Make your own Tersla power wall

[allover]

Looking at another site and thought you may be interested in how to make your own power wall


Only problem is getting the batteries, but i am sure some one will have a contact!

[allover]

= $10 per battery x 600 = $6,000 = phtttp unless you can pick them up second hand

[Dishtrackted]

[gordon_s1942]

= $10 per battery x 600 = $6,000 = phtttp unless you can pick them up second hand

I would be very reticent in buying second hand batteries unless you know exactly where they have been and used.
I remember a company like Jaycar advertised the sale of Gell Batteries at well below new price even though they were fairly new because it appears they were in a UPS system and there had been a fire and although not damaged, they were being replaced.
Obviously they sold faster than hot cakes to I would guess anyone who didnt have a system that you could not risk having a less than perfect battery on.

[ol' boy]

Thats pretty cool
His Samba Project is awesome too, those VW's are worth a fortune now.

[spook]

The only energy storage you should look at is lifepo4, the powerwall is li-ion, they can burn or explode and unbelievably expensive, yet incompatible Aus with off grid systems. The first thing you need to do is find out what your energy usage is, what you can reduce it to and then look at prices for storage capacity. You need 3-5 days of energy storage to become reasonably self sufficient and only lithium chemistries can do that for you at a reasonable price, weight and life span. You can choose between li-poly, li-ion or lifepo4. The first two have stability and safety problems, plus store at higher voltages, so are good for EV and hobby. For off grid or backup storage, lifpeo4 is the best overall, they are stable very safe and used properly, have a very long life span, but a bit more expensive. Most claims of life are over 1000 cycles, which is true if you don't use them right. But if you avoid full cycling, then theoretically, they can last indefinitely and we won't know that until they have been in service for 20 years.

Plus you need good dedicated solar charger controllers for them, cell voltage alarms and a couple of system meters. You can go for a BMS and active cell balancers, but if you have a real lifepo4 charge controller, they are not really necessary. The way you know you have a lifepo4 charger and not a modified lead acid one, is lifepo4 charging is bulk only, not temp, equalisation, trickle or float settings, all which will lower the life of your lifewpo4 cells. They also need to cut charging when the pack reaches 14v, restart charging at 13.6v and cut load at 12v.

When you work out what capacity you need, you calculate the size of your energy pack and work out the most economical, stable and workable way to achieve what you need. Retailers will offer you cell capacities for off grid off 100amp upwards, but when you look at the reality of the industry, you find EV and specialty installations all use smaller capacity cells. There are a number of reasons for this and the one negative of it is, you can have more connection problems, so using large capacity cells reduces the number of connections. For those who don't want to get into a making up a more complex but economic and long life system and have the money, large cells would be the way to go.

If anyone wants to source any thing to do with lifepo4, I'm the source finder for a small buyer group of long term friends which was originally started to get us cheap solar panels and gel batteries. Now we are into liffepo4, alternative fuels and energy generation. After nearly 20 years, have contacts all round the planet and now not only buy for ourselves, but others who want to get into what we call economic energy and life survival. Anyone who wants some help in getting new technology in these area's and how to set it up and use it properly from our perspective, send me a PM or thread and happy to help if I can.

[Dishtrackted]

Do you have an idea of costs to replicate power wall with lifepo4 ?

[spook]

I Believe the usable energy in the powerwall is only a few of kw, every ones power usage is different, so you have to build your system to suit your needs and afford ability. Many off grid people survive easily on 1000 ah of lifepo4, I use 700ah and my friends use from 500 to 3000ah. For a 1000ah system you put together yourself, you'd be looking at $5000-$6000. The cheapest way is 12v through 3000-6000w inverters, if you site your charge controllers close to your pack and have the inverter within 20-50cm, you can almost hardwire the inverter to the pack.

[Uncle Fester]

Generally LiFePo (The type I can find on Ebay) would be over twice the cost of using these 18650 and 4-5x the cost of using generic AGM lead acid.
This comparison is purchase cost per W/h only. Cycle life is not considered.

I do not find the use of these 18650 Li-Ion cells dangerous. Because they are so small, if one cell goes rouge it will just blow it's cap and in worse case a short flame might shoot out. The surrounding cells would not be affected, provided the enclosure is flame resistant.
I am certain Tesla would not do it this way if there is any possibility of danger.
DIY powerwall solutions might be a different story and a plywood or a flammable plastic cover over the positive side of the cells would pose a risk.

I would never attempt to make a firewall power wall with so called LiPo batteries as their individual cell capacity can be a lot higher and due to their thin polymer enclosure will burn and pass on the flames to the cells next to them.

BTW there are a few things from the links of the OP where I disagree. The worst idea is salvaging cells from used Laptop batteries.

[ol' boy]

So, what coming along to replace LifePo4, it sounds a bit old tech to me now

Or will this industry become another BETA vs VHS type scenario?

[Uncle Fester]

I am hoping for the breakthrough in super capacitors, charge in seconds, almost infinite lifetime or at least no cycle wear. There are some concepts in the pipeline but nothing ready for production.
Production of hydrogen direct from solar panels, easily stored in tanks (well, a special high pressure pump is required) then used in fuel cells as I mentioned here:

[Dishtrackted]

Honda is working on that



“A lot of this work is not necessarily for today’s economic situation,” said Mr Ellis.

“This is for tomorrow, when most people feel energy prices will be higher.”

[spook]

Generally LiFePo (The type I can find on Ebay) would be over twice the cost of using these 18650 and 4-5x the cost of using generic AGM lead acid.
This comparison is purchase cost per W/h only. Cycle life is not considered.

I do not find the use of these 18650 Li-Ion cells dangerous. Because they are so small, if one cell goes rouge it will just blow it's cap and in worse case a short flame might shoot out. The surrounding cells would not be affected, provided the enclosure is flame resistant.
I am certain Tesla would not do it this way if there is any possibility of danger.
DIY powerwall solutions might be a different story and a plywood or a flammable plastic cover over the positive side of the cells would pose a risk.

I would never attempt to make a firewall power wall with so called LiPo batteries as their individual cell capacity can be a lot higher and due to their thin polymer enclosure will burn and pass on the flames to the cells next to them.

BTW there are a few things from the links of the OP where I disagree. The worst idea is salvaging cells from used Laptop batteries.

Buying lifewpo4 cells or packs on ebay is not economic, the only way to to get them for DIY is from the suppliers or importers. We can get them for much less than on ebay and the size cells to use for off grid or mobile, is 40-50amp cells, they come in much cheaper then large or smaller cells because they seem to be the ones which give the most balanced and economic service. if a 100amp cell collapses you can lose all you storage, but if a 50amp cell collapses, you only lose and proportion and still gave energy. There is a business in Queensland which sells reasonably priced lifepo4 cells, can't provide a link but have seen a receipt from them which was a pretty good price, but the were 100amp cells.

[Guiseppe]

[allover]

Quote

I do not find the use of these 18650 Li-Ion cells dangerous. Because they are so small, if one cell goes rouge it will just blow it's cap and in worse case a short flame might shoot out. The surrounding cells would not be affected, provided the enclosure is flame resistant.
I am certain Tesla would not do it this way if there is any possibility of danger.
DIY powerwall solutions might be a different story and a plywood or a flammable plastic cover over the positive side of the cells would pose a risk.


I saw some where on his posts that he places an individual fuse to each battery in the hope it trips prior to detonation

[ol' boy]

So, this all comes down to Price vs Kw/h in Battery Technology over Lifespan (cycles)

Even with Telsa's own product, it comes in 2 variants, a 7Kw and 10Kw.
Its been said the 2 units are exactly the same, its just the 10Kw cycles deeper, but at the expense of Lifespan
Considering there is only $500 difference between the 7Kw and 10Kw, that would stand to reason.

The cost in all of this and the estimated savings, really don't look that attractive, yet.
But the concept may be a hit with locations where energy generation relies on fuel being shipped or flown in (Islands or Remote Towns etc)

Which really, has us way back to 25 years ago, when simple Remote Area Supplies were sized and built per property.

So has there been any speculative growth on Nickel / Manganese or Cobalt prices?

Will be interesting when Gigafactory 1 in Neveda kicks off and Gigafactory 2 in Japan.
Just watch as China copies all the technology and builds a Petrafactory in its own country.

So, how long until we can buy a domestic 100Kw pack from Bunnings?

[cmangle]

100.00 bucks for a piece of glass? Is he serious?

and Lithium IRON not ION is the way to go now . . no explosions!

[spook]

We paid landed in Tas, $1.10ah for our last batch and when our dollar was over $1US, $.84ah. Now the prices landed are between $1,16-$1,34ah, depending on which supplier you use and need to buy them in 5000ah lots to get the lowest price. That's because our dollar is so low and they will only deal in US$, not yuan.

There's also a difference in price and conditions between those imported via air and via sea, you have to work out which will be the cheapest and when bringing things in by sea, use a local shipping agent and by air chinese agent. Otherwise you may find your goods coming by sea will incur a chinese shipping company levy on the goods, which will dramatically raise the price. They claim it is to compensate for the difference between they Yuan and USA dollar, but won't do the same for the buyer

With air freight the concept is easy, but can be expensive, sea means they have to go the rounds through customs and you can end up with storage and extra costs to get the goods to you, air means they arrive at your door, or you collect from your shipping agent.

[Uncle Fester]

Quote


I saw some where on his posts that he places an individual fuse to each battery in the hope it trips prior to detonation

Nope.
A salvaged cell may have been deep discharged and even attempted to be recharged before you got them. It can then blow using the normal charge rate, well below the fuse rating.
Also he seems proud that he doesn't use balance charging because "it has worked for over a year in his Samba".
Unless you have a telemetric cell voltage detection as a phone app or something that warns you immediately if the cell charge voltage exceeds 4.25V or something that cuts the charge at that voltage (which would actually be a battery management system) then you could have a whole lot firecrackers and the fuses would do nothing about that.

[Guiseppe]

For a 1000ah system you put together yourself, you'd be looking at $5000-$6000.

I assume you mean the battery cost is $5000-$6000. My reasoning is as follows:

A string of 4 cells at 50 Ah to give 12V nominal at 50 Ah.

Therefore to get 700Ah there has to be 14 strings i.e. 14 x 4 = 56 cells.

56 cells x 50 x $1.1 = $3100 (say)

Add:

Solar panels at (say) $1.00/W = $3000

Installation kit (say) = $500

Installation cost (labour of CEC certified installer(s) (say) = $500

Charge controller (say) = $500

Inverter (say) = $2000

Cell connectors, wiring, etc., etc. (say) = $1000

Approx total cost = $10600

Deduct the appropriate credit (depends on area) (say) = $2600

All up cost approx.$8000

Plus genny for the cloudy winter days $(?)

System cost is $ (?)