Lithium Batteries [ Group Buy ]

I am ok with either Winston or CALB cells. They were the two on my short list when still looking to import cells for my car. And then I found a second hand set of GBS cells locally at a price I could not resist. :-)

Would the price for the 100Ah cells be about 100/180 * the price for the 180Ah cells? So about R600 and R900-R1200 after import?

John
 
I wish. Unfortunately you're looking at around slightly more than double that, depending on things.
Importing here usually works out to about double what the price is in China.

I need to pay for export in China, plus paperwork, plus shipping. Shipping is the cheapest part of all that.
Thats about RMB10-15k (R20-30,000).
Will probably be more due to the special certificates required for dangerous goods.
Landed in SA, I need to pay clearance, plus duties, plus vat. Thats usually about (R20,000 +[ Product Price * 1.14 + Duties] )
Then I need to pay for delivery +- 3-4,000
Clearance in SA is outrageously expensive.
I also need to hope that it doesn't get held up in customs, as that can easily add up to another R20k

So, before you even start, there are added costs of roughly R50-60,000 + [ Product Price * 1.14 + Duties]
You try to make sure that everything is good, and the shipping agencies don't f**k you, but it still can happen.

I've also got to fund money up front to buy the batteries, and bring in. Money costs money.. Looking at about 9% year there till they sell.
Lots of little costs that people don't see when importing ;)

So, say I brought in 1000 x 100Ah batteries for sale.

I need about 5% extra for faulty units as I'll need spares. I'll have to QC the other end in China too.

1050 @ RMB300 (not actual price but will suffice) x 2 for Rand Equivalent = R630,000
VAT = 88,200
Duties - HS Code 8507.60.8 for Lithium = Zero duty yay!

718,200 + R70,000 shipping to be safe.

R790,000 +- for a 1000 units.

So the *cost* price is about R790 a piece before any profit, and not counting in cost of money +-9%.
I'll also need storage and insurance this end, and some sort of sales.

Would need to sell at about R950 a piece at a _minimum_ to break even for 100Ah unit.
That barely covers the time both ends + staff costs.

Should give a good overview of why things cost what they do though!
 
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Depending on final price I would be up for 8 ( might convince myself to do 16 ) x 180 Ah batteries

Please keep the thread running :)
 
lsheed_cn said:
Would need to sell at about R950 a piece at a _minimum_ to break even for 100Ah unit.
Click to expand...

That is inside the R900-R1200 I extrapolated from your initial post with a R1500-R2000 estimate for the 180Ah cells.

If you can keep the selling price close to your R950 guestimate, I might go for 32 cells rather than just 16 and maybe 1 or 2 spare.

I'm prepared to pay at least part of it up front.

John
 
I'm really keen, but waiting for an answer from MLT Drives and Outback re support for Li battery charging. My system is 48V DC, so 32 or 48 required.
 
48V would be in sets of 16.

I leave tomorrow for Shanghai, no winter in Cape Town for me :)

Have someone going to the SNEC solar show tomorrow (paid one of my old staff to go).
Will see if any interesting storage products available at the show.
 
Arthur said:
I'm really keen, but waiting for an answer from MLT Drives and Outback re support for Li battery charging. My system is 48V DC, so 32 or 48 required.
Click to expand...

Arthur please post back their feedback since I'm using the same hardware. But I've read on other forums that at least the outback should work.
 
Outback will be fine, I have an FM80 in a completely offgrid application, and it can be configured appropriately.

MLT should be ok if you can set the peak charge voltage, and disable float (not really needed). Charging Lithium (LiFePO4) is a lot easier as its almost a case of charge with as much current as you can provide until you hit the right voltage, then stop.

I recommend about 80-85% max charge and 20% max discharge for longest lifetime.

lfp-la.jpg

I will be supplying balancers with the batteries, so you won't need to worry about cell balancing.


I would be able to supply test batteries to MLT for you if necessary, as they're local to me.
Heck, I could probably write the code for the unit too (embedded dev is one of my areas of expertise!) :)
 
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lsheed_cn said:
Outback will be fine, I have an FM80 in a completely offgrid application, and it can be configured appropriately.

MLT should be ok if you can set the peak charge voltage, and disable float (not really needed). Charging Lithium (LiFePO4) is a lot easier as its almost a case of charge with as much current as you can provide until you hit the right voltage, then stop.

I recommend about 80-85% max charge and 20% max discharge for longest lifetime.

View attachment 211616

I will be supplying balancers with the batteries, so you won't need to worry about cell balancing.


I would be able to supply test batteries to MLT for you if necessary, as they're local to me.
Heck, I could probably write the code for the unit too (embedded dev is one of my areas of expertise!) :)
Click to expand...

I would think that they should just add a lithium profile onto the software or disable stage 4 charging(float).
 
I think the absorption phase is the one you really want to get rid of. That is the one that will cause damage. On most systems you can set the float voltage, so one can just set it pretty low, say 3.35V per cell.

John
 
Many of the inverter/charge units that are designed for lead-acid have settings that are accurate to 0.1 V. Should be accurate enough to prevent overcharge, but might be a bit rough to implement an accurate low-battery cut-off at say 3.4 V ? That could be between 20% and 50%, according to the above graphs.
 
Keep in mind that the graph that lsheed posted was a charging curve and at a specific charging rate (0.5C). Discharging curves will look different for different manufacturers and cell sizes and rates. Here is one for the 100Ah Winston cells:

WB-LYP100AHA-2.png


From that, if you were to discharge at 1C, 80% would be about 3.0V
 
So after Tesla's reveal about the Powerwall I think it would be better to wait a bit and see. It will be interesting to see which countries they support and how much it will cost. The 7kWh packs seem to be the ones to look out for.

The questions I have about it is:

1. Is it 7kWh of usable power? I'd think it would be so? Pointless advertising it as 7kWh and then you can't get it out...
2. DC-DC Conversion. This is important since most of the current tech uses 48V. They say it does have a DC-DC converter built in. Hopefully it can do 48V.
3. Lifetime. The 10 year warranty would suggest that you would get at least 3650 cycles out of it.
3. Costs...3000*12. R36,000 not bad. Will probably cost more but lets use this price for now.

So if you use R36000 as the price and work on roughly 3650 cycles it comes down to R10 per cycle! This equates to 10 / 7 = R1.40/kWh. This is pretty much in line with Eskom prices.

So if these figures pan out to be, lets say 80%, accurate it means that we have almost reached grid parity for storage which is huge!
 
There isn't enough information yet about the Tesla batteries to really answer the questions.
Here are some of my guesstimates on that:

1) I'd guess 7KW usable, so probably 10KW actual.
I could be wrong. Referring to the 7KW device here.

2) They state its running at a few hundred volts, not 48V

From the powerwall page - http://www.teslamotors.com/powerwall

Power 2.0 kW continuous, 3.3 kW peak; Voltage 350 – 450 volts; Current 5.8 amp nominal, 8.6 amp peak output.

My guess is that its intended to tie into a (grid tie) inverter.
I've seen a few products that work like that eg solar <-> battery <-> grid tied inverter.

Will need to see more info to see how it is supposed to slot into an existing system though.
This will be good for those with hybrid grid tie inverters, but I'm guessing it may need new equipment for others.

They state its intended to sync up with Fronius Symo Hybrid, so I'm guessing I'm right on my supposition(s).


A good list of hybrid inverters here -
http://www.cleanenergyreviews.info/blog/2014/10/14/hybrid-solar-inverter-summary-2014

3) It doesn't say 10 years battery lifetime.
It says 10 years warranty. There is a difference. 10 years warranty doesn't mean that the batteries will necessarily last 10 years, just that the unit is warrantied for 10 years. You'll probably need to buy new batteries at some point even if you're within 10 years.

Its also not necessarily Lithium Ion for the 7KW unit my thinking it probably Lithium Iron Phosphate or Lithium Sulphur so they get a decent lifetime. Again, more information is needed. The 10KW battery is likely Lithium Ion as that is rated for weekly use.


Doesn't really change much for me, as its more expensive than DIY'ing it.
Will be great if they expand to South Africa though.

First countries look to be Germany, Australia, and the US though.


In other news, although I didn't make it to the Solar Show, I did get one of my staff to go, and will be picking up show materials from them sometime next week. Hopefully lots of good products to do some more research on :)


-
Did a bit more research. Tesla is actually using (L)NCA batteries (LiNiCoAl)- Lithium Nickel Cobalt Aluminum, not "Lithium Ion". Its similar but not the same.


At 60%-70% DoD appears to give about +-3000 cycles for NCA @ 25c (substantially less at 40C, so cooling is necessary for summer in our climate), and capacity is only down about 10%, so should last 10 years at daily cycle rates without too much loss assuming they stick to 20-80% charge, and have +-12KW of actual storage in the 7KW unit. LCA should be good to 15-85%, which is similar to LiFePO4.

Some testing here on the NCA cells Tesla uses - http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110003627.pdf

NCA is about 15% denser energy wise than LFP, so its a good solution for cars where weight is an issue.

I prefer a higher density battery though, having to deal with hundreds of 18650 batteries would be a pain.
TESLA does make their own battery management system and balancing for those though, and have been successful at managing that in their cars. Home storage is a lot easier on batteries than EV's, so lifetimes should be longer.
 
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Well one can hope right? If they provide a 350V-48V DC-DC conversion it really becomes an option. Especially if their international support is good. But we really need better information on this system and how it would be tied into existing inverters, if at all.

And I still think people should wait to just get some clarity on some of the points above before going the DIY route.

Some more talk if this here.

They also don't feel the love though. Maybe Musk is potentially planning a short term monopoly on 350V inverters that integrate with his pack...:D
 
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Their product is really intended to be stuck behind a hybrid inverter.

You can see that by the voltages. It will feed in nicely to a GTI (hybrid one)

Eg - my 10KW unit with 2 MPPT controllers takes up to 1000V @ 8A per controller.
I could stick 4 of the 7KW units in front of that for storage of 28KW (which would work nicely for my needs)
Would cost about 300% of my DIY'ing though..

Have to see how that gets charged though.
From a look at the data sheet for the Fronius Symo Hybrid, the GTI does the charging. I don't see a single phase unit though, its only 3 phase on the Fronius website (which is fine for me, as thats what I actually use)
http://www.europe-solarstore.com/do.../DBL_Fronius_Symo_Hybrid_EN_0114_as17_low.pdf

I think best to make a new thread for unrelated stuff though, this thread is more towards the group battery buy :)
 
I'm waiting on pricing on larger modules at the moment.

Balqon is doing pretty much the same as I'm going to be doing, so should be similar, albeit with prices adjusted for SA import costs.

Balqon is using Winston Batteries. Their BMS setup seems fairly similar to my own suggested requirements too, which is nice - means I'm doing it right :)
 
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Ok so I worked it out, my daily requirements is a 100kWh.

So lsheed, kindly suggest/recommend a complete system for me please.
 
100kWh seems a little high for daily requirements.

I'll bite though. May I suggest this:

Tesla PowerPack 100Kwh unit x 2 @ 25,000$ per pack (+- R600,000). 1 might be enough with solar, but I don't know discharge C rates for the PowerPack as they're not published yet. 2 to be safe.

Some solar to go along with that for charging - say 30KW to be safe @ R7 KW for another R210,000 so you should be able to charge a powerpack from empty to full in 5hrs + cater for other use.

Some sort of large scale offgrid 3 phase inverter in the 35KW range (to give some headroom). Not sure offhand but would assume somewhere in the 100k range. Will have to be 3 phase due to power rating.

Add another 90k or so for install costs. May also incur other taxes on import, so lets be safe and add 20%

You have 1M - 1.2M to spend?
 
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