18 - Power Accessories
Strategies For Keeping Your Mobile Phone Charged On Your Boat.

In the first article in this series, Using a Mobile Phone Aboard Your Boat, we described the benefits our mobile phone gives us during a typical day. These benefits are most appreciated during a night at anchor when they translate into a good night's sleep.

We use our mobile phone as an anchor alarm beside our berth. It monitors our position and alerts us if the boat has moved too far. This requires our phone to be on and accessing the GPS, often via Bluetooth. In the early days, we sometimes awoke to find the battery on our phone had gone dead. This only defeated the purpose of our anchor alarm, as now we merely stayed awake worrying about the battery going dead rather than the anchor slipping. Mobile Phone Today mobile phones are feature rich putting more strain on battery power.

This led to a search for the best ways to maintain power for our mobile phone and accessory devices while on our boat. What we developed was a combination of strategies including conservation, "opportunistic charging" and a variety of powering products.


The first step to maintaining dependable battery power is to ensure that you are conserving power wherever possible. This is a sound strategy for all aspects of your boat and throughout your life. If it's not being used, turn it off.

Most people are unaware of the many things on their mobile phone which are draining their battery life. Today's mobile phones have become feature packed - more applications, more components, faster processors - all things that can increase power usage. You need to become smart about the features they have and how to manage their use.

It is important that you read your user's manual and understand the power conservation features for your phone and how to use them. Spend some time exploring your phone. If you are familiar with how to access these features, you will be more likely to take advantage if them. Going online can be a great way to discover tips and techniques specific to your phone.

Here are features to consider when planning your power conservation strategy:

  • Backlighting
    There is no single bigger use of battery power on your mobile phone than backlighting. Having backlighting turned on can increase your battery drain by as much as 10 times. Keep it off if you don't need it and, if possible, dim it when you do. Backlighting adjustments are typically found under the Options or Settings menu on your phone.

  • WiFi
    Running WiFi on your phone can be another large use of battery power. When WiFi is on it will continually search for a WiFi signal. The WiFi radio is using power whether you are connected to a network or not. It is estimated that shutting off your WiFi radio can save as much as 40% of your battery usage. Learn how to turn off the WiFi radio on your phone if it is WiFi-enabled.

  • Phone Calls
    When you are making or receiving a call on your mobile phone you are burning much more power. But even when your phone is idle, waiting to receive or make a call, it burns battery capacity. Learn how to turn off the cellular radio on your phone. Of course, you cannot receive or make phones calls but there are likely times when you don't want to (while you sleep) or aren't able to (too far offshore).

  • Bluetooth
    As discussed in our article Adding a Bluetooth Headset, Bluetooth was designed for low power usage. Even so, it does use power any time you have it turned on. Any time you are not using Bluetooth, it should be turned off. Learn how to turn off the Bluetooth radio on your phone.

  • Internal GPS
    It is becoming more common for high-end phones to have an internal GPS. Turning the GPS off when you are not using it will save power.

  • Flight Mode
    One quick way to disable all of the radios on your mobile phone is to put your phone into "Flight Mode." Flight mode will disable the phone, WiFi and Bluetooth radios all at once. Ensure that you do not needed any of these radios for critical functions, such as accessing a GPS signal. Make sure you understand what components are affected when you are in flight mode.

  • Vibrating and Sound
    When your phone is vibrating or playing a sound, it is using large amounts of power. Fortunately the time it does this is typically short. In general, you will not need to be concerned about this. However, if you have a use that may cause it to run frequently, for example an alarm which continues to alert you until being shut off, you could burn through a lot of power without realizing it.

  • Updates
    Make sure you have the latest version of your phone's operating system. The operating system is one of the biggest drains on your battery and vendors are continually trying to improve performance. A new version could decrease your battery consumption. In general, it's a good idea to have the latest versions of any applications you use on your mobile phone.

  • Email
    Does your phone receive your email messages automatically? Using automatic email retrieval, or "push" email, will require your phone to maintain a network connection. This can really drain your battery power. Many of these systems allow you to set how frequently your phone checks for email. Consider setting it for less frequent checking, such as every 15 minutes or once an hour. Better yet, choose to check it manually, especially when you're trying to prolong battery life.

  • Online Services
    There are online services that also require your phone to expend battery power such as stock quotes or news feeds. Turning them off while on your boat will help conserve power.

  • Alerts
    Check that any alerts you may have previously set but no longer need are turned off. This will save CPU power and the power that goes to the audible, visual or vibrating signal.

  • Ringtones
    Using a simple ringtone rather than one of the elaborate musical tones uses less power.

  • Temperature
    If possible, keep your phone in a cool place. It is more difficult for the battery to hold its charge if it becomes hot.

You will find that using some or all of these techniques will greatly extend your battery life. But no matter how vigilant you are about your power usage, you will eventually need to recharge your mobile phone's battery. For charging, there are some techniques that will make this process simpler and more efficient on your boat.


With today's lithium ion batteries, the old notion that it is bad to continually top-off your battery is obsolete. It is fine, even desirable, to keep your battery fully charged whenever possible. Take advantage of any opportunity to "plug your phone in." When charging onboard take advantage of the power system on your boat. DC 12 volt charging Charging your mobile phone using a 12 volt cigarette outlet is a good strategy.

Use DC power to charge your phone anytime your are under power. Your boat readily produces DC power whenever the engine is running, which you can access using a 12v cigarette plug. If your boat does not have a 12v cigarette plug, install one. The extra draw used to charge the phone is minimal making this an efficient way to keep your phone charged. For power boats this will be whenever you are moving. For sailboats, the opportunity may occur less often but make sure you utilize the chance when it happens. The same is true any time you are using a generator.

A good alternative, particularly for sailboats, is solar or wind power. If you already have these systems installed take advantage of them. If you don't have these on your boat, there are several small scale systems that work well for topping off your mobile phone using solar power. Several of these are discussed below.

Of course, if you are heading ashore consider bringing your charger with you. Look for outlets in coffee shops, boating lounges, laundry rooms, wherever. An hour spent over a coffee and the paper can easily top off your phone's battery. Taking a courtesy car for a provisions run? Bring your 12v DC charger and plug it into the cigarette lighter of the car. Every little bit helps.


There are three potential power sources available to you on your boat: Alternating Current (AC), Direct Current (DC) and Universal Serial Bus (USB).

AC is the power that comes from a wall socket. AC allows large voltages to be transported over long distances and delivered for use. It is this capability that has made AC the form used to deliver electricity to our homes, offices and factories.

DC power is easily generated by small local systems and is readily stored for future use. DC can be converted to AC with an inverter but there will be a loss of efficiency in the conversion (there is also an efficiency loss when converting from AC to DC). The standard connector for DC on your boat is a 12 volt cigarette lighter plug. You will often see this type of power connection referred to as "12v."

Powering with USB has become common for low-consumption devices such as your mobile phone. In these cases, the USB cable acts as a bridging power cord transferring power from an AC or DC source to your phone. Using USB to charge your mobile phone and other portable devices is an excellent strategy, one we'll discuss in depth in a moment. It's probably one that you might not have considered before.

Unless you are plugged into AC power on the dock, we recommend that you avoid using AC to charge devices on your boat if possible. Instead look to 12v or USB chargers. There are lots of options available to create an excellent modular charging system with a small number of adapters and cables. USB Connectors A mini USB to standard USB cable makes charging easy.


The promise of portable devices has been a life unencumbered by bulky hardware, freedom from big carrying cases and excess hassles. Unfortunately, the reality hasn't always measured up. Different charging units, incompatible cables and disparate devices often meant that the accessories required an additional tote bag, usually bigger than the portable device itself!

However, much of this hassle can be eliminated with the right charging strategy - the USB strategy. USB stands for Universal Serial Bus and is the standard way a wide variety of devices can be connected to your computer today. It was designed for simple "plug-and-play" connectivity - the ability to simply plug in a device and have it "magically" appear on your computer. It supports "hot-swapping", the ability to connect or disconnect a new device without adding an adapter card or having to turn off your computer.

USB's popularity has made it the de-facto standard for connecting peripherals. It's even used in nontraditional computer-like devices such as video game consoles, with one of the oddest uses we've seen being a pair of heated slippers that plug into your laptop. Honest! (See Engadget's review for more information.) AC-to-USB Adapter AC-to-USB adapter works well when ashore.

An added feature of USB is the ability to power low-consumption devices without the need for an external power supply. Taking advantage of this capability can greatly ease the charging hassles for your mobile phone. The goal is to obtain a USB connection on your mobile phone. By using a USB cable and a few power adapters you can charge your mobile phone in almost any environment. DC-to-USB Adapter A DC 12v-to-USB adapter facilitates charging on your boat.

Most mobile phones today, and especially the high-end phones, come standard with USB connectors. They typically have mini USB connectors, a small version of the standard USB connector. Many phones come with a mini USB to USB cable which readily allows you to connect the phone to your laptop for data syncing and powering.

Some vendors, such as Palm and Apple, have custom connectors on their phones. These phones will typically come with cables providing a standard USB connector for connecting to a computer. Older phones, particularly ones which do not allow for the syncing of data, often have a custom power connector. For these devices you will need an adapter tip to transform the custom connector into a USB connector, or a special USB cable. In most cases, these special tips won't be needed for newer devices as they already have a USB connector.

Now that you have a USB connection for your mobile phone, there are several choices available for charging it. Of course, you can simply connect it to your laptop's USB port which works great when you are dockside and plugged in to shore power. In a pinch, you can even use the laptop's battery to charge your mobile phone through the USB port. DC Socket Outlet A DC Socket Outlet lets you power multiple devices at once.

For your everyday charging needs you only need a couple of charger adapters: one AC-to-USB and one DC-to-USB. These adapters are small, lightweight and inexpensive. An AC-to-USB adapter lets you use a standard wall outlet for USB charging. A DC 12v-to-USB adapter provides power using the cigarette lighter plug on you boat or car. There are even ones that provide two USB ports allowing you to charge multiple devices at once. Add a retractable USB cable, which goes from a mini USB connector to a standard USB connector, and you pretty much have everything you need to power your mobile phone through the USB cable. AC-to-DC Adapter An AC-to-12v adapter allows you to leave your Ac block chargers at home.

These components will meet your basic needs for USB powering. But like anything that works well, you will find that you are soon stretching the limits of this strategy. You will want to charge other devices using the USB strategy such as your external GPS, your iPod/MP3 player, and your Bluetooth headset. You may find that you are running out of power outlets. To combat this, you will need a 12v outlet adapter. Think of it as a power strip for your DC power. It will plug into your 12v cigarette plug and provide you with 2- or 3-12v plugs allowing you to power multiple devices at once.

Your next purchase should be an AC-to-12v cigarette adapter. This will allow you to plug into AC power when you are ashore or at the dock and plugged into shore power, offering you a 12v cigarette plug which will work with the devices mentioned above. These can be purchased for less than $10. By having an AC-to-12v adapter or an AC-to-USB adapter, you'll never need an AC charger for a device again. That alone will save 50% or more of the bulk you need for power accessories.

With these few components you will be able to meet any charging situation you encounter for your mobile phone, as well as for most of your other portable devices.

The USB Strategy

  • Acquire USB connection for all mobile devices

  • Purchase an AC-to-USB adapter

  • Purchase a DC 12v-to-USB adapter

  • Purchase an AC-to-12v adapter

  • Charge via USB if possible

  • Otherwise, charge via 12v

  • Leave your AC chargers at home


So what if you're the kind of person who wants backups to your backup. We understand. If you read our first article in this series, Using a Mobile Phone Aboard Your Boat, your may remember that we always have our built-in navigation system running, our mobile phone running ActiveCaptain Mobile as a backup, and our paper charts out with Post-It notes marking our location as a backup to our backup.

Of course, you can always carry an extra battery for your mobile phone. This requires shutting down your phone to replace it. In addition, you will need a reliable way to keep both batteries charged, either having a separate charger for the battery or regularly swapping the batteries on the phone. But the biggest drawback is that the extra battery will only work with your phone and not with any other portable device you have. We think there's a better way.

There are a variety of battery pack solutions available in differing configurations. On the low end are devices like the Turbo Charge which uses two AA batteries to provide up to 3 full charges for your mobile phone. Simply change the batteries for more charges. At around $25 it's one of the least expensive options but requires you to stock AA batteries. This is a good solution for emergency situations and is the perfect addition to your "ditch bag". Turbo Charge The Turbo Charge battery pack provides additional power when you need it.

There are rechargable products, such as the IOGEAR's GearJuice, about $35, which will charge your phone up to 3 times before requiring a recharge itself. The GearJuice comes with 7 connector tips offering support for a wide variety of devices as well as a USB cable. In addition, it comes with a full range of power adapters for charging your portable devices in the US and internationally. A gauge on the front indicates the amount of charge left in the GearJuice's battery.

The Datexx SuperBattery can provide up to 4 hours of talk time and 36 hours of standby time for your phone and comes with 4 mobile phone tips to support a variety of non-USB devices. It includes a USB charger and an AC adapter. To ensure you always have the power you need, there's also a hand-crank that generates 6 minutes of talk time for two minutes of crank time. But that's not all, it also includes a LED flashlight!

Onboard a boat you are perfectly situated to utilize an abundant and free source of power - the sun. There are several portable solar chargers now available that can be used for charging mobile devices. Bear in mind that these devices are relatively new and are evolving. With the increased emphasis on green technology, we expect to see more solar devices coming to market.

The Solio solar charger is compact and folds out to reveal three solar panels. You can charge Solio's battery using the sun or an AC wall socket. Fully charged it will recharge a mobile phone up to 2 times. One hour of sun exposure gives approximately 15 minutes of talk time or 4 days of standby time on your phone. The Solio Classic Solar Charger comes with 6 adapter tips including a mini-USB tip. Additional tips can be purchased separately. The unit sells for about $100. Solio The Solio uses the sun or an AC outlet charge the battery.

The biggest drawback we found with the Solio was the lack of a way to charge using USB. While you can charge your mobile device using the USB or mini-USB connectors, only AC power is offered as a backup to charging the Solio. We also found that effective solar charging required near perfect conditions. To meet Solio's advertised charging claims required direct sunlight to all three panels. Any deviation from this, such as charging through a window, cloud coverage or movement away from direct sun exposure, and the effectiveness is greatly compromised.

The UK company PowerTraveller has an interesting assortment of portable powering devices. The SolarMonkey will charge your phone directly from the sun. It even works under incandescent lights. A variety of connector tips are provided and other tips can be purchased separately. With the SolarNut attached, you can store unused solar power for an additional 15 minutes of talk time on your phone should the day cloud over. The SolarMonkey lists for about $51. The unit works well but lacks the battery storage capacity to be truly useful on your boat. PowerMonkey The PowerMonkey uses the sun, AC or DC to charge a battery pack. It can even power your phone directly.

The PowerMonkey eXplorer utilizes a high capacity battery with a SolarMonkey to store enough power to give you 96 hours of standby time on your mobile phone. You can use the solar component for charging the battery or to power the phone directly. An LCD screen displays the battery capacity and the level of charge, so you always know how much power you have available. To keep your mobile phone safe, the PowerMonkey eXplorer has three built in safety features - short-circuit protection, over-charging protection and over-discharging protection. In addition to charging the PowerMonkey via the sun, it offers backup charging options for an AC wall outlet and USB charging. With interchangeable heads for UK, Europe, US and Australia, you can charge it in over 150 countries around the world.

The PowerMonkey eXplorer comes with tips for a wide variety of devices including a mini USB and a USB connection. Additional tips are sold separately. Both components are water resistant and have rubberized casings offering added protection. And for the fashion conscious it comes in four color choices. The PowerMonkey eXplore is available in the US for about $100. We think this is a product you should seriously consider for your boat to power all your mobile devices.

The world has embraced a new "green" mentality of using our energy sources wisely. Many of us who own boats already understand this. A few days at anchor will teach you many things about how to use power thoughtfully. Like broader conservation strategies, when it comes to keeping your mobile phone powered on your boat, there is no single big idea. Rather, there are many small ones that when taken together can provide mobile flexibility and add up to significant savings.