Lithium Batteries

[oober]

Has anyone put together a pack with integrated bms at a decent price yet?

There are some local solutions like bluenova and freedomwon.

But the prices are still more expense than what we pay per kw/h.

 

[itareanlnotani]

You need to look at the price per KW over the lifetime of the product, not the upfront price.
They're not going to beat Eskom just yet.

Bluenova's pricing isn't too bad, Freedomwon are $$$ though.

 

[oober]

Yes have been looking at the lifetime price. Although I'm not sure how accurate the specified lifetimes are.

Seems that our prices still needs to rise quite a bit before these systems are cost effective.

 

[itareanlnotani]

Tesla Powerwall 2 might be interesting, depends on actual price here though.

Might beat current CoCT pricing anyway assuming its $5500 x Rand value. (which it won't be, but we can dream).
JHB you'd need to see what you get charged, I don't know offhand.

 

[oober]

Tesla Powerwall 2 might be interesting, depends on actual price here though.

Might beat current CoCT pricing anyway assuming its $5500 x Rand value. (which it won't be, but we can dream).
JHB you'd need to see what you get charged, I don't know offhand.

Currently paying R1.28 inclusive. I worked out using specs from this.

My calculations: Assuming average usage of about 9kw/h per day it looks like one can expect += 5000 cycles. I think these specs are for 10 years?

So if you take up to ten years pricing looks like: R114,700 / 5000 / 9 = R2.55/kWH excl VAT?

Assuming 10% increase on price it would take +-8 years before the system at current pricing becomes viable.

How are those calculations?

Also I don't know how long a system like this will last. Batteries degrade with time as well and there doesn't seem to be enough data to indicate +10 year performance. I've seen places where they mention 80% capacity after 10 years usage at certain daily cycles.

 

[itareanlnotani]

I went with 14KW x 365 x 10 = 51,100KW of theoretical power @ 10 year lifetime. Typically Lithium lifetime means to 80%, so may be longer - say 15 years.

5500* R14 / 51100 = R1.506 odd per kw over warrantied lifetime, which is better than CoCT rates, at least in the Cape.
Actual pricing will obvious depend on landed pricing, and actual lifetime / battery life depreciation, all of which are unclear as yet.

I'll probably make a post with calculations when more info is available. I did one for the previous Powerwall on goingsolar.co.za
If Tesla can keep improving like this each year, then we're quite close to being at the point where the grid is simply more expensive than battery + solar.

 

[oober]

I went with 14KW x 365 x 10 = 51,100KW of theoretical power @ 10 year lifetime. Typically Lithium lifetime means to 80%, so may be longer - say 15 years.

5500* R14 / 51100 = R1.506 odd per kw over warrantied lifetime, which is better than CoCT rates, at least in the Cape.
Actual pricing will obvious depend on landed pricing, and actual lifetime / battery life depreciation, all of which are unclear as yet.

I'll probably make a post with calculations when more info is available. I did one for the previous Powerwall on goingsolar.co.za
If Tesla can keep improving like this each year, then we're quite close to being at the point where the grid is simply more expensive than battery + solar.

Pricing getting close yes, but probably need to add about 20+% onto that price for importing which is still not too bad. Also I won't just be throwing out my 48V system to get a powerwall. So I have to go with something like the above mentioned systems or build my own.

Edit. Hmm it looks like powerwall 2 will include an inverter? Then it might not be so bad at all. Allows the 48V folks to easily switch over. And the inverter looks quite powerful as well.