[RE-wrenches] LiFePO4; WAS Availability of Powerwall Batteries

[Starlight Solar Power Systems]

Aloha Marco,

If most of your customers take good care of their lead battery banks, the cost may be well more than one could justify. The types of customers I service regularly destroy batteries for a few, repeated reasons. We offer the lithium battery because it overcomes all the reasons their batteries are damaged and offers self protection from the owners neglect or abuse.

I think a certain number of purchases are first adopter junkies. This fact is present in many tech industries: first Segway, iWatch and so on. Others perceive the value from benefits that lead can’t offer. I’ll just shoot from the cuff here:

One huge example is that it takes 40% less time to recharge LFMP. 
A PV solar system is always charging in the bulk mode so there are no electrons wasted as with lead in the absorb and float modes. Same thing applies with generator fuel savings.
Much higher charge efficiency than lead.
No Peukert’s effect whether you charge/discharge fast or slow.
You can walk away from our battery for many months with no maintenance required, no loss of capacity. 
Very low sag; Voltages always stay high with very minimal change over 90% of the battery.
You can use 100% of the battery without harm so much smaller banks can be used.
Single cell replacement at any stage of battery life.
Claimed cycle life at 3 to 6 times that of lead batteries. (we shall see)
Significantly higher and faster current available for inverters starting heavy loads; smaller inverter can be used.
Capacity monitoring and fault detection and protection are part of the package.
Far less degradation of capacity due to high temperature. 
There is no need to fully charge so PV arrays and generators can be smaller.
Fully protected system in case of user neglect.
MUCH higher charge current can be used, up to 3C; lead is about C/5, Trojan is C/6  
For our RV customer, a huge weight reduction, about 75%, and space savings. 
No testing, no monitoring, no log keeping, no equalizing, no cleaning, no worry about harming the battery, no replacing corroded cables and connectors, no break in period to achieve full capacity, I’m tired of thinking.


Of course, there are some disadvantages. For the average off grinder or battery backup, you will save money buying lead. You might even save a lot of money if your time is free. Some will simply want the advantages Lithium ion offers and pay the price now. I like those customers. 

Thank you,

Larry Crutcher
Starlight Solar Power Systems



On Jan 23, 2016, at 1:28 PM, Marco Mangelsdorf <marco at pvthawaii.com> wrote:

Aloha Larry,
 
To take a step back…what’s the compelling value proposition from the homeowner’s perspective to incur this non-trivial additional expense?  To be blunt, what’s in it for them?  Back-up power?  First adopter mojo?
 
Thanks,
marco
 
August,
 
To be sure, there is a fragility in using LFP batteries if the integrator does not understand the pitfalls….and there are many. In November a lithium battery and solar “dealer” emailed me for help. He had damaged an $8000 battery bank and wanted to know how to get it working again. After I told him a few things to NOT do, I then offered my expertise for a $250 consulting fee. No response.  I could tell of other cases where the unlearned have ruined their DIY installation or people have bought a LI-ion battery from dealers that won’t provide support. The stories are too many. 
 
I’ve been on the bleeding edge for 2 years now and I’m still discovering mistakes I made in the early application of our battery. Fortunately I am able to make the changes to hardware and software to keep the battery safe from humans. Lead is SO much more forgiving than Li-ion when it is not done right. 
 
We are up to 4-5 installations per month plus out the door sale of about 5 systems per month. I receive email inquiries daily about our LFMP batteries. I have high hopes for products from the likes of Tesla. As I have said in the past, Lithium battery technology IS the future for RE storage…lead, your years are numbered. 

Larry Crutcher
Starlight Solar Power Systems
 

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