diy solar

diy solar

LYP vs LiFePo4 charging etc

Daddy Tanuki

Solar Wizard
May 11, 2021
Flanks of Mount Fuji
So just ordered Winston that are doped withYttrium (sp) not a lot of data and they simply state charging from 2.8- 4.0
Was planning running them same as LiFePo4’s from 3.0-3.45 anybody have any experience with this?
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this is what is on Winston's website, one of the questions I have is what do they consider as normal temperature? (upper right hand chart) I would think it would be 25°c but not being listed...

the bottom left chart shows at least to me that probably a 3 volt LBCO would be fine, but that I should charge it up to about 3.6 regularly. and top balance around 3.75 or so.

it seems on discharge at what they term normal temperatures that at a 0.5c draw it seems to start around 3.4 (for a rested battery?) and then slowly drop to 3.1 before hitting its discharge knee at 3.0 and then rapidly dropping to 2.8 until i get more documentation it is hard to get a good idea without resorting to a WAG.

I think i might just take one cell and top it up to 3.5 and then measure it as it rises up to 3.75 to get a better idea of where the curve actually lays and then do a capacity test to see more closely where it starts to drop fast. I need to figure out how the lashup between the tester and a laptop works.

Standard temp is typically 25°C.

I've recently seen those charts, and they confirm my recollection.

Note how the capacity is > 100% when you charge to 4.0V. Charging to 3.6-3.65V should be the 100% mark, and a slow charge to 3.45V should be at or near 100%:


That shows just shy of 100% at just below 3.5V at 0.5C, and I expect that you aren't charging at 0.5C regularly.

Discharge chart shows a 0.5C draw will yield almost all the capacity above 3.0V.


So yep... 3.00-3.45 sounds like a luscious operating range - maybe 3.1-3.45

Any charge rate vs temperature data? Yttrium doping typically allows charging down to -20°C.
just got my bank to pull the lead out of its backside... 13k paid to winston.... was worried about shipping until i received this.

From: []
Sent: Tuesday, January 9, 2024 5:24 PM
To: morgan-engineering-repair
Cc: comdept
Subject: Re: RE: Dimension confirm from TSWB Celes to Ken

Dear Ken,

Thanks for your quickly reply.

About the shipping, we ship in hazardous package certified plywood crates, which are also padded with sponges to ensure that the shipment gets to you without damage. You can see the following pictures for reference.shipping crate.jpgwing
OK verified two things with Winston as I wanted to be 100% sure of this: charging at -25c is OK at .25c, but charging at any c rate at 25c will increase cycle count and cell life.

secondly the cells are brand new off of the line and not over runs, rejects, or warehouse queens.