"Lithium batteries" interesting read

[funflair]

https://www.amumot.de/lipo-lithium-batterie-wohnmobil/

I found this on a Liner forum in Germany and thought it was a really good read, I think you will have seen this already Michael @sallylillian I would like to pretend that I had read it all in German BUT no in reality I read it in Google Chrome which translates as you go.

Martin

 

[Wissel]

Interesting read.
I knew that Mastervolt LiFePO4 batteries had Winston cells inside. Didn't realise that Victron did as well.

 

[CazPaul]

This was an interesting quote from the article.

''Update 2018
New data sheets of the lithium batteries from Victron Energy now suggest that LiFePO4 cells are now being installed and no longer guaranteed that Winston Thundersky LiFeYPO4 cells are in rechargeable batteries. I don't know the background for the decision, but I think it's a pity. Actually, it is even a step backstage, which will certainly also make itself felt in the sales figures in the motorhome industry''

 

[funflair]

Interesting read.
I knew that Mastervolt LiFePO4 batteries had Winston cells inside. Didn't realise that Victron did as well.

Might be did rather than do for Victron now reading this, EDIT you beat me Paul

Update 2017
By now we know it for sure. Victron Energy uses Winston Thundersky LYP (LiFeYPo4) cells in its lithium batteries. I even opened a battery and looked up what's really in it.

VE 90Ah LiFePO4 with Winston cells


Update 2018
New data sheets of the lithium batteries from Victron Energy now suggest that now LiFePO4 cells are installed and can no longer be guaranteed that Winston Thundersky LiFeYPO4 cells are in batteries. I do not know the reasons for the decision, but think it's a pity. Actually, it is even a step backwards, which will certainly make noticeable in the sales figures in the motorhome industry

 

[funflair]

I didn't realise that they don't like being kept at 100% charge either.

Martin

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[CazPaul]

I didn't realise that they don't like being kept at 100% charge either.

Martin

Yes I,ve read that a few times Martin. Its still hard to fully understand though.

 

[Wissel]

I didn't realise that they don't like being kept at 100% charge either.

Martin

It's my understanding that 100% charge should be completely avoided to increase longevity. I have my charger set to charge to 3.55v per cell (14.2v) and my BMS set to completely cut all charging if any cell reaches 3.6v. That's probably around 95% charge and was on the advice of an engineer at EV Power.

Winston state a maximum cell voltage of 4.2v, which I've read Mastervolt used in their earlier LiFePO4 offerings and a lot died earlier than they should. They have now reduced this I gather.

I also have my low voltage set very conservatively at 3.1v, as going too low reduces lifespan as well. I lose a little capacity, but hopefully they will last far longer.

I didn't have any charging apart from solar for over a month in the summer. After the weather had turned, I woke up to no power one morning and after a few seconds of panic realised one of the cells had reached 3.1v and the BMS had shut the system down like it should.

It took a little while to get out of my old routine of trying to completely fill my batteries each day, but I way prefer how I have it now where after say 4 days I might glance at the app to see if I need to charge yet

 

[sallylillian]

What I found interesting was the quote
"In daily cyclical operation commute between 25% and 75%. In everyday practice, this is a bit more difficult."

So you only get use of 50% of the capacity.... same as AGM, GEL or Wet.

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[Wissel]

What I found interesting was the quote
"In daily cyclical operation commute between 25% and 75%. In everyday practice, this is a bit more difficult."

So you only get use of 50% of the capacity.... same as AGM, GEL or Wet.

Not sure if this quote was a mistake by the author or something lost in translation, but it's not the case.

I see figures quoted by suppliers saying that 100% of the capacity can be used. Whilst true, this would probably kill the cells in a short time span (like it would with other battery types). 90% though is usable without any damage at all, and this is quite conservative.

It's also really easy to keep a LiFePO4 battery in it's happy voltage range, as most BMS's should do this. If the voltage goes down to a predetermined point the system should shut down before damage can occur. Same with too high a voltage - charging is cut before damage. A lot are programmable as well (mine is) so even safer voltages can be chosen, at the expense of usable capacity, to prolong life.

Combined with not needing to fully charge LiFePO4, the BMS and solar makes this type of battery so easy to look after.

I tend to charge mine up to 14.2v every few weeks, then check the voltage every 4 days or so (unless weather is nice, then no need). If I see around 13.2v or below, I give them a charge.

Not sure exactly how much power I use, but I have a compressor fridge (240v model) plugged into a low power consumption Victron inverter which are always on. I never switch my MaxFann off and always have a few things charging. I also run a 12v PC with large monitor. I leave the PC on all the time (turn monitor off at night). I'd guess I use around 80Ah per day.

 

[DBK]

It was an interesting read, thanks for posting the link. But it reads as if he gives his batteries as much attention as if they were a box of puppies, or anything else you care to name which requires a lot of intervention.

My understanding is he doesn't think you need to change your main charger, but then he also talks about turning it off when required.

I am sure there is a lot of merit in these batteries but I'm happy, having just replaced all my lead ones this year, to wait a few years and learn from the experience of the pioneers like @Wissel

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[sallylillian]

It was an interesting read, thanks for posting the link. But it reads as if he gives his batteries as much attention as if they were a box of puppies, or anything else you care to name which requires a lot of intervention.

My understanding is he doesn't think you need to change your main charger, but then he also talks about turning it off when required.

I am sure there is a lot of merit in these batteries but I'm happy, having just replaced all my lead ones this year, to wait a few years and learn from the experience of the pioneers like @Wissel

You have made my point, if the Lithium's need the level of "babying" suggested then why invest. The only major benefit would be the high level of acceptance.
@Wissel The quote is down the article, but like so many things on the web do you believe the Gospel according to St Peter or the Gospel to St Paul, or Fred for that matter?

 

[Wissel]

It was an interesting read, thanks for posting the link. But it reads as if he gives his batteries as much attention as if they were a box of puppies, or anything else you care to name which requires a lot of intervention.

My understanding is he doesn't think you need to change your main charger, but then he also talks about turning it off when required.

I am sure there is a lot of merit in these batteries but I'm happy, having just replaced all my lead ones this year, to wait a few years and learn from the experience of the pioneers like @Wissel

That was my opinion as well. What a faff

Also, I found the charger comments a bit strange. I know when I originally did all my research I was told time and time again that these cells should be charged at specific voltages (lower than most types of battery). I bought a charger that had the exact profile I needed.

I went a little overkill with my setup, making sure that both my charger and BMS monitor temps and voltages and that either can switch the system off if needed. I did this to add a little redundancy, specifically so I could forget about them.

In my last system I was constantly checking my BM1 to make sure my batteries weren't getting low and it drove me nuts. I hoped this system would be better for me. It is. I don't even think about it now. In fact I would have forgotten to check them today if it wasn't for this thread, and they were getting a little low

I've said quite a few times that I don't think LiFePO4 is in anyway needed for most motorhome users yet. But if using a van a lot (or fulltime) and have a need for a lot of 12v power, it's invaluable in my opinion.

 

[sallylillian]

@Wissel Morelo are throwing lots of stuff up in the air for me. Their Lithium package is now a Hybrid one with Buttner inverter charger and Super B batteries. I have attached the manual for the Super B. I would be interested in your critique of the batteries.

 

[Pausim]

So you only get use of 50% of the capacity.... same as AGM, GEL or Wet

I don’t think so. My LiFePO4 quotes a cycle life of about 6,000 at 100% dicharge, rising to about 12,000 at 80% and around 24,000 at 50%. I know only time can tell for sure but with the battery management parameters now set I feel confident I can use it freely and not worry for several years. Do any lead acid batteries come remotely close on cycle life?

 

[Wissel]

@Wissel Morelo are throwing lots of stuff up in the air for me. Their Lithium package is now a Hybrid one with Buttner inverter charger and Super B batteries. I have attached the manual for the Super B. I would be interested in your critique of the batteries.

Can't comment much on those cells as not done enough research on them. Interesting that Morello are switching to them from Mastervolt though.

I don't know a great deal about LiFePO4 cells with built in BMS's as it's not something I really looked into apart from Victron. I can let you know that a complete Victron setup (3 x 90Ah, 1600w inverter/charger, B2B and MPPT with all the bits to make it as good as it can be) was quoted at around £6k.

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[Pausim]

Their Lithium package is now a Hybrid

Hymer are doing a hybrid package too. I am not sure I see the point because most of the weight advantage is lost and I can’t see any particular advantage of mixing battery types, particularly with the added complexity involved. Am I missing something?

 

[funflair]

Hymer are doing a hybrid package too. I am not sure I see the point because most of the weight advantage is lost and I can’t see any particular advantage of mixing battery types, particularly with the added complexity involved. Am I missing something?

I think Michael means a "hybrid" of manufacturers as in Buttner charger and Super B batteries rather than Hymers "hybrid" mix of Lithium and lead acid.

Martin

 

[funflair]

You have made my point, if the Lithium's need the level of "babying" suggested then why invest. The only major benefit would be the high level of acceptance.
@Wissel The quote is down the article, but like so many things on the web do you believe the Gospel according to St Peter or the Gospel to St Paul, or Fred for that matter?

The guy who wrote the article charges predominantly with solar so his solution is pretty easy on the face of it, and yes possibly he has over thought this slightly. Quote below from the blog,

Control the state of charge of the lithium battery itself.
I figured it would be easiest if you just did not fully charge the battery, if you did not need the full capacity anyway. For example, during summer holidays, when the solar system provides a lot of energy and is often consumed only slightly. Switching off the solar system would be a way - but it means that the battery would be discharged during the day again, which means unnecessary wear, because solar power is cheaper than lithium electricity. So there has to be a way to teach the solar controller to gently charge the battery without constantly charging it to 100%.
This function would also be useful if the motorhome is unused at home in the sun and no electricity is consumed.

Solution: Programmable solar charge controller

Vicpt charge controllers from Victron Energy are ideal for LiFePO4 batteries


Victron Energy's MPPT solar charge controllers can be easily customized with a self-made charging curve to achieve thedesired mode of operation described above.
To achieve this, the charging characteristic is set on the solar charge controller so that the battery can not be fully charged even if the sun is shining around the clock.

The same goes with a 230V charger , if the motorhome under the carport can not be supplied with solar power. In order to protect the battery from uncontrolled over-discharging by the self-consumption of BMS and other miniature consumers, the system must either be completely switched off, or you connect a shore power charger, which keeps the battery permanently in ideal state of charge by a special charging voltage.

Hach is the one effort now thinks so many. I would say, to have to be on the lookout for a power outlet while vacationing would be a lot harder for me than switching over a charge curve on a charger every few days or weeks.

Charging with solar power - that's how it works
The Victron Energy can be programmed via app pretty easy. This is possible with any Victron Energy SmartSolar MPPT charge controller or with the BlueSolar MPPT charge controllers with additional Bluetooth dongle.
I have created and saved three charging characteristics. Depending on the desired operating mode, I can give the controller the right profile in seconds.

I have put together 3 characteristics, which I can call just as you wish.

• Full performance (100% SOC)
• Summer operation (about 80-90% SOC
• Storage mode (50% SOC)

The following parameters are stored in the charge controller:

Power mode - always full for bad weather

Charging curve for full capacity and cell balancing


Here the battery is charged according to the Victron recommended charging curve. For normal operation this is ok, if always the full capacity is needed. When I see bad weather looming, I activate this profile the day before so that I have the full battery capacity for the bad weather period.

Setting values for the MPPT controller:

• Constant voltage 14.2V
• Maximum constant voltage duration 6 hours
• Maintenance voltage 13.5V
• Compensation voltage 0V
• Automatic cell balancing deactivated

Summer operation - no full charge

Summer operation, the LiFePO4 battery is spared


So that the lithium battery does not stand around every day, I lower the constant voltage and maintenance voltage slightly. For this I activate the cell balance for every 30 days with 14.4V.
This setting corresponds to about 90% charge level. However, whether the 90% are achieved depends on how empty the battery was in the morning. Due to the low constant voltage, the maximum charging current breaks down sooner and it takes some time until the 90% is reached. Here you can also play something, I set the constant voltage in the summer partly down to 13.7V, if I have more than enough solar power anyway.

Setting values for the MPPT controller:

• Constant voltage 13.6-14V
• Maximum constant voltage duration 6 hours
• Maintenance voltage 13.4V
• Compensation voltage 14.2V (Victron to 2018 14.4V)
• Automatic cell balancing every 30 days

Storage mode - steady state of about 50%

Storage mode for lithium batteries.


If the motorhome is not used and is in front of the house in the sun, the storage mode for a charge retention at about 50-70% charge state. For the lithium battery that is much more relaxed than when it gets anew every day with 14.2V on the cap.

Setting values for the MPPT controller:

• Constant voltage 13.15-13.35V
• Maximum constant voltage duration 6 hours
• Maintenance voltage 13.15-13.35V
• Compensation voltage 14.2V (Victron to 2018 14.4V)
• Automatic cell balancing DISABLED