I’m with you Steve. A generator is always needed, big battery or not. And a generator can cover those edge cases and more. In some cases that last kwhr of battery is coming at a high cost per use when your normal cycles don’t draw it down.
And plenty of people get by with mostly or all generator. I know my wife wants an on grid style resource so I aim for that. It’s spendy for sure.
The LiFeP batteries last 10x more charge cycles then lead acid, and you can discharge to 80% without degradation or a voltage drop off. So you need fewer batteries then LA where you are doing Discharge to 50% to try and extend the cell life.
They have come down in price, I don’t know if today is when you pull the trigger.
You probably want a generator but the key is not having to run the generator because that is typically most expensive source of power.
Anthony, I am fortunate. It is my wife who want to simplify back in-time.
She nagged me now that they are moved out of storage to restore one of her old families colorful porcelain enamel wood cooking stoves and move insides into the new place.
At one point she had me restore to use, her collection of oil lamps:
Instead I converted to Ni-MH rechargeable battery LED modern lanterns for click-switch Grid-outages. Overcast day so I can show the aways in place safe, clean alternatives:
In fact that should be every Praticalist’s ethics motto guideline . . . Good Enough.
Move on then to another of Life’s alligator problem to kill off.
Along with David Baillie’s motto:
Wanna’ change the world? Change your world first.
Another of his:
Collapse now - avoid the rush.
S.U.
Awe… I’m blushing. thanks Steve. Lithium for sure has its uses and its becoming the more common off grid choice for new setups with large loads. There are limits though. Cold is a problem so you are talking a heated battery box or room, Lifespan on the cells is mostly excellent… lifespan on the BMS that control the battery banks is yet to be determined; lots of new players out there. Cycles is a topic that can take hours to explain well. The gist is every battery manufacturer lists stats that showcase their product but create a test that their product shines in and the competition looks like a dog. So… off grid if you have a large generator component in the system… Lithium shines as you avoid the absorb cycle of lead acid. If you want to put in a small battery bank you will regularly discharge to 80 percent again lithium rules the roost in longevity. But say you have a bank that does nothing but wait for an outage? is lithium still the choice? no not at all. Say you do the correct thing and size your lead acid battery bank for a 25-30 percent max discharge cycle versus the false comparison 80 percent discharge in a head to head against lithium so common on the web sites. At 25 percent you will get 10 years plus of good service at half the cost of lithium. The hidden costs are the absorb cycles. So design, budget and choices will affect what works for you.
Anthony,
In my experience most of the better lithium battery packs have built in peak amperage limiters built into them to avoid cell damage. In lead acid its more a physical peak amperage limit due to chemistry.
David, which lead acid battery style would you suggest for such a backup bank? Flooded cell or AGM? 6v Cells or 12v cells?
I have a room that I could do either lithium or lead acid, it’s shared with my hot water heater and used to be the boiler room when we had an oil furnace, brick lined room partially underground. Wouldn’t be hard to make shelving unit and cover a wall in batteries.
It depends on your goal. If they sit idle most of the time or cycle shallow I would go lead acid. If you don’t mind the maintenance flooded is cheaper but you can stack agms into a smaller footprint. Agms tolerate idle times better. Either option go with the 6 volt options. If you will put them to full use (deep discharge) regularly the lithium benefits start to pile up…
I’m fairly battery agnostic.
would not use lead acid, and especially flooded batteries because they offgas hydrogen. That isn’t good in a closed space with a chance of spark. For example bricks can leak water. In fact it is probably against the building codes and if something does happen you will have insurance issues.
Because it is in a basement, it shouldn’t get to below freezing so the freezing argument is out. If it does get to freezing, then you have other issues with your house insulation that should be addressed.
I wouldn’t buy more then what you need at this point. Once the Automakers finish ramping up manufacturing, and a couple of more lithium mines come online. I think prices will start to drop. Then once buildings and equipment are amortized the prices can drop again because of lower overhead but that is at least 5-10 years down the road and does no good if you need them now. 
Just for example, the AA constant current rechargeable battteries that charge with a usbc port dropped about in half over the last couple of years. It is within the ballpark of being a couple of charges to break even. It isn’t worth buying alkaline batteries anymore for something you use. They don’t have the chloride in them that leaks and ruins the connector.
It’s technically external to the house. But it is built with the house if that makes sense. I was thinking of running my generator in there since we still have the chimney from the furnace, could pipe it up and out and have vents in the doors.
I’m not married to either idea, but my issue will be doing it piecemeal, and from what I understand all battery types hate when newer cells are added to the parallel due to cycles and amp hours being different.
And there is another option, a used battery from an EV. Lots of them will be available if they arent yet 
. Very very suitable to power your house. Downside is the Li-ion. LifePO4 will take another 5 years to become widely available.
i would contact GM or Ford, they both have systems for Houses and vehicles that can simultaneously handle multiple battery types and you change it in software. (useful for replacing parts of a car battery pack as well) Then see what they say about wiring, and what upgrades you need, for what you are planning in the future. Then see what they say. Their storage solutions mainly are in the garage because you can do vehicle to home with them, but to get the speed you need it is a huge amount of amps so keeping the wiring short helps keep the costs down. They are pricey right now, but I am sure costs will come down in the future.
You are good at wheeling and dealing, so an electrician friend that says, oh, you need to bury x line, and then you dig the hole, run the wire and have him make the two connections for a pile of sweet corn or something is going to be significantly cheaper then hiring an installer.
Lithium is great, but expensive, at least so far. For a big battery bank, in a warm room, with sufficient funding it’s the way to go. An advantage of lead-acid is low first cost. You may be able to afford a good sized bank at the beginning, where lithium would have to grow slowly. Flooded batteries have the advantage (and disadvantage) of adding water. You can equalize the cells with a controlled over-charge once in a while, then top off the electrolyte. Lithiums need this also, but you can’t over-charge or add electrolyte, so the BMS does the equalizing a little at a time, all the time. This works great, but does add to the cost.
It’s probably not ideal to add new batteries to old, but with the same voltage and chemistry, if they’re paralleled, it’s not the end of the world. Lithiums, with their BMS, can manage some of this. For lead-acid, I think they’re more forgiving in terms of final voltage.
Indoors, lead-acid would need to be vented, often a battery box with a lid vented to the outside. They also benefit from moderate temperatures. Cold reduces their capacity, but it’s not permanent, unless you leave them discharged, and they freeze.
Like my grampa used to say, “You pays your money, and you takes your choice.”
Oh, and you do have to live with the results 
As mentioned of it’s a basement the new code in most jurisdictions is going to be no batteries at all… Ontario now enforces this. But if you put a generator down there you are not one to care about codes already. I would do sealed though if you do it. If you are charging them primarily with the generator lithium makes sense. Lithium also is more tolerant of adding an extra bank down the road. Stay away from the existing car chemistries and stick with lithium iron due to thermal run away if it’s in a living space.
One more comment about lead-acid. When I was working a day job, the professor with whom I worked most of the time came across something I have not seen any where else. Alas, I can’t remember where he found it, so take that into account. Anyway, the charging voltage curve for lead batteries gets steeper as you approach full charge. Here’s a plot:
The plot stops at 80% state of charge, so you miss most of the steep part of the curve. I didn’t realize it before, but the plot shows similar behavior for lithium batteries, which shows all the way to 99% SOC. So as I remember (caution advised with that statement), by charging the lead battery into that curved part of the plot, you would get maybe 5% more capacity, but loose around 10% in lifetime. We charged the small sealed lead-acid batteries for the student lab to a final voltage of 13.8, instead of 14 or 14.1. Under light use they lasted ten years. Warning: this is not a controlled study, and your mileage may vary. I wonder, but have no idea, if there are similar lifetime effects with Lithium.
The problem with lower charging voltage, besides the reduced capacity, is that it takes longer to charge at the lower current that results from the lower voltage. This is important especially for generator charging.
Here’s a link to a paper that discusses some of this:
https://www.osti.gov/etdeweb/servlets/purl/20607163
It is not for the faint of heart, or short of time. Parts of it deal with corrosion, which depends on voltage, so some of this might even be true.
For what it’s worth,
Kent
It’s in no way attached to the ventilation of the house, it’s attached to an external wall at the lower ground level. But I can understand the fire/CO hazard. The furnace chimney is a full brick chimney and is separate from our fireplace chimneys.
I’m sure a lot of you follow this guy but in case you don’t. Pretty close to what you would pay for a pair of six volt Trojans though a lot less AH’s . Not sure what that means between lead acid and Lithium. I would learn how to convert those EV batteries to house power. They will be plentiful.
Well, The Good, the cutting edge, the Bad, and the Ugly…
Here is some of the last two…
I know our members are smart enough to avoid this 
You just need more of the lithium to get the same amp hours, but OTOH, they are good to 80% discharge for several thousand cycles. So pay more now, and they last a lot longer. They also weigh a lot less. They are VERY popular in the pleasure boating industry and for trolling motors which is rolls bread and butter business.
It actually brings up a few pitfalls. Not just the solar installers, but the permitting is a huge problem and ironically a large part of the expense.
If your jurisdiction has not signed up, ask to have them take part in this application.
then all the permits and i think inspections you need are spelled out for the installers and it goes much more quickly and far cheaper.
This is a video, and he does a decent explaining more in laymans terms the differences between micro inverters, string inverters, and how shading affects panel performance. This is his 10 year video for his system.
He is claiming his system has paid for itself in 10 years which is probably true. Given they have high rates in california, and he is doing time of day shifting to avoid the high evening rates. And certainly the original $10k system after tax rebates wasn’t 10k.
Apparently the powerwall allows you to use the cheap grid-tie inverter to keep power on during a power outage. Which I hadn’t ever thought about, but it makes sense.
“I have seen on the net” (which is not the same as, “I know it’s true”), that some Magnum inverters can be installed between batteries and micro-inverters, to mimic the grid if the real grid is down. I have such an inverter, but no micro-inverters, so hear-say is the best I can do.
Not only the powerwall, a real off grid inverter does the same. The rest can be cheapo standard on grid inverters. A lot of Canadian off gridders do this.
