LTO Lithium Titanium Oxide (Titanate) Battery 30S (now 32S)- Seeking the Ultimate Commuter Battery

[ElectricGod]

Educated...LOL...no not really. I did go to school for an EE in the late 80's, but otherwise any "education" I have is becasue I read about subjects that I want to know about. Anyone can do what I have done...if they stick to it. I remember not so long ago having no idea how mosfets work or how to use them, but then I read a lot and started messing with them and learned a lot in the process. Not rocket science at all.

That's the kind of education I'm talking about, learn by doing and asking questions. It is the best way for me to learn, break, break, perhaps fix, repeat...

It's how I am where I am in IT with no formal secondary education. I just don't learn in a theoretical venue. I have to do it and that's why I am here and participating in the discussions. So I appreciate comments like yours that are actually constructive and corrective of my own ignorance. Being where I am in IT also makes it so I can afford to learn by breaking in this hobby (just as long as I can avoid burning the house down)

I have acquired all kinds of measuring tools in the last year or so. I even picked up an oscilloscope recently and a somewhat decent Fluke DMM. Now to figure out how and when to use the 'scope...

I hated school. College was just a harder version of school that I hated even more. I learn best by doing too. If what I'm learning is too abstract and I can't directly use what I'm learning, then retaining it gets hard for me and pretty much get's useless rapidly.

 

[SamRich]

I'll be building an LTO pack soon. I intend to go to 131 volts or 48S. I currently have 24 LTO cells and have worked out how to connect together the tabs as cheaply and reliably as possible. My solution is to bolt together the tabs with brass M6 screws, washers and nuts. I can solder directly to the brass if needed for balance leads. Also the cell tabs will get folded over so that there is more aluminum to aluminum contact before they are screwed together. Brass isn't the best conductor so the folded over tabs will overcome any brass losses. Balance wires will attach via a screw lug. I intend to NOT use a BMS at all and use super cap boards for any balancing.

That picture makes me a bit nervous. How to do yo protect against accidental shorts while working on the pack?

 

[Inwo]

I store them like that all the time. All parallel.
I do get careless sliding them apart sideways. Then wake up for a couple weeks.

 

[ElectricGod]

I'll be building an LTO pack soon. I intend to go to 131 volts or 48S. I currently have 24 LTO cells and have worked out how to connect together the tabs as cheaply and reliably as possible. My solution is to bolt together the tabs with brass M6 screws, washers and nuts. I can solder directly to the brass if needed for balance leads. Also the cell tabs will get folded over so that there is more aluminum to aluminum contact before they are screwed together. Brass isn't the best conductor so the folded over tabs will overcome any brass losses. Balance wires will attach via a screw lug. I intend to NOT use a BMS at all and use super cap boards for any balancing.

That picture makes me a bit nervous. How to do yo protect against accidental shorts while working on the pack?

All cells are plus to plus. There's no reversed polarities here. After I screw together tabs and put a balance wire on them to build a pack, they get a piece of heat shrink tube over the tabs to keep them isolated.

 

[ElectricGod]

4 boxes of 20 cells arriving tomorrow...time to build a real LTO pack!

 

[miro13car]

LTO cells?
very low terminal voltage
I would need 50-60% more LTO cells than LiMn2O4 cells to build similar pack .
I prefer to extend life of LiMn2O4 by using 50-60% of capacity for average ride.
And my battery pack is super simple 11S1P !!

 

[SamRich]

4 boxes of 20 cells arriving tomorrow...time to build a real LTO pack!

Cool what configuration are you thinking about?

 

[ElectricGod]

4 boxes of 20 cells arriving tomorrow...time to build a real LTO pack!

Cool what configuration are you thinking about?

I'm going for 131 volts or 48S. I already have 24 cells so this will give me 2 banks of 48S and a few cells left over to make a car battery.

What people don't get about LTO is that it holds up very well in cold weather and hot weather. Most other lithium options don't. Then with the crazy looooong life spans of 10,000 cycles, they last a very long time. I will no longer care about how often I charge. All that will matter is getting to my destination and that's a question of capacity and managing my charge.

Yes...LTO does have a lower per cell voltage than other lithium chemistries and requires more cells to get the voltage you want. Anybody building a pack, whatever chemistry is made from, is making compromises to get one thing in favor of another. This is in some peoples minds is a bad thing.

Charge density per gram is owned by LION right now. LIPO is close, but down by about 10%, then LIFE which is another 5-10% and then LTO....another 10%. BUT all of those chemistries suffer from the cold and can't be drained dead and be unharmed. They all need a BMS. When have you ever set your controllers cut off at .5 volts per cell? For any other chemistry...never. I don't know how useful 24 volts will be, but if it keeps the EV creeping along at 3 mph instead of me walking...I'll take it! Only with LTO can I be impervious to cold weather. Only with LTO can I run down to dead flat. Only with LTO can I never think about how often I charge again. Everything has advantages and disadvantages. There are compelling reasons to choose LTO.

 

[parabellum]

cut off at .5 volts per cell

You know that some group in your pack will be lowest capacity? This group will not just discharge flat, it will reverse charge in some moment and l doubt any chemistry will take that easy, even DC capacitors are killed that way.

 

[ElectricGod]

cut off at .5 volts per cell

You know that some group in your pack will be lowest capacity? This group will not just discharge flat, it will reverse charge in some moment and l doubt any chemistry will take that easy, even DC capacitors are killed that way.

Yes I did, but it may not be relevant either. What I said was not covering all the implications nor was it intended to explore all the possibilities of what could happen. It was intended to show that you can do things with LTO that you can't with other lithium options.

 

[miro13car]

cold weather?
So you are talking Canada.
I am here with winter here for months
have simple winter and summer ebikes with different cell chemistries.
" they all need BMS..."
I run LiFePo 20Ah pouches in 12S 1P for years with no BMS whatever and they stayed ballanced just fine.
risk of destroyed cells due to cheap , faulty BMS is too high, I prefer to monitor my cells myself .

 

[ElectricGod]

cold weather?
So you are talking Canada.
I am here with winter here for months
have simple winter and summer ebikes with different cell chemistries.
" they all need BMS..."
I run LiFePo 20Ah pouches in 12S 1P for years with no BMS whatever and they stayed ballanced just fine.
risk of destroyed cells due to cheap , faulty BMS is too high, I prefer to monitor my cells myself .

Good for you and congrats.

I didn't buy LTO's so that you could tell me about how awesome your battery solution is. I bought them for my purposes. So anyway...good for you...

BTW...you did know this thread is about LTO's right? NOT other battery chemistries...so unless you have something to say about LTO's specifically and how you are using them, then what specifically are you adding here that's relevant?

 

[SamRich]

4 boxes of 20 cells arriving tomorrow...time to build a real LTO pack!

Cool what configuration are you thinking about?

I'm going for 131 volts or 48S. I already have 24 cells so this will give me 2 banks of 48S and a few cells left over to make a car battery.

What people don't get about LTO is that it holds up very well in cold weather and hot weather. Most other lithium options don't. Then with the crazy looooong life spans of 10,000 cycles, they last a very long time. I will no longer care about how often I charge. All that will matter is getting to my destination and that's a question of capacity and managing my charge.

48s Wow!
So two 10Ah packs? Will you be able to carry both at once? That's gotta be close to 100lbs total.
How are you carrying it?

 

[ElectricGod]

48s Wow!
So two 10Ah packs? Will you be able to carry both at once? That's gotta be close to 100lbs total.
How are you carrying it?

I have the cells. They arrived yesterday. 4 boxes didn't weigh 100 pounds. I don't have a scale to be sure, but I'm estimating 60 pounds for all 4 boxes.

They will go in a moped. Weight won't be the big concern, like it is on an e-bike. Still, I expect to get 100mph or more. 131 volts sounds like a lot if you've never built anything close to that voltage. I've built 2 EV's that run at 82 volts and another at 66 volts. My slow EV does 45mp, the other 2 at 82 volts do 60mph. It's time to make something fast. The moped won't run from LTO only. There will also be some LIPO in the mix for now too.

 

[miro13car]

SamRich
sorry this your thread. you decide what is in this thread.
please, do not contaminate

 

[SamRich]

48s Wow!
So two 10Ah packs? Will you be able to carry both at once? That's gotta be close to 100lbs total.
How are you carrying it?

I have the cells. They arrived yesterday. 4 boxes didn't weigh 100 pounds. I don't have a scale to be sure, but I'm estimating 60 pounds for all 4 boxes.

They will go in a moped. Weight won't be the big concern, like it is on an e-bike. Still, I expect to get 100mph or more. 131 volts sounds like a lot if you've never built anything close to that voltage. I've built 2 EV's that run at 82 volts and another at 66 volts. My slow EV does 45mp, the other 2 at 82 volts do 60mph. It's time to make something fast. The moped won't run from LTO only. There will also be some LIPO in the mix for now too.

I run 30S thinking about go to 32S for a little extra Wh. DC Voltage does get a bit more dangerous at those higher voltages so trickier to manage, but certainly do able.

My 11Ah cells are 390g each so that would be 80 lbs for 96 cells. I made my case out of thick Al so it added to the weight, that's why I was guestimating 100 lbs. Anyways, sounds like a cool and fast build, i'd like to see some pics and hear more about it as you get further into your build.

 

[parabellum]

4 boxes of 20 cells arriving tomorrow

Is Inwo able to send 20 cells per pack? I got 12 cells per pack 2 times, which I understand was packaging limitation. Not complaining, just trying to get confirmed. And I am not living in cold climate.

 

[ElectricGod]

4 boxes of 20 cells arriving tomorrow

Is Inwo able to send 20 cells per pack? I got 12 cells per pack 2 times, which I understand was packaging limitation. Not complaining, just trying to get confirmed. And I am not living in cold climate.

Yes, he can send them in larger quantities. Mine were purchased by the case, not by a smaller quantity. I think they are 22 cells per case. I originally bought in 12 cell quantities, but wanted lots more so I got them by the case.

LTO takes the cold just fine, but works in warmer weather too.

 

[ElectricGod]

I run 30S thinking about go to 32S for a little extra Wh. DC Voltage does get a bit more dangerous at those higher voltages so trickier to manage, but certainly do able.

My 11Ah cells are 390g each so that would be 80 lbs for 96 cells. I made my case out of thick Al so it added to the weight, that's why I was guestimating 100 lbs. Anyways, sounds like a cool and fast build, i'd like to see some pics and hear more about it as you get further into your build.

The cell count isn't very important, just be careful with higher voltages.

How are you balancing your cells? I'm planning on using super cap boards.

 

[Sunder]

Rejoining this thread, as it's getting interesting again.

On some of the colder mornings, my Multistars are getting a little saggy. Don't know how much longer they will last, so I am revisiting building a LTO pack. And I'm talking 10*C here, not below freezing.

Cold is just one reason I want to go LTO. The fact that I have to carry around nearly twice the capacity I need, just to keep it under 3C, is another. Just 30Ah, will deliver 300A on LTO - and I only need 150A.

So my motorcycle will probably lose 45-50kg from the weight of my bike - Sure, I'll lose a fair bit of range too, but its range I almost never use, except to extend the life of the battery (By not charging full, or running empty).

My biggest challenge is the BMS. Some people say LTO is robust enough to not need a BMS. I've been running 10S LTO without a BMS at a off grid holiday home without issues (aside from the occasional manual rebalance), so I'm almost ready to believe that. But for a daily rider on 55S, I figure it takes fewer bad cells to cause one cell to really go over max, so I want a crude balancer to stop the most extreme problems.

I have just put in a price enquiry for 28Ah pouch cells. Once I get the details back, I might do an Australian expression of interest here and on a solar forum I'm on, to see if we can do a whole pallet or group buy. No reason why the US should have all the fun.

 

[ElectricGod]

Rejoining this thread, as it's getting interesting again.

On some of the colder mornings, my Multistars are getting a little saggy. Don't know how much longer they will last, so I am revisiting building a LTO pack. And I'm talking 10*C here, not below freezing.

Cold is just one reason I want to go LTO. The fact that I have to carry around nearly twice the capacity I need, just to keep it under 3C, is another. Just 30Ah, will deliver 300A on LTO - and I only need 150A.

So my motorcycle will probably lose 45-50kg from the weight of my bike - Sure, I'll lose a fair bit of range too, but its range I almost never use, except to extend the life of the battery (By not charging full, or running empty).

My biggest challenge is the BMS. Some people say LTO is robust enough to not need a BMS. I've been running 10S LTO without a BMS at a off grid holiday home without issues (aside from the occasional manual rebalance), so I'm almost ready to believe that. But for a daily rider on 55S, I figure it takes fewer bad cells to cause one cell to really go over max, so I want a crude balancer to stop the most extreme problems.

I have just put in a price enquiry for 28Ah pouch cells. Once I get the details back, I might do an Australian expression of interest here and on a solar forum I'm on, to see if we can do a whole pallet or group buy. No reason why the US should have all the fun.

55S...sounds cool. How fast is your bike?

Hopefully you can make that group buy happen. In the USA, usually what that means is someone puts out the money and then people buy from them on an as needed basis. I tried a group buy some time back and no one gave me money. OH well. Hopefully you have better success down under!

I'm like you...I want low discharge rates.

Something that's banging around in the back of my mind is making my own balancing board. It doesn't need to be overly "intelligent" or complex. All I really need is reliable balancing that can work at a decent current level. However before I put any time into that, I have a few more LTO capable boards I want to explore. I got one option in the mail on Saturday, but haven't messed with it yet. It's a modular design with boards that daisy chain together. Each board is capable of 7S and I have 5 boards. You can chain together up to 16 boards or 112S. Supposedly you can balance at 1.2 amps which would be fairly nice. I seriously doubt you can since the components on the board are too small for that much current. The P- and C- mosfets on the boards are pretty weak, but I want to use it as a balancer only so I don't really care too much. This is it below. Anyway, more to come soon...

https://www.aliexpress.com/store/product/112S-35S-Lithium-Li-ion-LiFePO4-LTO-Lipo-Battery-Protection-Board-BMS-Balance-Bluetooth-APP-7S/2856009_32861093603.html?spm=2114.12010612.0.0.12763de24lskED

 

[themelon]

Something that's banging around in the back of my mind is making my own balancing board. It doesn't need to be overly "intelligent" or complex. All I really need is reliable balancing that can work at a decent current level. However before I put any time into that, I have a few more LTO capable boards I want to explore. I got one option in the mail on Saturday, but haven't messed with it yet. It's a modular design with boards that daisy chain together. Each board is capable of 7S and I have 5 boards. You can chain together up to 16 boards or 112S. Supposedly you can balance at 1.2 amps which would be fairly nice. I seriously doubt you can since the components on the board are too small for that much current. The P- and C- mosfets on the boards are pretty weak, but I want to use it as a balancer only so I don't really care too much. This is it below. Anyway, more to come soon...

https://www.aliexpress.com/store/product/112S-35S-Lithium-Li-ion-LiFePO4-LTO-Lipo-Battery-Protection-Board-BMS-Balance-Bluetooth-APP-7S/2856009_32861093603.html?spm=2114.12010612.0.0.12763de24lskED

So you finally got them. Perhaps I might have mine by the end of the year

One of the purposes for LTO that I am playing around with is a source/sink for charging and regenerative discharging on my test bench. Many of the better hobby chargers support regen discharge and when you are charging/discharging 40-50AH cells for testing the on-board double digit wattage discharge just does not cut it. And rather than simply waste the juice using one of several resistance discharges that I have I'd rather a) not waste the power and b) have a full plot of the discharge curve instead of simply the total. It would not take me long to kill lead acid batteries doing this. So I'm going to build a bunch of 6S3P blocks out of the 11AH cells. A couple will go into my truck and the rest on the test bench to be abused. The BMS's you link should be more than adequate for the later because the rate in either direction is not likely to ever be more than 20A.

 

[ElectricGod]

Something that's banging around in the back of my mind is making my own balancing board. It doesn't need to be overly "intelligent" or complex. All I really need is reliable balancing that can work at a decent current level. However before I put any time into that, I have a few more LTO capable boards I want to explore. I got one option in the mail on Saturday, but haven't messed with it yet. It's a modular design with boards that daisy chain together. Each board is capable of 7S and I have 5 boards. You can chain together up to 16 boards or 112S. Supposedly you can balance at 1.2 amps which would be fairly nice. I seriously doubt you can since the components on the board are too small for that much current. The P- and C- mosfets on the boards are pretty weak, but I want to use it as a balancer only so I don't really care too much. This is it below. Anyway, more to come soon...

https://www.aliexpress.com/store/product/112S-35S-Lithium-Li-ion-LiFePO4-LTO-Lipo-Battery-Protection-Board-BMS-Balance-Bluetooth-APP-7S/2856009_32861093603.html?spm=2114.12010612.0.0.12763de24lskED

So you finally got them. Perhaps I might have mine by the end of the year

One of the purposes for LTO that I am playing around with is a source/sink for charging and regenerative discharging on my test bench. Many of the better hobby chargers support regen discharge and when you are charging/discharging 40-50AH cells for testing the on-board double digit wattage discharge just does not cut it. And rather than simply waste the juice using one of several resistance discharges that I have I'd rather a) not waste the power and b) have a full plot of the discharge curve instead of simply the total. It would not take me long to kill lead acid batteries doing this. So I'm going to build a bunch of 6S3P blocks out of the 11AH cells. A couple will go into my truck and the rest on the test bench to be abused. The BMS's you link should be more than adequate for the later because the rate in either direction is not likely to ever be more than 20A.

Isn't "regen discharge" an axymoron? Regen puts current back into the battery and discharge takes it out.

The idea is sound. Use SLA's as a storage device for the charge in your LTO's and they also act as the load for the LTO's

Waiting on balance leads to arrive and then I can start messing with these boards.

20 amps is way inadequate for anything I'm likely to ever build. There are times when all I need is 20 amps, but there are also times when I need 60 amps or more.

 

[themelon]

Isn't "regen discharge" an axymoron? Regen puts current back into the battery and discharge takes it out.

The idea is sound. Use SLA's as a storage device for the charge in your LTO's and they also act as the load for the LTO's

Waiting on balance leads to arrive and then I can start messing with these boards.

20 amps is way inadequate for anything I'm likely to ever build. There are times when all I need is 20 amps, but there are also times when I need 60 amps or more.

Close, but not quite what I'm doing.

The LTO battery replaces the lead acid as the input power supply for the charger. That way I get a much longer life span out of my charging source AND I have an easier and safer way to ground isolate, than floating the DC ground in a AC to DC power supply, so that I can use something like say 2x 8 cell chargers to analyze a 16 cell pack that I can't split.

Obviously not 100% or even 80% efficient probably but allot better than 0% for battery analysis purposes. Actually it would likely be more than 100% efficient in the summer when counting the additional AC needed to remove the waste heat if I did not discharge outdoors.

That's all I would be using it for is analysis purposes on target cells. Although in the RC world they use it to not waste as much energy if they need to put their LIPO's at a storage charge when using a field charger, normally deep cycle marine.

 

[Inwo]

Rejoining this thread, as it's getting interesting again.

On some of the colder mornings, my Multistars are getting a little saggy. Don't know how much longer they will last, so I am revisiting building a LTO pack. And I'm talking 10*C here, not below freezing.

Cold is just one reason I want to go LTO. The fact that I have to carry around nearly twice the capacity I need, just to keep it under 3C, is another. Just 30Ah, will deliver 300A on LTO - and I only need 150A.

So my motorcycle will probably lose 45-50kg from the weight of my bike - Sure, I'll lose a fair bit of range too, but its range I almost never use, except to extend the life of the battery (By not charging full, or running empty).

My biggest challenge is the BMS. Some people say LTO is robust enough to not need a BMS. I've been running 10S LTO without a BMS at a off grid holiday home without issues (aside from the occasional manual rebalance), so I'm almost ready to believe that. But for a daily rider on 55S, I figure it takes fewer bad cells to cause one cell to really go over max, so I want a crude balancer to stop the most extreme problems.

I have just put in a price enquiry for 28Ah pouch cells. Once I get the details back, I might do an Australian expression of interest here and on a solar forum I'm on, to see if we can do a whole pallet or group buy. No reason why the US should have all the fun.

Something that's banging around in the back of my mind is making my own balancing board. It doesn't need to be overly "intelligent" or complex. All I really need is reliable balancing that can work at a decent current level. However before I put any time into that, I have a few more LTO capable boards I want to explore. I got one option in the mail on Saturday, but haven't messed with it yet. It's a modular design with boards that daisy chain together. Each board is capable of 7S and I have 5 boards. You can chain together up to 16 boards or 112S. Supposedly you can balance at 1.2 amps which would be fairly nice. I seriously doubt you can since the components on the board are too small for that much current. The P- and C- mosfets on the boards are pretty weak, but I want to use it as a balancer only so I don't really care too much. This is it below. Anyway, more to come soon...

https://www.aliexpress.com/store/product/112S-35S-Lithium-Li-ion-LiFePO4-LTO-Lipo-Battery-Protection-Board-BMS-Balance-Bluetooth-APP-7S/2856009_32861093603.html?spm=2114.12010612.0.0.12763de24lskED

I made some high current analog balencer pcs. I can send you one next time something goes your way.
As I recall 6s and 12s.