Tesla Powerwall in SA - prices and official launch window

I assume I have to buy the inverter with it at minimum. I dont have the option of solar panels, but it would be nice to store electricity somewhere and then power the house when we have load shedding. The powerwall will fit in my limited space too.
 
Nefertiti said:
I assume I have to buy the inverter with it at minimum. I dont have the option of solar panels, but it would be nice to store electricity somewhere and then power the house when we have load shedding. The powerwall will fit in my limited space too.
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That's a good idea!
 
zeely said:
7KWh = ~145ah @ 48v

Unless I'm missing something this really isn't a great deal.

I'm one of the few who have actually installed a grid tied solution. 12kwh of AGM batteries + Imeon 3.6 inverter. The entire installation cost me 56k. 3kw of panels will be another 35k installed - so call it a round 100k for batteries, grid tie inverter and 3kw of solar panels

$3600 x R15 = R54k just for 7kwh of batteries? Im guessing this is ex vat, ex import duties, ex ZAR fluctuations
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Your 12KW of AGM, is roughly equivalent to the 7KW of Lithium.

AGM has about 50% usable DoD if you want any sort of lifetime. I'd actually try aim for a 30% DoD, but that would be too pricey.
Lithium has about 85% usable DoD.

That 7KW is usable capacity (its actually closer to 10KW of battery in their pack). They rate that for 8 years (need to check). Will still be usable to 80% of original capacity at that point, so will still have a long usable life ahead of it.

Going back to your Lead Acid - your 12KW is about 6KW usable if you want any sort of lifetime.
It also likely takes up a good portion of space. It's also far more dangerous having around - the hydrogen gases need to be vented, or you have a risk of explosion.

If the rand wasn't half what it was a few years back, the Telsa Powerwall wouldn't seem expensive.
The issue with the Tesla though is its more of a Grid Tied solution.

Its really intended to hook into a Grid Tied inverter, as the charge voltages are in the 300-450V DC range.
This is likely intended for a panels (in series) -> Tesla -> GTI (grid tied inverter).


300-450V DC @ 8A ties in quite strongly to what their claimed outputs are for the battery output.
I still need to see one or have more details about an install to get a better idea of actual usage though.
Dearth of stats on the internet still..


Here, I'd strongly argue we're more in need of Off Grid or Hybrid. That may change if NERSA ever gets off its ass and publishes fair FIT rates. I'm not holding my breath on that though.


Personally I'm offgrid.

Lithium batteries are by far the better option, over "Dead Acid". Dead Acid is cheaper in the short term, but more expensive overall. Lifetime is what counts, not upfront costs. Better to invest in something that will last, even if it costs slightly more at the outset.

Only other solution that comes close for medium term storage at the consumer price level is probably flow batteries. Redflow ZBM is the closest to being available to consumers at the moment, and I'm watching and waiting..

Good overview of upcoming products here - http://redflow.com/wp-content/uploads/2015/07/pv-magazine_Storage_Special_Jul_2015.pdf (It's the PV Magazine Storage Special).
 
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lsheed_cn said:
Personally I'm offgrid.
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And that's the only case where any of what you've just said is remotely valid. Plus, you're still paying WAY more per kWh than any of us. The only time off-grid makes sense is when the cost of a connection is R50 000+/kVA, ie, the middle of nowhere.
 
lsheed_cn said:
Your 12KW of AGM, is roughly equivalent to the 7KW of Lithium.

AGM has about 50% usable DoD if you want any sort of lifetime. I'd actually try aim for a 30% DoD, but that would be too pricey.
Lithium has about 85% usable DoD.

That 7KW is usable capacity (its actually closer to 10KW of battery in their pack). They rate that for 8 years (need to check). Will still be usable to 80% of original capacity at that point, so will still have a long usable life ahead of it.

Going back to your Lead Acid - your 12KW is about 6KW usable if you want any sort of lifetime.
It also likely takes up a good portion of space. It's also far more dangerous having around - the hydrogen gases need to be vented, or you have a risk of explosion.

If the rand wasn't half what it was a few years back, the Telsa Powerwall wouldn't seem expensive.
The issue with the Tesla though is its more of a Grid Tied solution.

Its really intended to hook into a Grid Tied inverter, as the charge voltages are in the 300-450V DC range.
This is likely intended for a panels (in series) -> Tesla -> GTI (grid tied inverter).


300-450V DC @ 8A ties in quite strongly to what their claimed outputs are for the battery output.
I still need to see one or have more details about an install to get a better idea of actual usage though.
Dearth of stats on the internet still..


Here, I'd strongly argue we're more in need of Off Grid or Hybrid. That may change if NERSA ever gets off its ass and publishes fair FIT rates. I'm not holding my breath on that though.


Personally I'm offgrid.

Lithium batteries are by far the better option, over "Dead Acid". Dead Acid is cheaper in the short term, but more expensive overall. Lifetime is what counts, not upfront costs. Better to invest in something that will last, even if it costs slightly more at the outset.

Only other solution that comes close for medium term storage at the consumer price level is probably flow batteries. Redflow ZBM is the closest to being available to consumers at the moment, and I'm watching and waiting..

Good overview of upcoming products here - http://redflow.com/wp-content/uploads/2015/07/pv-magazine_Storage_Special_Jul_2015.pdf (It's the PV Magazine Storage Special).
Click to expand...

Somer very good points

1) the rand is ****ed, so powerwall doesnt make much financial sense
2) offgrid changes things massively. For a grid tied solution, how many times will you actually cycle your batteries? AGM's are rated to 80% discharge, but i've configured my inverter to only 50% discharge. I have yet to hit that limit and run out of batteries. Most AGM's are rated 500-1000 cycles. lets assume 500 cycles and 50% discharge 2x a week. That gives me 5 years before i need to replace. I'm guessing that in 5 years time, lithium batteries are going to be WAY cheaper than they are now, so in the long run, i'm actually saving money buy not buying lithium now.
3) it doesnt cost "slightly more at offset". It costs a bucket load more at offset. But again, if off grid is your application then your options are very limited
 
zeely said:
Somer very good points

1) the rand is ****ed, so powerwall doesnt make much financial sense
2) offgrid changes things massively. For a grid tied solution, how many times will you actually cycle your batteries? AGM's are rated to 80% discharge, but i've configured my inverter to only 50% discharge. I have yet to hit that limit and run out of batteries. Most AGM's are rated 500-1000 cycles. lets assume 500 cycles and 50% discharge 2x a week. That gives me 5 years before i need to replace. I'm guessing that in 5 years time, lithium batteries are going to be WAY cheaper than they are now, so in the long run, i'm actually saving money buy not buying lithium now.
3) it doesnt cost "slightly more at offset". It costs a bucket load more at offset. But again, if off grid is your application then your options are very limited
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1, 2 (addressing the 5 years down the line pricing)
Yup, the Rand *is* ****ed. Only going to get worse, especially now we've decided on bailing out SAA (*again*, see the just announced news on that vis a vis 17 billion reinjection from business development fund), and Nuclear. Any price decrease in Lithium based solutions is going to be offset by rand depreciation. We'll be lucky if we don't hit junk status by May-June.
Expect 20 to the dollar by end 2016 if we don't make some drastic changes.
In 2-3 years time, who knows where we'll end up. Again, any price drops in Lithium will be offset by that, so everything imported is going to get far more expensive, rather than cheaper.

LI is rated for 3000 cycles, at 80% DoD, so far cheaper than LA based with 500 @ 50% DoD..

The Tesla is 7KW usable capacity (actual battery capacity is more, in the roughly 9KW range @ 80% DoD), so equivalent to 14KW of LA (assuming 50% DoD) for same *usable* capacity.
Given it also includes the BMS then its not too bad in comparison pricewise.

Upfront costs are higher, but lifetime costs are far lower. You're right, most people are short sighted, or can't fund it upfront.
For those that can though, its a fairly decent deal.

Its more expensive than I can roll my own LFP based storage solution for, but not by that much, and its an out of the box plug in and forget solution.

If I had excess $'s at the moment, I'd probably be buying one. As it is, I'm keeping all my foreign funds the **** away from the rand...

I recognise that different people have different needs. I've always been a proponent of the right tool for the right job.
Not everything is a hammer, and not everything is a screwdriver. The price / lifetime ratio will be in the right spot for a lot of users...

Cape Town is currently R2.86+vat for > 600KW usage.
The Tesla 7KW daily solution can compete with that *already*, and make financial sense.

+-60,000 cost ( ignoring rest of system cost for pure battery calc).
7KWhr usage / day cycling. 365 days a year. 8 year lifetime @ 7KW discharge.
= 20440 KWhrs of output.

20440 x 2.86 = R 58.5K vs R60k +- cost. Pretty close.
You'll still get another 5-10 usable years out of the battery from that point, so lifetime costs are pretty much covered already at *current* costs.

Next year and the year after that when further Eskom / muni increases hit, its going to look a whole lot smarter to mitigate those kinds of costs. The only troubling thing in that equation is where the rand will sit vs the dollar.
 
lsheed_cn said:
You know nothing Jon Snow.
Click to expand...

Don't shoot the messenger because you don't like his message.

lsheed_cn said:
1, 2 (addressing the 5 years down the line pricing)
Yup, the Rand *is* ****ed. Only going to get worse, especially now we've decided on bailing out SAA (*again*, see the just announced news on that vis a vis 17 billion reinjection from business development fund), and Nuclear. Any price decrease in Lithium based solutions is going to be offset by rand depreciation. We'll be lucky if we don't hit junk status by May-June.
Expect 20 to the dollar by end 2016 if we don't make some drastic changes.
In 2-3 years time, who knows where we'll end up. Again, any price drops in Lithium will be offset by that, so everything imported is going to get far more expensive, rather than cheaper.

LI is rated for 3000 cycles, at 80% DoD, so far cheaper than LA based with 500 @ 50% DoD..

The Tesla is 7KW usable capacity (actual battery capacity is more, in the roughly 9KW range @ 80% DoD), so equivalent to 14KW of LA (assuming 50% DoD) for same *usable* capacity.
Given it also includes the BMS then its not too bad in comparison pricewise.

Upfront costs are higher, but lifetime costs are far lower. You're right, most people are short sighted, or can't fund it upfront.
For those that can though, its a fairly decent deal.

Its more expensive than I can roll my own LFP based storage solution for, but not by that much, and its an out of the box plug in and forget solution.

If I had excess $'s at the moment, I'd probably be buying one. As it is, I'm keeping all my foreign funds the **** away from the rand...

I recognise that different people have different needs. I've always been a proponent of the right tool for the right job.
Not everything is a hammer, and not everything is a screwdriver. The price / lifetime ratio will be in the right spot for a lot of users...

Cape Town is currently R2.86+vat for > 600KW usage.
The Tesla 7KW daily solution can compete with that *already*, and make financial sense.

+-60,000 cost ( ignoring rest of system cost for pure battery calc).
7KWhr usage / day cycling. 365 days a year. 8 year lifetime @ 7KW discharge.
= 20440 KWhrs of output.

20440 x 2.86 = R 58.5K vs R60k +- cost. Pretty close.
You'll still get another 5-10 usable years out of the battery from that point, so lifetime costs are pretty much covered already at *current* costs.

Next year and the year after that when further Eskom / muni increases hit, its going to look a whole lot smarter to mitigate those kinds of costs. The only troubling thing in that equation is where the rand will sit vs the dollar.
Click to expand...

1. The rand's depreciation is offset be salary inflation, so it's zero sum.
2. Lead acid is 500 cycles at 100% DoD, 1500 at 50%.
3. R60k (yeah, right) excluding panels, inverters, charges, insurance, etc. > R58.5 all in (and I'm not paying R2.86/kWh), plus it's all upfront - R58.5 is over the next 8 years.
4. 365 x 8 = 2922 cycles. You said it yourself, these things are rated for 3000 cycles, so you're going to be replacing it after 8 years, if not sooner.

For your off grid case, this battery is better than lead acid. On-grid is better than off-grid unless your connection costs are >R250k, and for on-grid, lead acid is ALWAYS better.
 
My original point stands. This isn't an AMAZING deal. Its average at best.

If it was AMAZING it would beat lead acid in every scenario hands down
 
Maybe the general LA ( car ? ) batteries sold in the market have 30-50% usable , but I have been buying stationary LA batteries with 70% usable. So lsheed, you are just like JS, you know nothing!
 
Drunkard is sure doing his name justice in the thread.

The gem of his senseless ranting being 100% Depth of Discharge on lead acid battery.

And it sad because guys that actually "know" usually refrain from posting any further as they have nothing to prove when fools with Google knowledge tries to be smart.
 
The_Traveller said:
Maybe the general LA ( car ? ) batteries sold in the market have 30-50% usable , but I have been buying stationary LA batteries with 70% usable. So lsheed, you are just like JS, you know nothing!
Click to expand...

Please keep your mouth shut when you when you have limited knowledge on a subject , you can join the same line as Drunkard

Isheed and anyone else with half a brain knows that the DoD is related to the number of time you can cycle a battery , so at 70% DoD your batteries will have to replaced a lot sooner.
 
Jaws677 said:
Drunkard is sure doing his name justice in the thread.

The gem of his senseless ranting being 100% Depth of Discharge on lead acid battery.

And it sad because guys that actually "know" usually refrain from posting any further as they have nothing to prove when fools with Google knowledge tries to be smart.
Click to expand...

"The guys that know" stop posting because they have nothing to back up their bull****, like your claim that 100% DoD on VRLAs is "senseless ranting". Prove it. Because I sure as hell can prove my claims, with datasheets. No, I'm not posting first, because then you'll just disappear quietly like the clueless loudmouth you are. You want an education, I explain this all to you carefully, for R2 000/h. My knowledge isn't free.

Jaws677 said:
Please keep your mouth shut when you when you have limited knowledge on a subject , you can join the same line as Drunkard

Isheed and anyone else with half a brain knows that the DoD is related to the number of time you can cycle a battery , so at 70% DoD your batteries will have to replaced a lot sooner.
Click to expand...

Here are the facts: For on-grid installations (UPSs, etc.) the batteries won't be cycled often enough to kill them. They will die after 10 years anyway, so you might as well get full use out of them. VRLA is absolutely superior in this situation.

For off-grid installations, there may be a case for the iBattery, but you'll need to run the numbers against 20-year lifespan flooded lead acid (twice the lifespan of lithium). Either way, you're paying far, far more than anyone on grid is paying, so it's only worth it if your connection is going to cost hundreds of thousands.
 
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