I'll add to this-- get a cheap 240V generator that can run the well pump, preferrably propane.
Help with home battery backup system
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Thank you so much for taking the time sharing all your great ideas, wattmatters!
ATS is really important. As I mentioned above, if I'm not here, I don't want my wife having to panic with a flashlight, and understand how to manually switch to backup. Outages freak her out a bit, and I just don't want to have her depending upon rational thinking to restore power.
The same applies to having a backup propane generator. Yes, you don't have the degradation issues as with gas, but those generators still require maintenance, oil changes, etc. It would have to be stored somewhere, and horsed into position to use. She's tough, but having messed around with generators myself, I don't want to put her through that.
I'll have to re-read your thoughts on connections, etc. I understand enough to ask the right questions, but I'm going to have to look up a few terms and stuff to follow your ideas.
I read up as much as I could find on the Sol-Ark 15k, and watched a couple of videos, and it sounds great, and seems like it would fit the bill. I did find some criticisms about the Sol-Ark 12k, and how it struggles with "unbalanced loads." I don't understand that, but I think I need to read up on single-phase, two-phase, and three-phase to understand.
I checked the specs on the Sol-Ark 15k, and it draws 90W when in "sleep mode."
ATS is really important. As I mentioned above, if I'm not here, I don't want my wife having to panic with a flashlight, and understand how to manually switch to backup. Outages freak her out a bit, and I just don't want to have her depending upon rational thinking to restore power.
The same applies to having a backup propane generator. Yes, you don't have the degradation issues as with gas, but those generators still require maintenance, oil changes, etc. It would have to be stored somewhere, and horsed into position to use. She's tough, but having messed around with generators myself, I don't want to put her through that.
I'll have to re-read your thoughts on connections, etc. I understand enough to ask the right questions, but I'm going to have to look up a few terms and stuff to follow your ideas.
I read up as much as I could find on the Sol-Ark 15k, and watched a couple of videos, and it sounds great, and seems like it would fit the bill. I did find some criticisms about the Sol-Ark 12k, and how it struggles with "unbalanced loads." I don't understand that, but I think I need to read up on single-phase, two-phase, and three-phase to understand.
I checked the specs on the Sol-Ark 15k, and it draws 90W when in "sleep mode."
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Thanks, Shimmy. As I mentioned above, I'm trying to devise a system that's pretty much hand's-off for my wife, in case I'm not here. Gas/propane generators require maintenance, and horsing around. She can't do that, and I don't want to have the system depend upon augmenting with something like that.
Are you concerned about a long-term absence or a short-term absence-- would she need to be able to endure the duration of a hurricane outage?
In my book, the inverter is to address the immediate things, and the generator is for when you have time to get it set up and run. Propane limits the maintenance requirements. For one person (trying to conserve) a 300-gallon "day tank" should give you 6-7 days of safe operation.
Bluedog225
Texas
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Yep. My champion dual fuel will never see gasoline.
As concerns the wife, good point. Not sure how I’d handle that. Makes it much harder if systems are involved.
Thanks Shimmy and Bluedog225. My concerns about generators, and me not being here to take care of the heavy/dirty jobs, is planning for my passing. Chances are, my wife will be around in this home for a while after I'm gone, and I'm trying to plan ahead.
Breaking away the well pump into a circuit that would allow for the use of a generator would add a level of complexity that would make it prohibitive here. It's wired direct into the house, and would require an auxiliary outlet, with perhaps a transfer switch? Too much for my wife. Not that she couldn't manage it, but it's just an extra layer of things for her to worry about.
Breaking away the well pump into a circuit that would allow for the use of a generator would add a level of complexity that would make it prohibitive here. It's wired direct into the house, and would require an auxiliary outlet, with perhaps a transfer switch? Too much for my wife. Not that she couldn't manage it, but it's just an extra layer of things for her to worry about.
svetz
Works in theory! Practice? That's something else
I saw where if you're out of town you want to make it as easy as possible for your wife.
The new 175W flexible panels are lightweight (6.2 lbs) and have 25-year warranties. They're running about $1.75/W now. You could pre-cable the setup to the inverter's PV input from a generator inlet box you attach to the house. Then she'd just have to unroll them in the yard and plug them in to recharge the battery.
From the prior discussion you'd want something like eight or nine 175W flex panels. So roughly a $3,000 add-on.
Bluedog225
Texas
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That being the case, a large propane tank and stationary generator may end up being the “best” option. I’m not sure solar is going to be any easier than that. Or cheaper given what you are after.
Ask the best.
Ask the best.
Thanks, svetz -- I was just looking at those flexible panels, blankets, etc., this afternoon. Unfortunately, they just don't put out the voltage to meet the requirements of the larger standalone systems.
Bluedog225 -- a generator still requires maintenance, and tanks need fillups, which we already have experienced complete nonexistence in disasters. I'm really not a fan of solar, tbh, for our needs. I just want a battery backup charged from the grid. No, it won't serve all needs for all situations, but at least it will get us through a couple days, and allow some time for planning if necessary. 99% of the time our outages are less than five hours, usually only an hour or two. We can rough it, as long as our food is OK and we have water if longer.
Bluedog225 -- a generator still requires maintenance, and tanks need fillups, which we already have experienced complete nonexistence in disasters. I'm really not a fan of solar, tbh, for our needs. I just want a battery backup charged from the grid. No, it won't serve all needs for all situations, but at least it will get us through a couple days, and allow some time for planning if necessary. 99% of the time our outages are less than five hours, usually only an hour or two. We can rough it, as long as our food is OK and we have water if longer.
wattmatters
Solar Wizard
Totally understand. Back when I started with backup power, it was a generator, power inlet and manual transfer switch. Despite my best efforts, the wife just wasn't going to use the generator, despite electric start and everything being in situ ready to go if needed.
So I moved to the next step with the off-grid PV/battery system, still connected to the transfer switch in the same way the generator was (and can still be if needed). My wife is OK with flipping the switch, and the system is now set up such that this is all that is required for the home to have backup. Everything else is taken care of and backup power is on.
It may be I go the ATS route one day as well but instead I have decided I will progress towards running general household loads from the off-grid system instead, with grid supplemental as required. Non essential high power loads (e.g. ducted aircon, induction stove, oven etc) will still be grid powered only. Transfer switch is then used "in reverse" where the grid becomes the backup should the off-grid system go down.
Again I totally understand, and the battery + inverter electrical backup system is the first source of energy and can operate automatically. Happy wife.
But presumably you are not always going to be away when an outage occurs and so having the additional backup source of energy is extra insurance for when you are there.
I still have our generator. If our outage is multi-day and the weather is poor, then solar PV won't cut it to keep the batteries charged, so I will still need an alternative way to supply them some energy.
Even if it's just a 9kg BBQ bottle or two and a small generator. 1 kg of propane ~= 14 kWh of energy, and let's say conversion efficiency of the generator in turning that propane into electricity is 20% (about normal for 70% load rating, e.g. a 1 kW generator running at 700 W).
A 9 kg BBQ bottle can then provide 25 kWh of electrical energy. A 45 kg tank can provide something like 126 kWh of electrical energy. That's quite a lot of spare capacity if needed. Plus the gas can be used for cooking/boiling water if needed.
Propane fuelled engines reduce maintenance significantly (it's bad gasoline left in carburettors and fuel tanks which is the biggest issue and this is pretty much eliminated with a propane system). If the unit is not used often, then the oil and air filter like won't need changing all that often either. Just keep it well covered or in its box. Do a test of the system once a year, or at least in the lead up to storm season. Just like cleaning out the roof gutters, it's an occasional maintenance job which can be scheduled.
Ask away. I had to learn it all to come up with what we did, but by no means is what we did what you should do. Every case is different and the solutions will be too.
That's part of what I was referring to with the solution to run an essential loads panel full time through such a unit - they are themselves consumers of energy, so you have to allow for that, either in terms of extra grid energy consumption (90 W = 2.16 kWh/day) or to expect they will be a pretty steady draw on any battery backup so that 2.1 kWh/day is required just to have such a system operating. IOW you'd want to have that much battery capacity just to keep the unit operational, let alone available for powering loads. It's a system overhead.
Wow, thanks again, svetz! Yeah, the "being here" part of an outage is a biggie. If you don't have ATS, or at least part of the system depends upon auxiliary generators (that aren't configured for auto-start), the system is worthless. There's a lot to be said for "set and forget!"
I do keep a couple of BBQ tanks on hand, because during the winter when temps drop below a certain point, I have to run a propane heater in my greenhouse. Otherwise, on marginal nights, an electric heater or two is sufficient. So, those tanks could be hooked up to something else as you suggest. The greenhouse is actually one of my worries during an outage. If it happens during the day, and the sun is shining, I'd lose thousands of dollars in plants very quickly. It has a 5,000cfm exhaust fan running from 8am to 7pm most days. It requires about 275-300W, I think.
It's really a whole new way of thinking to make a house energy-efficient in terms of appliance-use, etc. I've only progressed to the "don't use it" phase when there's an outage, but the next plateau is actually operating the house all the time using less. Can get complicated!
I do keep a couple of BBQ tanks on hand, because during the winter when temps drop below a certain point, I have to run a propane heater in my greenhouse. Otherwise, on marginal nights, an electric heater or two is sufficient. So, those tanks could be hooked up to something else as you suggest. The greenhouse is actually one of my worries during an outage. If it happens during the day, and the sun is shining, I'd lose thousands of dollars in plants very quickly. It has a 5,000cfm exhaust fan running from 8am to 7pm most days. It requires about 275-300W, I think.
It's really a whole new way of thinking to make a house energy-efficient in terms of appliance-use, etc. I've only progressed to the "don't use it" phase when there's an outage, but the next plateau is actually operating the house all the time using less. Can get complicated!
wattmatters
Solar Wizard
Solar PV and battery energy storage systems do have a way of getting people to sharpen their thinking about energy consumption. What, when and how much. Often there are simple or cheap wins, some are less easy nor cheap. Some things can be viewed as longer term initiatives, like replacing appliances when they need it with more efficient options.
Over past six years we have managed to shave over 20 kWh/day from our consumption and use 32 kWh/day less energy from the grid. There is much more yet to do on that front.
You seem dead set against a STBY Gen.
You can lease a large tank and the company will come out to fill it when you ask. I did this for my house when I lived in WI. It was cheap then too, a little over a buck a gallon. I think less than $1,500 delivered to fill a 1000 gal. tank. Propane was for the furnace, and one fill would last me the whole winter.
If you are just needing power for when the grid is down, a whole house generator is a lot cheaper than inverters and batteries. And you can get more power that will last a long time.
You are worried about not being around for your wife. Just get a service contract for yearly inspections/tune-ups. Many of the STBY gens do bi-weekly or monthly 5 minute self tests and can report any issues back to the company.
Also, inverters can have malfunctions/failures and batteries degrade. So that is not plug and play for your wife long term either.
You can lease a large tank and the company will come out to fill it when you ask. I did this for my house when I lived in WI. It was cheap then too, a little over a buck a gallon. I think less than $1,500 delivered to fill a 1000 gal. tank. Propane was for the furnace, and one fill would last me the whole winter.
If you are just needing power for when the grid is down, a whole house generator is a lot cheaper than inverters and batteries. And you can get more power that will last a long time.
You are worried about not being around for your wife. Just get a service contract for yearly inspections/tune-ups. Many of the STBY gens do bi-weekly or monthly 5 minute self tests and can report any issues back to the company.
Also, inverters can have malfunctions/failures and batteries degrade. So that is not plug and play for your wife long term either.
Thanks, Danke, for your input. Actually, the advantages for a battery backup are all pluses for me. A standby generator would have to be placed outside, next to our service line. That location gets brutal full sun all day. I know there are covers for them, but we would have to be here to open the cover while it's running, or it would overheat. Also, the heat coupled with humidity is quite severe on electronics. I've given up on using exterior ground fault outlets...even in our garage. They last about 6-8 weeks. Yes, there are electronics in standalone battery systems, but they are designed for such use, and, in our garage, would be fine. I'm not aware of the services you mentioned for generator maintenance around here...my wife would probably have to make arrangements through an electrician, maybe? They don't call this the "redneck Riviera" for nothing! lol
I've checked the consumption on those propane generators. It's not insignificant. We don't have a location, or the desire, to have a large tank in our front yard. Our experience during the hurricane makes me hesitant to have anything like that exposed to flying debris. I still have nightmares over what we went through.
We were quoted $20,000+ for a nat gas generator. It's looking like we might be able to get something like the Sol-Ark 15k for under $10k. Will says that the current crop of solar components should last 20 years or more...I'm not sure I'd trust an auxiliary generator that long. A battery backup would only require a new battery(ies), I would suspect...not a full replacement.
I've checked the consumption on those propane generators. It's not insignificant. We don't have a location, or the desire, to have a large tank in our front yard. Our experience during the hurricane makes me hesitant to have anything like that exposed to flying debris. I still have nightmares over what we went through.
We were quoted $20,000+ for a nat gas generator. It's looking like we might be able to get something like the Sol-Ark 15k for under $10k. Will says that the current crop of solar components should last 20 years or more...I'm not sure I'd trust an auxiliary generator that long. A battery backup would only require a new battery(ies), I would suspect...not a full replacement.
OK, so I totally misunderstood the specs on the Sol-Ark 15k. It says in the manual that it can provide 12kw backup, 15 with PV, so, I naively assumed there was battery storage included. Duh! There is a user thread that I just found that little tidbit.
I just watched a user video on YT that says the unit can handle any battery you want to hook up to it, so I'm looking at the EG4 LifePower 5.12kWh for $1499. I don't want to screw up my understanding of this before I get too far down the decision-making process. How many of these batteries can be added? There are four busses inside the unit, but can the batteries be bridged into a single buss? Does it have to be an even number, or could it be, say, three batteries for a total of 15kWh?
Thanks so much to everyone for helping me understand all this, and for the recommendations!
I just watched a user video on YT that says the unit can handle any battery you want to hook up to it, so I'm looking at the EG4 LifePower 5.12kWh for $1499. I don't want to screw up my understanding of this before I get too far down the decision-making process. How many of these batteries can be added? There are four busses inside the unit, but can the batteries be bridged into a single buss? Does it have to be an even number, or could it be, say, three batteries for a total of 15kWh?
Thanks so much to everyone for helping me understand all this, and for the recommendations!
So, would that mean that only two batteries can be connected? Or, could a higher number be linked together before tying into the Sol-Ark?
Thanks!
As many batteries as you wish as long as you keep it to the numbers I posted.
If you had say 12V batteries, then 4 in series would give you 48V.
Or more than one 48V battery (or group of batteries that equal 48V) in parallel as long as they add up to no greater than 9900Ah.
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svetz
Works in theory! Practice? That's something else
Low? Voltage is additive when panels are in series, small is great as you can generally arrange them to fit any system.
See What does it mean to have solar panels in parallel and series?
For example, the MPPT input voltage range of a Sol-Ark 12k is 150-425V. The 175W flexible panel has a Vmp of 19.5V and a Voc of 24V. To generate 6 kWh of energy per day at an insolation of 4 you'd need a 1500W array or 9 panels. 9 x 19.5 = 175.5V, so it would work with the Sol-Ark.
(For those just joining, permanent roof mounting is a no-go for him, and he wanted something light enough his wife could handle when he was away to recharge the battery, the 175W Flexible panels are 6.2 lbs each, see #27).
If you're consuming 6 kWh of energy per day, a Sol-Ark 15kW sounds like serious overkill unless your in-rush current is very high. The 15 kW refers to power, not energy (you can hook as big a battery as you want to increase energy). In one day a 15 kW inverter could theoretically provide (15 kW x 24h=) 360 kWh or energy. It'll drive 62.5 amps. About 60x what you've indicated you need.
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