Should I bet on the near future of battery technology?

openplanet · May 2017

I need to purchase a new 48 volt battery bank. Intend to buy 8, 6-volt batteries in the 350ah range. If quality and longevity were my highest priority (which they might be) I'd buy Rolls. But my question is this: Given the blazing pace of change in battery technology, would it be smarter to go with the cheapest possible solution that'll get me through a couple years, on the assumption that at that point there will almost certainly be more cost-effective options.

Just interested to know people's thoughts.

westbranch · May 2017

There are a bunch of Lithium Iron Phosphate LiFePO4 types coming on to compete with Tela's Power wall

jonr · May 2017

I see places that claim to have the LG Resu LV in stock. 18 years worth of cycles....

westbranch · May 2017

Jonr, I found lots of search hits in Europe, are there any in N.A. yet? PS lots of fine print to the warranty....

Marc Kurth · May 2017

openplanet said:

I need to purchase a new 48 volt battery bank. Intend to buy 8, 6-volt batteries in the 350ah range. If quality and longevity were my highest priority (which they might be) I'd buy Rolls. But my question is this: Given the blazing pace of change in battery technology, would it be smarter to go with the cheapest possible solution that'll get me through a couple years, on the assumption that at that point there will almost certainly be more cost-effective options.

Just interested to know people's thoughts.

It is a matter of degree. Acceptance of a new technology isn't an event, it is a process.

Lithium batteries are gaining momentum as you read this and they are being applied to RV/marine/solar systems daily. The existing sales are largely driven by the promise of more deep cycles and less weight in the case of mobile applications. Some sales literature will quote superior charge/discharge rates and wider temperature tolerance, but that is already available with some lead-acid designs.

Once we see field verified applications prove that they really will perform long term...... per the marketing projections/estimates, the world will come running.

In the mean time, biting the bullet to invest 3-5 times the capital outlay to reap the rewards later - requires a certain leap of faith. Feel free to climb out on the "bleeding edge of technology" and let us know how you are doing in a few years!

Don't forget to include the cost of that invested capital.........

Marc

westbranch · May 2017

Marc, I just thought of another issue and that is B. Bank expansion, ie adding more capacity after say 4 years due to increased/ing loads. I have not seen this issue addressed in the ,to date, literature... As these systems have essentially a separate additional bank to add with its own BMS etc there, theoretically, should not be any imbalance between banks... thus that problem may be solved....????
thoughts?

Estragon · May 2017

The inability to charge at freezing temps so far makes all these shiny new lithium banks a non-starter for me. Reading through some of the warranties also makes me wonder how they will last in real-world use. Personally, I would go with replacing the bank with whatever reasonably priced L16s are available locally.

The expansion angle is interesting, but I guess if we separated charge control down to the cell level we could add to lead banks as well.

Dave Angelini · May 2017

westbranch said:

Marc, I just thought of another issue and that is B. Bank expansion, ie adding more capacity after say 4 years due to increased/ing loads. I have not seen this issue addressed in the ,to date, literature... As these systems have essentially a separate additional bank to add with its own BMS etc there, theoretically, should not be any imbalance between banks... thus that problem may be solved....????
thoughts?

The LG can add a second bank at any time. If you guys are looking for answers, look at Australia. Two years of LG history and I can't find anything bad. Because each bank is a completely separate system (they can't run at the same time) each will have its own spec.
The RESU 10 will support 5kw continuous and 7 kw peak but if the second bank is less KWH, it will have less continuous and peak output.

PNjunction · August 2017

Don't get hung up on the "pace of change" and just changing for change sake. I Love LFP, but consider this:

You were thinking of buying a Rolls bank. That means you aren't going to get generic golf-cart cells from them. With LFP, you don't know, unless you do your homework and DEMAND that your supplier reveal that along with the cell-specs to you. Some assume you are too dumb as a consumer to know the difference between crap LFP cells and good ones anyway, so there is no point telling you or peeling back the re-wrapping of cells.

With large-capacity prismatics, you know what you are getting, just like with lead-acid for the most part. With full specs. Hey, just like lead acid. But in today's world, unless you DIY it yourself, you are at the whim of the purchasing department.

The reality for the future is everyone is looking to make a way to hide the technology inside from the consumer, and eventually proprietize the connectors, internals and charging systems and play the patent-troll sue-ball game.

Lead-acid is basically an "open system", with a century or more of basic tech behind. Not too much is proprietary. You can still slap some clamps on a lead-acid and charge. With lithium magic-boxes, (unless you know what you are doing) heh, no chance.

softdown · August 2017

I may consider buying a used lithium electric car battery. Apparently, according to Horsefly, there are ~2 million used lithium car batteries that will soon be available. Down to ~ 50% capacity now....that is still a lot of power.

Technology early birds always seem to pay a large premium while often playing the guinea pig role. These claims of 15-20 year lifespans have no real world examples that I know of.

I would currently buy more lead unless weight and charge efficiency was an issue. Lithium should be well "tried and proven" by the time some good deep cycles are ready for recycling.

Now my "Post Comment" box is not working for at least a long minute. Just became useable..... Someone is controlling this board.

XSive · August 2017

New to the forum, thought I would jump in as I purchased 48 used Winston LiFePO4 (out of car) originally they were 180AH but averaging about 135AH now. I am just building the house so I will keep everyone posted as to success with the batts or not. I have 46 320W mission Solar panels to use in the project and am looking for a CC or 2 now. I have room for up to 32 of the 72 cell modules on my garage roof. We are off grid in Southern Oregon.

littleharbor2 · August 2017

XSive Welcome to the forum. Sounds like a sizable project you have going there. It would be nice to see the progress as you go. You need to start your own titled thread which you can update as you build.

BTW you have come to the right place if you need technical questions on your build. There are a number of very knowledgeable members here

From the size of your proposed system you definitely will be in the market some of the larger controllers. There are some pretty sophisticated offerings out there these days. A few of the Mfg. that come to mind would be Midnite Solar, Outback, Schnider/Xantrex and Magnum.

Raj174 · August 2017

Hi XSive and welcome to the forum,
Sounds like a good opportunity to learn balancing, charging and other characteristics of LFP batteries.
Might not be a good idea to buy any more solar equipment before you have a plan for a balanced system designed to meet your specific power requirements, designed for the in the area you live in. For example, your choice of 24 cell 320 watt panels will not allow the use of flooded lead acid batteries without the use of a special high VOC CC, as two panels in series will not produce enough voltage and 3 in series will produce a high VOC.
Many people make the mistake of buying the wrong equipment before they have a final design.

Rick

softdown · August 2017

Raj174 said:

Hi XSive and welcome to the forum,
Sounds like a good opportunity to learn balancing, charging and other characteristics of LFP batteries.
Might not be a good idea to buy any more solar equipment before you have a plan for a balanced system designed to meet your specific power requirements, designed for the in the area you live in. For example, your choice of 24 cell 320 watt panels will not allow the use of flooded lead acid batteries without the use of a special high VOC CC, as two panels in series will not produce enough voltage and 3 in series will produce a high VOC.
Many people make the mistake of buying the wrong equipment before they have a final design.

Rick

XSive said this:
" I have room for up to 32 of the 72 cell modules on my garage roof"

mcgivor · August 2017

Probably an auto mistake "correction" issue, best to start a new thread is good advice, to actually deal with specific problems related to a particular installation, or proposed installation.

softdown · August 2017

mcgivor said:

Probably an auto mistake "correction" issue, best to start a new thread is good advice, to actually deal with specific problems related to a particular installation, or proposed installation.

Yes....it is an off grid question with lithium batteries. I suspect we were all a tad overwhelmed with our first real solar system. Unless we upgraded on a linear scale.....or had a background in similar areas. I jumped from a very simple 12 volt to a good 48 volt system. Felt like giving birth....I guess.

XSive · August 2017

Raj174 said:

Hi XSive and welcome to the forum,
Sounds like a good opportunity to learn balancing, charging and other characteristics of LFP batteries.
Might not be a good idea to buy any more solar equipment before you have a plan for a balanced system designed to meet your specific power requirements, designed for the in the area you live in. For example, your choice of 24 cell 320 watt panels will not allow the use of flooded lead acid batteries without the use of a special high VOC CC, as two panels in series will not produce enough voltage and 3 in series will produce a high VOC.
Many people make the mistake of buying the wrong equipment before they have a final design.

Rick

Thanks for the welcome Rick,
Just posted here as the discussion was about battery tech, used car batts, and which direction to go. I decided not to go FLA as it is old tech and there are many alternatives at good pricing. With the advent of the number of EV's out there now, there are plenty of opportunities for salvage batteries that will serve our home storage needs quite well. People run into things with their cars just as often in EVs. For example, my 420AH LiFePO4 set cost me $2200. Used, but they will have a gentle remaining life in my garage. I will start a new posting about my project. Thanks

Raj174 · August 2017

softdown said:

Raj174 said:

Hi XSive and welcome to the forum,
Sounds like a good opportunity to learn balancing, charging and other characteristics of LFP batteries.
Might not be a good idea to buy any more solar equipment before you have a plan for a balanced system designed to meet your specific power requirements, designed for the in the area you live in. For example, your choice of 24 cell 320 watt panels will not allow the use of flooded lead acid batteries without the use of a special high VOC CC, as two panels in series will not produce enough voltage and 3 in series will produce a high VOC.
Many people make the mistake of buying the wrong equipment before they have a final design.

Rick

XSive said this:
" I have room for up to 32 of the 72 cell modules on my garage roof"

Thanks softdown,
I intended to type 24 volt. To bad they don't make an auto correct for that.

Rick

softdown · August 2017

XSive said:

Raj174 said:

Hi XSive and welcome to the forum,
Sounds like a good opportunity to learn balancing, charging and other characteristics of LFP batteries.
Might not be a good idea to buy any more solar equipment before you have a plan for a balanced system designed to meet your specific power requirements, designed for the in the area you live in. For example, your choice of 24 cell 320 watt panels will not allow the use of flooded lead acid batteries without the use of a special high VOC CC, as two panels in series will not produce enough voltage and 3 in series will produce a high VOC.
Many people make the mistake of buying the wrong equipment before they have a final design.

Rick

Thanks for the welcome Rick,
Just posted here as the discussion was about battery tech, used car batts, and which direction to go. I decided not to go FLA as it is old tech and there are many alternatives at good pricing. With the advent of the number of EV's out there now, there are plenty of opportunities for salvage batteries that will serve our home storage needs quite well. People run into things with their cars just as often in EVs. For example, my 420AH LiFePO4 set cost me $2200. Used, but they will have a gentle remaining life in my garage. I will start a new posting about my project. Thanks

Being unfamiliar with EV technology, I don't know if the 420Ah is referencing 12, 24, 36, or 48 volts.

Raj174 · August 2017

softdown said:

XSive said:

Raj174 said:

Hi XSive and welcome to the forum,
Sounds like a good opportunity to learn balancing, charging and other characteristics of LFP batteries.
Might not be a good idea to buy any more solar equipment before you have a plan for a balanced system designed to meet your specific power requirements, designed for the in the area you live in. For example, your choice of 24 cell 320 watt panels will not allow the use of flooded lead acid batteries without the use of a special high VOC CC, as two panels in series will not produce enough voltage and 3 in series will produce a high VOC.
Many people make the mistake of buying the wrong equipment before they have a final design.

Rick

Thanks for the welcome Rick,
Just posted here as the discussion was about battery tech, used car batts, and which direction to go. I decided not to go FLA as it is old tech and there are many alternatives at good pricing. With the advent of the number of EV's out there now, there are plenty of opportunities for salvage batteries that will serve our home storage needs quite well. People run into things with their cars just as often in EVs. For example, my 420AH LiFePO4 set cost me $2200. Used, but they will have a gentle remaining life in my garage. I will start a new posting about my project. Thanks

Being unfamiliar with EV technology, I don't know if the 420Ah is referencing 12, 24, 36, or 48 volts.

Likely 48 volts if he is considering using them as a house battery. And on a 48 volt inverter they can be configured for a single or parallel strings at 48, 51.2 or 54.4 volts. My LFP bank is 51.2V or 16 3.2V cells at 195AH in series.
The OP may have 2 or 3 strings. Winston cells come in sizes of 90, 100, 160, 200, 260, 300, 400 and up to 1000 amp hours.

Rick

XSive · August 2017

I plan on 3 strings 16S3P, each string is coming in at 130AH so 390AH in parallel. (48V) The batts originated @ EV West from a 1977 Ferrari GT 308

Bob

karrak · August 2017

@XSive, welcome to the group of people with LFP DIY batteries. Nice to be able to get the second hand batteries at a good price.

I would be interested to know how old the batteries are and what their internal resistance is now that they have lost around 25% of their capacity, also what the variation in capacity between the the cells is.

You mention 3 strings in your last post. Did you mean wiring 3 cells in parallel and then wiring the 3 cell blocks in series or wiring the 16 cells in series and then wiring the 3 strings in parallel?

Thanks
Simon

XSive · August 2017

Posted a new discussion about my project not wanting to hijack Openplanet's thread. I am still accessing all of the batts, takes time to do all of that. I found one out of 25 that won't make the cut so far. The cells are 3.2V so 16 in series would get 48v nominal like Rick was suggesting. I am hoping that we can get 130-140AH out of each bank for 390-420AH in parallel.

Bob

softdown · August 2017

XSive said:

I plan on 3 strings 16S3P, each string is coming in at 130AH so 390AH in parallel. (48V) The batts originated @ EV West from a 1977 Ferrari GT 308

Bob

Now I am a bit more confused though I tend to wake up that way with regularity. '77 Ferrari? Converted to electric? People do interesting stuff for sure.

Should I bet on the near future of battery technology?

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