An Proto-Teach Éireannach

[Scruff]

Hi JW,

Thanks, to be honest I've never noticed the limit nor does it usually affect external link posts I've noticed in other forums.
I break up the posts because otherwise I get confused with all the links and it's more difficult to edit when there's an error when the pics are seemingly random text. Also if the computer does something squiffy midway I don't lose an hour of whittering...all about redundancy me.
I start a new post per take a breath space / sidebar / subject change.
No need on my behalf but not a bad idea none-the-less.

If we were putting suggestions in the box I'd add can we have more emoji's?

[JW]

Like redundancy Scruff 

"I break up the posts because otherwise I get confused with all the links and it's more difficult to edit when there's an error when the pics are seemingly random text. Also if the computer does something squiffy midway I don't lose an hour of whittering...all about redundancy me."

The keyword is Hyperbolic function 

 

[Scruff]

Marvelous things JW. Great applications!

Satellite dishes, heliostats, bulletproof helmets, Rock agus Roll lanterns...

I'm a fan of a good hyperbolic paraboloid myself. 

[JW]

https://lightspeedinterface.com/?s=hyperbolic

[Scruff]

https://lightspeedinterface.com/?s=hyperbolic

Reminds me of how other people look at me sometimes when I wax on about the esoteric properties of batteries and application phenomenon.

I find it quite interesting that the speed of light has never been measured. We have only devised ways to measure the round trip of light returning to the source/observer.

There's no evidence to refute that it's potentially 2C leaving the origin and instantaneous once reflected.

[JW]

https://www.youtube.com/watch?v=kaOOfci2YC8

try that one

https://lightspeedinterface.com/wp-content/uploads/2020/11/110520a-1024x845.jpg
\
hyperbolic function

[JW]

Oh ive been waiting for this statement

Please refer- I find it quite interesting that the speed of light has never been measured.

https://lightspeedinterface.com

I personally wrote this, I also think the universe is infinite... 

[Scruff]

Sorry JW it's all a bit Esher to me.



If we're exchanging art & music though...not a bad idea having a soundtrack to a post.

Here's the speed of light discussion:

I think you'd enjoy this:

You have to watch it 4 times, then watch a doc on all the bits you missed, then watch it again...


Hey...if the universe is infinite does that mean I'm the centre of it? 

[JW]

Last time I asked someone about the universe being infinite and they said "let us get back to you on that...

 

[Scruff]

Someone else told me 'twas expanding..

[JW]

Oh boy,

I have moved twice recently and cant find my whole library, working on this.

[Scruff]

Blimey is that a singularity engine JW?

[JW]

Lol

I made this picture, not copyied from anywhere

[Scruff]

I like it. A gem for the mancave.


Li-Fi results are in....definitely something there alright. Not so significant this time but there's some minor untapped depth and I've not cycled her as much as WuPoG.

The good news is it's reversible [citation required], time frame unknown but longer than sulphation takes defo.

I'll repost the original V1 discharge results so save yee scrolling up through conversation:



Here's the release cycle...we don't care about that so much as she was taken to a much higher SOC threshold.



Here's the V2 discharge post-release.



Edit: {I'm rerunning the test tomorrow...it just dawned on me I never synced the meter the last time and it started the test reading 98% as full}

She's triggering LVD on (usable) SOC 5% or Voltage >(whatever I said at the time)...40mins
In this case Voltage (13.1V I think) as I was testing at C1 when I set it...fix that tomorrow.

She's running dual chargers for trade secret reasons.
I reckon I can push them harder and add 15A to absorp, reducing the charge times.

Dunno about the more cowbell button yet. It might not be a job for MS because there's no tail current setting in their controllers!! I hope yer listening MS! The centre of the universe is calling you out.   

[Scruff]

Hey Li-Ion lobbyists!
Are yee talking through yer hats?
Have yee any data to back up your claims?
Do yee live in a world of make-believe and acceptable profit margins?
What was it before Li-ion? AGM are better than car batteries was it?
 D'yee know what a white paper is?
 If li-ion lasts 10 billion cycles why are phone batteries being replaced every 2 years?
Better seal 'em in there...more money innit.
Truth-dealer's will never be rich!

Round trip test round 3 results are in!
The only thing I did differently was remember to sync the Ah counter meter and let the battery sit at LVD cutout overnight.



More cowbell/memory release charge cycle mod sanctioned.

"Howdya make a SunSaver MPPT a dual profile charger?"

Glad you asked!

Load two custom profiles.

[Scruff]

Li-Fi has been fitted with more cowbell.



€5 for anyone who spots the secret switch.



I thought about giving her low temp charger foldback and it's a little difficult. Then I looked at Lead-Fi and decided that that's the better answer. Low temp? No worries! Send her!

The ProStar MPPT has this feature. Not so many more controllers I'm aware of.

Charge times are reduced 30mins. In the absence of SS MPPT Bsense terminals, I foresee there'll be a bittov timer adjustment required to knock another 30mins off depending on the feedback I get from the current settings trial.
It's a case of you get what you pay for/wasn't enough room situation I'm told regarding the omission.

She's charging at C2...fun as that is it's not practical with a large battery so I wouldn't be getting too excited about it.
She'll be charging an hour faster than Lead-Fi. I could keep going to C0.5 but that'd require hardware improvements and exponentially more expensive solutions.
Her TS MPPT is walking wounded; derated by 10A. I amputated some FETs a former owner massacred and can't get replacements. I'm also pretty close to the load limit of the "solar in" conductors to boot so not so motivated to keep pushing.

[Scruff]

I've been tweaking Li-Fi, Charge times are down from 3h10m to 2hr5m. That took a lottov finessing.
I've enabled EQ cycling on Li-Fi and WuPoG every 15 cycles to a near-zero tail current.

From my observations, this LiFePO₄ memory effect is producing diminishing returns of ~1% per cycle when using voltage-based absorption thresholds until a release cycle is performed.

The implications of this are quite significant. I spent a long time looking for this graph for LiFePO₄



That's data from LMO cells.

The dataset for LiFePO₄ does not exist/has not been published/I can't find it.
All that I can find is cycle data from li-ion plating country 100% SOC to datapoint, but no centre oscillating aperture.

So does this mean that batteries like Pylontech claiming 6k cycles to 80% DOD has voltage thresholds, coulomb counting and an applied capacity derating factor built into the BMS. Orr just charges to 100% & claims an unprovable fantasy figure,
alongside "LiFePO₄, No memory effect"

Oh wait here's a datasheet...
So it's limited to 90% DOD. Making it a 2.16kWh battery. Rated to 60% plated capacity after 6k cycles.
Why do they claim 6k to 60% plated...isn't 80% plated the industry standard?

Hrmmm who else is big....Battleborn?

"Conversely, LiFePO4 (Lithium Iron Phosphate) batteries can be continually discharged to 100% and there is no long-term effect. You can expect to easily get 3000 – 5000 cycles at this depth of discharge.

*Approximately 75-80% of the battery capacity will remain after 3000 cycles in applications recharging at 0.5C or lower. We have seen life spans well over 5000 cycles in our lab testing.*

"

5k cycles? Really? Not 1k assumed result = times 5? C2 in C1 out = 625 days continuously operating test...
90% user usable aperture.



Did I ever mention that after using an FLA battery in a van as a 6-month annual full-time liveaboard for 5 years I ascertained from my collected data I was effectively on < cycle 180 to 30% DOD.







That leady battery oughta last me another 55 years so!

Pity, it's not as useful as a battery with no self-discharge that I oughta store empty.

Oh wait, that's what this is for! Sources are better than collectors!

[SparWeb]

More F*ing cowbell!

I've started doing a bit of a deep dive in to Li-Ions (for work) and come up with interesting stats but the stuff I'm looking at is proprietary (like what you've heard).  All I can really do it summarize in words what I'm seeing.

Are you just looking for the DOD that you can get away with for repeated cycling without killing the cells?  I can go sniffing around and see what I can come up with.

[mab]

All very interesting stuff - If/when i go for an EV (when i can afford one) I'll want to understand the batteries and how to keep them going.

I know lead- my current off grid battery is AGM which i bought some 2nd hand in 2005, and some more 3rd hand and in dubious condition in 2014, but they're still going (although i don't do capacity checks - not intentionally anyway - but they still hold up well during the unintentional deep discharges that have happened now and then).

I expect that when i eventually have to replace my AGM's I should stick with lead (never really saw the point of Li for stationary applications anyway).

[Scruff]

Are you just looking for the DOD that you can get away with for repeated cycling without killing the cells?  I can go sniffing around and see what I can come up with.

Highest amount of kWh and lowest rate of usage deterioration per € Sparweb.
Alongside practical applications.

To be honest what I'm really looking for is the truth. Are they really any better than 170 year old proven technology when you filter out all the associated BS.

I'm glad I didn't buy an off the shelf/proprietary BMS. It'd be much harder to compensate for the issues I'm finding. Penny to a pound the BMS writers are just ignoring the problems. 2k cycles is an awful lot. But I can't help myself and demand does that make it ok to throw away another 2k because it makes things inconvenient to utilise them?
Most of the hardware I test is compromised either intentionally or otherwise...not good enough.

All very interesting stuff - If/when i go for an EV (when i can afford one) I'll want to understand the batteries and how to keep them going.

Life would be easier with an alternative li-ion flavour like NMC, LMO...more volatile though.
I was reading the battery kinder garden site yesterday looking for that elusive incriminating graph that doesn't exist. They claim phone and laptop batteries are "less industrial" hence the 600 cycles...what a loada horse manure....they're being overcharged it's the same flippin' chemistry. It's better outtov the box performance to overclock them and you sell more phones when you build in a predictable 2-year failure mode, ask why they're not replaceable if this isn't a factor?
20% larger cell, with a 20% lower discharge envelope lasts about 4 times longer and costs a coupla grams.

I know lead-

You'd think they'd be a no-brainer.
All you have to do is "over"-charge them to 1.28 SG once per month, add water as required and they become immortal.
For flooded that means 2.47V per cell + 5mV per cell per degree below 25°C to a tail current of 40mA.

Now why is that so hard to do? 
People complain about the maintenance..effin' automate it the dopes!

I think I'll SG performance test some chargers I have, to demonstrate the charger manufacturers, are accountable for the bad rep. lead gets. Incidentally, the same ones pushing li-ion for better profit margins. The issue could be resolved much more inexpensively with a lead LVD/HVD BMS and a high fidelity charger.
I have a blue one...I already know that's dire. I fitted it and removed it two weeks later.

I expect that when i eventually have to replace my AGM's I should stick with lead (never really saw the point of Li for stationary applications anyway).

As far as I can tell it's all based on lies & propaganda. Hard to blame anyone because it's compounded, things are taken as fact if it's broadcast enough. For instance somebody show me a factory fresh lead-acid battery that is <90%RTE, pretty please with sugar on top, because most institutes claim 80% and I cannot demonstrate this in normal operation, it's a once a month maintenance cycle co-efficient only.

[Scruff]

Snowin' out today. I'm still working on Li-Fi...my usage envelope was 15% too high.

Battery was 3°C...so not only do I have to store it empty, not charge it below freezing (or use high charge rates in low temps so even 5°C is harmful just not prone to ignition) I also have to keep enough in the battery to discharge it aggressively to get them up to a comfortable operating temperature or give it an electric blanket before I can charge it. 

Lead-Fi is ROFL.

[DamonHD]

Well, while I have largely stuck with LA for some of the reasons that you allude to* for my small off-grid system (~400Ah x 12V gel) and treated it quite well (with a Morningstar controller), its capacity is fading generally after ~8Y and it is not especially enjoying being in my shed at close to 0C either.

*Eg, there's a huge range of good, tested LA solar controllers out there, and nothing is likely to catch fire.  Less so with even LFP.

Rgds

Damon

[Scruff]

I derate the lead for ambient conditions. It's just increased internal resistance. We're 15°C nominal so new lead I derate 10% and in Winter a little more.

LiFePO₄ suffer from permanent damage due to lithium plating and loss of active material as a symptom of electrons travelling faster than li-ions in cold weather operation. This can cause thermal runaway under 0°C but varying degrees of irreversible harm with low temp charging. Most BMS only protect against fire not cell damage.

If we give them electric blankets then the effective usable capacity derating will be vastly higher. This V2G....never gonna make money for the V owner.

If there's no low temp throttling or cutoff in the Li-ion system Solar can be quite a liability in Winter. If there is throttling it becomes redundant/power on demand only instead. 

[tanner0441]

Hi

If you look you can find a BMS that does over temp and under temp protection but they only seem to be for the bigger setups. 60Ah and above
Though i have seen them for the 26650 and 32700 range of cells. The PCB has provision on the board for a pair of 10k NTP thermistors. it's up to you to wire them and tape them to the battery pack.  Good use for kapton tape.

Brian.

[Scruff]

Hi Brian,

WuPoG has 3 tier Overtemp and Undertemp protections. Li-Fi's Overtemp is inverter cutout, the under temp protection is send Lead-Fi instead and she's a runt I'm not investing more into.

The MS ProStar MPPT can give me temperature proportional charger foldback control that's the only one I know of that does this. I think most BMS just have single setpoint cutouts.
The cells aren't suddenly at risk under 0°C and grand above it. Depending on the charge rates they can be getting damaged from <25°C it's that under 0°C it's conventionally agreed that thermal runaway is a realistic risk. Lithium plating is as benign and progressive as lead sulphation.




There's a lot of studies on how the cycle count dives at lower temperatures when you use at high C rates. Given the cost of the cells most are used at high C rates.

Sulphation is much easier deal with...charge to 1.28SG once a month. Li-ion plating.. ...don't overcharge it, but you have periodically fully charge it to mitigate memory effect, don't float charge it, don't hold it at high SOC & don't charge it in cold temperatures.

[Scruff]

I really don't get it. But then I do measure things instead of believe the marketing so there's that.

They're new, they're half the weight, they're fashionable. I can't dispute any of that.

They're also super expensive, require substantial electronic management, sensing, feedback and control, so more expense and complexity...points of failure.
They're not very good at all outside their comfort zone; Cold temps or sustained loads.

The astronomical cycle counts are contrived. First off I've never seen a study that wasn't; "I cycled it until I got bored and then multiplied my answer by a factor of my patience". Most then conclude that the larger number like 60%-70% of usable original capacity makes them look better than the industry standard 80% lead uses...because it does.
They don't factor the low temp operation cycle reductions. They're highly unforgiving and the finikiness is mental.
I spent two days setting an CC absorption voltage threshold on a cell that ±10mV corresponds to 10% SOC.

None of my BMS has a transistor between the main power terminal and the load. Every off the shelf one I've seen does.
They're not failsafe. They will fail. You won't know when they do in a lottov cases & they bottleneck the system.
Battleborn state that if you connect a 4kW or greater inverter (and other devices having large input capacitance < 10 microF) to their battery then you'll break it and that's your fault.

[tanner0441]

Hi

Our local Lidl's was selling 2Ah 20V tool batteries for £7.50 they have 5 18650 cells in and a BMS, with a single thermister tucked between two of the cells. I bought a few because I can't buy 5  18650 cells for that. I have stripped a couple down the cells have their own brand name, cell type, voltage and capacity. first thing I did was weigh them I now have four in an Opus battery analyser which cycles them 3 times. to display the measured capacity.

Be interested to see the Ah/gram rating. I also have an iMax B6 but that is a pain, though it will do from S1 to S6 it only gives the total capacity or one cell at a time.

I would like some of the 80 to 100 Ah cells but not at £80 a pop, so I am using Lead Acid for the spot welder.

I'm impressed with the items you're turning out and I would never thought of using flight cases as cabinets.

Brian

I have some "Ultrafire" 9000 mAh rated cells... Hmm methinks someone with a very cavalier attitude to the truth.

[Scruff]

One of the many problems with off the shelf BMS and chargers is we are limited by the motivation, inspiration and marketable design principles of that hardware engineer...who are often over-ruled by bean-counters. Hence I rather build my own.
Unfortunately, there's a strong undercurrent of that's good enough and it'll improve sales down the line.
I also think blue and teal production houses are too big and they're designing hardware from their gridder concrete buildings for off-grid without a clue how it's supposed to perform and propping it up with pdfs and marketing.
It's readily apparent to me when engineers have not used their own hardware by the decision making.





The cells aren't that expensive, 18650 road is pretty labour and test gear intensive.

^those are genuine...lots aren't. They're so well matched they don't need balancers it would appear. I've usually unpluggged mine because they sound horrendously nausieating , I've been aggressively cycling WuPog for weeks and they're still identical holding voltage correct to 1mV.

The flightcases came with the 200Ah Schlicktron Gels I have that were being thrown out. I actually just wanted the cases turns out the batteries were tippy top too.

Everything in rock and roll comes in a flight case. Go figure.


I've Victron, Sterling, Ctek and MorningStar chargers knocking around....I'll start SG performance testing them pretty soon. I think the results will be enlightening as to what's really the problem with lead.

[Scruff]

I started Spring cleaning my hover van and I'm taking the opportunity to do that SG testing. I've some rather interesting observations to add while I'm at it.



The battery temps were 3°C and I took a moment to imagine what would be the scenario if I moved with the times and had installed a Battleborn 100Ah retailing at $1200 instead of my trusty FLA Crown Cr235s 235Ah retailing £300

First of all if I was about to adventure I'd be starting with an empty battery because that's the way to keep them healthy.
Then when I turn on the engine I'd get this...



Where they'd hit overload and disconnect.
Grand so...I can fix that by installing a £600 current limiting device like this Sterling "120A Input" B2B charger that seems to ceiling at 80A output.
...How'd I get 112A so? Cable!



So grand I could actually charge it I'd just be doing irreparable harm to it and reducing the cycle count by an order of magnitude.

Get li-ion they said...faster charging they said...
Leave port with an empty battery they say! 
Might as well empty the fresh water tanks while I'm at it will I?

What?! Oh yes you can charge lead at C2 that's what the meter says innit!
Those crowns are pushing 7 year old now...tell me I'm killing them...

[Scruff]

Moving on...



Behold the Reigning Champ, the bread and butter. Humble Sunsaver MPPT.
I've hybridised it to do mains and solar because well we're about to see how good the contenders are...

Here's our Reference Cell and State of Charge to benchmark too.



That's off the charts good...the battery is only supposed to go to 1.28SG by the way.

What was that about killing them? 
It's not for lack of trying. She's a year round liveaboard not a weekend warrior.


I'm running a 50% discharge currently.

Next up to the plate is this lemon..



Quoted 98% efficient, tested between ~60% and decimal.
Internal completely useless temp sensor.
Derates 17% after 5 mins operation.

Place yer bets!

[Scruff]

Schlictron attempted to cut mustard and failed. Would you trust these tunts with your investment? Tens of thousands have and are now buying Li's from them!





1.26 I make that 90% SOC, 100% claimed by an Amber LED. Good thing I didn't tune my SOC meter to reset when the charger tells me eh?



Absorption setpoint 14.6V + 100mV of temp compensation from the ever so generous internal temp sensor located beside the FET heatsink inside the IP-rated enclosure.
If temp compensation worked that ought to be 0.65V (30mV per degree °C below 25°C)



What's this lead acid 80% efficiency thing about Victron? Doesn't your website say that? Were you using a competitor's charger when you got that answer?



In the interest of fairness to our next contestestant I'm letting the Sunsaver finish the job for Schlicktron.
The SS is handicapped, I've throttled it to 14.4V Abs storage setting instead of 14.8V touring. I've also throttled the programmable remotely sensed temperature compensation to 20mV



Get that blue shyte off my vessel!
Next up:



50% DOD test confirming my 7ish year old FLA is 100% capacity remaining. No thanks to blue boxes.

[Scruff]

Let me tell you all about the benefits of LFP 1°C out today...you know what that means? It means I've about €15k of useless hardware in my workshop totalling 5.2kVA and 3.5kWh.

You know what they need? More weight, expense and complexity! Solar freakin' battery heaters bro! 

I'll get on with testing the useful ones will I?

How did the smartest battery charger in the world do?

[Scruff]

I rest assured in a job well done as imparted by another infallible amber LED.



This one doesn't have temperature compensation. It has a snowflake option instead.



14.5V?! Are Scandanavian Winters warmer than Irish Summers? 




Is that it? 99%? Job Done?
But I thought lead-acid was 80% efficient? It says so on the internet?! Everywhere! Especially in Li-ion promo pieces. My Li-Ion is 0% efficient today..did I mention that?

Load compensation doesn't seem to be working!



Specific gravity 1.25 I make that.



85%Charged. Outpaced by a blue box...how embarrassing!
I thought they'd do better to be honest.

The marine version is much better. It goes to 105% with external temperature sensing. What I don't like about it is the "low noise" option that derates a 15A charger to 3A....I just swap the noisy fan for a silent one instead...dopes! 

Next up!



In the interest of fairness to the next contestestant I let the SunSaver finish the job for Ctek.