An inexpensive alternative to lithium-ion batteries for energy storage

[MillCreek]

https://www.nytimes.com/2018/09/26/business/energy-environment/zinc-battery-solar-power.html

This sounds interesting: a less expensive alternative to lithium-ion without the scarce minerals, cooling issues and explody parts.

[Brad Johnson]

It's a giant rechargeable hearing aid battery.

Brad

[Ben]

Possible tangent. I've had an interest of late in battery energy for home emergency backup. I was looking at the Tesla Powerwall (not that I would pay for one, but am interested in the tech), and it was interesting to me that it is not compatible with generators - solar charging only. I'm not sure if that's an issue with the battery type or not.

I'm very interested in an efficient battery solution that would allow enough energy to say, run a gas furnace, or a small water well pump for maybe 5-10 hours of runtime each, then as the batteries deplete, the ability to turn on a generator for a few hours to charge them back up, and/or have 1KW of solar panels as an additional trickle charging option. Seems like now, the only alternative for that is the standard wet cell (and a whole bunch of them)?

It would just be cool to have compact high output emergency power that could be silent at night. Run the genny for a few hours during the day for a "quick charge" so you either don't need an acre of solar panels or can additionally just have fewer solar panels as supplemental slow chargers to keep the batteries up when there's not an outage.

[Brad Johnson]

Until $$/watt storage comes down significantly, my interest in whole-home battery backup systems is in theory only.

In terms of space (by total volume, not just square footage) wouldn't it be better to have fuel storage and a small generator rather than using the same space for batteries? Plus, the cost. A battery-based whole home backup power system with enough reserve to handle a 3-5 kW constant load for more than a score of minutes is going to easily run five figures. From what I'm seeing you will be $20,000-ish into an installation for that kind of capacity.

Briggs makes a 10kW standby generator that I see priced at around $2700. Runs on propane and has a rated consumption of 1.2 GPH at 50% load, so figure 1.5/hr just to be conservative. New 250 gallon propane tanks are approximately $1500. At roughly $2.50 per gallon that's $625 for a fill. Add in another $1000 for wiring and incidentals and you're $6000 into a system that is ready to provide 150+ hrs of 24/7 power as-is, or several weeks if used ultra-conservatively and supplemented with a good heating stove and a couple of inexpensive consumer-grade 100-300 watt solar panels for low-draw loads like phone chargers and such. The remaining $14,000 (vs. the battery system) is money to spend on food, ammo, and more fuel. The system can also be refueled indefinitely, and at any time of day, vs. the battery system's inherent daytime and meteorological condition restrictions.

Brad

[Ben]

Until $$/watt storage comes down significantly, my interest in whole-home battery backup systems is in theory only.

Yes, this is key and why I'm interested somewhat in theory only right now. I do have high hopes that this type of battery storage becomes affordable at some point. Especially for longer outages, I'd prefer it to using the propane tank both for heating and power, though for intermittent outages a whole house generator running on propane with auto kick-in is probably currently still the most viable option. Also much quieter than my current portable generator. :)

[zahc]

Batteries complement generators well. Usually if you have a small generator, it gets killed when things like your fridge kick on, but it can easily power it on average. Thus you may need a 3500W generator for your house even if your daily average power is only 400W. That's why you could have a $5kW power inverter running off a battery bank, and run the generator as needed to top off the battery bank, and save a lot of fuel compared to constantly running a generator that would give equivalent service.

I think lead acid batteries are still cheapest cost per joule.

[Scout26]

The biggest problem with batteries is you only get a fraction of the percentage of energy out, that you put in.  (IIRC, the best you can do is ~35% out of the energy to charge the battery.)    Plus most have to "rest" for a period after charging otherwise you lose even more output.  I know that our forklift batteries required an 8 hour charge then an 8 rest before we could use them (and almost get 8 hours out of them).  We ultimately went to propane forklifts, simply because during our busy season, they would not last an entire shift before dying.

Plus cost wise, it was cheaper to buy propane then electricity, again because the input>output problem.  

It would much cheaper to have either an NG or propane generator (depending on which fuel you use in your home already) and simply build a sound deadening shelter around it for weather and theft protection.  

[JonnyB]

Summer fill propane price here in rural Minnesota was $1.42 per gallon; well below what Brad wrote. Even in midwinter, we paid $1.72 per gallon. (Of course, several years ago, it was $6 plus, but we were burning wood in the outdoor boiler, and cared not at all.

Oh, yeah: $0.06 of that is for leasing the 500-gallon tank; no need to buy one.

JB

[Firethorn]

The biggest problem with batteries is you only get a fraction of the percentage of energy out, that you put in.  (IIRC, the best you can do is ~35% out of the energy to charge the battery.)   

That is all problems with lead acid batteries, not LiIon.  Lithium's problem is that it likes to catch flame and explode if overcharged, it is fine with high immediate discharges and has a charge efficiency of around 95%. 

[Ben]

I still don't understand why the Powerwall is not approved for generator use, given the generator has stable power generation. It doesn't seem all that much different than what you do when you plug your electric car into a fast charger.

I thought one of the big selling points of the Powerwall was not just the "reduced grid use", but also the off grid capability. Solar is not a steady charge source for off grid, especially in the Winter in places that get real Winter.

[zxcvbob]

It's a giant rechargeable hearing aid battery.

Brad

Those hearing aid batteries also work well in vintage camera equipment designed for 1.35V mercury batteries.  Silver oxide batteries and alkaline batteries are the wrong voltage, and the error that causes is significant.  Except they don't last for very long.  

[MillCreek]

I get my zinc-air hearing aid batteries at Costco. Perhaps I should connect a bunch of them in series to see what happens.

[Firethorn]

I still don't understand why the Powerwall is not approved for generator use, given the generator has stable power generation. It doesn't seem all that much different than what you do when you plug your electric car into a fast charger.

I thought one of the big selling points of the Powerwall was not just the "reduced grid use", but also the off grid capability. Solar is not a steady charge source for off grid, especially in the Winter in places that get real Winter.

Simple answer is that they haven't programmed that use case in.

If you really want this sort of capacity, you just buy an inverter/charger solution elsewhere than Tesla.  There are solutions out there that if you have solar panels, batteries, and a generator will run your off-grid system from the solar panels if it can, the battery if it can't, and start up the generator to charge the batteries when they get low, shutting it off when the batteries are *near* fully charged.

[charby]

The biggest problem with batteries is you only get a fraction of the percentage of energy out, that you put in.  (IIRC, the best you can do is ~35% out of the energy to charge the battery.)    Plus most have to "rest" for a period after charging otherwise you lose even more output.  I know that our forklift batteries required an 8 hour charge then an 8 rest before we could use them (and almost get 8 hours out of them).  We ultimately went to propane forklifts, simply because during our busy season, they would not last an entire shift before dying.

Plus cost wise, it was cheaper to buy propane then electricity, again because the input>output problem.  

It would much cheaper to have either an NG or propane generator (depending on which fuel you use in your home already) and simply build a sound deadening shelter around it for weather and theft protection.  

I'm looking at living part of the year post retirement on a sailboat, I'm interested in newer battery technology because I'd like AC and refrigeration and not having to take extra fuel for a generator.

[Scout26]

I'm looking at living part of the year post retirement on a sailboat, I'm interested in newer battery technology because I'd like AC and refrigeration and not having to take extra fuel for a generator.

Fuel will weigh less then the batteries and will be easier to replace...

[Firethorn]

I'm looking at living part of the year post retirement on a sailboat, I'm interested in newer battery technology because I'd like AC and refrigeration and not having to take extra fuel for a generator.

They make fridges, don't know about AC, which uses a process patented by Einstein, that uses burning fuel to run the refrigeration process. 

https://www.warehouseappliance.com/?t=Propane-Refrigerators-10-Cu-Ft-by-ez-freeze-prices-and-information&p=17299089775507077333027
http://www.portablefridgesonline.com.au/how-3-way-fridges-work

[charby]

Fuel will weigh less then the batteries and will be easier to replace...

Even at 20-30 days at sea?

[charby]

They make fridges, don't know about AC, which uses a process patented by Einstein, that uses burning fuel to run the refrigeration process. 

https://www.warehouseappliance.com/?t=Propane-Refrigerators-10-Cu-Ft-by-ez-freeze-prices-and-information&p=17299089775507077333027
http://www.portablefridgesonline.com.au/how-3-way-fridges-work

I know about ammonia refridgeration.

[Fly320s]

Even at 20-30 days at sea?

I would think that a few good solar panels will keep your batteries charged fairly well, so you can run fewer batteries.  I don't know how much you'll need to run AC, but a small 'fridge is easily powered.

[lee n. field]

I get my zinc-air hearing aid batteries at Costco. Perhaps I should connect a bunch of them in series to see what happens.

I hear Tesla uses 15K of them in their car.
:-)

[Scout26]

AC is a HUGE power draw.   You'd need a huge battery bank to power an AC unit for any length of time. 

Again, ammonia refrigeration would probably be an easier way to go, if you want AC.  If it's just to power a fridge, and run/recharge some small electronics, then yes, batteries and solar panels.   But with solar panels, it's very much a size = power calculation. 

[Brad Johnson]

AC is a HUGE power draw.   You'd need a huge battery bank to power an AC unit for any length of time. 

Couple of rule-of-thumb power company usage estimators give 4500w as the draw for a 3 ton residential unit.

Brad

[Scout26]

Even a medium sized window AC unit will draw about a 1700w.  (15 amp at 115AC).

https://www.rapidtables.com/calc/electric/watt-volt-amp-calculator.html

[charby]

Also need electricity for the water maker

[just Warren]

https://newatlas.com/sprinkle-sodium-powder-batteries/56539/