(Continued from Part 1.)
DETERMINING HOW LONG A PPS CAN SUPPLY POWER
To determine how long a fully-charged PPS will last, three things must be considered:
1.) The wattage of the device being powered
2.) How long you need it to run for, and
3.) The wattage capacity of the PPS battery.
As previously mentioned, to simplify the math some of the battery rules are ignored such as maximum drawdown percentage of a battery and the energy loss when inverting from 12 Volts DC to 120 Volts AC.
Appliance Wattage – Nearly every 120 VAC electric device has the wattage stamped on the bottom or labeled elsewhere. An average LED light bulb in your home uses 6 watts. A typical box fan is 100 watts, a coffee-bean grinder 130 watts, a soldering pen 350 watts, a food processor 400 watts, a blender 600 watts, and a rice cooker uses 700 watts. The higher the wattage, the more electricity the device uses and the faster that it will draw down the battery.
Run Time – A device may have a high wattage but won’t drain the battery much if it’s only for a short period of time. Things like coffee grinders, food processors, and blenders won’t draw the battery down significantly since they’re only on for a few minutes each time that they’re used. Ditto for things such as a drill press or a jigsaw doing a small job. A 700-watt rice cooker on the other hand, is on for 30 minutes at a time and will be a significant drain on the battery. And the heavy resistive loadof a 1,500-watt space heater will drain it in no time.
Wattage Capacity of the PPS – As mentioned already, the wattage capacity of the PPS refers to the total watts the PPS can store as well as the peak watts that it can supply at one time. This number allows you to calculate which items will run, and for how long.
The lights powered by our PPS should be LED since they use less than 10% of the electricity that incandescent (filament) lighting uses. Because LED lighting wattage is so low, even though lights are generally left on for hours at a time the battery drawdown will be much less than with almost any other device.
When assessing how long a PPS battery can provide electricity for, the expected weather for the near future must be taken into consideration. Cloud cover means little or no opportunity to recharge a PPS with PV panels. I use both a barometer and the rainfall records I’ve kept for 10+ years to compare with current forecasts made by the weatherman. After the SHTF, I’ll be using my barometer and those records as best I can to make my own forecasts when weather predictions are no longer available from the National Weather Service. In my locale, there are certain months when I get a lot of rain and others when it’s mostly sunny and cloud-free. By keeping in mind the expected amount of sunshine in the immediate future, we can better regulate our PPS usage and to what degree we should implement conservation measures when we expect cloud cover to limit recharging opportunities.
If my PPS were the only source of electricity after the SHTF, then I’d have to be an energy miser at certain times of the year when there’s a lot of consistent cloud cover. However,if it was used only for lighting, I could easily go for a week or more without recharging. If I conserved and only ran one light at a time, which would be very doable, I could use it for a couple of weeks, if necessary. A good strategy, however, is to always top off the PPS whenever the opportunity presents itself. Even a few hours of sunshine, including partly cloudy, can restore some of the charge in the PPS.
With all that out of the way, let’s dive into what kinds of lights we can expect to use with a PPS.
PORTABLE POWER STATION LIGHTING OPTIONS
The four options for PPS lighting are:
1. Rechargeable lights
2. 5-volt lights which plug directly into the PPS USB ports
3. 12-volt lights which can be plugged into the various types of 12v outlets on the PPS.
4. The same 120-volt lights we use now, plugged directly into the PPS 120-volt inverter outlet. It must be kept in mind that 120-volt lighting draws the battery down more quickly than a 12-volt light with similar wattage. This is due to the inefficiency and power loss when the battery energy is inverted from 12VDC to 120VAC via the PPS’s built-in inverter.
TYPES OF LIGHTS FOR PPS USE
There are three basic types of illumination devices that can be used with a PPS:
1. “Lamps”
2. “Lights”
3. Flashlights and headlamps
1. Lamps – These look like the everyday floor and desk lamps we use now but at a low DC voltage. They tend to be more attractive than other types of DC lights. They come as rechargeables or can run directly from the 5-volt USB or 12-volt ports. Some are dimmable and with some of the better ones the light can be changed from warm to white. Depending on the PPS battery size and lamp wattage, some can last 8-40 hours on a single PPS charge. Search “rechargeable lamps” and “12-volt lights for RVs and boats” then click on “images” to get a visual idea of some of the variety of lamps available. RV and boat lights will typically run directly off the PPS or other 12-volt source and generally aren’t rechargeable.
2. Lights – More often than not they’re portable and more versatile than lamps. These often look like lantern-style camping and emergency lights but also come in other shapes and configurations. Different types vary in total hours on a single charge and pricing. Search “rechargeable lights” and click on “images.” The lantern-style models have a wire handle on the top for carrying and hanging. Other types of lights are designed to be permanently mounted and run directly off the PPS.
3. Headlamps and flashlights – these are indispensable around any homestead but for regular indoor lighting they’re not especially feasible for long-term usage. They come in all sizes, battery capacities, and brightnesses, but for indoor use they tend to provide more light than necessary even on the low setting, wasting electricity. For lighting a room, most won’t stay charged for very long when constantly lit compared to the intermittent usage they’re designed for. Flashlights aren’t typically designed to hang or stand up in such way that the light is evenly dispersed over an indoor area. In order to conserve energy in a grid-down world, flashlights with low, medium, and high settings should be used on the lowest setting that gets the job done.
Surprisingly, the best use for my headlamp during my lighting preps test was for cooking. It cast no shadows, provided light wherever I was looking, and even on the low setting, the light was bright enough to replace my normal overhead lighting.
It’s becoming more common for larger rechargeable flashlights to come with a USB port so they can act as a mini “emergency power bank.” This allows things like cell phones to be plugged into the flashlight USB for charging, or for other devices to run directly off the flashlight. The flashlight essentially acts as a micro-PPS and while the capacity is very limited in a post-SHTF homestead, it can have its place, even for running lower-wattage LED lights. While it may seem silly to do that today, in TEOTWAWKI-ville we’ll have to make some radical changes in how we think about and use our precious resources. While today it wouldn’t make sense to use a flashlight as a mini PPS to power a lower-wattage LED light, after the SHTF it will be a different story depending on our recharging capabilities and to what degree energy conservation will be necessary.
LIGHT TEMPERATURE
When shopping for lamps, lights, or flashlights, in addition to looking at the watts and lumens a third number is often listed: Kelvins. This number is generally between 1,000 and 9,000 and represents the brightness scale from “warm” to “daylight,” aka white light. The lower this number is the warmer the light will be, the higher it is the more harsh white it will appear. The classic “warm” light is yellowish candlelight. Harsh white lights are great in the workshop or dentist office, but they are very unfriendly in the home. Though I haven’t tried very many different Kelvin ratings, the ones I have in the 4-4,500 range seem just about perfect.
An upcoming article in this series will share with the reader my week-long preps-testing experience using my LED lights in a simulated grid-down experience. One thing that I hadn’t counted on, or really even thought about before that test, was light temperature. Of all the few-day and week-long preps tests I’ve done, as trivial sounding as something like light temperature seems, it turned out to be one of the more valuable things I’ve learned in my testing. The differences in light temperature are so stark that by the end of the second day I was online ordering a lot of new lights to provide me with warm lighting. As another testimony about the importance of preps testing, even seemingly tiny things like light temperature can surprise us.
After doing this preps test, I feel certain that bright white light in the home as opposed to warm lighting would have negative psychological effects and make a stressful post-SHTF world even more stressful than it needs to be.
(To be concluded tomorrow, in Part 3.)