DCP), up to 1.5 Amps

The Team

Test and Burn-in

It takes a lot of testing to make a quality electronic product, testing of the design itself and testing of individual products. We've made a few generations of prototypes for the PWRLNK-55, carefully testing each batch, and improving the design each time from lessons learned.

It is well known in the industry that if an electronic device is going to fail, it generally fails the first time it is powered on, and a device that works for a few hours has a very high probability of working properly for many years. This process of running devices to catch any possible issues before they get to customers is called "burn-in".

We have a 100% burn-in policy - each PWRLNK-55 will be tested and run for a few hours on racks of custom designed Arduino based test boards to make sure it will function properly. This looks quite primitive, since the test board layout depends on the exact product layout. But the basic coding for the Nano (left on the breadboard) is done, as well as the design for dynamic load generation with voltage and current monitoring.

They will be finalized as soon as funding is assured. The plan is to put groups of 5 boards onto aluminum plates and then mount the plates in standard 19" racks, allowing many boards to be tested at the same time. This approach will allow us to scale testing capacity as needed.

It's the design and coding that matter
It's the design and coding that matter
Data logger setup for long term voltage, current and temperature measurements
Data logger setup for long term voltage, current and temperature measurements

Use of Funds

Funds raised through Kickstarter will help us bring PWRLNK-55 into production. Our manufacturer's minimum requirements, upfront and parts costs are reasonable at 1,000 units. We will need to build a number of racks with boards for test and burn-in, and hire a contractor to help out. Shipping will be included in the US.

Rewards

Aside from lots of PWRLNK converters, we think a motto like "Power is the Missing Link" just cries out for a T-shirt with "The Missing Link" on the back and our logo on the front. And one of those little oval stickers too.

We're from the little country of PWRLNK! (photoshop, not real yet)
We're from the little country of PWRLNK! (photoshop, not real yet)

Timeline

Here's a rough outline. Boards can be shipped as soon as they pass testing, so we expect to start shipping in November.

  • Aug - Kickstarter campaign 
  • Sep - mfg lead time, buying parts
  • Oct - manufacturing
  • Nov - test/burn-in
  • Dec - finish shipping

Risks and challenges

There are always risks involved in manufacturing electronic devices, and shipping products in general, but we have worked hard to minimize them. From a manufacturing point of view this is a relatively simple project. There are no complex injection molded parts or any advanced tooling.

We have produced a good number of prototypes and have tested them well. This will be a continuing effort before and during the campaign.
We've both brought many products to market, and have a good network of technical specialists to consult if any surprises pop up.

Finally, we have a local US contract manufacturer lined up with sample production data for the latest prototypes. They are familiar with Kickstarter projects and they buy direct from manufacturers to avoid distributor delays.

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Support

  1. Select this reward

    Pledge $1 or more About $1

    Our THANKS - All supporters get their names on a special Kickstarter page on the pwrlnk.com website.

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    A PWRLNK oval sticker with our logo.

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    The "Missing Link" T-Shirt

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    Pledge $38 or more About $38

    A PWRLNK-55 Versatile Power Converter, and a barrel connector (5.5mm OD, 2.1mm ID)

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    Limited 39 backers
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  5. Select this reward

    Pledge $38 or more About $38

    One PWRLNK-55 Versatile Power Converter.

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    Pledge $75 or more About $75

    Twin Pack - Two (2) PWRLNK-55 Versatile Power Converters.

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    Pledge $110 or more About $110

    Three (3) PWRLNK-55 Versatile Power Converters.

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  8. Select this reward

    Pledge $145 or more About $145

    Four (4) PWRLNK-55 Versatile Power Converters.

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  9. Select this reward

    Pledge $180 or more About $180

    Five (5) PWRLNK-55 Versatile Power Converters.

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    Pledge $300 or more About $300

    The MAX-PACK Ten (10) PWRLNK-55 Versatile Power Converters.

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Funding period

- (31 days)