# Cheaper Grid Storage now shipping



## PhantomPholly (Aug 20, 2008)

Energy density no better than Lead Acid, but many times more cycles and 1/3 the cost per KwH of LiIon.

Story here.


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## Sunking (Aug 10, 2009)

Interesting indeed, but I see a lot of PR's like this and they never see the light of day and become vaporware like EEstor and NanoSolar. Time will tell.

One thing that strikes me is the $300/Kwh and 5000 cycles I find a bit odd. Today you can buy a Rolls 4000 series RE Battery line which is FLA at roughly $150/Kwh with 5000 cycles at 20% DOD. Are they claiming 80% or more DOD @ 5000 cycles.


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## Shane Jackson (Sep 28, 2011)

Sunking said:


> Interesting indeed, but I see a lot of PR's like this and they never see the light of day and become vaporware like EEstor and NanoSolar. Time will tell.
> 
> One thing that strikes me is the $300/Kwh and 5000 cycles I find a bit odd. Today you can buy a Rolls 4000 series RE Battery line which is FLA at roughly $150/Kwh with 5000 cycles at 20% DOD. Are they claiming 80% or more DOD @ 5000 cycles.


Try again! the 4000 series has a 2000 cycle life at 20% DOD (which makes for a LARGE battery bank...)

The 5000 series is the ones rated for 5000 cycles at 20% DOD. And they run closer to the $250-300 per KWH range.

The DOD % to cycles is not mentioned for these new batteries.... If it can do a decent DOD % to life cycles... it could be a good option for off grid applications.

Chance of it seeing the light of day for consumer market.... not too good. We can only hope.

Shane


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## Sunking (Aug 10, 2009)

Shane Jackson said:


> Try again! the 4000 series has a 2000 cycle life at 20% DOD (which makes for a LARGE battery bank...)
> 
> The 5000 series is the ones rated for 5000 cycles at 20% DOD. And they run closer to the $250-300 per KWH range.


Shane that was just a typo on my part. I use a lot of the Surrette 6 CS 25P batteries(5.76 Kwh) in cell sites and pay $890/each from Southwest Battery in DFW. Only point I was trying to make is it is a Press Release, and those are just that, words on paper.


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## Shane Jackson (Sep 28, 2011)

Yep... one could always hope....

As for the price on the 6 CS 25P.... seems very reasonable. I may have to pick some up for my off grid project.

Thanks,

Shane

Just found this on their website:

Aquion’s batteries can be repeatedly cycled to 100% depth of discharge without capacity fade. 

Check out http://www.aquionenergy.com/technology

If that is true..... bye bye lead.


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## PhantomPholly (Aug 20, 2008)

Yeah, I forgot to post that link. I'm curious about the fact that in their technology they clearly state it is only for stationary applications - I wonder if a car remaining upright would work ok. But, the ability to go to 100% DOD is certainly nice to have.

I too was not impressed by the price, but I think they are basing the "value" on total cost of ownership. Where I think these might shine is for a small pickup conversion, where weight is not as prohibitive as in a sedan, and also in garden tractors which are subject to a lot of abuse (again that 100% DOD advantage).

The temperature range is good, and I suspect a lot of folks on this forum with lead-acid may be able to replace their batteries with these and get improved performance.


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## PhantomPholly (Aug 20, 2008)

Page 7 of this PDF gives capacity vs. voltage and energy density charts. 

Would someone who understands how to interpret these provide a comparison to lead acid, e.g. if you replaced 500lbs of lead acid with these would you get more or less available energy?

Edit: Some other tidbits from the pdf - little or no need for BMS; high tolerance for cell-to-cell mismatch.


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## Sunking (Aug 10, 2009)

PhantomPholly said:


> Page 7 of this PDF gives capacity vs. voltage and energy density charts.
> 
> Would someone who understands how to interpret these provide a comparison to lead acid, e.g. if you replaced 500lbs of lead acid with these would you get more or less available energy?
> 
> Edit: Some other tidbits from the pdf - little or no need for BMS; high tolerance for cell-to-cell mismatch.


Yeah I can help you out with that. 

They have left out one the most important parameters with respect to EV's, Specific Density, but assuming based on the energy density it will be less than flooded lead acid which is not good.

OK first is the voltage capacity discharge curve expressed in SOC voltages:

100% = 1.75 volts
50% = 1.25 volts
40% = 1.00 volts (maximum recommended discharge)
0% = .5 volts

That is problematic for an EV. Ideally you want the discharge curve as flat as possible from full charge to 100% DOD. For example a standard FLA battery is 2.1 volts @ 100%, and 1.75 volts @ 0%. So for say a comparable 12 volt battery FLA is *12.6 down to 10.50 volts*, and this battery would be *14 down to 4 volts*. That is really going to limit usage to the top 50% because at 50% DOD you drop a 14 volt battery down to 10 volts. You would not be able to use the last 50% capacity. Therefore no gain over FLA because you want to limit FLA to 50% DOD.

But here is the wet blanket they do publish energy density of 24 to 28 wh/L. To compare FLA is 60 to 75 wh/L, and LiPo is 200 to 300 wh/L. That means the battery will have to be physically 2 to 3 times larger than a FLA for a given capacity, and over 10 times as large as a LiPo for a given capacity. Just based on that spec alone pretty much eliminates their practical use for EV's.

The spec they did not publish as I eluded to earlier is critically important to EV is the Specific Energy stated as wh/Kg. I can only assume it is less than FLA of 40 to 50 wh/Kg. LiPo is up around 130 to 200 wh/Kg. That means if my assumption is correct, this battery would have to be 2 to 3 times heavier than FLA for a given capacity and up around 10 times heavier than LiPo. Not good.

So based on what they published, not a candidate for EV applications IMHO. FLA has them beat and no where close to LiPo.


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