Winston LFP life?? Real world usage

Ampster today the easiest analogy to define a LiPo is a battery in a Foil like Pouch aka Coffee Bag vs say a cylindrical or prismatic solid structures. It allows manufactures to make the just about any shape they need to fit the application. Example cell phones, netbooks, and tablets. In other words mold it into any shape required. There is no specific chemistry used and can be any of the ones already mentioned including LFP.

A true LiPo of yesteryear did not find many applications because they exhibit a high resistance which really limits what they can be used for. They are as you said used a polymer solid electrolyte. Today that has been replaced with a gelled electrolyte. So today what is called LiPo can be any of the chemistries, but it boils down to the case it is made out of or rather a lack of a shell or case. That makes them dangerous because they can be easily punctured. What it does is improve Energy Density which is expressed as wh/Kg. Without a metal case can make the battery 20% lighter in weight.

Hope that helps.

Sooooo. Getting back on topic of Winston life, you won't find anyone that has had 7000 real world cycles of their Winstons as the cells haven't existed that long.

In practice, you will find many 2010 and onwards battery packs still performing as new. (ie cycling anywhere from 80 - 20% daily)

The common factor of longevity is well known - keep SOC between 20 and 80, don't charge cells above 35deg c or below freezing.

If you are in Australia and are getting your system professionally installed, you are better of using the BYD system. Not much more expensive, warranted for 10 years, integrates with SMA and Victron.

As I mentioned earlier, I had good luck with the Winston's I used in an EV. They were also used in some small yard trucks used in Los Angeles Harbor to move containers. The local distributor, Balqon did that implementation in 2012. I haven't heard anything negative about that project.

Speaking of BYD, it looks like they are trying to have a presence in the US:
http://www.byd.com/cn/en/BYD_ENProdu...817!-900746506

They have been manufacturing buses for the public transportation sector for a while. Several years ago I toured an assembly plant in Lancaster, California.

The battery test centre in Canberra Australia has been setup with manufacturer's batteries that under go accelerated x3 discharge/charge cycles per day. https://batterytestcentre.com.au/
The discharge end point is aggressive at about 10% SOC for most brands. In test report 5 they have measured capacity fade. Not looking good for a Calb (Winston equivalent) that have faded to 80% after 1000 of these aggressive cycles. BYD and Alpha ESS (both self contained LiFePO4 with integrated BMS) down to 90%

The Calb had an early battery failure and there has been some poor reliability of SOC from its REC Bms (hard to get exact details on what happened from website and reports- no mention of balancing or how the 32x100Ahr cells were setup and monitored). All this testing was in a controlled temperature setting. I would suggest that in the real world Australian environment (especially if remote and unattended and a coastal location) relying on precision electronics to control the battery charge and discharge to a 80-90% levels that the manufacturer's are pushing is pie in the sky stuff. As I think tom rickard said somewhere - glad that the battery test center is not installing off grid systems (my understanding is that they were all installed and adjusted by the suppliers or to manufacturer's specs).

But I understand your pain, we are being ripped off here in Australia with cost of batteries, the best I have seen from a local supplier is 180AHr Calb batteries is $288 each. If you want to get to A123 quality then I believe there is an Australian manufacturer that supplies military/industry -lithbattoz.com.au (?previously lifetech out of Taiwan) but at x3-4 the price.

So if you are going to go down the cheaper import from chinese suppliers and prepared to take the risks I would base calculations on a 50% discharge cycle if you want to come anywhere near a 10 year lifespan. If you want to look at chinese suppliers here is a list that you can check out at your own risk (not affiliated with or used any of their products)




and as some have said in an attended off grid LiFePO4 storage system that is initially well balanced and operated away from the knees of the voltage curve a complicated BMS may not be necessary.

That is good input. There is no doubt that there are quality cells being manufactured in China. The hardest part is finding a reputable seller that will sell you the ones that come out on top from their binning process. Among the DIY electric car community there were positive reports in the USA about Calbs coming with as much as 10% greater capacity than what the cell said. That was years ago and the US distributor may have had some influence over quality.

Installing lithium batteries without a BMS is like driving a car with a blindfold on. Good luck.

When it comes to important stuff that can have severe consequences upon failure, I don't trust anything made in China. Others may disagree, but that is my opinion.

Do you think that Lithium batteries have a higher level of need to be monitored?

As the state-of-charge goes up the charge-controller automatically changes from BULK charge to FLOAT charge, etc. I just wish that my charge-controller was more friendly in terms to doing the EQUALIZE charge.

To have the batteries monitored does not add any benefit to the charge-controller.

Absolutely.
High voltage, low voltage, amps in, amps out, charge cessation at 33F


And nobody's charge controller ever mucks up.
And no need for race car drivers to wear nomex fire suits, because there is a fire truck there now.


no, but it makes it nice not to have to replace Li batteries as often as FLA The BMS should both throttle the charger and the inverter to keep the batteries within normal operating parameters. Flooded batteries & AGM batteries are extremely forgiving of mistakes. Li, not a bit tolerant of error. Maybe they will be better at handling abuse in 30 years, but as of now, they need tight monitoring and safeties.

A higher level? Higher than what? Lead acid batteries don't need to be monitored for safety, they just die quietly.. Granted, the more monitoring you do to LA bats the longer they last, but its not really a safety thing, its an economic issue. But with lithium, its almost exclusively about safety.

A proper lithium setup will have double redundant controls over the lithium pack. A good quality charge controller and then a good quality BMS with supervisor authority over the charge controller, and then a contactor "kill switch" that disconnects the battery pack.

My off grid system uses a REC BMS fitted with a contactor to disconnect the pack from the Sunny Islands.. The BMS communicates and controls all charging parameters and sends the SI's commands.

The system I built for my neighbor also uses a REC BMS, but his array is DC coupled. For that, we use a Victron Charge (SmartSolar 150/60) controller and the REC BMS has the ability to open and close the "ENABLE" signal to the controller.. and if that fails, the BMS can disconnect the controller via the main bat contactor.

We use Lithium Ion batteries encased in Hoffman 14ga NEMA electrical control panels that should be able to withstand a lithium ion fire. Each box has a 5 inch hole to allow hot gasses to escape. On the outside of the box, covering the 5 inch hole, we have 2' deep by 8 inch wide stainless steel C-Channel that acts like a tunnel to channel the gasses where we want them to go. The "tunnel" is loosely packed with stainless steel scrubbies that resemble Brillo pads, but much coarser and loosely packed. This is our spark and flame arresting device.

While I have no doubt the entire system will self-destruct if the battery goes rogue, the fire won't spread.

As a community, if we don't encourage people to take the proper safety measures, the insurance companies are going to lobby governments to control these lithium batteries.. .and once that happens, you can say goodbye to being able to easily obtain them.

It is already here in the form of NEC 2020 which essentially specifies that an Energy Storage System (ESS) must be UL approved. Pb batteries are an exception to that. It may take a while to be adopted by states and each AHJ in the states.
This will benefit Tesla, LG Chem and others who already have UL approved products. I use the term UL approved loosely and am not distinguishing between UL Approved or Certified. For details the code should be consulted.

Here is a discussion of the new code and some insight on how it may affect the DIY community:
https://diysolarforum.com/threads/ne...-5#post-185112
This subject may deserve its own thread but I suspect it may not affect many users here. I will be affected and am looking at options.

I gambled on buying 20 x 60ah LFP used Winston Thundersky. They were nicely compressed.
When I got them home realised they were 22 years old! By reading the bar code numbers.
​​​​​​I tested the capacity as a 16s1p, 20A draw, managed about 50ah.
Impressive!

For the life cycling span and energy capacity remains of the Thundersky Winston is quite powerful ! One of our companies electric forklifts installed Thundersky Winston cells since 2007, it still works even today 2023 , say almost 16 years !
The whole battery capacity is over remarked capacity for 10~15%. That's why its remaining capacity is still that high instead of declined year after year.