When the Sun lets you down.
Loyal OGH reader Randy from Wisconsin recently commented that for several weeks in June and into July he barely got anything at all out of his well planned, high-budget home solar power system due to nearly constant clouds and rain. His dilemma highlights a problem common to many off grid amateurs. Since most of us run solar as our primary source of off grid electricity, what is the “plan B” when the sun is weak?
You have options.
From a preparedness standpoint, it’s not a good idea to have only one source of off grid electricity. If you are off grid for hobby or recreational purposes then you can probably forego a “plan B” altogether. For those who classify themselves as survivalists, preppers, or EMCOMM folk, there are options and they are not necessarily difficult or expensive.
Expand your solar capacity.
Suggesting solar as an “plan B” to solar sounds like nonsense circular logic, but hang with me here. When the skies are overcast, there still is diffused light coming through. If you have extra solar, you will be able to make the most of that weak sunlight. A bigger net catches more fish, right?
This principle works great in my portable setup. I use a 27 watt folding solar panel, which is much more than I should need for the 5 amp-hour battery it supports. So if I hit a day when the sun isn’t cooperating, my oversized panel goes a long way in keeping me on the air. The exact effectiveness of my panel is difficult to quantify, but in overcast conditions I can operate my FT-817 for hours or even days and barely discharge the battery.
Expand your battery capacity.
If a bigger net catches more fish, then a bigger tank holds more fish. It’s not complicated. increasing battery capacity gives you longer runs between charges. Some operators may be limited due to physical weight and space, or funding, but anything they can do to bump up the battery will help pull through weak sunshine.
Keep it in balance.
Expanding solar or battery capacity too much runs the risk of kicking your system out of balance. For example, suppose an operator hooked up a 150 watt panel to their 5 watt QRP radio and ten amp-hour battery. Sure, they have a “big net” for cloudy days, but the rest of the time the panel is seriously underutilized.
Likewise, if the operator instead gets a much larger battery than they have solar capacity, yes they’ll have the benefit of extra run time when the sun is weak. However, when the sun comes back it will be a long while before the battery is fully charged again.
Ideally the battery and the solar should be increased together. If you are increasing only one or the other, then don’t let the ratio drift too far apart. The “trick” works but only to a point. After that there are diminishing returns.
Wind power.
Wind power is not too popular among off grid hams, and it’s not hard to understand why. Good wind turbines are quite expensive for the power they produce. Being mechanical devices, they are prone to breakdown. Then there are the installation requirements. Solar panels can just be set out in the sun and moved around if needed. Wind turbines must have sturdy permanent mountings to withstand wind load. Yet in spite of these shortcomings, wind power is a viable “plan B”. The few operators who do use turbines are usually very satisfied with them.
Those who want to have wind power as part of their plan B but can’t bear the financial commitment should consider a home brew system. The internet is chock full of step by step instructions on DIY wind turbines, and most of them are very inexpensive.
Pedal or human power.
It was many decades ago at my first or second Field Day. Someone in my operating group brought out a home brew bicycle generator. It was crudely made from an old bike, some scrap metal struts, a large fan belt, a car alternator, and of course a battery. Since me and my friend Andy were the strapping teenage studs amongst the old out of shape dudes, we were drafted to provide the pedal power. It was a real physics lesson. Pedaling was easy, until the load switched on! Then we had to sweat!
I’m really ambivalent about the utility of pedal or human powered generators because they don’t seem to produce much power for the effort involved. An Olympic-level bicyclist can produce a sustained output of around 350 watts, or roughly half a horsepower. You can certainly bet an ordinary person will come in well under that.
I would say that since pedal powered generators can be thrown together for almost no money, it might be worth having one as part of your plan B just for the heck of it, or maybe for fun/demonstration. For survival/disaster/EMCOMM purposes, carefully consider the time & calories spent versus the energy harvested. When SHTF, your strong & healthy team members may be more useful doing something other than pedaling a bike. Also, surplus World War 2-era hand crank generators are still available; prepare to lay out big money for them.
Gas generators.
Tried and true gas generators are probably the most popular plan B. In fact for many hams, they are plan A! There’e good reason for this. They are relatively inexpensive, can produce a lot of power, and are so ubiquitous that spare parts and support are easy to find.
There are two types of generators: conventional, and inverter. Inverter generators are more efficient, quieter, and produce cleaner power, but they are also much more expensive than conventional versions. For sure, get an inverter generator if your budget allows.
No matter whether you go with a conventional or inverter, it’s in your best interest to have a tri-fuel capable model. Tri fuel generators can run on gasoline, propane, or natural gas. This gives you more options when fuel is scarce. If you already have a generator and it’s not tri-fuel capable, DIY conversion kits are available on line for not too much money.
Perhaps the biggest disadvantage to generators is sourcing the fuel. In a SHTF situation, fuel will be very hard to get or not available at all. In addition, you’re somewhat limited as to how much fuel you can safely store on your own property. Generators are typically not practical for long term use. They are only as good as the fuel supply.
All considered, a generator is a must-have for any off grid ham, no matter what other plans they have made.
Implementing your plan B.
The good news is that implementing a secondary alternative power source is fairly easy and not necessarily expensive. All of the options presented here are within reach of the average ham. You may already have the needed materials. With a little thought and organizing, it should not be too hard to create a backup to your backup.
Resources.
This previous Off Grid Ham article explores wind power in more detail.
Click here for more information about generators.
Here is an Off Grid Ham article that discusses batteries and battery capacity.
Another great article.
I have picked up Redodo LiFPo4 batteries when they are on sale (that’s all the time) and they are a lot lighter than lead acid ones.
I do have a little Honda generator that runs clean and quite and just sips fuel. I also have a generator that runs solely on propane. I choose this one because the propane can be 25 years old and still gets the job done without going bad in the fuel tank or carb.
I would like to try the can shaped wind generator (Sorry I don’t know the name of them right now). They are small fairly quite and don’t seem to need heavy mounting.
Excellent! I went with 4ea 3.8-48vdc Simplify batteries after my 2nd bank of L16 blocks reached end of life. Life couldn’t be easier, when we have sun. We have to run a generator daily from November to February because of clouds, snow or the low sun angle.
The LFP04 batteries are three years old and are performing like the day I flipped the switch on them. The function of the batteries is 95% efficient and maybe a little better. To that point, the run time of the generator is reduced so that is a direct reduction of fuel cost and reduced maintenance/oil changes. When one runs a generator every day the difference is pretty obvious.
In our off grid situation I had a distinct problem with deep cycle lead batteries (FLA). They like to work hard as in they like a substantial discharge but ALSO a substantial recharge. Ya have to make em bubble and stir up the juices EVERY day or most days for health AND longevity. I can do neither. But LFP04 could care less. They are just fine with a partial charge – in fact that is preferable. And the whole State of Charge thing…. You stop at 50% for lead batteries or you do lifetime damage. LFP04 batteries are kind of yawning at 50%.
But ya have to pick the technology for how you use it. A high end LFP04 battery is pretty expensive. But a high end FLA battery not used correctly can be at least as expensive over its lifespan. Did I mention efficiency and generator fuel yet? And to the technology we are not going to be carrying 15kW of battery to a bug out location. We live in that bug out location. Hmmm, there’s a consideration.
Hi JR, great to hear from you. My home system is on wet cell batteries that are past their service life and at this point are just kind of creeping along. I think it’s time to spend some real money and go lithium. Unfortunately that also means upgrading the charge controller.
Yup. I had to replace my inverter when changing over to LFP04 as its low voltage cut out was intended for lead and would damage lithium blocks. Fortunately the charge controller’s adjustments were flexible enough for lithium.
BTW, when I first changed over to LFP04 I had 3 of the batteries when commissioned. But if I had one fail prematurely I wouldn’t want to get by with 2 during generator season. Or any season for that matter. So I added a 4th. So I am ‘over batteried’ which one can do with LFP04. It was a good thing to do. I only charge them to full once per month so the internal BMS can balance the cells.
Large lithium batteries for my home setup are still on my wish list. The cost is a heavy factor for me even though I am well aware that conventional wet batteries cost at least as much if not more over time.
Hi Jed, I have a small Honda 1400 watt conventional generator that is used primarily for jumping cars in the winter. I also have a larger 7000 watt generator that is mainly used to push a welder, but can be plugged into my house if needed. I’d like to get an inverter generator but my wallet just can’t handle it right now.
I truely know what you mean about the wallet. I just ordered three more Redodo batteries that I don’t need at the moment but may when the US and China issues get worse. I will have to suck in the belt a bit for a while to pay for them but they will be worth it. I am an old guy and though I hope to live forever I hope the batties will out last me. Looking at what I have, what I need and the future is my guide.
I would say to go ahead and hook them up. Just modify your charging routine to fill them to 90% max and don’t take them below 40%. You will probably get a very long service life out of them. Hopefully the Mfr has a Voltage : SOC chart/graph so you know the voltage targets.
As a retired commercial/industrial electrician,.. and being involved in conventional electronics since before I did it for the US Navy, Im acquainted with skin effect, for instance, even with lower power frequencies; Im also very well aware of the benefits of 3 phase. What I dont see is how you say its advantageous to run your 3 phase power down THREE wires to a rectifier (3 phase bridge) is better then having the rectifier at the generator source and running DC down from that rectifier to the battery system. First, remember useful power is calculated using RMS, not PEAK power. If you consider skin effect your AC wiring will be more resistive over DC. Ampacity maybe found under table 310-16 (or others depending on other factors) or there of depending on what NEC edition you refer to. What is better? 3- stranded 12 ga wires(minimum) or 2- 10 ga. solid/stranded conductors? I did some calculations recently.. and if memory serves the 3 phase output of a certain wind turbine was about 24-25 amps per leg.. but the DC was about 40 amps output from the bridge rectifier.
If we were talking I-squared R losses, the advantage is to do with running higher voltage over the distance and transforming it down or using heavier wire. Utility companies will often generate 13.8K volts out of their generators and transform it up in the range of 250K for long runs as opposed to increasing the size of the conductors by 10,000% to reduce those (I-squared R) losses.
While I could get into reactive issues and losses, I don’t think there is enough here to really matter. But you dont have it with runs of DC, especially if you put a capacitor across it at the rectifier.
I could do the math… but I shouldnt need to! (besides, hard to do it on a standard keyboard!)
Hi Gary, thanks for your comments. While you are technically correct, in this context it’s a distinction without a difference. Keep in mind we are not talking about large industrial applications or power lines sending of hundreds of thousands of volts across three states. The average home wind turbine will produce at most a few hundred watts and send it down a relatively short wire. So while the laws of physics still apply, it seems to me that obsessing over skin effect in a 50 foot run of wire is geeking out to a level of minutiae where the results don’t justify the effort.
Nice article, Chris. As you pointed out, I found out about the limitations of solar power first hand after I put the system in back in March/April of 2023. (Gads is it really over a year already?) I knew there was no way solar was going to be as reliable for me up here in Wisconsin as it is for my friends in the SW of the US, but I didn’t think it was going to be quite this bad. I got little to no power at all from, oh, about late October through February because of cloud cover during the winter. I anticipated that, though. I didn’t anticipate our spring and summer were going to be this wet and cloudy, though. Even when we have had sun, it’s been partly cloudy resulting in drastically reduced production. Of course my solar panel situation was woefully inadequate all along, though. We needed to get the roof replaced on the house and garage so I’ve been limited in how many panels I could get up. Now that the roof is replaced I can get panels up on the garage roof which will improve things considerably.
I did think of all of that though and I had a Plan B already in place. I have a 7.5KW Generac gas powered generator, and a gadget called an EG4 Chargeverter which is wired directly into the busbars of the battery bank. I feed 240V from the generator directly into the Chargeverter which let’s me dump about 5 KW into the batteries. I can charge the batteries from almost empty up to 100% in about 5 hours with that, and then can run the house off the batteries for about 24 – 36 hours. Back in, oh, April, I think it was, we had a huge winter storm through here that knocked out power to a large part of the northern half of the state so I had a chance to test it in real world conditions and it all worked pretty much flawlessly, including the chargeverter and generator.
also be prepared for some steep price hikes in the very near future. Thanks to the new tarrifs on imported equipment from China prices are starting to creep up. Despite all of the hype you may read about switching production to US factories, the fact remains that that almost all of this equipment is made in China, and it’s going to be years before US production facilities can be brought on-line in enough quantity to make a dent in the prices. I just ordered a pallet of 450W solar panels and the price per panel has already gone up almost $50 each from what the price was back in May.
Hi Randy, I live in a similar climate as yours and see the same issues with solar. My panels are on the roof. I originally installed them on a hinge so I could tip them up to a better angle in the winter, but quickly discovered that it didn’t really make a difference so I stopped bothering to crawl up there every Fall and adjust them.
Along the lines of what I mentioned to another reader in this comment section, I’ve discovered that with these small home systems a lot of the practices, theories, and procedures don’t make a meaningful difference in system performance. In other words, if I had a huge solar farm with thousands of panels, yeah, angling them up in the winter would matter. But for small time guys like us it’s just being picky with no real results to show for it.
I haven’t checked prices on off grid stuff lately; maybe I should do that to stay in the loop.
As always it’s great to hear from you. Thanks for providing the inspiration for this article.
EXACTLY!!
What Im looking at is a 500 watt turbine unit that runs the 3 phases down to wherever the electrical network is.. and they goes into something of an MPPT with an input bridge rectifier built in.
On a note: I was into ham/radio electronics long before I became a licensed sparky.. and understood skin effect for radio frequencies.. It was a real surprise to take it up in the apprenticeship. I just don’t see the relevance when it comes to power frequencies.
I use an Ecoflow battery with my car camping setup. When I was looking at options for a second battery I found they have a nicely priced generator that interfaces with their batteries over a 48VDC cable. It can be programmed to autostart when the battery level reaches a set amount, and will shut down when full. I used it in the club Field Day digital tent this year, where it worked great. Solar all day, it kicked on and ran for around half an hour over night and one more start just after dawn. I barely touched the gallon of fuel, and best thing was I didn’t have to think about it. Just worked.
I asked.. “What kind of even are we preparing for?” Someone hits a power pole and knocks out power for a few hours? Hurrican X that shuts down a portion of the grid for a few days or weeks?? Wouldn’t it be easier to just buy enough fuel for a generator to run our rigs for a few weeks? Why all the solar panels, expensive batteries?
I think most of us prepare for a MUCH greater event.. perhaps an HEMP that covers most of the US? If this is so, how limited is our prep! Its great to have our radios up and running but how long will you have water if you have city water? Or a well? What are you going to do when what limited water you stored is gone? Or if the satellite systems are down.. that tractor-trailer not only is on there own without communications but with no fuel it wont matter. If we have an HEMP (and your radio survives!).. we can certainly help in communications.. until we succumb perhaps, by lack of preparations neglected.
Will your radio equipment survive that HEMP/EMP??
Not to be so negative.. but what reality are you planning for?
I will share my own ideas if others ask for comment. It is not at all my idea to be discouraging! In short, I live in Alaska.. Retired Electrician… and building my cabin homestead/farmstead in a totally off grid location so Im starting pretty well from the ground up. While still building, acquiring things has been for a LONG time. STARTING with solar panels and the decision as to what voltage I wanted to run. I chose 12vdc.. because it was extremely common.. batteries and a great deal of equipment, besides ham radio equipment. Secondary voltage for the cabin is 120vac from a pure sinewave inverter of size.. and a separate inverter for just my 120vac well. Note that most inverter claim a SURGE capacity of about 100%. It was in pushing I got them to tell me.. this “surge” is only good for a small fraction of a second. Not enough for something like a pump unless its standard capacity will hold it. Be warned. For those who many not be aware, when it comes to powering your home, HEAT and COOLING are primary what makes your electric meter spin… and a good rule of thumb is if it needs 240… ITS FOR A REASON!! Also, 120/240 inverters in 12 volts are very limited and expensive.. so I planned to avoid all 240 equipment- from stove to water heater and clothes dryer. Only my welding equipment runs on generator… which, BTW, is diesel. Storing diesel is FAR safer. Wood and solar are my primary heat sources.
For many this is just to hard to consider.. but consider what you CAN do to extend beyond a few weeks or months, should something REALLY serious come upon us. Communications is VITAL should this happen.. but you have to survive first.
Below is some thoughts on, well, if we have an EMP/HEMP.. well, such doesn’t come form a tornado! I know the following will make me sound like paranoia.. But looking around today.. not so sure paranoia is the word…
My plans include a food storage location as well.. It seconds as a fall out shelter. (Please understand, when you live in Alaska.. you are at the end of the line. Food and supplies that, IF they make it across the country to Port of Seattle.. are not likely to make it all the way to Alaska!). I figure if Im going to build it.. might as well make it suitable for such. What most people don’t know is that when it comes to radioactive fall out the decay starts as soon as the blast is over.. and 99% of that decay happens within 48 hours. After 14 days its pretty safe. Another note: 90% of the post nuclear deaths come from radiation poisoning. The very thing most people choose to remain ignorant of because they feel they can do nothing!
This goes well beyond ham and communications.. but staying on the air takes more than just electricity!
Hi Gary I really appreciate your detailed comments. You hit a point I often consider myself: How much preparation is enough? It’s not realistic or even possible to be ready for every possible scenario. The guy who is prepared to go three days may be worried he might need seven days. The guy prepared to go seven days may be worried he might need ten days. And so on and so on.
For my own purposes, I prepare as much as my money, resources, and physical space will allow and don’t worry that it might not be “enough”. It’s the best I can do; it’ll have to be enough.
You mention you live off grid in Alaska. I remember years back there was a reality show called Railroad Alaska. If you’re not familiar with it, a side story within the series are the off grid residents living full time in the Alaska wilderness who depend on the railroad for transportation, supplies, etc. It occurred to me that these people, as independent as they think they are, could not live as they do without that railroad and the cities it serves. In one episode, the son of an elderly off-grid resident races to make the train so he can deliver life-critical blood pressure medication to his mother. In another episode, a young family goes through a whole lot of hassle and effort to haul a propane powered refrigerator to their homestead. The irony hit me. These folks claim to be independent and self sustaining, and for the most part they are, but as soon as something breaks, or there is an emergent medical need, they head straight for civilization. After all, propane powered refrigerators don’t naturally grow in the Alaskan bush.
How long would they last out there if the railroad stopped running? Many of them could last a fairly long time, but their standard of living would go way down and their lifespan would probably be shortened. Even the toughest of the tough will sooner or later need a dentist, or a fan belt, or a battery. With no source for these things, they’d be done just like the city folk.
I’m not bringing this up to denigrate or throw shade on people who live this way. In fact, I respect their grit and nerve and determination. But I do want to make the observation that even people living in the Alaskan wilderness are still dependent on a structured supply chain, modern transportation infrastructure, and technology. I believe that no one is truly “self sustaining”.
Off Grid Ham is not a “survivalist blog”, but I am well aware that survivalists/preppers make up a big part of my reading audience. With that in mind, I address their off grid communication needs as best I can. They’re on their own for the rest.
Gary, I once again really appreciate your input. I’m sorry I went on so long, but a thoughtful comment like yours deserves a robust reply. I hope you’ll stop by Off Grid Ham again soon.
The notion of “balance” really relies on the idea of fixed or inflexible consumption. The more you think about adjusting consumption, the more flexible that “balance” becomes. Imagine over-sizing the solar relative to the storage, and making hay while the sun shines. There are a lot of high load things, like pumping water, anything involving lots of heat generation like baking, that can be done when the sun is shining, storing that energy as the products, instead of expensive chemical battery cells. Our ancestors scheduled their lives around annual and daily solar cycles because it works.
Hi Jay, thanks for your comment. You are correct. A secondary benefit to oversizing solar is the ability to operate devices solely on solar without having to draw on battery power. The more you can get done without tapping the battery, the more battery you’ll have when you really need it.
Thanks again for your comment; I hope you’ll stop by Off Grid Ham again soon.