Solar system batteries-Is Tesla Powerwall working

[kalakoa]

LiFePO4 batteries will provide a much longer service level

Can I buy them on-island and load them into my truck?

[randomq]

Watered my GC2's this morning. It is an extra chore, but easy and 1/3 the price per usable watt hour. (Less if you run them below 60%).

If I could afford a LiFePO4 pack I would totally do that though. Maybe in a few years!

[kalakoa]

Watered my GC2's this morning. It is an extra chore

Installed a "watering system" on my L16s -- worth it.

http://usbattery.com/install-battery-wat...ng-system/

[kander]

I know the Build it Green guys are selling LIFEPO4 packs. But the issue is that even though they dont explode into flames like the other lithium chemistry batteries, the shipping is just stupid crazy expensive. So I dont know of many places keeping a big supply of them.
Everyone that has went the way of Lifepo4 batteries has been extremely pleased.

[Wao nahele kane]

Forthe DIY out there.
The Tesla power wall uses Li-Ion 18650 batteries around 3500mAh each.
In other words, it's possible to build your own LiIon power wall, there's many online examples and builds.

[Wao nahele kane]

The safer option on the DIY side is the LiFePO4 chemistry and the 18650 is a common size.
As an example, these would come to $1875 for enough to build a 10kWh bank.
Look at this on eBay http://www.ebay.com/itm/182797197441

[kalakoa]

these would come to $1875 for enough to build a 10kWh bank

Outback NC200 would cost about the same, but you get a factory unit with a warranty.

Making my own battery pack sounds fun, but dangerous, and not insurable.

[Mikites]

There are better options than the 18650 cells for a bulk storage. If your thinking about going that route google prismatic lifepo4 cells.. they can be had in many capacities from 10-300ah per cell, many are rated for 1c charge and 3c discharge and rated for greater than 5000 cycles at those rates with 80% capacity remaining. They will run slightly higher in cost than nano carbons when you compare useable AH (50% dod on nanos). There is debate about BMS longevity in all lithium battery packs, personally I have had more failures due to BMS than cells, and 80% of the cell failures were due to failed BMS. There are variables that need to be considered before going that road, but it’s not difficult or scary and can be a very reliable long lived solution.

[kalakoa]

variables that need to be considered

I considered the practical: NC is a stable proven technology available off-the-shelf today, and this set of batteries should last long enough for the next "better" technology to become proven and available.

I was seriously considering NiFe ... but then it's special-order and shipping, etc.

[Mikites]

I’m using NC also on one of my personal systems, great dollar to ah ratio over the expected service life make sure you keep your max charge current under 60a per string and have an extended absorb time to keep them topped up, 3 hrs seems to be the sweet spot for me from a typical night with 75%SOC. Of course using end amps would be better if you have that option. This is where the Li chemistry batteries really shine... no absorb time at all.. bulk directly to float.