Cambios

 *'''Voltage''': Unit: Volt (V). If comparing different batteries and devices you should know the nominal Voltage. Non-rechargeable Alkaline and Lithium batteries provide approximately 1.5 V. Rechargeable NiMH batteries have a slightly lower voltage of about 1.2 V. Rechargeable Lithium-Ion batteries supply 3.7 V. All USB devises work with 5 V. This applies to USB power consumers and USB power banks with Lithium-Ion batteries. These power banks have electronics that steps up the voltage to 5 V. For more information see Table 113: See the battery and power bank specifications section.*'''Electrical Current''': Unit: Ampere (A) or Milliampere (mA). 1000 mA equals 1 A.*'''Electrical Power Consumption''': The commonly used unit for small electrical devices is Watt (W) or Milliwatt (mW). 1000 mW equals 1 W. For DC consumers the power consumption can be calculated by multiplying the supply voltage with the required electrical current. In example a GPS device that is powered with two AA NiMH batteries (2 x 1.25 V) and draws a current of 50 mA has a power consumption of 125 mW (or 0.125 W). Manufacturers sometimes provide the power consumption in Ampere (A) or Milliampere (mA) what is scientifically incorrect but not an issue if the voltage is known. The conversion between current (A) and power (W) is made by multiplying the current with the voltage.*'''Electrical Energy Consumption''': The technical correct unit is Watthour (Wh). Note the difference between power and energy: power (W) is the rate of consumption while energy (Wh) is the accumulated consumption. So the energy consumption is the summed-up power consumption over a given time span. If you want to compare power and energy with hiking than power is like the speed and energy is like the distance covered.

*'''Specific Stored Energy: ''' The technical correct unit is Watthour per Kilogramm (Wh/kg). This number tells how much electrical energy is stored in relation to the weight of the battery or power pack. You can calculate the specific stored energy of a battery by dividing the stored electrical energy (Wh) by the weight of the battery (kg). As a hiker you obviously want this number to be high, to have as much as possible energy packed into as little as possible weight. But the battery chemistry puts physical limits to this. Understanding this helps to identify obviously false advertisements. I.e. if someone offers an AA NiMH battery with a capacity of 3500 mAh he scams. See the table about battery and power bank specifications for more detailed information.*'''Energy Transfer Efficiency''': When charging an electrical device i.e. with a power bank some losses occur. A part of the energy will no end up in the charged device i.e. the smartphone battery but get lost in form of heat while charging. The common unit for efficiency is Percent. An energy transfer efficiency of 75% means that only ¾ of the stored electrical energy ends up in the charged battery. When charging a device from the grit in a town you do not need to worry about this, but when charging a device on the trail with a power pack this becomes relevant.

*'''Generated Electrical Power''': Unit: Watt (W). Today a wide range of outdoor gear promises a free recharge of your electrical consumers on the trail. Most common are solar panels but also water and wind turbines pushed on the market. The most weird gear I have seen is a stoves that promise to produce electrical energy using the thermoelectric effect. The power might be free but always comes with a weight penalty. Therefore the following is of importance:*''Specific Power Generation: Unit'': Watt per Kilogram (W/kg). This is the actual archived power output divided by the weight of the device. This number shows the difference between a gadget that just appears cool and an actual useful piece of gear.

 *2 x NiMH Rechargeable Batteries (2 x 2.2 - 3.0 Wh): 2 to 3 days *2 x Alkaline Non-Rechargeable Batteries (2 x 3.0 - 4.2 Wh): 3 to 4 days *2 x Lithium Non-Rechargeable Batteries (2 x 4.5 - 5.25 Wh): 4 to 5 days

 *InReach Mini with an internal 1250 mAh battery (4.6 Wh): Approximately 5 days *Newer InReach SE+ and Explorer+ models with an internal 2900 mAh battery (10.7 Wh): Approximately 10 days *Older InReach SE and Explorer models with an internal 2450 mAh battery (9.1 Wh): Approximately 10 daysThe energy consumption of a smartphone is generally higher and varies substantially depending on the model and how it gets used. I assume that everyone knows that intense use can consume one full battery charge per day but keeping it in airplane mode with the GPS deactivated will make the internal battery last quite long. The internal Lithium-Ion batteries have depending on the model a capacity between 1’800 and a little over 3’000 mAh what corresponds with 7 to 12 Wh of stored energy. So, the smartphone energy consumption ranges from virtually 0 to about 12 Wh per day. This high variability makes it difficult to issue specific recommendations what recharge method is optimal.

An inexpensive recommendable USB power monitor is the [http://portablepowersupplies.co.uk/home/premium-usb-dc-power-monitor PortaPow Dual USB Power Monitor ]. 

 {| class="wikitable"|+Battery and power bank specifications! Battery Type ! Stored Energy ! Weight ! Specific Stored Energy ! Nominal Voltage ! Actual Range ! Comment|-| colspan="7"|Rechargeable AA Batteries|-| AA NiMH Battery | 2.2 – 3.0 Wh 1’800 – 2’500 mAh | 25 g | 85 – 120 Wh/kg | 1.2 V | 1.4 – 1.1 V | New quality NiMH batteries have a capacity of 2’000 – 2’500 mAh but over time and with frequent use this drops.|-| colspan="7"|Non-Rechargeable AA Batteries|-| AA Alkaline Battery | 3.0 – 4.2 Wh 2’000 – 2’800 mAh | 23 g | 130 – 180 Wh/kg | 1.5 V | 1.6 – 1.1 V | Alkaline batteries are good for devices with a low power consumption (GPS).|-| AA Lithium Battery | 4.5 – 5.25 Wh 3’000 – 3’500 mAh | 15 g | 300 – 350 Wh/kg | 1.5 V | 1.8 – 1.5 V | Lithium batteries have the highest specific energy but are more costly.|-|colspan="7"| Other Rechargeable Batteries and Power Banks|-| Lithium-Ion Battery | Depending on size | Depending on size Approximately | Approximately 200 Wh/kg | 3.7 V | 4.1 – 3.7 V | Most devices with build in batteries have Lithium-Ion batteries installed.|-| 5000 mA Power Bank | Nominal 18.5 Wh Effective 13 - 15 Wh | 120 – 150 g Nominal| Nominal 125 – 200 Wh/kg Effective 100 – 160 Wh/kg | 5.0 V | 5.0 V | USB power banks are specified based on the capacity of the internal Lithium-Ion batteries (3.7 V) and not the output voltage (5.0 V) of the USB port.|-| 10’000 mA Power Bank | Nominal 37 Wh Effective 26 - 30 Wh | 180 – 240 g | Nominal 125 – 200 Wh/kg Effective 100 – 160 Wh/kg| 5.0 V | 5.0 V Table 113: Battery and | USB power bank specificationsbanks are specified based on the capacity of the internal Lithium-Ion batteries (3.7 V) and not the output voltage (5.0 V) of the USB port.|} 

[[File:discharge batteries.png|frame|NiMH battery discharge curve. For GPS devices the discharge current is typical 0.1 A or less therefore the highest curve of the diagram is applicable. Image: lygte-info.dk]]Be aware that the battery voltage depends on the charging state, the temperature and the load during use (consumer). When fully charged the voltage is slightly higher than the nominal voltage. During use the voltage drops. By measuring the voltage the battery state can be estimated.This is particular helpful when using rechargeable NiMH batteries. A fully charged NiMH battery provides 1.4 V at an ambient temperature of approx. 20 ºC (open-circuit voltage). At the beginning of the discharge cycle (first 10% of capacity) the voltage drops quickly to 1.3 V where the “plateau” starts. Once the plateau is reached the voltage slowly decreases during use to about 1.2 V (80% of capacity). When the battery is nearly empty the voltage drops again sharply (last 10% of capacity).  

 *For the GPS use pairs of batteries that you always charge and use together (best mark the batteries i.e. A1, A2, B1, B2, C1, C2, D1, D2 to easily identify pair A, B, C and D). Don’t mix a fully charged battery with a half-empty battery in the GPS. This makes your GPS faint quickly and may damage the batteries permanently (reverse-charging). *Don’t overcharge batteries. This is best done by charging two pairs of equally empty batteries together in the Goal Zero Guide 10 charger (With the Goal Zero device you must charge 4 batteries together otherwise this charger does not work. By combining 4 batteries with a similar discharge state the charger works more effective and the batteries suffer less.) *Don’t overheat batteries. Keep the batteries in a shady and ventilated location when charging. The gear pockets on the back of a solar panel is not suitable to hold the charger while charging. *Be aware, that poor copies of brand batteries are sold in dodgy places (eBay, street vendors, ...) that have often a much lower capacity than advertised. Therefore, get your NiMH batteries before your trip in a trustworthy location. I made good experiences with the eneloop NiMH batteries (2’000 mAh) and the four NiMH batteries that come with Goal Zero Guide 10 plus charger (2’300 mAh). *Be careful with high-capacity NiMH batteries that are rated with more than 2’000 mAh. These batteries are more sensible to over-charging or reverse-charging what can accidentally happen if two batteries with different discharge states are mixed in one device. I will test on my next investigation trip the eneloop Pro batteries with a rated capacity of 2’500 mAh. They are more fragile so let’s see how they behave in the field!

 *Fully charging an InReach Mini with an internal 1’250 mAh (1.25 Ah) Lithium-Ion battery: **Stored Electrical Energy of internal battery: 1.25 Ah x 3.7 V = 4.6 Wh**Required power bank energy for recharging with a 75% Energy Transfer Efficiency: 4.6 Wh / 0.75 ≈ 6 Wh**This corresponds to 1’650 mAh of the nominal power bank capacity *Fully charging an iPhone 7 with an internal 1’960 mAh (1.96 Ah) Lithium-Ion battery:**Stored Electrical Energy of internal battery: 1.96 Ah x 3.7 V = 7.3 Wh**Required power bank energy for recharging with a 75% Energy Transfer Efficiency: 7.3 Wh / 0.75 ≈ 10 Wh**This corresponds to 2’650 mAh of the nominal power bank capacity 

 *Select your power bank wisely. Compare weight and capacity before purchase. Stylish slim power banks may look nice but have typically a worse specific energy rating (more weight for the same capacity). *Avoid discharging Lithium-Ion completely. Better top up your smart phone and InReach when the remaining power drops below 25%. Lithium-Ion batteries do not suffer from a “memory-effect” like the obsolete Nickel-Cadmium batteries but dislike deep discharges. It is better to recharge a Lithium-Ion battery several times instead of fully discharging a battery and then recharging the battery completely. *I suspect that bringing the internal battery of a smartphone or an InReach all the way up to 100% results in more losses. There¬fore, if recharging such a device with a power bank on the trail, stop charging once reaching about 90% battery charge. Of cause, this does not apply when charging a device from the grit during a resupply stop in a town. Then get everything fully charged. *If using a power bank to recharge the InReach and a smartphone keep some reserve in the power bank to later choose depending on circumstances for what you need the energy more. Navigation or communication in case of an emergency.

[[File:navegacion con GPS 8.JPG|thumb|Left: Standard in Chile (Type L, CEI 23-16 VII. Same as Italia and Uruguay) Center: Current Standard in Argentina (Type I, AS 3112. Same as Australia) Right: Older Standard in Argentina (Type C, Europlug)Image: Martín Lizondo]]A USB charger is required to recharge the smartphone and the USB power bank during resupply town visits. In Chile and Argentina, the same voltage and grit frequency is used (220 V / 50 Hz) but both nations have different sockets. In Chile a USB charger with an Europlug  works perfectly fine. For Argentina an additional Type I  adapter may be useful. 

 *carrying and using a tablet on the trail, *relying on recharging in less favourable condition (areas with normally cloudy weather), *travelling in a bigger group with more power-hungry smartphones and cameras or  *if you don’t need to care much about weight (packrafting with very little hiking).

 *5 W solar panel: Approximately 250 g *AA battery charger: 65 g *Mini-USB cable: 10 g *6 x AA NiMH batteries: 6 x 25 g = 150 g

 *Option 1: 20 Alkaline batteries (460 g). This hypothetical set provides roughly 30 days of power for the GPS device but no recharge for the smart phone or InReach. *Option 2: A 10’000 mAh USB Power Bank and 10 Alkaline batteries (Approximately 440 g). This hypothetical set provides roughly 15 days of power for the GPS device, two smartphone and two InReach Mini recharges. *Option 3: A 5’000 mAh USB Power Bank, 10 NiMH batteries and an AA NiMH battery charger with a cable (Approximately 460 g). This is a hypothetical set of someone that opts for rechargeable AA NiMH batteries instead of Alkaline batteries for environmental and/or cost reasons while recharging the AA NiMH batteries in towns only. This hypothetical set provides roughly 10 days of power for the GPS device, one smartphone and one InReach Mini recharge. 

 *Don’t buy a solar panel with a build-in battery (integrated power bank). This only seams handy but is not. While charging the battery inevitably overheats what quickly deteriorates the battery. Also, if just one of the two components deteriorates you have to scrap both. *I prefer foldable solar panels as they are more robust during transport. A single thin panel needs more care as it is easily crushed in the backpack. But a single panel without folds is easier to set up and to align to the sun. Choose whatever you find appropriate for you. *I know I repeat myself, but this is really important: Test your panel before relying on it! Rated values are normally exagger¬ated. You probably need to purchase a panel that is rated as 7 W or 10 W to get the recommended 5 W power output. Best use one of these tiny USB power monitors that indicate voltage and current to verify the actual performance after purchase. *Align your solar panel vertical to the sun when charging. To find the optimal angle tilt and rotate the panel to created the larges possible shade on the ground. The largest shadow means the most sun on the panel. When charging while hiking choose a suitable average position for the solar panel on the backpack. *While charging, connect the charged device(s) with a long enough cable to the solar panel to keeps your charged gadget(s) in a shady and ventilated location. Avoid placing the charged devices in the pockets on the back of the solar panel. These pockets might be useful to carry your charging gear while not using the panel but not when charging. *Carrying a USB power monitor on the trail is also handy to optimize the orientation of the panel to the sun and to check what is happening in suboptimal conditions i.e. cloudy weather. If you see that the charging current is unreasonable low don’t hazzle yourself with fruitless charging attempts. Many USB power monitors have two USB outlets. This makes the power monitor a handy “splitter” to charge two devices simultaneously from one USB outlet (i.e. in towns).  *Some smartphones react oddly to variable charging currents. If the USB power output is temporary reduced these devices readjust to the reduced power output and continue charging with the reduced current even if the USB power output recovers to a higher level. If i.e. a cloud passes the solar power output drops and when the sunshine is back the smart phone uses only a fraction of the available power. This effect is particular annoying when charging while walking. The changing orien¬tation and the shade of trees along the trail inevitably results in a fluctuating power output.

 *Another barely known effect is the solar panel response to a partial shading. If i.e. 10% of the solar panel surface is covered the power output drops typically much more than just 10%. I tested solar panels that loose around 90% of the power output when 10% of the solar panel surface is in the shade. It needs a special solar panel configuration and a good electronics to minimize this effect. If you have a USB power monitor you can verify yourself how your panel reacts to partial shading. *Be aware that solar panels work best at lower temperatures. This makes a bright fresh morning the best time for charging. Just take make sure to tilt the solar panel enough to harvest the maximum amount of energy while the sun is low.

 *Maximum USB charging current: 0.8 A (rated and measured)

 *Goal Zero Charging Efficiency: 65% to 70%

 *Goal Zero Power Bank Mode Efficiency: 60% to 75%

 *Alkaline batteries should not be used to generate USB power with a Goal Zero Guide 10 due to an even lower efficiency caused by the poor Alkaline battery behaviour at a high discharge current. Efficiency is likely to be less than 40% so more than half of the energy is converted into useless heat. *Lithium batteries may be used as an emergency backup to generate USB power with a Goal Zero Guide 10. If using 4 Lithium batteries with a capacity of 3’000 mAh (4 x 4.5 Wh) approximately 11 to 13 Wh of USB power can be generated. Since Lithium batteries behave well at high discharge currents this conversion is reasonable efficient.

 *Maximum USB charging current: 2.1 A (rated) / 1.7 A (measured)

 *EBL USB Quick Charger Charging Efficiency: Approximately 45%