E-Mail 'Backup Power, A Review by KS' To A Friend

16 Comments

1. I recommend moving to Nevada. Better sunlight year round. Better gun laws. No Governor Moonbeam nor Senator Fine-stench!

   Nice article. I was going to purchase one of these but this solidifies my decision that it’s time.

   Thanks again!

2. When selecting higher output 250-300 watt panels be aware of their design voltage. Most single panels in this range are 30-48VDC output. Your controller must be rated accordingly. If your system is 12-15VDC design, you will likely need to parallel multiple 20-60 watt panels to get the higher wattage output.

3. Good write up, excellent well thought out testing and recommendations.
   I particularly like the idea of assembling my own system. I learn by doing.
   Running one appliance at a time is not a problem for us. We already use this approach with our gasoline generators.
   KS mentions how quiet things get when “the city background noise is gone”.
   This is also true in rural areas.
   Thank you.

   1. S.E. AZ? I think I know you

      1. Sorry woodchuck. I know a few squirrels but no woodchucks.
         I am close to but not in the redoubt….yet. (PNW) Working my way there a little at a time.
         Thanks for asking.

4. How about I voicing prices on the items reviewed? That would make the review much more complete and useful. Otherwise, good info. Thanks,

5. The kWh consumption you listed for the fan has to be wrong. I assume you meant 1200 Wh (or 1.2 kWh), which would be right for a fan pulling 100 watts; which is what my fan pulls on the high setting.

   1. Yeah, I noticed the same mathematical error

6. Running a freezer for one day then taking two days to recharge is pointless, after two days you won’t have anything left frozen. It seems like and excellent way to maintain power for lights radios and to run some tools off of but it, IMHO, would not be feasible to try to use for food storage. I wouldn’t count on something that could let me down over a couple of cloudy days.

7. I am a retired electrical engineer and have lived totally off grid for 12 plus years. Off grid living is not as simple as folks would have you believe. For solar the biggest factors are your latitude, exposure time for solar panels to sunlight, and weather (sunlight just doesn’t penetrate 2 foot snow covered solar panels). Obviously the equator is ideal and Alaska is ridiculous based strictly on latitude. Northern Redoubt borders on ridiculous in winter so plan on a generator or other backup. My recommendation is zero continuous electrical appliances such as an electric refrigerator or freezer. An occasional appliance such as a washer, well (depending on storage tank size), or a vacuum cleaner can be scheduled for use when you are running the generator to charge your batteries. I use LP (liquid propane). I get by with an “on demand” hot water heater, kitchen range, refrigerator/freezer, and chest freezer, all on LP. I use roughly 200 gallons of LP per year. I don’t even run the pilots on the kitchen range. A “grill type” butane lighter works great at roughly $4.00/year and there isn’t that smoke from a match.

8. It looks like it would take three of these units to maintain power on a refrigerator/freezer. It would certainly take at least a 300w panel to charge faster. It maybe better to get 3 to 6 100w/12v panels paralleled to make it charge much faster.

   As for sun hours per day, the further south the better. There are charts showing what the average sun hours per day are based on different locations. There are places here in Michigan that average 2.9 sun hours per day over the course of a year. In the southern tier counties the average is about 5 sun hours per day.

   On the whole I think it would be better to build up a solar generator system from scratch. I think the price would be cheaper and provide much more power over a longer period of time.

9. For those if us into re-purposing…
   I have seen those solar powered interstate ” Constructon Ahead” warning signs in government surplus sites.
   Could they be a resource?

10. If youre at all handy with basic tools, “The Prepper Project” has downloadable easy to follow instructions to build your own solar generator. It is definately less expensive and has more muscle than most any “preassembled”. Highly recommend. Look ’em up.

11. We’ve had grid-intertied solar for 16 years. Rates and time adjustments for Time-of-Use went up two years ago, resulting in higher costs at the annual ‘trueup’. We have a Humless, bought in 2013, which can be recharged a variety of ways, solar included. But because we are grid-intertied, when there’s a power outage, our power is cut, too (so that we don’t electrocute a power restoration worker down the line from us). We do have a receptacle on our solar array; would that have power with which to recharge your reviewed product, or our Humless? On a great solar day, we produce about 5 Kwh with our 30 panels and 2 inverters.

12. I work in the portable power generation field. I have some additional perspectives and ideas on how to evaluate this system, the highlights I will share. I like the idea of incorporating a solar component into one’s electrical power sources. I have around 1200W of panels along with other associated components to convert the energy captured by the panels into voltages I can use. The big advantages with Solar are OPSEC, since it collects energy without making noise, and longevity. My panels will still be collecting energy 20 years after an EMP attack, long after I run out of gasoline for my generators.

    I don’t consider this a generator. Its really a solar power system with storage and power conversion capabilities. It can capture a maximum of 180W for 6 hours a day for a capacity of 1080 Whr per day. In real life it won’t produce that much since industry standard for rating the 180 W of panels is based on a panel receiving full sun at the equator at noon. To put that capacity in perspective, 1000 Whrs is equivalent to operating a 1KW generator for an hour a day, or about 9-10 Oz of gasoline in an inverter generator. They did include an efficient MPPT charge controller in the system.

    In terms of storage, the battery is rated for 1500 Whr (12.8V, 115 AH). The LI batteries have advantages over Lead acid, though at a higher cost. As noted by KS, the battery capacity is significantly higher than the panel output over a day. The LI battery will be good for and is probably needed to feed the power inverter the energy it needs for its rated 1500W output.

    Outputs include 2 USB ports, 3 12 VDC ports, and 1500 W from a pure sine wave converter. The inverter has a 3000 W surge capacity. At 1500W output the inverter would drain the battery in an hour. The pure sine wave output is important for many loads. The 3000W surge capacity is fairly common for a 1500 W inverter. Accurately assessing the power quality would require an expensive analyzer (fluke makes a few). Technology has progressed enough that I don’t worry about the power quality on inverter generators or pure sine wave inverters from reputable companies. The worst case loads will be AC electric motors. Refrigerators and freezers don’t seem to draw much. Air conditioners are a tough load and beyond the capacity of this system. Use these to stress your system.

    This system would be good for charging phones, powering small electronics, maybe a tablet, LED lamps around the house but for anything else I would recommend a larger system with more solar panel capacity.

13. You need to be very careful when adding more solar panels to these small units as you may exceed the maximum charge rate of the storage battery. Normally the charge controller should limit the current (amps) going into the battery bank, but if it doesn’t you will cook your batteries causing premature failure. Just adding panels may not fix your problem. Check with the Manufacture to see what the maximum rate of charge should be. These are small units and designed for limited use, Just because it is rated for 1500 watts output doesn’t mean it will do that very long before you use up your very limited battery storage.
    If you are planning on running more than a few LED light bulbs for very long you will need to invest more money on a larger system and I would get in touch with someone who has a lot more knowledge in designing a system for your needs. The first thing you need to do is decide exactly what your requirements are and then design a system that will meet them. No one size fits all.

Comments are closed.