LIFEPO4 Battery discussion thread

wingnut771 said:
Probably 3.65V The highest cell has the lightbulb connected. Don't walk away at this point.
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I am a bit skeptical of this type of balancing. If you have a couple of cells being kept at 3.65 and up you will kill them.

From what I researched you can’t keep a Lifepo4 cell at 3.65 for long.

As long as he checks the highest cell voltage at current charging it should be fine I guess, but it can’t be at 3.65 and up
 
denmendez65 said:
I am a bit skeptical of this type of balancing. If you have a couple of cells being kept at 3.65 and up you will kill them.

From what I researched you can’t keep a Lifepo4 cell at 3.65 for long.

As long as he checks the highest cell voltage at current charging it should be fine I guess, but it can’t be at 3.65 and up
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Its not, BMS cuts off over 3.65V. This is the point of the power supply to hold voltage just before bms cuts out. Bat 3 is cutting out at 54V.

You have much to learn Padawan.

A 100W lightbulb is pulling 30A from one cell, much faster than a 100mA balancer can. So lightbulb is only connected for a few seconds I would guess.
 
wingnut771 said:
Its not, BMS cuts off over 3.65V. This is the point of the power supply to hold voltage just before bms cuts out. Bat 3 is cutting out at 54V.

You have much to learn Padawan.

A 100W lightbulb is pulling 30A from one cell, much faster than a 100mA balancer can. So lightbulb is only connected for a few seconds I would guess.
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Makes me think I should get tubular batteries. Lithium just has too much stuff that LA doesn’t.

Unbalanced cells, cells swelling, fires that can’t be put out etc.

Why did they go out of balance to begin with?
 
denmendez65 said:
Makes me think I should get tubular batteries. Lithium just has too much stuff that LA doesn’t.

Unbalanced cells, cells swelling, fires that can’t be put out etc.

Why did they go out of balance to begin with?
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They never were in balance in the first place. That's how mass manufacturing works. You wont have to worry about this with your jk bms.

LFP Tubular = LFP prismatic = LFP pouch. Its all the same thing in different shapes.

You're welcome to waste money on cylindrical cells instead of the square ones and make 10 times the work for yourself assembling 10Ah cells. Good luck finding 100Ah+ cylindrical cells.
 
denmendez65 said:
Makes me think I should get tubular batteries. Lithium just has too much stuff that LA doesn’t.

Unbalanced cells, cells swelling, fires that can’t be put out etc.

Why did they go out of balance to begin with?
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Once it is balanced then a 20mA balancer should be able to handle the slight differences in resistance between the cells.
 
wingnut771 said:
They never were in balance in the first place. That's how mass manufacturing works. You wont have to worry about this with your jk bms.

LFP Tubular = LFP prismatic = LFP pouch. Its all the same thing in different shapes.

You're welcome to waste money on cylindrical cells instead of the square ones and make 10 times the work for yourself assembling 10Ah cells. Good luck finding 100Ah+ cylindrical cells.
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I meant Tubular Lead Acid.

I will think about it when the time comes to replace the GELs which looks like will be in 3 to 4 years from now.

This is for one of the Chada manufactured Tubular LA batteries. With my current DOD and even before I got the Omnivolt I was only doing 20 to 30% DOD.

On these Tubular LA batteries that is between 3500 and 4000 cycles. 10 years easily.

Once every 6 months I top up with distilled water. They are designed to lose very little when charging unlike the older Flooded LA battery types.

No FAF about fires, balancing and all that nonsense.

IMG_1623.jpeg
 
denmendez65 said:
I meant Tubular Lead Acid.

I will think about it when the time comes to replace the GELs which looks like will be in 3 to 4 years from now.

This is for one of the Chada manufactured Tubular LA batteries. With my current DOD and even before I got the Omnivolt I was only doing 20 to 30% DOD.

On these Tubular LA batteries that is between 3500 and 4000 cycles. 10 years easily.

Once every 6 months I top up with distilled water. They are designed to lose very little when charging unlike the older Flooded LA battery types.

No FAF about fires, balancing and all that nonsense.

View attachment 1912181
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Oh LA.

You think you dont have to balance LA?

Yeah, maybe you should stick with LA then. They balance by overcharging them to 16V and boil the high cells.

How much you going to spend on those tubular ones? How many Ah is that?
 
wingnut771 said:
Oh LA.

You think you dont have to balance LA?

Yeah, maybe you should stick with LA then. They balance by overcharging them to 16V and boil the high cells.

How much you going to spend on those tubular ones? How many Ah is that?
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Well not the way Lifepo4 needs to be done with bench power supplies etc.

You just buy, fit external balancers and that’s it. My GELs when I tested them last week where all within 0.01V after letting them rest for 4 hours.

Not bad for 1.5 years in service.

Can get a tall tubular 200ah 12V for 5k.
 
denmendez65 said:
Well not the way Lifepo4 needs to be done with bench power supplies etc.

You just buy, fit external balancers and that’s it. My GELs when I tested them last week where all within 0.01V after letting them rest for 4 hours.

Not bad for 1.5 years in service.

Can get a tall tubular 200ah 12V for 5k.
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and what about the 6 2V cells inside the 12V gel?

Anyway, if cavedog had patience then he wouldnt have to do a thing.
 
cavedog said:
Manually balancing is so difficult. Damn
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Okay I think I'm done with manual cell balancing. I charged each cell up to 3.6v. They seem to be within 30-40mV of each other now. I think I will let the bms do the rest. I will leave it on 56v for a while and then I'm done.
 
cavedog said:
Okay I think I'm done with manual cell balancing. I charged each cell up to 3.6v. They seem to be within 30-40mV of each other now. I think I will let the bms do the rest. I will leave it on 56v for a while and then I'm done.
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56V is 3.5V per cell.
 
wingnut771 said:
56V is 3.5V per cell.
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Yes I just want to be sure the balancer kicks in. Since i have no access or even an understanding of how the balancer works I'm sure at 3.5v the balancer will kick in if its passive.
 
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