A good power pack can turn a crisis into a manageable situation. Power packs can be used for general lighting, to power small appliances or operate a radio.
As a homeowner, I have experienced several power outages lasting days not hours. The final straw was when we went without power for a week, no heat, no hot water, no lighting and it was a bone-chilling 16 degrees outside.
We eventually installed a whole house 16 KW natural gas generator, installed a 350-watt solar tracking system (off-grid), purchased a small portable generator and bought a couple of portable power packs.
Now I am prepared.
Not everyone is going to go to that expense, but I would certainly recommend purchasing at least one good portable power pack.
It is very easy to keep it always on charge and ready for use. I also would recommend adding a solar panel to recharge the power pack in case power is not restored after a few days.
A solar power generator is any device that is capable of harvesting sunlight and converting it to a useful working voltage, this can be DC (direct current) for charging storage batteries or AC (alternating current) which requires an inverter to convert DC to AC for running household items. What makes it a solar generator is the ability to recharge using a solar panel.
A solar-powered generator, or power pack, is usually kept plugged into city power and removed when needed. The size of the internal battery in the power pack will determine how heavy, or how portable it is. It will also determine how long it can provide power.
A charge controller is basically a voltage and/or current regulator to keep batteries from overcharging.
It regulates the voltage and the current coming from the solar panels going to the battery. Most “12 V” panels put out about 16 to 20 volts, so if there is no regulation the batteries will be damaged from overcharging.
A power inverter takes DC and changes it to AC so that it can be used to power household items. The power inverter is one of the most critical components when sizing a system and yet it is the one component that can make a solar power generator ineffective. There are two types of inverters, modified sine wave and pure sine wave.
A pure sine wave inverter is recommended for sensitive electronics such as modern day TVs, variable speed power tools. The size of the power inverter will determine what you can operate
The battery is probably the weakest link in this chain of components. The most common storage battery used in power packs today is lead acid AGM (insulated glass mat) deep cycle. Small, compact power packs usually only have around 35 AH, if they use a lead-acid battery. To go with a bigger lead-acid battery will add a lot of weight.
The downside to any lead-acid battery is the weight it adds to the system making it very difficult to transport. The limiting factor of almost all power packs is the capacity of the battery, measured in AH (ampere-hours). A 100AH (ampere hour) battery weighs about 85 pounds.
A new type of battery is a LiFePO4 (Lithium Iron Phosphate), it is 1/3 the weight, has 3 times deeper discharge state and 3 times the duty cycle. However, it cost about 3 times as much.
A power pack with a 100 AH LiFePO4 battery will weigh around 35-45 pounds instead of 90 pounds.
Compact Power Packs
There are several small power packs you could purchase but most of them are only suitable for charging computers, cellphones and running some LED lights. listed below is the complete line of Goal Zero Yeti. There are many power packs to choose from but Goal Zero is a well-built system with a good reputation.
The Goal Zero is light-weight, about 15 pounds, and it is certainly appealing to dry campers to charge electronics. The downside is that it will not charge much for very long. You can only charge a 50-watt laptop twice, however, do you really need a laptop if you are dry camping. It would be great for keeping LED lights on all night.
- 168Wh lead-acid battery portable power station can power up to 5 devices at once (14Ah @12V)
- Continuous 80W, 160W surge modified-sine wave inverter, 2.1A USB ports, 120W 12V ports
- Charge phones, tablets, cameras, tablets, and other small devices
- Recharges from AC, 12V or solar panels (sold separately)
- Designed and engineered by power station experts with a US-based customer service center
The Yeti 400 is an example of how LiFePO4 batteries can reduce the overall weight. This unit only weighs a few pounds more than the Yeti 150, has around 2.5 times the capacity and it provides AC power; the Yeti 150 did not.
- 428Wh lithium portable power station can power up to 7 devices at once (39,600mAh at 10.8V/119,000 at 3.6V)
- Continuous 300W, 1200W surge pure-sine wave inverter, 2.4A USB ports, 120W 12V ports
- Charge phones, tablets, laptops, cameras, and most small devices. Provides power for small appliances, lights, CPAPs and more
- Recharges from AC or pair with a solar panel (sold separately)
- Designed and engineered by power station experts with a US-based customer service center
- 1425Wh lithium portable power station can power up to 10 devices at once (single cell equivalent capacity: 396Ah @3.6V)
- Patented AC inverter (output, pure sine wave) and 60W USB-C power delivery ports
- WiFi connectivity, simply connect a Yeti through your WiFi router and control it remotely using the Yeti App
- Charge phones, tablets, laptops, cameras, drones, and more. Powers your refrigerator, blender, TV, lights, power tools and medical devices
- Using App, check battery level, power in and out, even turn ports on and off, all from the palm of your hand.
Yeti 3000 Lithium Portable Power Station WiFi Mobile App Enabled, 3024Wh/280Ah Silent Gas Free Generator Alternative with 1500 Watt
- The Goal Zero Yeti 3000 Portable Power Station stores 3,075 watt-hours in a replaceable lithium battery pack with a variety of high-power outputs capable of running 10 devices at once.
- Features our exclusive patent-pending Pure-Sine Wave AC Inverter rated for 1500 watts continuous power and a 3000-watt surge. Run fridges, blenders, swamp coolers, tools, sump pumps, and more all at the push of a button.
- It operates with no noise, no fumes, no gasoline – making it perfectly safe to use both indoors and out. Recharge the internal battery by plugging it in at home, or pairing it with solar panels, sold separately.
- Check power usage and control the Yeti Power Station from any mobile device via the free Goal Zero Yeti App. It’s easy to check battery levels, turn ports on and off, and even update firmware from almost anywhere.
- No additional maintenance or operation costs resulting in a total cost of ownership that’s less than half of a gasoline generator
The Yeti 3000 is no toy. It is comparable in price to a small whole house generator. The bulk of the cost is the LiFePO4 battery, a typical 100AH Battle Born LiFePO4 is $949, and you would need another one just to produce the 200 AH.
Charging Power Packs With Solar
So, now that we know that there are some advantages to having power packs and that they can be recharged with a solar panel, how do we do that?
The Goal Zero power packs are a good starting point for a small portable unit. Most of these units come with a built-in AC inverter and a small internal battery. They can be transported fairly easily to any room in the house or carried in an RV (depends on your RV). I am listing these power packs because they have a good reputation and they are packaged very nicely, but they are a little pricey. Remember, these are under the category of “Bug Out Power Packs”, this means to light out in a hurry with what you need. If you were to want a power pack for the home nothing beats a large bank of batteries in a garage or basement.
Bigger Is Better
I would not recommend charging your power packs with Nomad solar panels, they are compact and well suited for the small power packs but grossly inefficient for the larger systems. It would take a long time to recharge using such a small panel.
When these power packs are discharged it takes quite a while to recharge them. If you use the charger that comes with the Yeti it is going to take some time. This process can be greatly accelerated in a couple of ways. You could do something innovative like this guy in the video below. By using (4) chargers he reduced the time considerably.
This is actually safe, provided you are recharging a system with a LiFePO4 battery. These batteries can be recharged much quicker than lead-acid.
DO NOT ATTEMPT WITH LEAD-ACID BATTERIES
The other option is to use recharge the system using solar panels and an MPPT charge controller. Goal Zero sells Boulder solar panels and they are larger than the Nomads. But just throwing a couple of large solar panels isn’t the solution.
In the video above he installed an MPPT charge controller module, its purpose is to maximize the output from the solar panel and allow more current to flow. The video clearly shows that the MPPT did not make a big difference. However, when he put all of the chargers in parallel he was producing 220 watts of power which equates to 18.3 amps.
A typical 100 Watt solar panel produces 5.1 amps in full sunlight. It will only produce that if it stays in direct sunlight all day. In other words, it needs to follow or track the Sun. If we add a second 100 Watt solar panel we will now produce 200 Watts (theoretically) in reality we will produce something less. If our panel was 100% efficient we would realize 16.66 amps @ 200 Watts. But a typical panel is only 15-18% efficient and so we will only realize about 10 amps. This is still better than what the Goal Zero charger produces but we can produce more.
Increase Power & Efficiency
If you are serious about using solar, you need to consider what you need it for, where you will put it and how will you recharge it if the utilities are down for an extended period of time. To increase the power we need to add additional solar panels. To increase efficiency we could use an MPPT charge controller and we make our panels track. The more power we produce, the more critical the storage battery is. If we produce more power we need to store that power, if we produce it quickly we need to charge it quickly and lead-acid are not well suited for that.
Better Solar Panels
Purchase (2) 110 Watt Sun Power flexible solar panels. The combined weight is less than 10 pounds. They are 24% efficient, one of the highest rated panels on the market, and they will produce a total of 12.8 amps. I realize that this is not earth-shaking but there are other steps we can take.
Better MPPT Charge Controller
A 20 Amp MPPT will not only maximize the charging voltage it will allow you to put more current to the battery so you could handle the second solar panel.
Make Your Panels Track
This is not nearly as complicated or as expensive as you might think. Solar trackers are incredibly affordable and so are motors and actuators. The only challenge is creating a suitable mount while still keeping it portable. The other solution is to make it semi-portable.
Build Your Own
It is now possible to build your own portable solar tracker. Working from a downloadable set of plans that include dimensions, photos, step-by-step-step instructions, and a parts list.
Please follow this link to read more about the Portable Solar Tracker.