LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

[newhaul]

Originally Posted by john61ct

Depends on your market. When quality deep cycling lead is available locally for ~$1 / Ah @12V, changes the calculus drastically.

I have not seen quality LFP sources here for under $7-9 / Ah delivered, often much higher.

ok how about calb cells for $4 per ah delivered. Direct from the manufacturer.


Side question when are you going to pull the trigger and buy some cells to run your own tests on ?

[john61ct]

Originally Posted by mat jam

Are there any major retailers carrying Lithium?

To be clear, I would like Lithium to live up to the manufacturers specs however thus far all data suggests otherwise. It would be helpful if people addressed the main points re: Lithium.

All the points are being addressed just fine, for those willing to just pay a lot for a proprietary packaged system.

OceanPlanet sells both Lithionics which Bruce helped design, and Victron.

If you want low risk that's what I recommend, but total cost per Ah @12V will be many times higher than even the priciest lead banks.

The higher risks and greater uncertainties come when you want to just buy quality bare cells and DIY / buy OTS the protective gear.

No, not rocket science, especially if you are happy just following the cell maker charging specs.

But certainly not easy either - full setpoint adjustability seems to be very rare, as is just monitoring / protecting at the pack level without cell-level wiring on 24x7.

[john61ct]

Originally Posted by mat jam

that if you take your batteries below 50% SoC you can expect hundreds NOT thousands of cycles.

That is objectively false for LFP, certainly in low C-rate House bank usage and when caring for them "avoiding the shoulders", neither of which are the case in the video.

It is however true for **other** lithium chemistries.

There are many users getting past seven years and 2000 cycles with little or zero degradation.

You haven't seen the data yet is all. Maine Sail has recently posted his, and IMO there is no more reliable source.

All that said, it is always the case for **every** batt chemistry, that drawing down deeper average DoD results in drastically shorter life cycles than shallow usage.

Say 5000 cycles rather than 30000 is my guesstimate in the case of LFP (in low C-rate House bank usage and when caring for them "avoiding the shoulders")

Finally do please start your own thread arguing this point, this one is cluttered / endless enough without rehashing LFP- skepticism.

This thread at this point should be for productive implementation details posted by those already convinced of the chemistry's value.

[newhaul]

Originally Posted by mat jam

. Are there any major retailers carrying Lithium?
.

who do you consider a major retailer
West marine carries them .
Wal-Mart has them .
Heck your local auto parts dealer likely has them .

[john61ct]

Originally Posted by transmitterdan

In an industry obsessed with fire risk one wonders how the name Fire Fly made it out of the marketing department. Not to mention the obvious double entendre of not putting them on airplanes especially due to risk of fire. Sheesh....

Well since production rates have been unable to keep up with rising demand anyway, whatever helps put on the brakes just leaves more for the rest of us

[john61ct]

Originally Posted by newhaul

you can get all of those brands direct without the markup that a reseller will add.

However the part of my post you quoted was wrt the bms not the Lfp cells .

Yes I was refuting to your suggestion that I just ask the cell maker for BMS suggestions.

And if I spend say $6 grand on a batch of cells, and 15% of them test out as below spec, I do not want to just eat it, since sending back to China is too costly.

I'd rather pay a bit more up front and deal with a seller in North America.

[john61ct]

Originally Posted by newhaul

who do you consider a major retailer

West marine carries them .

Wal-Mart has them .

Heck your local auto parts dealer likely has them .

Again, you are not IMO talking about cells suitable for this use case. What, 12V drop-ins sold as vehicle Starter batts?

Apples to oranges.

[john61ct]

Originally Posted by newhaul

ok how about calb cells for $4 per ah delivered. Direct from the manufacturer

So $16 per Ah @12V?

[newhaul]

Originally Posted by john61ct

Yes I was refuting to your suggestion that I just ask the cell maker for BMS suggestions.

And if I spend say $6 grand on a batch of cells, and 15% of them test out as below spec, I do not want to just eat it, since sending back to China is too costly.

I'd rather pay a bit more up front and deal with a seller in North America.

my bad I was actually saying to talk to the manufacturers of the bms units directly. Not the cell manufacturer.

[newhaul]

Originally Posted by john61ct

So $16 per Ah @12V?

no $4per ah at 12v
We have had this discussion several times already.

[newhaul]

Originally Posted by john61ct

Again, you are not IMO talking about cells suitable for this use case. What, 12V drop-ins sold as vehicle Starter batts?

Apples to oranges.

yes 100ah " drop ins" for vehicle starting I was posting that in response to mat asking for major dealer that has Lfp batteries.
It seems to me that all of his posts are directed towards " drop ins"

[john61ct]

Then almost every aspect of that discussion is off topic for this thread.

And certainly not relevant to the video either.

[newhaul]

Originally Posted by john61ct

Then almost every aspect of that discussion is off topic for this thread.

And certainly not relevant to the video either.

correct as well as several points in the video that are no longer correct due to the new data that has come out in the 5 years since that video was made.

[CatNewBee]

Thats a pitty, in the US this stuff is soo overpriced.

I got my Winston cells for 1.20 € / Ah from a reseller in Europe - so around 1.35 US$ or for 12V 4.80€ or 5.40$.

For quality deep cycle AGM of GEL we pay over 2.80...3.00€ per Ah, that is insane. I know, starter batteries are cheap, but they are not fit for the purpose, I do not want to change my batteries every season.

LFP are only 60% more expensive than quality GEL or AGM SMF batteries. and they last 5 times longer. So what not to like about them?

I suggest, get over the pond and buy them in Europe, nice sail via Bermudas and the Azores.... You'll find here a great variety of good BMS too. Bring your own BlueSea ML RBS solenoids, they cost in Europe twice as much as in the US.

You can let ship them the cells to Gibraltar to avoit VAT payment and refunds...

[john61ct]

Yes, what I keep emphasizing, good lead is 1/3rd the price and locally sold quality LFP lots more expensive and less well supported.

Completely changes the risk profile when ROI only starts after ten years.

Sail over to buy it in Europe is realistic for some I suppose?