Lithium Ion Batteries

HowTo

HowTo

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Hi all

Lithium Ion what is the ideal discharge on batteries. (50% or even less)​

 
AlphaJohn said:
View attachment 1326550

Best practice is to be neither full nor empty.
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Nice graph. Even at 100-25 you'll still be at 80% capacity after 10 years of daily cycles! Lithium is great ain't it!

The 75-65 one... Heck you'll only have used 10% of your batteries... So no wonder they can still do 10,000 cycles they only really did 1/7th of the work the 100-25 cycles did
 
richjdavies said:
Nice graph. Even at 100-25 you'll still be at 80% capacity after 10 years of daily cycles! Lithium is great ain't it!
Click to expand...

Thats why most manufacturers claim 80% charge retention over 3000 cycles (based on 80%-20% usage in 20°)

Some (Not all) BMS take this into account and cut at 80/90% SoC. IE My SAKO's cut at 13.8 instead of normal 14.2
 
richjdavies said:
Nice graph. Even at 100-25 you'll still be at 80% capacity after 10 years of daily cycles! Lithium is great ain't it!

The 75-65 one... Heck you'll only have used 10% of your batteries... So no wonder they can still do 10,000 cycles they only really did 1/7th of the work the 100-25 cycles did
Click to expand...
Indeed also got to love data, I have done about 108 cycles in in 222 days so I have a very long life expectancy left around 17 years plus. this is based on 100% dod at 3000 cycles but I do around 50% most days so I can almost double that expectancy.

Just 2-3 weeks to see how system holds up on shortest day :)
 
Snyper564 said:
Indeed also got to love data, I have done about 108 cycles in in 222 days so I have a very long life expectancy left around 17 years plus. this is based on 100% dod at 3000 cycles but I do around 50% most days so I can almost double that expectancy.

Just 2-3 weeks to see how system holds up on shortest day :)
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Also siting in that boat. My batteries should in theory last more than 20 years. My question now is at what point does the physical age of the battery start to accelerate the degradation? Can't find that much useful info on that.
 
WollieVerstege said:
Also siting in that boat. My batteries should in theory last more than 20 years. My question now is at what point does the physical age of the battery start to accelerate the degradation? Can't find that much useful info on that.
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Not sure all I know is I will use these batteries into the ground. in 10 years+ there will be new tech anyway
 
Snyper564 said:
Not sure all I know is I will use these batteries into the ground. in 10 years+ there will be new tech anyway
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My plan to. If overall available storage dropps below what I need, I'll just add another battery. Great advantage of a modular system.

Still can't believe there are people out there that believe once the batteries reach 80% you need to throw all of them out and buy new ones.
 
WollieVerstege said:
My plan to. If overall available storage dropps below what I need, I'll just add another battery. Great advantage of a modular system.

Still can't believe there are people out there that believe once the batteries reach 80% you need to throw all of them out and buy new ones.
Click to expand...

Normally a bad idea to mix Old & New,

Better practice would be to over spec with at least 20%. Lucky most things are moving towards energy saving so tomorrow's fridge will use alot less power than todays so will help with that.
 
See attached pic. Time 5:15 up to 7.15 straight line 80% SOC. At that point was using Esdom power to supplement.
Any comments to why this was happening?
Can you go lower? At 7:15 daughter was using Hair dryer, then the SOC 78% went lower. Load 1632 went up and Battery 1468 usage also went up.

Using Pylontech UP5000
 

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HowTo said:
See attached pic. Time 5:15 up to 7.15 straight line 80% SOC. At that point was using Esdom power to supplement.
Any comments to why this was happening?
Can you go lower? At 7:15 daughter was using Hair dryer, then the SOC 78% went lower. Load 1632 went up and Battery 1468 usage also went up.

Using Pylontech UP5000
Click to expand...
What do your time of use settings look like... you need to look at both in conjunction
 
Mzezman said:
What do your time of use settings look like... you need to look at both in conjunction
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Did so and reported values. You can only see 1 cursor.(5:15)
If I up the curser next position then I reported the new Values. See the spike
 
HowTo said:
Did so and reported values. You can only see 1 cursor.(5:15)
If I up the curser next position then I reported the new Values. See the spike
Click to expand...
He means show us your System Mode / Work mode 1 screen, the one that looks like this:
1654809959500.png

I'll bet that you have a entry at 05H00 that states discharge until 80%.
And another at 07H00 telling it to discharge to lower than 80%.
 
Magnum said:
Be specific. Lithium Ion or Lithium Iron?
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1654835796926.png

Lithium ion = LiFePO4 or LiNixMnyCozO2 or LiNiCoAlO2 or LiMn2O4 or LiCoO2

That said the Graph I linked was testing done with NMC (Nissan LEAF) but its said that LFP have similar outcomes in dynamic stress tests.

All Chem's have the same basic rules that kill cycle life:
Overload, and overheat is the biggest killers followed by don't stay full nor empty.
 
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