LTO bulk,absorption and float voltage for Multiplus 2

[insippo]

What settings should there be for Multiplus 2 for such a battery? The battery is 25S3P 30ah.

 

[LydMekk]

Is this a premade battery? Link to the manual or specs?
Or is this something you have made yourself?

 

[RCinFLA]

Need to look at particular cell specs. LTO is the only lithium-Ion battery that takes the name of the negative electrode material. They can use a couple of different positive cathode materials that results in slightly different cell voltage.

Probably the most common cathode material, for LTO cells, is LMO. Blue line in below graphs is the cell voltages. Cell terminal voltage is positive cathode potential minus the negative anode potential. LTO anode has very high potential (bad for cell voltage and therefore cell energy density), which yields low cell terminal voltage, but is very rugged giving long longevity (cycles life) of LTO cells.

 

[Lt.Dan]

Need to look at particular cell specs. LTO is the only lithium-Ion battery that takes the name of the negative electrode material. They can use a couple of different positive cathode materials that results in slightly different cell voltage.

Probably the most common cathode material is LMO. Blue line in below graphs is the cell voltages. Cell terminal voltage is positive cathode potential minus the negative anode potential. LTO anode has very high potential (bad for cell voltage), which yields low cell terminal voltage, but is very rugged giving long longevity of LTO cells.

View attachment 166296

This is very cool, I have some LTO cells and want to make a starting battery with them. Where can I learn more about and understand about this Anode vs Cathode Potential?

 

[RCinFLA]

You can google info. Some sources are pretty techy, some more down to earth explanation so just scan to find article to fit your understanding of terms.

LTO anodes do not expand when fully charged. Graphite expands about 11% which is why LFP finally wear out. LTO is more expensive material than dirt cheap graphite.

Most other lithium ion batteries with higher cell voltage die due to degradation of cathode electrode, with the exception of LFP positive cathode material which is very rugged. LFP cycle life is determined by graphite anode, not cathode material like most other batteries.

You don't want to mate up a short cycle life cathode material with an expensive long cycle life LTO anode. That would not make sense. A LTO anode with LFP cathode cell would likely outlive you, but you would have to put up with 2.0v cell terminal voltage. It would also have an almost perfectly flat discharge voltage curve.

 

[Lt.Dan]

You can google info. Some sources are pretty techy, some more down to earth explanation so just scan to find article to fit your understanding of terms.

LTO anodes do not expand when fully charged. Graphite expands about 11% which is why LFP finally wear out. LTO is more expensive material than dirt cheap graphite.

Most other lithium ion batteries with higher cell voltage die due to degradation of cathode electrode, with the exception of LFP positive cathode material which is very rugged. LFP cycle life is determined by graphite anode, not cathode material like most other batteries.

You don't want to mate up a short cycle life cathode material with a long cycle life anode. That would not make sense. A LTO anode with LFP cathode cell would likely outlive you, but you would have to put up with 2.0v cell terminal voltage. It would also have an almost perfectly flat discharge voltage curve.

So when are you going to start designing and manufacturing batteries? Lol

Love the info. Thank you

 

[insippo]

Is this a premade battery? Link to the manual or specs?
Or is this something you have made yourself?

This battery from airport package truck. 36s3p LTO cells 12ah. Maybe 10ah. No one sign on package. I use from this 25p3s. I would like to make this battery into two. More capacity. Part of the battery is currently unused. I have 48/5000 multiplus. x3 pcs. Today i use one from these. Im waiting lfp cells.

 

[orangezero]

That picture you posted seems similar to the individual lto cells I picked up a while back. Never seen them put together before. I wish I had that many...

I think mine are 10ah, 2.2v flat pouch cells. I believe they are to be charged to 2.85v and you stop discharge before 2v. They have similar plastic housings around them in grey.

I put 7s2p in a case and the voltage fluctuates a lot more than Lifepo4 for sure. This isn't the best for a lot of inverters perhaps, but I can just check the voltage and have a better sense of how charged the pack is. I think mine run something like 19v down to 14 or 15v usually. I tried using it as a low temp battery for my car but it wouldn't generally tend to charge it and then it got too low and threw errors in the car. Software expects lead acid.

You do things correctly and you may give those to your grandkids some day. I kinda feel bad when I don't use my pack because the age degradation will likely kill them before the cycle degradation does. I think every single one of these cells is either used or new old stock that sat on a shelf. Mine at least looked brand new, but probably will when people used them in packs like this and then tear them apart.

The guy I bought them from said he tested several cells by charging over 5v, then letting them sit and then they later acted normal, same with the cells he let go down to 0v and they worked well later. I would highly recommend not doing this...

https://srikobatteries.com/product/microvast-10ah-20c-lto-prismatic-cells/ may have some more info than what I remember.