DIY Lithium Guide

[john61ct]

Originally Posted by Maine Sail

You've made similar shot in the dark statements here and elsewhere and all I know is that you seem to have more info on this than I do

I sure don't Rod, like you say shots in the dark.

I certainly **hope** there will be a functionality-based assessment process that will allow for LFP systems cobbled together by amateurs, as we do with lead now, rather than requiring only certain approved vendors' very expensive "complete systems" to be certified.

[john61ct]

Originally Posted by zboss

Who is making the programmable discrete BMS's favored by professional installers now?

By professional installers, I only know of full packaged systems like Victron, MasterVolt, Lithionics.

And user-installed DIY on the other hand.

[Maine Sail]

Originally Posted by john61ct

I sure don't Rod, like you say shots in the dark.

I certainly **hope** there will be a functionality-based assessment process that will allow for LFP systems cobbled together by amateurs, as we do with lead now, rather than requiring only certain approved vendors' very expensive "complete systems" to be certified.

The ABYC standards are performance based. The ABYC neither includes nor excludes any vendors nor does the ABYC certify anything. The standard will set performance based criteria an installer, builder, DIY or manufacturer needs to meet in order to be considered safe and in compliance with the standard.

[john61ct]

Excellent!

[john61ct]

Originally Posted by TheThunderbird

In setting a 3-Phase charger for Lithium, what's better? FLA, GEL, OR...??

I would only select charge sources that allowed for user-defined profiles, custom setpoints.

Sterling ProCharge Ultra and ProMariner Pronautic P do this, not sure of other shore power chargers.

Or a quality adjustable power supply, able to be turned off by a voltage-sensitive relay, or say a BM measuring trailing amps.

[john61ct]

Originally Posted by Davidhoy

What does "prismatic" mean in regards LiFePO4 batteries? From what I've read it mainly refers to flat, rectangular cells, as opposed to cylindrical cells. Clearly the flat rectangular cells can take up less space than cylinders, but is there something that makes them inherently safer than other cells?

I've just learned that 18650s aren't even LFP, but Lico (lithium cobalt), at least all the 3.4V ones on the retail market from Chinese OEMs for Panasonic/Sharp, LG, and Samsung

That in itself is a deal-breaker, my understanding is that out of all the LI chemistries, only LiFePO4 is safe enough to use on a boat.

Now if a Tesla pack (they use their own proprietary 18650 LCO) were to be available one day, including all its protective BMS functionality but adapted for 12V House bank usage, maybe I would think about it, but I suspect that's at least a few years away.

[john61ct]

Originally Posted by TheThunderbird

YTTRIUM? Due to its basic voltage, you come up with 5x batteries for a 12V system, and again there is some mismatch...

I thought Winston used a Yttrium component in its LFP cells? LiFeYPO4?

Or do they make separate lines, one with one without?

[Maine Sail]

Originally Posted by TheThunderbird

In setting a 3-Phase charger for Lithium, what's better? FLA, GEL, OR...??

GEL would be closest voltage wise but bear in mind it is the "absorption duration" that is the killer. If you can't adjust the absorption time to 0 minutes to a max of 30 minutes you will see cell damage and shorten cell life.

By dropping charge voltage to 13.8V you can get by with a slight absorb duration at up to 30 minutes at CV. The higher the absorption voltage e.g.: GEL/14.1V the shorter the absorption duration needs to be.

For example: (12V nominal pack)

Charge Voltage 14.6V / CV Duration = 0 min
Charge Voltage 14.2V / CV Duration = 10 min +/-
Charge Voltage 13.8V / CV Duration = 30 min +/-

I have destroyed piles of LiFePO4 cells in testing, from very expensive CALB prismatics to piles of cylindrical cells, even premium brands like A123. Duration at voltage is by far the bigger killer than voltage alone and lead acid chargers all do longer duration absorption then LFP can safely handle unless it can be duration programmed down to 0 - 30 minutes (voltage dependent). Oh and LA chargers also float & float = BAD for LFP..

Charge sources for LFP really need to be fully programmable including voltage and duration.

[zboss]

I found this USA importer and distributor... Bright Star.

Anyone have experience with these cells?

Why Our Batteries Are Better

[Maine Sail]

Originally Posted by john61ct

I would only select charge sources that allowed for user-defined profiles, custom setpoints.

Sterling ProCharge Ultra and ProMariner Pronautic P do this, not sure of other shore power chargers.

Or a quality adjustable power supply, able to be turned off by a voltage-sensitive relay, or say a BM measuring trailing amps.

Sterling PCU and PM Pronautic P can only be set for voltage and will have too long a CV duration so they need to be manually managed by the owner... Charlie has a new algorithm in the B2B chargers that is CV duration programmable to 0 min but this is not yet available in his chargers.

[Colin A]

Originally Posted by Maine Sail

GEL would be closest voltage wise but bear in mind it is the "absorption duration" that is the killer. If you can't adjust the absorption time to 0 minutes to a max of 30 minutes you will see cell damage and shorten cell life.

By dropping charge voltage to 13.8V you can get by with a slight absorb duration at up to 30 minutes at CV. The higher the absorption voltage e.g.: GEL/14.1V the shorter the absorption duration needs to be.

For example: (12V nominal pack)

Charge Voltage 14.6V / CV Duration = 0 min
Charge Voltage 14.2V / CV Duration = 10 min +/-
Charge Voltage 13.8V / CV Duration = 30 min +/-

I have destroyed piles of LiFePO4 cells in testing, from very expensive CALB prismatics to piles of cylindrical cells, even premium brands like A123. Duration at voltage is by far the bigger killer than voltage alone and lead acid chargers all do longer duration absorption then LFP can safely handle unless it can be duration programmed down to 0 - 30 minutes (voltage dependent). Oh and LA chargers also float & float = BAD for LFP..

Charge sources for LFP really need to be fully programmable including voltage and duration.

I always wonder about this. Alot of Lithium brands seem to say using a gel profile is OK (lithionics Victron). I wonder how they get away with that. They also seem to say floating at 13.5 or 13.6 is OK. I have been looking at the new Simpli Phi batteries they call for charging at 14.4 volts but then no float (cut off charging entirely). But then go onto say they are drop ins, which seems to be asking for trouble.

[Maine Sail]

Originally Posted by Colin A

I always wonder about this. Alot of Lithium brands seem to say using a gel profile is OK (lithionics Victron). I wonder how they get away with that. They also seem to say floating at 13.5 or 13.6 is OK. I have been looking at the new Simpli Phi batteries they call for charging at 14.4 volts but then no float (cut off charging entirely). But then go onto say they are drop ins, which seems to be asking for trouble.

Sometimes I suppose they just want to sell batteries........ This is not unlike what the battery makers did to GEL batteries when they said it was OK to use flooded charging voltages. To this day the GEL market has never recovered despite them being some of the longest cycling lead acid batteries ever made.

The 10K Mastervolt LFP battery I have in my shop, that was murdered using Mastervolts own charge guidance, and factory integrated charge sources, is evidence enough that some of these manufacturers have simply failed to do the proper homework before setting charge guidance for lead acid designed charging sources.

I personally don't need any more evidence that high absorption with too long a CV duration & float voltages damages LFP than the piles of cells I have ruined/diminished capacity of by testing various voltages and charge parameters then re-capacity testing them. No one else was doing this testing so I did. I spent good money on my bank so I wanted this info for my own education.

I have CALB SE cells that lost 11% of their capacity just sitting at 100% SOC without any charge source connected for a period of approx 12 months. I have premium A123 LFP cells that lost 27% floating at 3.35V (13.4V) and cheaper Chinese LFP cells that lost 41% floating at 3.35V (13.4V). Initial capacity was all pre-tested before starting these tests so a solid baseline was available to work from.

I have done this because the white papers on floating LFP and extended CV duration are basically non-existent. Why? Likely because it is only those of us in the marine, off-grid and RV world who would try to adapt LFP to lead acid charge parameters...

LFP is really quite simple:

• Charge then STOP CHARGING & use the energy

• Don't float

• When not in use leave them sitting at 40% to 60% SOC in a cool environment

Dockside you take them off line and use the lead acid back up or find a shore charger that can be set to maintain 12.9V - 13.0V and can hold them at a midpoint SOC.

[john61ct]

Originally Posted by Maine Sail

When not in use leave them sitting at 40% to 60% SOC in a cool environment

I've read posts from people seemed otherwise knowledgeable, that Stored SoC should be as low as feasible (well above BMS cut-off of course), preventing any chance self-discharge would reach the user-defined "zero floor".

So say LFP self-discharge in storage condition is 3%, isolated of course, and it's possible owner won't top up for up to six months, floor is conservatively defined as 10% SoC, so say 30%?

Or if I *know* I'll be on board monthly to top up, 15%?

Or do you think there's *no* longevity advantage to storing below 40%?

[john61ct]

Originally Posted by Colin A

But then go onto say they are drop ins, which seems to be asking for trouble.

AKA fraudulent claims, as is standard in the industry, and for which there are no consequences in the US market.

To my mind, the only true drop-in would be one that had charge control with boost and buck conversion built-in, along with the LVD / OVD protection.

But of course that would still be set to too high a voltage. Is there **any** "touted as LFP compatible" system that is set to stop at or under 3.5Vpc ?

I think that's even the case with Bruce Schwab's Lithionics setup, or is that adjustable?

My theory is the batt mfg don't actually *want* our banks to get maximum longevity. . .

[john61ct]

Originally Posted by Maine Sail

Sterling PCU and PM Pronautic P can only be set for voltage and will have too long a CV duration so they need to be manually managed by the owner... Charlie has a new algorithm in the B2B chargers that is CV duration programmable to 0 min but this is not yet available in his chargers.

Yes, I knew that about the mains chargers.

My workaround if I needed unattended would be set to 3.4Vpc and minimum Absorb, but only if I knew a load would be active, so the bank didn't just sit there that full.

Does any shore charger on the market do better?