What is better value than buying a Tesla Power Wall.. NZ$10k for 14KwH.. Doe'snt seem very viable yet.
Your asking for best value battery tech and then using an example of an entire system containing chargers, GTI etc. So is the question really about battery tech or a complete solution ?
AGM and GEL batteries are still the best value / buck for a high performance home battery bank with minimal maintenance.
Tubular Gel especially are very good generally. Have long lifespans, high efficiency (as good as lithium in reality)
Cost around $350 per Kilowatt-hour of storage (AUD) for cheaper brands
However you will still need a charger, charge monitoring and an Inverter to be like the Powerwall. If you added all those things it will probably end up more expensive.
So really it depends on your needs.
Old forklift batteries, They get retired from forklifts due to not holding a working days charge, but for stationary use you can use several banks of them.
https://youtu.be/ZH2sACTgWcQ
The cheapest is to convince the government to do it for you and make them change from PPE to net metering, and stop worrying about storage. Local storage is a really really bad idea in the economic sense. It is the ultimate waste of natural resources.
How does that fit with Tesla's vision for storage?
(incidentally I agree with you)
We have several members who have done exactly what others have said above, plus we've helped set up more. There are plenty of places to get damn cheap
SLA, AGMs etc Charging is MUCH simpler than LiIon, for the most, you only need trickle / boost rates, a simple charger. Cell balancing limits are also MUCH wider.
Some members have put systems together for $2-3K for up to 3days storage. There are a plethora of cheap / 2nd hand inverters etc around.
The ONE thing we do advise though - assemble the packs on a pallet or similar, then gently vibrate the lot. We usually use a simple small windmill with belt drive.
This increased longevity and shortens maintenance times greatly. Any vibration method is fine, and it doesn't need to be constant.
How does that fit with Tesla's vision for storage?
(incidentally I agree with you)
I dont know, but this is how I imagine battery storage:
This is about 1 MWH and has 20 years of battery life. If it breaks down, it will be repaired by trained staff, it can be repaired easily, almost plug and play. Has built in redundancy and fire suppression. Most people don't realize how violent a lithium battery fire is. This would just add to the usual "domestic destruction" caused by gas canisters, Christmas trees and feral ostriches.
And it has 96% efficiency. Powerwall is 92%.
Yeah I'd certainly prefer that than a whole bunch of Li Ion cells strapped to the wall of my house. I used to take expired LiIon cells apart and chuck them in buckets of water so I know the damage you can do with them.
http://batterytestcentre.com.au/results/Ampetus Super Lithium
Telstra PW 2
LG Chem REsU
There was talk about requiring battery storage in its own bunker after one set a garage on fire.
@digsys - which members are you talking of?
... @digsys - which members are you talking of?
ATA - Alternate technology association
AEVA - Australian Electric Vehicles Association (yep, members also into off-grid systems)
Aurora Solar Car association - some members into solar / backup systems.
Plenty of posts in the related forums (also FB). One guy has just(?) done a 500,000 ex-Tesla cells group buy. It was mentioned last month, but I haven't
followed it up. Group buys are popular though.
I'm wondering why would anyone waste money on lithium instead of using the chemistry with the lowest cost / kWh (lead acid or whatever that might be), since the weight and volume are not important in this case.
Lithium is already a scarce resource considering the demand for cars and other mobile devices.
You need to calculate the cost per year. I don't know about Tesla batteries, but judging by my phones and laptops, Li batteries won't last more than 5-6 years if heavily used.
I think SLA is still the best choice. They're cheaper and last longer than AGM. Maintenance is not that bad - may be 3-4 hours per year.
I'm wondering why would anyone waste money on lithium instead of using the chemistry with the lowest cost / kWh (lead acid or whatever that might be), since the weight and volume are not important in this case.
Lithium is already a scarce resource considering the demand for cars and other mobile devices.
After factoring in lifetime, Nissan Leaf batteries are cheaper per kWh than lead acid or at least competitive. And while lead acid likes to stay fully charged, lithium in general likes to stay around half charged. Ultimately, a combination of the two would probably be the best for off grid - lead acid for reserve and lithium for regular use.
I think if you have access to the grid, it will be cheaper to buy inverter and change your energy meter to two-way one, if law in your country allows that. In my country changing energy meter costs pennies. Batteries I think should be used when you can't affordably connect to the grid. In this case I would go with SLAs.
I'd say flooded lead acid is probably the best bang for the buck. If buying new, I hear golf cart batteries are pretty good. AGM and Gel are generally more expensive per amp hour, and cannot as easily be maintained. Good old school flooded you can open the caps and check electrolyte levels and add more distilled water as needed. VRLA, Gel, AGM etc DO vent sometimes, except when they do, you can't easily refill them. They tend to have a shorter life span because of this.
If you setup a good flooded acid battery bank and take good care of it, it should last 10+ years. The telco ones tend to last 20+ years. They do lose charge capacity over time but if you oversize from the get go and avoid discharging them too much they will last longer.
They are also simpler to charge, because you can float charge them while the load is also connected. Lithium ion is probably going to get to a point where it will be cheaper than lead acid and their higher density means more capacity per square foot of space, but they are much more complex to charge because they need to be balance charged and at very specific voltage/current. This gets complex if you are also drawing energy from them while they are also being charged, such as a renewable energy setup.
Lithium is already a scarce resource considering the demand for cars and other mobile devices.
Maybe. It's less an issue of absolute scarcity, and more of ramping up capacity.
The supply of Cobalt, on the other hand can be a real concern.
Lithium ion is probably going to get to a point where it will be cheaper than lead acid and their higher density means more capacity per square foot of space, but they are much more complex to charge because they need to be balance charged and at very specific voltage/current. This gets complex if you are also drawing energy from them while they are also being charged, such as a renewable energy setup.
The point where lithium batteries are as cheap as lead acid is surprisingly close. Decent quality LiFePO4 batteries are now available for just a bit more per Wh than conventional deep cycle lead acid and actually cheaper than AGM.
Lead acid should also ideally be balanced but that's not possible in most cases.
Lithium is already a scarce resource considering the demand for cars and other mobile devices.
Maybe. It's less an issue of absolute scarcity, and more of ramping up capacity.
The supply of Cobalt, on the other hand can be a real concern.
Lithium cobalt batteries were to blame for the 787 fiasco. LiFePO4 or lithium manganese would be safer alternatives for large batteries. Tesla is using a proprietary chemistry that uses cobalt but is far less flammable.
Lead acid should also ideally be balanced but that's not possible in most cases.
Flooded lead-acid cells are balanced using a controlled overcharge which should be periodically done anyway to prevent stratification in stationary applications.