NJ2X: Solar Power

Showing posts with label Solar Power. Show all posts

November 15, 2016

Field Test: Nomad 7 Solar Panel Performance

This article is part of a series about using the Nomad 7 Solar Panel for amateur radio use on backpacking trips. Be sure to review our prior article, "Project: Regulating the 12v Output of the Nomad 7 Solar Panel". In this article we bring the project together with a field test during a high adventure backpacking trip in the Californian Sierras.

Golden Trout Wilderness

The Adventure

Our hiking group decided to take a 5-day / 52-mile (83.7 km) hike through the Golden Trout Wilderness located in the Sierra Nevada range in California. The Golden Trout Wilderness is 474 mi² (1227.65 km²) (303,511 acres) of rugged mountainous beauty. The wilderness is named for and protects the habitat of golden trout which is California's state freshwater fish.

Photograph of a golden trout being help in the palm of a hand.

California's state freshwater fish the golden trout.

Elevations range from about 680 feet (210 m) to 12,900 feet (3,900 m). An abundance of wildlife inhabit the Golden Trout Wilderness including Monache deer, Sierra Nevada red fox, pine marten, cougar, black bear, rattlesnake, and scorpions. We would be off the grid completely for the duration of our 52-mile trek. No electrical power. No stores or restaurants. No mobile phone service. Perfect!

Scorpion encountered while trekking in the Golden Trout Wilderness

This meant that each member of the team would need to pack what he would need to survive for 5-days in the wilderness. Here is what I stuffed into my backpack:

Topographical map
1 gallon zip lock bag to keep the the map dry
Compass
Small tube of sunscreen
Insect repellent
Fleece jacket
Rain shell
Boonie Hat
Quick drying pants that convert to shorts
Headlamp
First aid kit
Waterproof matches in a waterproof container
Small butane lighter
Knife
Dehydrated food for 6 days
Trail snacks
Bear canister
Hip canteen
1.5 liter water bag
Water purification chemicals
Tarp
550 cord
2 trekking poles
Bivy
Sleeping bag
Sleeping pad
2 pairs of wool socks
2 wicking undershirts
1 quick-drying shorts
2 wicking long sleeve shirts
Fuel canister
Backpacking stove
Small foil pack of chili peppers
Whistle
Cook pot
Toothbrush
Toothpaste
Liquid soap
Baby wipes
Ultralight super absorbent towel
Toilet paper
Trowel
Kenwood TH-F6A tri-band HT
Nomad 7 Solar Panel (modified and regulated)
iPhone for pictures
Earbuds

My backpack weighed around 38 lbs. at the start of our journey. Weight is extremely important on a long trek with significant elevation changes. Every bit of additional weight requires more energy from the backpacker. The weight is most apparent when climbing several thousand feet in elevation.

We knew we would be isolated throughout our trek. Our adventure was scheduled to start immediately after the mountain roads became clear of snow so we were pretty sure we wouldn't encounter very many people (if any). Communication is critical in an emergency situation.

Emergency Communication Gear

We had two hams in our group so we naturally decided to pack a set of two-way radios and solar power. The Kenwood TH-F6A HT radios would allow us to maintain communication with each other if we became separated or if someone had to hike out to get help. The radios would also provide the possibility of calling help directly from a mountain peak through either a repeater or another amateur radio operator.

Photograph of the Kenwood TH-F6A tri-band amateur radio

Kenwood TH-F6A Tri-band HT

We packed our Nomad 7 solar panel that we had modified to provide output via Anderson Powerpole and a pigtail suitable for the Kenwood HT's. The solar panel would allow us to keep our radios and mobile devices charged for the duration of the trip.

Photograph of the Nomand 7 Solar Panel and Kenwood TH-F6A tri-band amateur radio

Nomad 7 Solar Panel and Kenwood TH-F6A

Field Test Results

Our Kenwood TH-F6A radios worked great during our trip. We used them to maintain communication between the front and back of our group while hiking. We also used them to maintain communication when exploring the area around camp. Fortunately, there were no emergencies during our adventure.

On two occasions we inadvertently and unknowingly dropped our radios while crossing obstructions. In both instances we noticed the radios were no longer attached to our packs and quickly retraced our steps to recover the radios. The Kenwood TH-F6A is well-built and suffered no damage from either incident. From this experience, we learned that clipping the radio to the pack is insufficient for securing it. We improvised lanyards from lengths of 550 cord to positively attach our radios to our packs. The lanyards allowed the radios to be used while hiking without the risk of falling off and becoming lost along the trail.

We are blessed in California with an abundance of sunshine which we harnessed with our Nomad 7 solar panel to recharge our iPhones and Kenwood TH-F6A. We chose to recharge one device at a time so as to minimize the charging time. In full-sun, the Nomad 7 seemed to recharge our iPhones at about the same rate as we would have experienced plugging them into a wall socket charger. The Nomad 7 did a great job of recharging our Kenwood TH-F6A for the first few days. On our last day, while recharging our Kenwood F6A via the Nomad 7 solar panel, the radio stopped charging and would no longer power-on. We believe the unregulated (15vdc in full sun) output of the solar panel was the cause. For more on this read our article Project: Regulating the 12v Output of the Nomad 7 Solar Panel.

We decided to protect our remaining radio from damage by not connecting it with the solar panel for the remainder of our trip. Having at least one functioning radio in the event of an emergency was our priority.

We tried recharging while hiking by tying down an open Nomad 7 to our backpack. This didn't work very well as were constantly moving in and out of sun and shade. We found it more effective to recharge when stopped on breaks, lunch, or while setting up camp. Being stationary allowed us to orient the solar panel to maximize sunlight exposure.

The Nomad 7 is very well made and durable. We gave ours some unintended rough treatment while backpacking and it kept working the entire trip. This is an important quality in any backpacking gear. Packs and their contents tend to get knocked around a bit while trekking.

Even though we didn't have an emergency, it was comforting to know that we could recharge our devices during our 5-day trek through the Golden Trout Wilderness. Our batteries would certainly have been depleted after 5-days of usage had we not had a solar panel in our packs. We really enjoyed being able to shoot photographs to our hearts content with our iPhones without worrying about running out of power. At 1.4 lbs, the Nomad 7 solar panel was definitely worth the additional weight. We were disappointed to have one of our Kenwood radios stop working as a result of charging it from the unregulated Nomad 7 solar panel.

Mountain meadow in the Golden Trout Wilderness

When we returned home, we subsequently went to work to solve the issue by regulating the output of the solar panel at a lower safer voltage (see Project: Regulating the 12v Output of the Nomad 7 Solar Panel). We are looking to our next adventure and packing our (now regulated) Nomad 7 solar panel. We know we now have the perfect backpacking adventure amateur radio and solar power setup.

See you on the trail. 73.

NJ2X

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July 2, 2016

Project: Regulating the 12v Output of the Nomad 7 Solar Panel

This article is in a series about using the Nomad 7 Solar Panel for amateur radio use on backpacking trips. Our prior article was, "Project: Fabricating a Anderson PowerPole to 3.4mm dc connector for the Kenwood TH-F6A".

Something went wrong during field testing of recharging our Kenwood TH-F6A HT radio using the Nomad 7 Solar Panel. Sadly, our TH-F6A stopped charging (lights went out) and would then no longer turn on. This issue occurred within only a few minutes of charging in full sunlight.

There are a couple of possibilities for the failure:

The TH-F6A blew one or more of its three fuses due to the relatively high voltage (15Vdc) of the Nomad 7 Solar Panel in full sun. The TH-F6A is rated at 10Vdc to 16Vdc though the radio's internal voltage regulator converts voltages greater than 10Vdc to heat. It is possible the 15Vdc caused overheating and blew one or more of the fuses.
A fuse was blown when the 3.4mm connector was plugged into the radio with power applied to the connector (not supposed to do this per the manual).
Other failure mode? If you have an idea, please post a comment to this article.

We will post an update once the radio has been diagnosed and repaired by Kenwood.

In the meantime, we decided that adding a voltage regulator to bring the voltage to about 11 volts would be a prudent move. We found an inexpensive ($1.75), lightweight, and low-power, adjustable DC-to-DC switching voltage regulator for sale on eBay that fit the need. This regulator can be set to produce a stable 11Vdc with an input voltage between 5Vdc and 32Vdc. The seller claims the MOSFET (LM2577 operating at 50KHz) switching voltage regulation design is 94% efficient. This means more solar power directed to the battery and less lost to heat.

DC-DC Auto Boost Buck Adjustable Voltage Regulator

Here is the specification sheet that came with the module:

Technical Parameters

Model Specification：DSN6000AUD Automatic Buck module
Module Properties：Non- isolated boost (BOOST)
Rectification：Non- Synchronous Rectification
Input Range：3.8V ~ 32V
Output Range：1.25V ~ 35V
Input Current：3A ( max ) , no-load 18mA (5V input , 8V output , no-load is less than 18mA. Higher the voltage , the greater the load current . )
Conversion efficiency：< 94% ( greater the pressure , the lower the efficiency )
Switching frequency：400KHz
Output Ripple：50mV ( the higher the voltage , the greater the current , the greater the ripple )
Load Regulation：± 0.5%
Voltage Regulation：± 0.5%
Operating Temperature：-40 ℃ ~ +85 ℃
Dimensions：48mm * 25mm * 14mm ( L * W * H )

To keep it flexible we went ahead and soldered on a pair of Anderson PowerPoles at the input and also the output. Everything still fit nicely within the carrying pouch of the Nomad 7 Solar Panel. We also modified our operating procedure so that we will only plug and unplug the 3.4mm connection to the TH-F6A when no power is applied.

There is a small brass set screw on the voltage regulator module. Turning this set screw allows for very precise selection of output voltage. We used our multimeter to monitor the voltage during adjustment. Once set, we used a large piece of heatshrink tubing to encapsulate the module and electrical tape to seal the ends. This will keep the module waterproof which is important on backpacking trips.

Testing

1) Measure the voltage output of the voltage regulator. Our voltage regulator produced about 11Vdc which was exactly where we wanted it for use with the TH-F6A.

2) Charge the TH-F6A battery. We used our second Kenwood TH-F6A for testing. The battery was a little low so we plugged everything together and it charged perfectly.

3) Confirm that TH-F6A still functions after charging. After charging the battery, we disconnected the radio from power. We then turned on the radio and everything worked perfectly.

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June 25, 2016

Project: Fabricating a Anderson Powerpole to 3.4mm dc connector for the Kenwood TH-F6A

In our prior post, "Project: Hacking the Nomad 7 Solar Panel for Amateur Radio Use", we explained how to replace the stock 12Vdc 8mm male connector with the more useful Anderson Powerpole connector.

In this post, we describe how to make a pigtail cable to connect the Kenwood TH-F6A triband HT to a 12Vdc power source via an Anderson Powerpole connector. As our starting point, we purchased a Kenwood PG-2W cable from Universal Radio. The Kenwood PG-2W cable comes with fuses already installed.

Kenwood PG-2W

Step 1: Slide on a short length of heat shrink tubing

Slide on a short length of heat shrink tubing over both the tinned ends of the PG-2W cable.
The tubing will be used to dress the cable and provide a little strain relief.

Kenwood PG-2W with heat shrink tubing slide on

Step 2: Solder on Anderson Powerpole contacts

Solder (or crimp) on the Anderson Powerpole contacts onto the tinned ends of the PG-2W cable.

Kenwood PG-2W cable with Anderson Powerpole contacts soldered on

Step 3: Install the Anderson Powerpole housing

The positive wire is clearly tagged on the PG-2W.
Install the Anderson Powerpole housing such that the positive contact is inside the red side of the housing.

Step 4: Test the cable

Using your voltmeter, confirm that the positive contact on the 3.4mm dc connector is connected to the red Anderson PowerPole contact

PG-2W cable back packaging label showing the connector polarity. The center pin is positive.

Kenwood PG-2W cable - back of the package showing polarity of the 3.4mm dc connector

Voila! That is how we fabricated our very own pigtail to connect the Goal Zero Nomad 7 solar panel to the Kenwood TH-F6A radio for the purpose of recharging the radio's battery.

The Nomad 7 solar panel with an Anderson PowerPole soldered on.

Nomad 7 with Anderson Powerpoles connected

The Nomad 7 solar panel in full sun charging a TH-F6A.

Goal Zero Nomad 7 V2 solar panel charging the Kenwood TH-F6A HT Transceiver via Anderson Powerpole cables

In the next article in this series, we share our project to regulate the 12v output of the Nomad 7 Solar Panel.

Good DX and 73, NJ2X

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June 18, 2016

Project: Hacking the Nomad 7 Solar Panel for Amateur Radio Use

In our earlier article, "Backpacking Amateur Radio Power: Alternatives" we explored various solutions to powering electronic devices (iPhone and an amateur radio HT) while backpacking. The Goal Zero Nomad 7 solar panel met our requirements the best.

Goal Zero Nomad 7 solar panel

In this post, we explain step-by-step how we modified the Nomad 7 solar panel to make it more convenient to use in amateur radio applications.

Goal Zero has made a very handy little solar panel in the Nomad 7. It provides power via a USB port and a 12Vdc port. This makes it possible for us to recharge our iPhone (5V USB) and Kenwood TH-F6A (12Vdc) from the Nomad 7. One of the great things about standards is how many of them there are. There are innumerable standards for 12v power connectors. We prefer the Anderson Powerpole connector for our 12Vdc applications. Unfortunately, the Nomad 7 provides 12Vdc via an 8mm connector.

Nomad 7 solar panel with its 8mm connector

Nomad 7 12Vdc via an 8mm connector

Nomad 7 5Vdc via a USB connector

In order to connector our Kenwood TH-F6A to the Nomad 7 we would need to make a pigtail. We considered purchasing Goal Zero's 8mm female to 4.7mm male pigtail assembly for $4.99 and then cutting off the 4.7mm connector and replacing it with an Anderson Powerpole. However, this seemed like unnecessarily complex solution that would add weight and cost. Weight comes at a high cost for backpackers.

Commercial 8mm female to 4.7mm male pigtail assembly.

Goal Zero's 8mm female to 4.7mm male pigtail assembly

After talking this over with our friends at Santa Cruz Electronics we came to the conclusion that the simplest, least weight, and lowest cost approach would be to simply cut off the 8mm male connector from the Nomad 7 and solder on an Anderson Powerpole.

Replacing the 8mm male connector with an Anderson Powerpole

Step 1: Cut off the 8mm male connector

Leave enough wire on the Nomad 7 to comfortably solder on an Anderson Powerpole connector.
Leave enough wire on the 8mm connector to solder on an Anderson Powerpole later if needed.

Step 2: Strip the coaxial cable

Carefully strip the black plastic sheath about 1 inch. Take care not to cut any of the copper wire.
Twist the copper braid into a single wire for soldering.
Strip the white wire to the same length as the Powerpole connector.
Slide on a short length of heat shrink tubing over the coaxial cable.

Step 3: Verify the positive and negative contacts

Place the Nomad 7 in full sun and verify the positive and negative contacts using your volt meter.
Our Nomad 7 produced 15.15 Vdc in full sun (open voltage). The Kenwood TH-F6A has a specification limit of 16V.

Nomad 7 open voltage of 15.15Vdc as displayed by a digital volt meter.

Nomad 7 open voltage (15.15Vdc)

Step 4: Solder (or crimp) on the Anderson Powerpole contacts

We prefer soldering the contacts to minimize resistance and assure good contact.

Soldering the Anderson PowerPole contacts

Step 5: Insert the contacts into the red/black Anderson Powerpole housing

Be sure to install the red side on the positive connector.
Use your volt meter or your Anderson Powerpole Polarity Checker to confirm that the red connector has been installed on the positive contact.

Step 6: Shrink the heat shrink tubing

Slide the heat shrink tubing up so it is snug with the Anderson Powerpole.
Using a heat source, carefully shrink the tubing so it tight around the wires.
This dresses the construction and provides some strain relief for the connector.

Voila! The 8mm male connector has been replaced with a much more useful Anderson Powerpole connector on the Goal Zero Nomad 7 solar panel. We can now connect our Nomad 7 to a wide variety of devices and cables that we have fabricated using Anderson Powerpole connectors. This seems like such an obvious design choice it makes us wonder why Goal Zero didn't choose the Anderson Powerpole instead of the 8mm connector to begin with? Come on world, it is time to rally around the Anderson Powerpole for 12Vdc applications.

Anderson PowerPole connectors soldered onto the Nomad 7 solar panel

Nomad 7 with Anderson Powerpole installed

In our next post (Project: Fabricating a Anderson Powerpole to 3.4mm dc connector for the Kenwood TH-F6A), we will build a pigtail for the Kenwood TH-F6A HT so we can recharge the radio's battery from the Nomad 7 via the Anderson Powerpole connector.

Good DX and 73, NJ2X

Articles in this series:

June 11, 2016

Backpacking Amateur Radio Power: Alternatives

In our prior post (Backpacking Amateur Radio Power: Requirements) we discussed our requirements for powering our electronics in the backcountry including an HT and an iPhone. We defined our requirements in the form of a user story with acceptance criteria.

USER STORY: As a backpacker, I need a way to use my TH-F6A radio and iPhone 6 during my backpacking trip and not run out of battery before the end of the trip so that I can have fun with the devices during the trip and have them ready for use at any time during the trip in the event of an emergency to call for help.

ACCEPTANCE CRITERIA:

Must allow the backpacker to use the device a little or a lot as needed.
Must be flexible enough to allow the backpacker to use the solution regardless of duration (our typical backpacking adventures range from from 1 night to 15 days).
Must not add significant weight to the pack (i.e. < 1.5 lbs / 0.68Kg).
Must be able to maintain power for an iPhone via the USB connection (5Vdc USB power).
Must be able to maintain power for a Kenwood TH-F6A via the 12Vdc connection.

In today's post, we will explore potential alternative solutions and compare them against our requirements.

Option 1: Conserve the battery

Pros

Practical approach
No cost
No added weight

Cons

Conserving the battery means using the devices sparingly over the trip. For the iPhone it means leaving the device powered off during the hike and powering it on when needed. Not very convenient for snapping photos while trekking. Keeping the HT powered off is a bit more feasible. However, we like to use the radios in our backpacking group to keep the front and rear in communication as we go to since we tend to string out a bit.
This approach doesn't meet our acceptance criteria of being able to use the devices as much or as little as needed during the trek.

Option 2: Pack extra batteries

Pros

Provides additional power when needed and quickly.
Cost is within reason. A TH-F6A HT battery would be around $36 for 4000mAh. The mophie powerstation plus 3x with Lightning connector retails for $99.
Packing one set of batteries would meet the weight limit acceptance criteria.

Cons

On longer trips, one set of extra batteries may not be enough.
Some conservation of battery power is still required.

Option 3: Pack a portable generator: BioLite Wood Burning Campstove

Pros

Claims to provide portable power (USB).

Cons

The BioLite Wood Burning Campstove had mixed reviews on Amazon.com.
Heavier than our acceptance criteria (2.07 lbs/0.94Kg > limit of 1.5 lbs/0.68Kg)
Can recharge via USB only. It does not provide 12Vdc recharge capability.

Option 4: Pack a portable generator: K-TOR Pocket Socket Hand Crank Generator

Pros

Possible to recharge both USB and 12Vdc batteries.
The weight is under the limit per our acceptance criteria (1.0 lbs/0.45Kg < limit of 1.5 lbs/0.68Kg)
Cost is reasonable at $54.00 on Amazon.com

Cons

The K-TOR Pocket Socket Hand Crank Generator had mixed reviews on Amazon.com. From the reviews is sounds like hand cranking is laborious and takes a long long time to recharge. This is a material consideration since backpacking can be physically exhausting. Having difficulty imaging cranking for hours after a day of backpacking 16 miles with elevation changes.
Requires packing the transforms for iPhone and HT. This adds additional weight.

Option 5: Pack a solar panel: Goal Zero Nomad 7

Pros

Recharges USB devices.
Recharges 12Vdc devices.
Lightweight at 1.4 lbs/0.64Kg which is less than our acceptance criteria limit of 1.5 lbs/0.68Kg.
Easy to use and requires no physical effort to generate power.
Cost is reasonable at $77.31 on Amazon.com
Solid reviews on Amazon.com.
Well made and durable.

Cons

Need direct sunlight to recharge. We have sunshine in abundance here in California so this isn't a material concern.

Option 5: Pack a solar panel: Goal Zero Nomad 7 is the clear winner among our alternatives. It fits the requirements very well. We are looking forward to putting it to the test.

In our next post in this series, "Project: Hacking the Nomad 7 Solar Panel for Amateur Radio Use" we will show step-by-step how we modified our Nomad 7 to make it more convenience to use with our Amateur Radio setup.

We will review how well the whole setup worked on a challenging backpacking backcountry adventure in our final post in the series.

Good DX and 73, NJ2X

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Articles in this series:

Backpacking Amateur Radio Power: Requirements

Backpacking Amateur Radio Power: Alternatives

Project: Hacking the Nomad 7 Solar Panel for Amateur Radio Use

Project: Fabricating a Anderson PowerPole to 3.4mm dc connector for the Kenwood TH-F6A

Project: Regulating the 12v Output of the Nomad 7 Solar Panel

Field Test: Nomad 7 Solar Panel Performance

June 4, 2016

Backpacking Amateur Radio Power: Requirements

So how do you bring an iPhone and HT on a backpacking trip and use them without running out of battery before the end of the trip? In this post, we explore this question and the related requirements.

We have been doing a lot of backpacking lately in the mountains of Northern California. Backpacking is great exercise, physically challenging, and a great way to immerse yourself in nature. A backpacker must carry everything needed for the trek including food, water, shelter, clothing, first aid, and personal items. Our 3-day/2-night pack weighed in around 30 lbs / 13.6 Kg. Weight comes at a big cost to a backpacker, so the objective is to minimize.

When trekking in the backcountry there is often no mobile phone coverage. Mountain peaks sometimes provide a line of sight to a faraway cell tower which can yield one or two bars of signal. In our experience, the valleys are barren of mobile phone signal. We still carry our cell phones on backpacking trips because the phone provides a good camera and can also serve as a potential emergency communication device. Being able to summon help when you need it most is invaluable.

Amateur radio VHF/UHF repeater coverage in the backcountry is more readily available than cell phone coverage in the places we have been hiking. This makes the amateur VHF/UHF HT a valuable companion on a backpacking trip. In an emergency situation, communication can make a tremendous difference in the outcome.

We programmed our Kenwood TH-F6A tribander radios with as many repeaters as we could covering the areas we like to travel and backpack in Northern California. The TH-F6A transmits 5W on the 144 MHz, 220 MHz, and 440 MHz amateur bands. We also programmed them with the various simplex calling frequencies. We bring them on every trip. Sometimes we also use our TH-F6A with our TinyTrak4 TNC and GPS for APRS tracking. The TH-F6A has a wide-band receiver which allows us to listen to broadcast radio in camp (AM/FM).

Kenwood TH-F6A Triband VHF/UHF HT is perfect for backpacking

The challenge with bringing electronic devices on a backpacking trip is using them without running out of power before the trip ends. We don't simply want to throw the devices into our packs powered off during the trip in order to save the battery. So what are the requirements for the solution? We defined our requirements in the form of a user story with acceptance criteria:

USER STORY: As a backpacker, I need a way to use my TH-F6A radio and iPhone 6 during my backpacking trip and not run out of battery before the end of the trip so that I can have fun with the devices during the trip and have them ready for use at any time during the trip in the event of an emergency to call for help.

ACCEPTANCE CRITERIA:

Must allow the backpacker to use the device a little or a lot as needed.
Must be flexible enough to allow the backpacker to use the solution regardless of duration (our typical backpacking adventures range from from 1 night to 15 days).
Must not add significant weight to the pack (< 1.5 lbs/0.68Kg).
Must be able to maintain power for an iPhone via the USB connection (5Vdc USB power).
Must be able to maintain power for a Kenwood TH-F6A via the 12Vdc connection.

Now that we understand our requirements, we are ready to explore potential solutions in the next article.

Good DX and 73, NJ2X

Articles in this series:

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