Outdoor Adventure USA

We'll cover the essential basics of electrical power, the necessary components of building an off-road electrical power system, and newer products that make this very easy. We'll also try to help you determine what you really need.

We've done this in various prior nets. You might review these as some of the subject matter was covered in more detail. One such net is:

OAUSA Net - September 10, 2020 - Alternate Power in the Wilderness I & II

The same knowledge and approach are applicable to your home electrical power and may help in planning for grid down and unreliable grid situations, which seem to be happening more often, as populations and the need for power (e.g., EVs) increases while our power grid capabilities actually shrink (e.g., anti-nuclear, anti-hydroelectric, anti-fossil fuel "green" politics).


California-style on-road solar power: must buy EV, but you can't charge it!

The off-road (aka "overlanding") scenario involves "off the grid" (i.e., away from public power utilities) for days to weeks, likely with friends, often camping in a tent, and likely breaking and setting up camp once every few days to explore new areas.

People obviously have been camping without electrical power for millennia, so we acknowledge that having electrical power is a convenience, though a potentially great convenience.

So, we need to arrive at a system that meets your electrical power requirements without breaking the bank. Let's get started with some basics ...

But first, what important day is it today?

Quick Product Spotlight: Starlink for RVs

A friend set up his Starlink system at a shooting range last weekend. The range has no cell service or WiFi.

Internet speeds varied, presumably with atmospheric conditions and satellite access, but Starlink provided decent Internet access and phone service to about ten people. Someone streamed Ben Shapiro on YouTube.

Phones were ringing instead of leaving shooters to relax with their shooting and socializing.

Good thing?

Starlink for RVs provides the ability to pause and un-pause service at any time and is billed in one-month increments, allowing users to customize their service to their individual travel needs.

Starlink for RVs is not designed for use while in motion.

Starlink setup at range, requires open view of sky toward the north, powered by Jackery Explorer 500. Starlink power requirements vary but can get up to 75 watts, averaging maybe 50 watts. WiFi was available up to 75 yards away.

By itself, the Jackery could probably power Starlink for around 8 hours. The 120-watt solar panel was part of the test. Partly cloudy day, so the panels provided between 15 and 100 watts, though enough on average to exceed Starlink's average draw on the battery.
If you felt the desire for Internet and phone connectivity / communication while well off-road in areas without cell service, this might provide a solution. It is of course too large to be carried on one's person like a Garmin, SPOT, or ZOLEO handheld device.

Who cares about those red rocks? Let's stream some Netflix!!

Electrical Power Basics

Electricity is the flow of electrons through conductive materials. Here's something that explains all you need to know.

• Voltage (volts or V) is the "pressure" of electrical flow
• Current (amperes or amps or A) is the rate of electrical flow
  
• Power (watts or W) = Voltage (volts or V) x Current (amps or A)
• Energy (watt-hours or Wh) = Power (watts or W) x Duration (hours or h)
• Sometimes, if the voltage is well known (such as a 12V system), energy is specified in amp-hours or Ah. The watt-hours can be calculated by multiplying the amp-hours by the volts.
  

Voltage is important because many electrical sources, interfaces, and connectors are restricted to specific voltages.

Current is important because it along with voltage determine the amount of power.

We don't need to know about resistance (ohms) except that too much resistance will waste electrical power. Thicker wires have less resistance.

We care about power because it specifies the overall power limits and rates of power consumption.

We care about energy because it specifies the total energy required, available, or consumed.

Electrical Power Uses and Requirements (Off-Road)

Every electrical device or appliance consumes electrical power to run. This may be very apparent such as an electrical appliance that has a cord which must be plugged into an external power outlet, but many devices are now cordless, relying on batteries which are recharged from an external power source.

One of the first steps in calculating your off-road power needs is doing an inventory of all of the devices and appliances you plan on using, determining their individual power consumptions, and allocating them to available power sources. Some (e.g. phone) might be charged while travelling.

120VAC Off-Road?



Rechargeable battery Ni-MH AA

• 1.2V x 2.4 Ah = 2.9 Wh
• x how many?

Phone + Camera iPhone 14 Pro Max

• 16 Wh battery (as best I can tell from articles)

Rechargeable battery, HT Kenwood TH-K20 (5 Watts)

• 7.4V x 1.8 Ah = 13.3 Wh

Rechargeable battery, flashlight 18650

• 3.7V x 3.1 Ah = 11.5 Wh

Electric Vest

• 7.4V x 2.6 Ah = 19 Wh

Tablet iPad 11 Pro

• 29 Wh

Refrigerator ARB 50 qt "maintain sub-freezing temperatures in 90°F heat"

• 12V * 1.35A = 16.2W
• x 24 hours = 389 Wh

Base station Kenwood TS-480SAT (100 Watts)

• 13.8V x 20.5A = 283 W
• x transmit how long?

Inverter - convert 12VDC to 120VAC

• Watts x how long (e.g., 1000 Watts x 0.5 hr = 500 Wh

Heating 12V Electric Blanket (auto shutoff)

• 72 watts while running

Heating / Air Conditioning ClimateRight CR5000ACH

• Air Conditioner 5,000 BTUs/hr for 700 Watts (BTU = British Thermal Unit)
• Heater 4,300 BTUs/hr for 1300 Watts (3 BTUs/hr = 1 Watt)

Heating Mr. Heater Portable Buddy (Propane)

• 3,000 or 9,000 BTUs/hr propane -> 1,000 or 3,000 Watts eletrical

Cooking: Range

• 7,000 BTUs/hr per burner -> 2,500 Watts

Meters that provide Watt-hours

Connects inline using Powerpoles. Other versions available. Can be used for voltages up to 60V.
Connects inline with typical USB Type A and newer USB Type C connectors.
Connects inline with AC power.
Calculate Your Energy Needs

• Heating, cooling, cooking still not practical
• Monitor your electrical use (how far do you let your devices' batteries run down?)
• Total your energy consumption in watt-hours per day (natural solar cycle)
• Allow for growth

Electrical Power Storage

Off-road power sources are limited. When traveling, your vehicle’s alternator provides electrical power to keep your vehicle’s battery charged and run lights and instruments essential to your vehicle’s operation. Normally there is excess power generated which is available through power outlets, generally 12V, but the power available can be very limited, perhaps to as little as 120W in many vehicles.

Storage means battery. Your battery's capacity must be sized to account for all of your expected electrical power use, generally for a day. In addition, you must allow for some numbers of days of being unable to generate power (maybe due to weather) ... whatever risk you're comfortable with. Lastly, once you have electrical power available, your desires and ideas for using it might well grow.

In previous nets, I called lithium-based batteries "the future", but I believe that future is now.

Lithium Batteries

In my opinion, there's no longer any doubt that lithium batteries are the way to go despite their expense.
Disadvantages

• Cost 2.5x AGM
• Requires special controller (but most current controllers handle lithium)
• Shouldn't be charged under 0°C (lead acid to -22°C)

Advantages

• Half the weight of similar sealed lead acid
• 4x the number of recharge cycles to greater depth of discharge (DOD)
• Can be nearly fully discharged without harm (but recommended to 80%), not just 50%
• Very high charging rate if power available
• Very high discharging rate (100A) if power needed
• Minimal self discharge
• No minimum charge current
• Maintains capacity in low temperatures
• Runs well at high temperature

Lithium vs. SLA Performance in Cold Battery Comparison


Renogy LiFePO4 100 Ah

• Price dropped from $900 to $700 over last 2 years
• Now includes Bluetooth interface to monitor battery
• Now includes BMS (battery management system)
  "provides short circuit, over charging and over-temperature protection while maintaining a balanced voltage across all cells"

Vmaxtanks AGM 100 Ah Renogy 100 Ah LiFePO4 vs. Vmaxtanks 100Ah SLA AGM

• $700 (price down by $200 over 2 years) vs. $275 (price hasn't changed)
• 29 lbs vs. 68 lbs
• 80% DOD (1024 Wh) vs. 50% DOD (640 Wh)
• 2000 cycles vs. 500 cycles (?)
• Lifetime 1.0 MWh vs. 0.3 MWh (cycles x DOD Wh = megawatthours)
• ... 6.4x life vs. 2.5x cost

Lithium is most cost effective battery, if you can justify the initial cost


As the following graph of voltage versus depth of discharge (DoD) shows, it's difficult to know by voltage what the DoD is for lithium batteries. Note that voltage remains roughly the same until 80% DoD.

Use a battery monitor (direct wire or Bluetooth) to determine watt-hours going in and out of your battery for accurate DoD status.

Electrical Power Generation

Being offroad assumes you won't be able to simply "plug-in" to recharge your power storage, unless you're lucky and come across some place like the Bar 10 Ranch.

Maybe in the future, we'll come across these charging stations which might permit topping off various power storage systems (aside from off-road EVs).
Jeep plans remote solar-powered charging stations for electric off-roaders Until then, the possible sources of power generation are limited to:

• Vehicle alternator, while travelling
  • Probably a key energy source, which can be tapped via power (cigarette lighter) outlet, direct connection to alternator, or DC-DC charging systems. When traveling, your vehicle’s alternator provides electrical power to keep your vehicle’s battery charged and run lights and instruments essential to your vehicle’s operation. Normally there is excess power generated which is available through power outlets, generally 12V, but the power available can be very limited, perhaps to as little as 120W in many vehicles.
• Wind
  • I've seen these work well during a good wind in an open area, but sufficient wind is often antithetical to a good camping location. It is great to be able to generate power during the night.
• Solar
  • The key source of energy other than vehicle. Solar panels are easy to set up, easy to take down. Works most of the time in typical camping conditions.

Vehicle Alternator (DC-DC Battery Chargers)

A DC-DC battery charger is usually installed in your vehicle. It connects to your alternator (i.e., vehicle starter battery) and charges your auxiliary (aka "house") battery.

Many DC-DC chargers can accept solar input and simultaneously make use of that and/or alternator power.

http://www.westmountainradio.com/produc ... ic-pwrgate
https://redarcelectronics.com/collectio ... y-chargers
https://redarcelectronics.com/products/the-manager30
https://www.renogy.com/battery-chargers/
https://www.victronenergy.com/dc-dc-con ... n-tr-smart
https://www.olyssolar.com/product_Info-25-51.html


Solar Panels

We won't talk about panels in detail. There is more information here.

• Solar panels have stayed around the same efficiency for many years, roughly converting 20 - 23% of the solar radiation energy that falls upon them.
• Solar panels generally provide around 100 watts per 20" x 43" (about 2' x 4') panel.
• Solar panels generally provide between 18 and 25 volts. If there is a voltage limitation on your controller's solar input, divide by 25 to determine the number of *series* panels supported.
• Newer panels are better at providing power when partially covered by shadows. Previous panels had all cells connected in series, which reduces the current to that of the lowest producing cell when one is even partly in shadow (see below diagram).
• Rigid (aluminum frame) solar panels are cheapest (around $130 for 100-watts), but difficult to store. Some people (myself included) keep one permanently mounted on their vehicle's roof. Around 15 pounds.
• Folding panels are convenient and easy to set up, especialy with respect to where the sun is. A friend recently got a Rockpals 100-watt folding panel (list $190) for $150. Around 10 pounds.

Important information to keep in mind when connecting panels.

Panels of different voltage ratings connected in parallel are limited to the lowest voltage Panels of different ampere ratings connected in series are limited to the lowest current

Off-Road Electrical Power System Components

Here's a diagram of a typical solar power system.

The individual components of a solar system, battery, panels, controller, and possibly an inverter have almost become commodity items. Unlike previous nets, I won't get into details about building a system (components, wiring, fuses, connectors, etc.) since I believe the time has come for "power stations".

Portable "Power Stations" and "Solar Generators"

It seems there has been an explosion of vendors offering “power station” solutions instead of individual components such as batteries, panels, and controllers. I suspect the reason for this is because lithium-based batteries are so much lighter than lead-based batteries that a power station that offers reasonable capacity can actually be picked up by an average person.

Previously I thought it was a waste of money to go with a power station rather than building your own.

Firstly, I didn’t really need the portability as my AR 50QT “fridge freezer”, the primary appliance I want to power, stays in my vehicle.

Secondly, all of the power stations emphasize AC power which I’ve avoided as DC-to-AC inverters are not that efficient at the small loads (e.g., USB adapter) that I needed, and I’ve designed around not using AC power. Good information on inverters:

https://www.inverter.com/what-is-inverter-efficiency

Lastly, the battery capacity (watt-hours) provided by earlier models was low—especially relative to cost—such that it made much more sense to buy a bigger battery and DIY a solar power system. For a good safety margin, I’d like to be able to run my refrigerator for four days without additional power input which is around 1000 Wh.


However, when I’ve shown friends who are looking for off-grid / off-road power my system (below)—which has been 100% reliable—their eyes glaze over.

The desire to avoid DIY complexity and adopt simplicity of a single-box power station greatly exceeds any desire to save a few bucks. And in fact, due to increasing competition, features have increased while prices have started to come down.

If you want to take a stab at building your own system, I thought this was a great YouTube video from a guy who has given much thought to it:

DIY Auxiliary Power System for Camping, Overlanding, Travel


I won’t be doing a survey of all current power stations, just providing a list of vendors after having reviewed many of them and will point out the important features to look for.


On to the power stations. Here's a list of links to power station vendors.

https://www.jackery.com/
https://www.bluettipower.com/
https://www.goalzero.com/
https://us.ecoflow.com/
https://www.rockpals.com/collections/po ... er-station
https://www.renogy.com/phoenix-300-power-station/
https://www.anker.com/portable-power-stations
https://wagan.com/collections/power-cube
https://www.bougerv.com/collections/power-station
https://lionenergy.com/pages/solar-generators
https://seedevil.com/collections/battery-power-stations
https://inergytek.com/
https://dakotalithium.com/our-batteries ... ower-kits/


Features of Power Stations / Solar Generators

Note: a power station becomes a solar generator when you plug in a panel.

• Battery capacity (watt-hours)
  • most significant determinant of price
  • sometimes hard to ascertain as some venders rate their stations by the wattage of their AC output
• Recharge inputs
  • AC (How many input watts or speed of recharge from Shore Power / AC?)
  • Solar panel (What are the voltage limits? How many panels in series (about 25V per panel)? How many total watts? What type of connector?)
  • DC (vehicle port outlet / “cigarette lighter”) (How many watts? Can it be limited to not stress vehicle fuse or alternator?)
• Outputs (type and number)
  • USB, number, type and wattage (Type A and/or C and power (watts) – typically USB has been 5V at around 2A max – USB C can provide up to 100 watts to devices that are designed to accept it)
  • 12V power outlet / “cigarette lighter” (watts, might be specified in amps)
  • 12V Powerpole
  • AC (110/120 volts (Maximum watts? Pure sine wave? [Can run sensitive electronics?])
  • 19V Laptop
• Used to start a vehicle? (not aware of any Power stations)
• “Pass thru” charging (Can you charge the station while powering devices? Some warn against charging while using)
• Support for additional batteries for capacity expansion
• Support for additional units for capacity expansion
• Weight (Can your back handle it?)
• Display (Quality of information to ascertain station and panel status, legibility, nerdly data joy)
• Warranty
• Carrying Handle (Can it fold out of the way?)
• Dimensions / size (Does it fit where you have room for it?)
• Battery technology (Lithium ion, LiFePo4, … Note: lithium batteries can catch on fire)
  • LITHIUM IRON PHOSPHATE VS. LITHIUM-ION: DIFFERENCES AND ADVANTAGES
• Is it flat on top (to hold devices while recharging?)
• Noise (Does it use fans?)
• Lifecycle (How many recharges to what depth of discharge?)

Comparison of Jackery Explorer 1000 to new Explorer 1000 Pro

These pictures of the Jackery Explorer 1000 and new "Pro" version make the Pro appear smaller, but the dimensions are similar and it weighs more.

Jacker Explorer 1000 Jackery Explorer 1000 Pro
Here's a feature by feature comparison. I like the availability of USB Type C output, the ability to charge from AC in two hours, the longer warranty, and larger number of cycles, but is that worth another $250?
Following is the result of a poll taken in an overlanding group on Facebook. Do these guys really know anything? Who knows, but FYI.

Seasonal Solar Power Considerations

Earth is tilted at an angle of 23.45 degrees. which causes seasonal variations as the earth revolves around the sun. The sun takes different apparent paths across the earth's surface due to earth's the rotation while revolving.


The rows in the table corresponds to the Spring/March Equinox, Summer/June Solstice, Fall (Autumn)/September Equinox, and Winter/December Solstice.
The intensity of solar radiation, what is converted to electricity by solar panels, changes due to not just weather and atmospheric conditions, but the amount of atmosphere that it must travel through to reach a panel. The lower the sun's elevation, the less solar radiation gets through. This is true whenever the sun is lower in the sky, such as morning and evening, but also during winter compared to summer.

The follow "stereograph" plots show the sun's elevation (angle above the horizon) versus azimuth (position from east to west for different times during different seasons for Page, Arizona. The darker red line corresponds to the June Solstice (longest day of the year). The point of these is to show the daylight duration and sun's elevation during different days of the year.
Same thing for March and September Equinoxes, when day length is approximately 12 hours.
Same thing for December Solstice (shortest day of the year).
At Page, Arizona (for example):
Mar 20th, 12.2 hours day length, maximum sun elevation 53 degrees.
Jun 21st, 14.7 hours day length, maximum sun elevation 30 degrees.
Sep 22th, 12.2 hours day length, maximum sun elevation 53 degrees.
Dec 21st 9.6 hours day length, maximum sun elevation 77 degrees.


The point of all this is to emphasize that the amount of solar energy available to you during winter may be half or less than that available during summer. If you are getting much of your power from your vehicle's alternator, this may not be much of a concern, but must be considered if you plan on staying at a base camp for a number of days.

The following graph results from an analysis I did a few years ago for roughly 37 degrees north.

If you only have a panel pointing straight up (first column), the energy you'll harvest will be less than a third during winter. Keeping a panel pointed at where the sun will be at noon (fourth column) does much better but still much need supplementing.

It remains my opinion that the easiest way to harvest more solar energy is to simply get more [identical] panels in parallel. The voltage won't increase and your controller will take as much current as it can.
Recommendation

• Take an inventory of geological formations and trees to determine where shadows are likely to fall. You may have significantly less time to harvest solar energy during the day.
• During summer, your roof tap panel pointing straight up is sufficient (depending on power requirements).
• During winter, wire in another panel in parallel.
• If possible, always at least point panels to where the sun will be at solar noon (azimuth 180 degrees in the northern hemisphere). See Solar Path Calculator below.

Solar Path Calculator

Solar Path Calculator

Check in please - Thanks - Bernie

I couldn't check in last week as the Internet was down for 12 hours, the first time that the Internet was ever down for any length of time, except for maybe a few minutes to an hour 2 or 3 times over the years. I missed the monthly South Cars TIN and this net although the South Cars TIN is available via a podcast. Now if I can get this to post as it wouldn't post the first time...just got a White screen the first time...