PINNED - Lithium battery conversion/info

[steves1977uk]

Sorry to burst your bubble, but the iCharger is nowhere as reliable electronically as the Powerlab 8 which I've used weekly for the past 8 years. Yes, the PL8 had incorrect charge/balance algorytms for LiFePO4 cells which they added with firmware updates with BM's help.

All I'm saying is these type of issues is usually due to the firmware not matching the cells algorytms properly, which can be fixed in future updates if the iCharger programming team are still issuing them.

Steve

[Burgerman]

Dont worry about that rude poster you wasted time answering, it was I think, that ignorant frenchman with a bad attitude that isnt welcome here so he is gone. For the 3rd time...

[Scooterman]

Lipo as used in hobby stuff and lithium ion as used in phones, teslas, laptops etc all drop voltage reliably as they discharge in a linear fashion. So cell balance and state of charge are easy to monitor or do at any voltage or state of charge.

I see what you mean. Because Lifepo4 voltage discharge is so flat for say 90% of time it’s difficult for electronics to measure SoC accurately

[steves1977uk]

Dont worry about that rude poster you wasted time answering, it was I think, that ignorant frenchman with a bad attitude that isnt welcome here so he is gone. For the 3rd time...

It was sussed that he came on claiming the iCharger has no issues.

Steve

[fishinjunky]

lets put together our theories for my issues with icharger. That way we can test our theories an narrow down these issues and try to find solutions.

possible theories for the icharger going into c/v early or right away:

1. buggy / unoptimized firmware
2. bad connections / bad solder joints or less than perfect connections / solder joints
3. beginner error in programing the icharger
4. resistance causing voltage drop making the icharger compensate with higher voltage causing early c/v phase
5. cell is already mostly charged. ( i already tested this by discharging first to be sure )


also has anyone tried using MG chemicals 847 carbon connective paste for improving connections. I think the small surface area of the welded studs isnt giving a very good connection. Would this stuff help or just add more resistance?
https://www.amazon.com/MG-Chemicals-Car ... X3VG&psc=1

[fishinjunky]

Dont worry about that rude poster you wasted time answering, it was I think, that ignorant frenchman with a bad attitude that isnt welcome here so he is gone. For the 3rd time...

i knew it was him soon as i saw his post

[Burgerman]

Its like this.
The charger will not go to CV until the cells actually reach 3.600V or whatever you have configured. This need only be ONE cell that sees 3.600V. At this point the charger is "braking" that high cell, and its not enough as the balance current is overwhelmed by the charge current. So charge Amps falls.

The way to find out if this is happening is to look at the CV voltage on the charger. Which is bad connections or thin cables are the cause will see this voltage at the charger. Even while the battery shows less. Due to resistance.

So measure it with a digital volt meter, and observe whats happening.

It may also be some configuration error on input or power supply or charge settings.

[fishinjunky]

lets put together our theories for my issues with icharger. That way we can test our theories an narrow down these issues and try to find solutions.

possible theories for the icharger going into c/v early or right away:

1. buggy / unoptimized firmware
2. bad connections / bad solder joints or less than perfect connections / solder joints
3. beginner error in programing the icharger
4. resistance causing voltage drop making the icharger compensate with higher voltage causing early c/v phase
5. cell is already mostly charged. ( i already tested this by discharging first to be sure )


also has anyone tried using MG chemicals 847 carbon connective paste for improving connections. I think the small surface area of the welded studs isnt giving a very good connection. Would this stuff help or just add more resistance?
https://www.amazon.com/MG-Chemicals-Car ... X3VG&psc=1

those of you with pl8 chargers better hold onto them dearly an pass them down to your children one day like a precious family heirloom. IM JELOUS

[Burgerman]

I have 4 chargers and no children. Thats the way I like it. I have no idea which way up they go.

[fishinjunky]

I have 4 chargers and no children. Thats the way I like it. I have no idea which way up they go.

Same here bm im glad I didn't have any, the ones with fur is enough

[Burgerman]

Yep. This is what they look like on the council estate a mile away.

[Burgerman]

Seriously I dont think iChargers are bad. If I had no pl8 left I would be fine to use one. They just lack the real control, graphing software development and like expresso that would be a serious downgrade and be missed. And they only other thing is that they have no proper way to set termination current other than as a percentage of charge current. Most hobby chargers do that too, as its a dumbed down way to decide when charge ends. Recently when there was a firmware update to allow it to go to 1% after years of ignoring the requests to fix that, so in the past it made them a bad choice to charge big packs that were high impedance compared to the typical lipo pack that hobby users bought them for mostly.

Even now it means that if you reduce or increase the charge rate amps you also have to do a little mental maths to figure out what the correct termination current then is. If there is one... It may not go low enough for some packs at high charge rates. Will it still charge them? Yes. But will stop a touch too fast to allow the large high impedance cells to level up properly. Does it allow you to set say a fraction of a percent?

Lets say you were to charge a 40Ah odyssey. Correct 2 stage charge profile reccomended for cyclic use says charge at 14.7V until 1000thC at the 20h rate is achieved. Thats a terminaton current of 40mA. So would need a charge termination of 0.1 % of the charge current. Thats the same issue if you charge a lifepo4 pack at the 1C rate. Although that would need around 0.2% to 0.4% of the 40A charge rate. But 1% that they now allow is just about enough on life.

[shirley_hkg]

I charge at a much lower rate overnight, 20A and even less. . With a genuine 220Ah useable energy, I never have to top up intermittently, or missed a date because I forgot charging.

[Burgerman]

The advantage of a big pack!

[Scooterman]

The difference between LIPO and LITr yHIUM ION.

LIPO, Can be charged and discharged at up to 12C and 130C, so super high currents, and very very dangerous... Can be discharged to 3.6 or 3.7V safely. 4.2V charge.

LITHIUM ION, slightly more energy dense. Cannot do more than 1C charge or prefereably less. Or between 1 and 20C discharge depending on actual cell specs. And can be discharged down to 2.5V typically. 4.2v charge. Also can be dangerous but not as bad as lipo.

Sorry mate I missed this post when previously replying.

So which is typically used in everyday tech gadgets, such as laptops, phones, bluetooth speakers, shavers, etc?

And which type was in the Sony laptops which caused that plane cargo hold fire a few years ago?

[Scooterman]

Lipo as used in hobby stuff and lithium ion as used in phones, teslas, laptops etc all drop voltage reliably as they discharge in a linear fashion. So cell balance and state of charge are easy to monitor or do at any voltage or state of charge.

Silly me, should have read a bit further down shouldn't I!

[Burgerman]

The highly dangerous lipos are pretty much only used where a small pack has the ultimate in high currents capability. For e.g model planes, helis, etc. Where a 3 or 4A battery can provide hundreds of amps when needed and charge in about 6 mins...

Everything else uses a type of normal lithium ion and theres a few different variations. All are very similar though. Take the standard sized 18650 cells for e.g. Those can be capable of 1A max, up to 30A. As the internal resistance decreases which makes them capable of 20A even 30A, the capacity decreases. So a high amp one is low capacity. Typically half.

So in my RC trasmitter, which uses tesla sized 21700 cells, I choose the largest capacity cells in that size. That means they are only capable of 1C instead of the 20 or 30 that is possible. And so take ages to charge. But that doesent matter in this case as much as the huge 5000mAh capacity. So I get a long run time at low continual current drain. This is what lithium ion are best at. My heli needs high current from its 4000mAh (4Ah battery) It takes around 130A during high speed "punch out" manoevers. So a high rate 70C to 130C lipo is the only solution for that. The lithium ion cells wouldnt be capable anyway and would die fast trying.

LiPo = 100 to 200 cycles... Sadly. Medium capacity, very high currents.
Lithium Ion (cobalt type) cells 500 to 1000 depending on how well they are managed. Best Ah per volume of all. Cant do big currents. Safer.
LiFePO4 is 1000 at 1000% discharge. 1500 to 2000 at 80% DED. 4 to 6k at 70% discharge... Safe. Cant do big currents at all. Although some hobby ones can!
Lead deep cycle 400 to 500 cycles. 5 times lower capacity... Can do big currents at least good ones can. Typically only for a few secs before voltage collapses.

[fishinjunky]

Seriously I dont think iChargers are bad. If I had no pl8 left I would be fine to use one. They just lack the real control, graphing software development and like expresso that would be a serious downgrade and be missed. And they only other thing is that they have no proper way to set termination current other than as a percentage of charge current. Most hobby chargers do that too, as its a dumbed down way to decide when charge ends. Recently when there was a firmware update to allow it to go to 1% after years of ignoring the requests to fix that, so in the past it made them a bad choice to charge big packs that were high impedance compared to the typical lipo pack that hobby users bought them for mostly.

Even now it means that if you reduce or increase the charge rate amps you also have to do a little mental maths to figure out what the correct termination current then is. If there is one... It may not go low enough for some packs at high charge rates. Will it still charge them? Yes. But will stop a touch too fast to allow the large high impedance cells to level up properly. Does it allow you to set say a fraction of a percent?

Lets say you were to charge a 40Ah odyssey. Correct 2 stage charge profile reccomended for cyclic use says charge at 14.7V until 1000thC at the 20h rate is achieved. Thats a terminaton current of 40mA. So would need a charge termination of 0.1 % of the charge current. Thats the same issue if you charge a lifepo4 pack at the 1C rate. Although that would need around 0.2% to 0.4% of the 40A charge rate. But 1% that they now allow is just about enough on life.

Hey bm I cut the lugs of my charge leads in half to check the solder joint. Well I highly suspect a very poor solder joint and bad connection combine with the small surface area on the terminals. I did some testing with multimeter and the voltage tested at the cell is 3.3v the iCharger shows 3.3v from the balance lead an 3.7v from the changing leads ( when charging). I changed leads an it went from 3.7v to 3.8v the solder joints were even poorer done on them.

In conclusion I highly suspect I made very very poor soldering connections.
I'm redoing them all with a hydraulic crimper and solder with the right high quality solder am flux the way you recommended. Also will lightly sand off any aluminum oxide from the terminals then apply a very tiny amount of mg chemicals 8463 conductive silver grease to the terminals

The ichargers small screen is a bit annoying. Need a old Gameboy magnifying glass to read it.

But I'm having fun with it. Kept me busy an not bored all winter

[Burgerman]

When soldering, you MUST wtch the solder run into the joint and flow freely following the flux. Once you see that happen all is good. I used to do house plumbing and central heating. My dads company. I regularly did a whole house, hundreds of soldered fitting on pipes. I never evn bothered checking soldered joints. Once you see the solder melt and flow then theres no need. They just cant leak.

Always allow the materials you are heating to melt the solder. Not the iron... Otherwise you are just attempting to stick it on!

[fishinjunky]

When soldering, you MUST wtch the solder run into the joint and flow freely following the flux. Once you see that happen all is good. I used to do house plumbing and central heating. My dads company. I regularly did a whole house, hundreds of soldered fitting on pipes. I never evn bothered checking soldered joints. Once you see the solder melt and flow then theres no need. They just cant leak.

Always allow the materials you are heating to melt the solder. Not the iron... Otherwise you are just attempting to stick it on!

You hit the nail on the head. The solder just coated the outside of the wire with air gaps very ugly. You would definitely NOT approve.

[Scooterman]

This below, is an incorrectly sized anderson terminal. It isnt the best way to crimp. But it makes the process of handling it, adding flux/solder simple and allows a one handed idiot proof solder joint. Assemble, and heat...

https://www.wheelchairdriver.com/crimp-solder.htm

Crimping Andersons without a hydraulic crimper is bloody hard work. But of course I managed it! Lol

(with one handle on the bench and the other extended with a piece of steel tube).

[fishinjunky]

WOW! using good quality solder the correct flux and a hydraulic crimper is WAAY better than how we were doing things. The solder flowed very nicely

also im getting a toque wrench. The seller of my cells says the torque for the WELDED studs is 15 nm. What you guys think does that torque sound right?

this time im doing everything right (hopefully . i just need to slow down a little an completely LISTEN to you experienced guys) i would like a torque wrench for consistency. Im sure most of you more experienced guys can go by feel for the right torque but my mom doesnt have that experience.

[Burgerman]

Torque wrench may be a little overkill. But if you think you need it...
Thats about 10 or 12 ft/lb from memory which I work in... so about right I think.

[LROBBINS]

https://www.fastenal.com/content/feds/pdf/Torque%20of%20Metric%20Stainless%20Steel.pdf

[fishinjunky]

i was reading a review some guy did on lifep04. He had a 12v pack in his rv an he absolutely tortured and abused them badly over charged over discharged over heated ect. and they still lasted 8.5 YEARS before going bad. Lifepo4 is such an amazing chemistry.

hey bm,
if i care for my pack correctly how you recommend how long do you think they could last? I probably only drive 1/4 the distance you drive in a day when your out and about. But im sure that will change now with more range

what are the most important things to get a long life out of the cells?

[Burgerman]

One of mine is a decade old. Still good to go. But I put a smaller one in a mower and it lasted 2 years. Automatic BMS charging system. So as usual it all depends...

Important?
DONT discharge deeply.
DONT go over 3.600V as set up on your charger.
Dont leave them in hot places.
Dont take out high currents per Ah. Max discharge C rate...
Luck! Buy good cells...

Basically they dont like extremes.
Not full. Not empty. Not high discharge or charge rates.

[shirley_hkg]

If copy BM model , 15 years easily , say one charge per week.

[fishinjunky]

Got the charging leads done I'm getting around 0.3v voltage drop 3ft total cable length (this is charging a single individual cell) is that accessible?

A little over 2 weeks ago I charged 7 cells to 3.6v individually. I'm just now charging the 8th cell individually to 3.6v . Will I need to charge the other 7 agian before assembling the pack? Or will they be close enough to the 8th cell?

[fishinjunky]

Got the charging leads done I'm getting around 0.3v voltage drop 3ft total cable length (this is charging a single individual cell) is that accessible?

A little over 2 weeks ago I charged 7 cells to 3.6v individually. I'm just now charging the 8th cell individually to 3.6v . Will I need to charge the other 7 agian before assembling the pack? Or will they be close enough to the 8th cell?

I meant to type is that acceptable

[Burgerman]

The amount of voltage drop depends on the cable resistance and the current. Presumably volts are 28.80V.

So how many amps? At 0 amps, there will be zero voltage drop.