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Lead + Lithium?

cwk

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Jan 21, 2020
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I’ve got a 48v lead acid golf cart battery and need more storage. I’m looking at the 5.2kWh 2V Tesla batteries and would like to run two in series to replace or add to my existing battery. Are there any gotchas I should consider first? Can I integrate these with my existing lead acid setup?
 
 
unfortunately lithium found in tesla is real lithium, not the one we generally speak about (LiFePo4 or LFP) on the forum.
the charge curve for LFP and the mini/maxi voltage for Lead and LFP are pretty compatible, so you can mix them.
For real litium , this is a bit different and add complexity. so the real power available at T time (or when charging) will need to be calculated
differently for lead and lithium.
 
I agree you could mix them for charging but aren't the states of charge different on discharge?

Edit....they are closer then I thought....When lead acid is at 70% discharged LFP is near fully discharged....But still think one will discharge a lot faster then the other...if it is the lead then you might ruin that battery? If it is the LFP and it has a low volt cutoff you may get it to work?
 
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but in that case (Tesla wall or Tesla car battery) this is not LFP, but real Lithium-ion cell (in 18650 or 2170 ).
 
I agree you could mix them for charging but aren't the states of charge different on discharge?

Edit....they are closer then I thought....When lead acid is at 70% discharged LFP is near fully discharged....But still think one will discharge a lot faster then the other...if it is the lead then you might ruin that battery? If it is the LFP and it has a low volt cutoff you may get it to work?
Doesn't quite work that way. LFP and Li-Ion have a very flat discharge curve. Meaning they stay at the same voltage pretty much right across. There are numerous charts showing that. Unlike FLA which starts to drop voltage as soon as you start using it. Remember an FLA/AGM can only be discharged safely to 50% DOD @ 20hrs, while LFP & LiIon can go to 95% DOD or 5% SOC.

LiIon typically come in cylindrical cells in the 18650 or 21700 format, BUT now there are also some LFP variants in these same formats (they do not look exactly the same) For an 18650 cell. the 18 stand for the width of the cell, 650 is the length of the cell in millimeters.

21700 size was originally designed by Tesla for the EV's because collective they store more power and it was easier to package. Older Tesla models have 18650 cells. They are ALL Li-Ion not LifePo4, lifepo is not the best for vehicles due to density of power per gram of weight.

New Tesla Powerwalls will come with two favours of battery depending on origin, with new contracts having been signed for the Energy Storage Market. Tesla will continue to focus on EV Batteries. After today's "Battery Chat" with Elon, things are about to get shake up yet again as the Maxwell & Dry Electrode technology comes into play.

DISCLOSURE: I am a Tesla Long investor and have been since inception. Therefore anything Tesla pops up on my desk instantly.
 
So if can you completely replace the AGM with the Tesla. If so where is the best place to purchase a Tesla battery configured for 48 volt 100 amp system.
 
tesla wall 1 are 48V 300A (about 14KWh) , Tesla Wall 2 are more .Since a Tesla battery is several time the capacity of tesla wall (the smallest Tesla car battery is 60KwH, but up to 100 for the high end models), it is probably a lots more amps and volts. (around 360V)
 
tesla wall 1 are 48V 300A (about 14KWh) , Tesla Wall 2 are more .Since a Tesla battery is several time the capacity of tesla wall (the smallest Tesla car battery is 60KwH, but up to 100 for the high end models), it is probably a lots more amps and volts. (around 360V)
Two separate questions:
1) Is there an easy way to add another state to the Tesla power wall system, my state is left out :(

2) On this site, they describe building a 24 volt solar system built with the tesla battery (shown below), for the golf cart, if hooked in series, assuming you can, this would power the golf cart but appears an overkill. The two batteries required are over 2000.00 used and most carts are only rated between 50 and 120 amps. You would not have plug and play system as a BMS and charge system would need to be adapted. Do you agree?
Tesla Model S, 24V, 250Ah, 5.3kWh, 444 Panasonic Batteries
 
if you need power, i do not think Tesla is better than anything else. It is just Hype, because it is written Tesla on it.
for the same price of a Tesla wall 1 , you can get twice the power in chinese battery (or half price for same power).
Tesla car batteries are made for a car, so unless you get one salvaged for almost nothing, you get no gain going that way.
Tesla give no support out of a tesla car.
Cheap chinese LFP is about 1500$ for 8 cells at 200A. that makes 5KWh.
to get the equivalent of a Telsa wall 1, you would pay 4500$, while a Telsa wall is about 8000$.
you will need to add a BMS (150$) and some converter/controller (about 600$).
 
Thanks guys. Since my 6V Interstates are going on 2 yrs old, it's probably time to replace anyway.
My question now, is the same one gman is asking above. Since my current (no pun intended) battery is 48V and for various reasons I want to maintain that voltage, can I simply run two ebay-special 24V 5.2kWh Tesla batteries in series (with BMS/cell balancers) or will there be some sort of unintended consequences?
 
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