Chaz Peling: Backup Power Solutions

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The tall towers are Batteries, 7.8kWh, Aquion Energy. That DC disconnect box is usually covered, but I was showing on another forum how we added new battery tech to an old system. the 2 boxes over it are charge controllers, one very old, connected to an old string of 2kW of panels, and the more recent Outback MPPT which is only connect to about 600W of more recent panels. The older charge controller I have is likely, by the looks of it, the same one that David H. has in his system above. Trace was bought out by Xantrex, so same device, same color, different name. The large rectangle to to the left is the inverter. This inverter will also automatically start a generator when the batteries are low, but I have never utilized that. This is a 48V system, and these are 48V batteries.

House faces due magnetic south, older panels are 24 12Vpanels sold as 110W each, these were made by Astropower, so this is for an “actual” 2kW at the house, those go to the older charge controller still and are the max that that “half” of the inverter will take, it will take 2 strings of panels, each limited to 2kW. These panels are wired together in sets of 4 as I have a 48V system. There are 3 more recent panels, made by Evergreen, these are sold as 210W each, and a set of 3 is what would match the voltage best for my system, the inverter would handle more power on this string, but we dont realy need it.

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I have a separate studio on my property also, but on my same solar electric system, with its own kitchen and bath. I have a small electric tank water heater for it, just a 20 gallon one from home depot, and it realy does not use much power. The refrigerator there is small due to space limitations, adaquate but smaller than a usual household one. And, we have had 2 people take back to back showers there without issues. It seems likely to me that our American houses have a "bigger is better " mentality, and this is seen with both refrigerator size and hot water tank size.
I sub metered the studio, and last year kept track of its power usage with 2 people in it. The coldest winter months used a bit more power as the tank water heater was outside. I tracked 7 months and it used between 84 and 130 kWh a month, this was January thru July. This electricity usage provided hot water, refrigeration, a small 1.7cu ft washing machine, cable modem and wi-fi box, a couple laptops, LED lights, and fan when hot. The cooking stove was propane, and heating was wood. So, around 100kWh of power a month.
refrigerator in our studio is only 4.3cuft, due to width limitations, and is this one: http://www.homedepot.com/p/Magic-Chef-4-3-cu-ft-Mini-Refrigerator-in-Sta…
It uses 329kWh a year, which I think is high due to how small it is ! But, small ones do not realy use less power. You can get about 2 or 3 times as much cu ft for the same power usage, if you have the room for it.

Hot water heater we have is this one, http://www.homedepot.com/p/Rheem-Performance-20-Gal-6-Year-2000-Watt-Sin…

washing machine is this one https://www.walmart.com/ip/Danby-1-7-Cu-Ft-Capacity-Portable-Top-Load-Wa…

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Ok, I’ve got a bit of time now to sit down and share some about my large off-grid solar system that powers my main house. I’m not sure how much help this will be to anyone though, esp. since there are some oddities in it all due to working with a bad solar install company. I don’t want to dredge up all the strife I had getting this done to a workable level. In the end I just fixed things myself. That said, unless you are really familiar with electrical work and how to do solar I would still think a system of this size is best done with people who do know what they are doing. I don’t regret hiring someone to design and install it. I just wish I had hired someone else. Despite me thinking I had a decent understanding of solar systems going into the project I still learned a good deal.
Ok, the system is 4400 watts of panels, half are 12 volt Evergreen 210 watt panels, like mntnhousepermi has. The other half are 24 volt Solar Cynergy 230 watt panels if I recall correctly. I might have the brand wrong. Here are some photos of the array and mounting.


We located it where it is because this spot had the best overall exposure to sun throughout the day and was close to the outbuilding you see in the background of the first photo. That building is where the batteries, charge controllers, and inverter are. The idea was to keep the DC powered wire run from the panels to the equipment short for less power loss over the line. This is an issue when it is DC power as opposed to AC.
The shot from the back is so you can see the mounting structure. It is galvanized metal pipes mounted into the ground with cement. Onto this is an aluminum panel mounting system, extruded aluminum tubes with channels designed to hold the mounting brackets shown in the third photo. As you can see these brackets are fairly simple with a little lip that goes over the panel and screws down tightly. This is much easier and nicer than what I had done on my mid-sized system that I rigged up where I was trying to mount them using predrilled holes on the backside of the panel frames. The installer said this system was rated for at least 100 mph winds. Thankfully I haven’t had to test that yet!
The panels are also wired up together in the back in various combinations of series and parallel to get the voltage and amperage that will work best with their respective charge controllers. Here’s a picture of those.
If my panels had all been of the same type, or at least of the same voltage I could probably have used just one of these Midnite Solar Classic charge controllers as long as it was rated to handle the potential power input. However, because I have two types of panels in this system I needed a controller for each. There is a communication wire between the two charge controllers that lets them talk to each other so they can switch to their various states of charging together. These are MMPT type controllers. Something I didn’t realize going into this was that with this type controller at least the input voltage can be way higher than that of the battery bank. My system is a 48 volt system, yet one of my sets of panels is wired to feed in about 90 volts the other tends to be 60 or so. The MMPT charge controllers then make their adjustments to the voltage/amperage to feed into the battery bank what is optimal. As I understand it this increases the efficiency of the system overall.

My battery bank is 8 of these Magna Power AGM 12 volt 245amp/hour batteries. They are wired to created two parallel strings of 4 batteries that are wired in series. In other words two groups of 48 volts. To me this is the weakest point of my off-grid system. I feel like I really should have a larger battery bank, and this is after I’ve enlarged what the company I hired left me with! It does work anyway, though it gets seriously stressed around the winter solstice and I expect this will result in a shorter life of the battery bank than it should be. Given that this represented about $4000 worth of batteries I’m not happy about it. My hope is that when I do need to replace the bank there will be better options available. My sense is that there already are.

This last photo shows all the stuff mounted on the wall and my insulating box around the battery bank. A downside to locating all this in the building it’s in is that it is an unheated building. When the batteries get cold, ie during the winter solstice when I need the most storage capacity, they will lose storage capacity. The insulating box is to keep them just that little bit warmer. I’m working on finishing up a project now where I’ve built a greenhouse off the south side of this building. In addition to it’s functions as a greenhouse, it is also to serve double duty as a heater of sorts for this building in the winter. I’ll see how well that works out this winter.
You can also see the 4400 watt pure sine wave inverter in this last photo. It is the big white box. I also consider this a weak point in the overall system in terms of resiliency. If that breaks down I lose power. With most of the other components the system would be reduced in capacity but still function. I’ve been considering buying a second inverter to store as a backup. Of course right now I also have the back up of the power grid too. The line still runs to my house and all it would take is a phone call, a $40 hook up charge, and a few days to get a lineman out to hook me back up.
I should also note that all the circuit breakers, switches, fuses, wiring and such is in a box that the inverter is hanging on. The black cord you see coiled up on the left side of the photo is what I can run outside and hook up to my propane generator if I need to use it to charge the battery bank up.

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Mr. Pei, as far as your question goes regarding the yearly power use of my Marathon water heater the simple honest answer is that I don’t know. Because it’s wired directly into the circuit breaker box I can’t easily put a kilowatt meter on it to read real world usage. I can tell you that when it turns on to heat up the water it’s drawing about 2100 watts. From a full tank of cold water from my well to hot water I’m going to guess that it takes at least an hour to heat it. That would mean 2.1 kilowatts. It might take longer. It does seem like it took longer the very first time I powered it up. Of course usually it’s not that long because I’m not draining the tank fully so it’s a mix of hot and cold water being heated back up to fully hot.
Whatever my actual yearly usage is though everyone elses would be different depending on how much hot water they used. As I recall they said this heater was supposed to lose only 5 degrees over a 24 hour period if it was just sitting. Assuming this is true then most of the power will be consumed heating up the replacement water when you do use hot water.
Looking at my entire electric usage (hot water, well pump, lights, fridge, etc.) I roughly figure that with the losses in the entire system added in I need to generate about 4 kilowatts a day on average when I’m working to be conservative, like around the winter solstice. What has surprised me with going off-grid was the realization that outside the 6 week period around the winter solstice I actually have way more power than I need. Thus I’m often looking for ways to use it productively rather than my old mode of always trying to conserve. I’ve found that there are significant periods of time in the spring and fall when I can heat my home with electric space heaters if it’s a sunny day!

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David, thank you very much for that information. Regarding other, better battery options, maybe Nickel-Iron. Dr. Tom Murphy, guest on PP, switched from lead-acid to N-I. Perhaps they can be left to others in a will upon death. He says he still owes a post on how his N-I has been performing. Hopefully that is blogged before you must purchase. https://dothemath.ucsd.edu/

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mr. pei wrote:
David, thank you very much for that information. Regarding other, better battery options, maybe Nickel-Iron. Dr. Tom Murphy, guest on PP, switched from lead-acid to N-I. Perhaps they can be left to others in a will upon death. He says he still owes a post on how his N-I has been performing. Hopefully that is blogged before you must purchase. https://dothemath.ucsd.edu/

Nickel Iron are great batteries, but they do need maintenance, and not just adding water, to make them last forever, you need to do an electrolyte refresh every 8 to 10 years. Better than lead acid, yes. Cross your fingers on Aquion going back to production. I would buy Iron Edison over lithium Ion or lead acid, for sure

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Thank you both for that info on nickel iron batteries. That type really hasn’t come to my attention before. I’ll be sure to look into it!

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A complete solar electric, large enough to power the studio apartment on my property, or some other cabin, is very inexpensive, if you can install yourself, Installation of basics, and panels, is not hard if you are somewhat handy. This is for a stand-alone, not grid-tied, system : $2,000. https://realgoods.com/the-weekender-complete-solar-pv-kit

One large enough for a conservtive house, about the size of mine, so plenty large for well-pumping, dishwasher, washing machine, etc… of a normal household : $9,000 https://realgoods.com/the-cabin-complete-solar-pv-kit This looks extremely similar to Dave’s houshold PV system, above, same inverter. This package has an inverter and batteries that would easily support more panels, if you wanted to go up to 4.4, like Dave’s, it wouldnt cost much more as panels are not that expensive.
I believe that the length of wires from the panels to the inverter is an extra, and depends on the distance between the two for each location.

If you ever had questions, the technicians at Real Goods are very good.

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Hi everyone, this is a great topic, thread and comments. Thanks a lot.
Here is a super website to help identify the “top 10” most energy efficient household appliances, by category, energy efficiency, brand, purchase price, annual KWH consumption, annual energy running cost etc - and then to dive more into the detail of whatever interests you…
http://www.toptenuk.org/products/categories
Website stats are based on European standard 240V AC…nevertheless, still a great guideline for US located folks. Brands are mostly globally available…
If anybody knows any other similar websites - for example - that cover more heavy duty household infrastructural equipment, such as water heaters, heating systems and the like, then PLEASE SHARE! :slight_smile:
Here also are a couple of sites containing energy consumption calculators:
http://www.electrical101.com/energy-calculators.html
https://www.maximintegrated.com/en/design/tools/calculators/general-engi…

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Hi fellas (and hi to everyone else too of course),
Great comments from you all - thanks a lot!
My previous post earlier today offered a website link to help identify cost effective and low energy use refrigerators and other household appliances (note - the website has nothing to do with me personally or anyone I know…I’m just an ordinary Joe and PP.com member, not selling or promoting anything). My comments below are based purely upon my own personal off-grid experiences…I personally live permanently in a mountain house, at an altitude of 1 km (3’300 ft), in the east central Swiss Alps, Switzerland. I enjoy living the whole subject of preparedness / off-grid, it interests me enormously and warms my heart as a lifestyle.
REGARDING REFRIGERATION SPECIFICALLY: For maximum efficiency and convenience, why not consider setting up a combination of independent refrigeration methods, each purposed around the variety of different refrigeration needs that you undoubtedly have - rather than a one-size fits all single refrigeration setup. For example…let’s consider several normal “average” human needs and a few well known refrigeration brands - such as Liebherr, Siemens and Dometic:

  1. An ultra-low consumption dedicated refrigerator (without freezer function). Circa $300 to $400 should get a brand new A+++ 5 Cu Foot (5 ft³) one, consuming only 60-70 KWH per annum (example = Liebherr Comfort TP1720)...just to keep food short term fresh and preserved.
  2. A low-ish consumption dedicated chest freezer (again, circa $300 to $400 should get a brand new A++ 8.4 Cu Foot chest freezer (8.4 ft³) without defrost function, consuming 170 KWH per annum, such as the Liebherr GT2632...or...if you're thinking higher end, circa $1'100 to $1'300...for a 12.7 Cu Foot (12.7 ft³) freestanding freezer with automatic defrost function, consuming only 225 KWH per annum - such as the Siemens iQ500 GS58NAW41)...or maybe consider 2 x mid-sized freezers instead of 1 large capacity freezer, offering a backup in case of failure and also the ability to switch one off completely if frozen food depletes...thus reducing the load on your battery bank. Whatever.
  3. An ultra-low consumption 12/24 Volt DC/100-240 AC top-loading (chest style) portable compressor systle refrigerator/freezer, A++ 1.9 Cu Foot, consuming 70 KWH per annum via AC or 0.75 KWH per hour via DC, capable of refrigeration through to deep freeze -22 C (-7 F), or freeze -12 C (10 F) at outside ambient temperature of +32 C...such as the Dometic CFX65W...the type used by many RV'ers, travellers and campers. The CFX range is a latest Dometic design, reducing energy consumption by 30% compared with their previous designs.
So...why consider a combination approach using all 3 types mentioned, instead of a single 1-size-fits-all refrigerator? Generally speaking, we can only consume so much fresh food per week...so a good capacity refrigerator is highly valuable (compared to an oversize one, which is often exactly that)...combined with a smaller portable refrigerator/freezer. This combination permits the periodic transfer of daily essentials from the larger "fixed" refrigerator to the smaller portable one...enabling to keep the door closed on the larger fixed refrigerator for several days, minimising energy consumption - while you open and close the portable "chest style" refrigerator multiple times a day (where the cold air cannot escape downwards and outwards upon opening the door, due to the chest style design). The portable refrigerator can be carried around in the car on journeys, holidays or emergencies...and can also be taken into the yard/garden containing beer, wine, burgers, ice cream or whatever and be powered by a small 12 V and solar panel for the entire day without problem. In other words, you retain full flexibility for many different circumstances (normal or emergency) and minimise energy consumption by design, all at the same time. The portable "compressor" style refrigerators (rather than the "absorber" style) help to massively reduce energy consumption whilst retaining highly efficient cooling. And naturally, the use of a fixed and dedicated standalone medium term food preservation freezer makes a lot of sense, in addition to the 2 short-term refrigeration methods described...with each of the 3 methods specialised towards its own design function, rather than being a compromise of all 3. Cost and space available are clearly very decisive factors for most people. Personally, I use all 3. IN GENERAL: Regarding off-grid anything and if you can afford it and if you have the space available - I've found that it's generally best to "purpose and dedicate" the battery bank setup and appliances specifically to the job in hand. Meaning: have several battery bank setups, independent of each other - that are dedicated exactly towards the goal. Exactly as Chaz and Adam discussed in the podcast, some daily "essentials" are very low power consumption "handful of watt" items (such as USB charging the mobile phone, LED lights, recharging torches, small radio, MP3 player, laptop etc). Thus, having a small 12V DC setup with several recharging options (i.e. solar, or small rechargeable 3 or 400 watt "portable AC/12V/USB power pack" for traveling or emergency situations) dedicated to "low consumption tasks" will happily service this requirement and can be scaled up pretty easily as small rechargeable items accumulate. Beyond that, most people have a sway of "smallish to mid-size" more power hungry items (e.g. larger stereo/amplifier/surround sound, powered speakers, 19" LCD TV etc, small power tools, game consoles such as Xbox360, PS3 etc, juicers and blenders, yadayada) - which individually all tend to operate somewhere in the 200 to 500 Watt range. On their own, they're pretty manageable with a small battery bank and recharger setup (solar, small portable power pack, small generator, small inverter or whatever), but start using a few at the same time and they soon overpower your setup. Having a separate "mid-capacity" battery bank for these type of items / with several recharging options (solar array, small generator etc) / with one or two mid size inverters, charge controllers etc - means: that it's possible to "manage" your way through tricky periods when your mid-size battery bank is a little depleted by the more power hungry items...and you find yourself with only 5% charge on your mobile phone, needing to do a 1 hour conference call, starting in 10 minutes time. Having the smaller setup alongside the mid-size one, solves little emergencies and keeps you flexible, while your mid-size battery bank restores its health. Beyond that, everyone of us has a large sway of power hungry appliances, whether we realise it or not. AC powered microwave ovens, ovens generally, pumps, vacuum cleaners, irons, kettles, hair dryers, toasters, sandwich makers and the like, air conditioners, larger power tools, compressors, boilers, heating systems etc - generally any appliance that heats up, cools down, pumps, sucks, spins or blows...is going to quickly use up all the battery capacity that you have and more besides. All these items tend to come in at 800 to 3'000+ watts each - all of them... And naturally enough, if you wish to power up these kind of items, it all requires a sizeable and robust battery bank, with a combination of both sustainable and on-demand recharging sources (if sustainable is not up to the task, just at the moment that you need it be) and with some fairly heavy duty inverters, together with capable fuse boxes, heavy wiring etc for safety reasons. Whilst that is obviously the challenge, the good news is - that most of these hungry items are not as "lifestyle essential" as you might think. Not using them all the time...or better still - using an alternative instead, is easier than you might think...but only when you think about it...in advance. And if you're prepared to adapt. Having several different battery bank setups - aimed by design towards low consumption / medium consumption / high consumption appliances and tasks, allows flexibility and scale up...and also human learning / acceptance / adaptation at a speed and intensity that suits the individual. It takes time...and money...and above all - the desire to face up to some challenges and short term inconveniences that easy-life living has mostly erased for the majority. But the reward - for me anyway - is brilliant and worth it I think.
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would be very expensive. I can see having a smaller, maybe even portable, for a separate building on the property or camping that can be used in a bug out, but otherwise, these multiple systems for just around the house would be very pricey ! And, not more environmental considering the manufacturing of batteries and electronics, it seems. So, I can see the argument for a small, portable dc only system, wether one has a larger solar system, or if it is all a household has for emergency uses, but cannot see the advantages of have 2 larger, mid-mid or mid-large, for the same house.
I use small electric appliances off of my one batterybank with no problems, water pumping(not small), electric kettle, toaster, bread maker, etc… for many days in a row when it is raining. Batteries and inverters and especially the wiring is very expensive.
Having separate freezers/refrigerators work for some people, especially those with alot of frozen items, but adding all the numbers of yours together does not seem like much to any annual energy savings, and alot of floor space by having 3 separate units ? This is one I have looked into alot for my house, and so far have not seen enough of an advantage to chest freezer-style refrigerators to justify the increased cost, but I revisit this often, and do not know for sure what I will do next time I need a new one. I may well try a horizontal one out then. We all have different needs, I produce alot on site that needs refrigeration, I barely use freezer space. For others, it is the other way around ! Idealy, I would like to have a root cellar, and spring box – but, for now, time and money constrains. Unlike most people, I produce my own dairy, and so generally have 3-12 half gallon jars of milk, various cheeses, jars of pickles and seasonally 10 dozen eggs to see thru the molt and winter slow down. Eggs of course do not need to be refrigerated, but do if they are being stored for so many months in a hot area like here.

By the way, there is a link to an appliance energy consumption site up in one of my earlier posts, not all inclusive, I dont think it has summit appliance in it, but just about all of the typical ones you can get in America

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You are right, some typical items realy use too much electricity to use on a battery system, electric ovens, electric space heaters, electric hot water heating. Most reasonably priced solar/battery sytems do not connect to these devices. I think some people with alot of money to burn do power these, but for a typical household, they are not a battery drain as they are not used on a battery system, at least this is what I see around here. ANd, as I said a few super expensive systems owned by people with a whole lot of money who will put in enough to power everything electric they might desire.

Bt, most out here conserve first and then make a system

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Completely agree with that sentiment.
My living circumstance has some extreme outer edges. In summer months, due to the trajectory of the sun and the topography of the surrounding alpine mountains, I get up to a maximum of 8.5 hours of sun. In winter, I get 43 minutes in total, per day. That’s it. 2 years ago, that was 49 minutes…but the fir tree forest adjacent to my home (which I don’t own and which grow on UNESCO protected land - thus I can’t chop them down) grew 2 feet higher in that time…and aren’t going to stop growing in future…so my 43 minutes will be less or none foreseeably. And obviously, its cold in winter, with an average 60 cm permanent frozen snow cover from mid-Dec until mid-April.
To be less reliant on AC (which can black out in winter weather), I needed to setup differently. Solar helps, but is not a sustainable year round solution for me. Also not wind (the mountains shield against the wind for the most part), also not hydro (there’s no viable stream/river/waterfall that I can access for hydro, although I have fresh flowing alpine water.
So to minimise AC use I need to conserve as priority and then optimise for maximum efficiency out of the appliances in use, the battery capacity that I have and the charging methodologies available…and simply use alternatives.
At the local state level where I live, hydro dominates AC production (excellent). But that doesn’t help me in a black out or a white out. Only viable backups, efficient and affordable. So yes - conserve, then system. Same here too.

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Geedard wrote:
Completely agree with that sentiment. My living circumstance has some extreme outer edges. In summer months, due to the trajectory of the sun and the topography of the surrounding alpine mountains, I get up to a maximum of 8.5 hours of sun. In winter, I get 43 minutes in total, per day. That's it. 2 years ago, that was 49 minutes...but the fir tree forest adjacent to my home (which I don't own and which grow on UNESCO protected land - thus I can't chop them down) grew 2 feet higher in that time...and aren't going to stop growing in future...so my 43 minutes will be less or none foreseeably. And obviously, its cold in winter, with an average 60 cm permanent frozen snow cover from mid-Dec until mid-April. To be less reliant on AC (which can black out in winter weather), I needed to setup differently. Solar helps, but is not a sustainable year round solution for me. Also not wind (the mountains shield against the wind for the most part), also not hydro (there's no viable stream/river/waterfall that I can access for hydro, although I have fresh flowing alpine water. So to minimise AC use I need to conserve as priority and then optimise for maximum efficiency out of the appliances in use, the battery capacity that I have and the charging methodologies available....and simply use alternatives. At the local state level where I live, hydro dominates AC production (excellent). But that doesn't help me in a black out or a white out. Only viable backups, efficient and affordable. So yes - conserve, then system. Same here too.

I would imagine you must have a wood stove, which is how I do space heating here on my mountain, and I often cook on the woodstove in the storms too.

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Geedard wrote:
Hi everyone, this is a great topic, thread and comments. Thanks a lot. Here is a super website to help identify the "top 10" most energy efficient household appliances, by category, energy efficiency, brand, purchase price, annual KWH consumption, annual energy running cost etc - and then to dive more into the detail of whatever interests you... http://www.toptenuk.org/products/categories Website stats are based on European standard 240V AC...nevertheless, still a great guideline for US located folks. Brands are mostly globally available... If anybody knows any other similar websites - for example - that cover more heavy duty household infrastructural equipment, such as water heaters, heating systems and the like, then PLEASE SHARE! :-) Here also are a couple of sites containing energy consumption calculators: http://www.electrical101.com/energy-calculators.html https://www.maximintegrated.com/en/design/tools/calculators/general-engi...

I had fun Drooling at the UK site looking at refrigerators ! We have absolutely nothing in this range in the USA ! For example, a 12 cu ft ( 343liter) refrig/freezer that uses under 200kWhr a year, for 530pounds. American refrigerators are all much larger, and the smaller ones, when you can find them, must use the same condensors or whatever of the larger, as they do no use as much less as you would expect.

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Correct.
Wood burning for heating house and water boilers, cooking when necessary (or when inconvenient some other way) + Ethanol cooking spirit designed for cooking Cheese Fondue…used indoors or outdoors (heating up pots and pans of food and sauces - or for boiling the water in a stove-stop Cafetiere for quick hot coffee (without need for heating the stove itself). Not smelly like propane.
Battery for DC directly / AC with inverter, solar battery recharging when available or battery charger / controller that recharges 12 V DC batteries using methanol (recharge rate circa 200 amps every 24h). Methanol in a sealed container has unlimited shelf life. 10 litres of methanol (circa 2.5 US gallons) fairly silently monitors and recharges my 12 V DC battery round the clock for circa 3 weeks.
Propane sometimes…e.g. gas grill BBQ.
240V/400V Generator for really heavy duty appliances, or when noise is not a showstopper.
Petrol driven appliances such as chainsaw, strimmers, lawn mower, hedge trimmers etc.
Only wood is really sustainable year round, solar viable half year, all others must be purchased and act as affordable convenience or multiple backup options.