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

[themelon]

The biggest problem I have is I need to make this easy to use from a battery connection and recharging standpoint so no one has the excuse that it is too complicated to use and shirk their mowing responsibilities. I have new found appreciation for all the work the power tool companies put in to making these things dummy proof.

Most power tools do balancing in the pack or they have many small connectors to balance in the charger. The packs are not complex...5 or 6S at most so this is very simple to do. when you get into many more cells, then balancing gets lots more complicated. If you look at a lot of 40 volt chordless tools, they will use 2 batteries so that balance charging stays simple.

you can stay easy and fool proof if you use an onboard balancing system that no one but you has to think about. If all your family has to do is plug in to charge, they will see your electric mower as easy to use.

You should see DeWalt's 20/60v flex batteries. They are basically 3x 5s 2ah strings in one package. I think the charger does them in parallel but I have not tested that theory yet. The pack connection has I think 8 or 10 blades so the tool can use them 3s5p or 15s.

The DW790 brushess miter saw uses 2 of them for a 30s ~120v.

 

[themelon]

I haven't figured out how to program this yet, but it will handle LTO, LIFE or LION/LIPO. This is 5 boards or 35S stack. You can stack them 16 tall or 112S. I think realistically they will balance at about .5 amps despite the sales page and docs saying "up to 1.2 amps". Obviously, this in LIPO. By default from the factory it is set up for LION so that works for this 32S pack too. Once I figure out how to program it, I'll give it a try on a 48S LTO pack.

I did a post over here that goes into more depth.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=88676&p=1390216#p1390216

I did finally get the 10 of those boards I ordered...

 

[ElectricGod]

I haven't figured out how to program this yet, but it will handle LTO, LIFE or LION/LIPO. This is 5 boards or 35S stack. You can stack them 16 tall or 112S. I think realistically they will balance at about .5 amps despite the sales page and docs saying "up to 1.2 amps". Obviously, this in LIPO. By default from the factory it is set up for LION so that works for this 32S pack too. Once I figure out how to program it, I'll give it a try on a 48S LTO pack.

I did a post over here that goes into more depth.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=88676&p=1390216#p1390216

I did finally get the 10 of those boards I ordered...

Hopefully you will have better luck than me at programming the boards. I have another 8 coming too.

 

[ElectricGod]

Lots more (46) 7S boards arrived. Now it's time to build an LTO pack.

 

[spinningmagnets]

Please post up if these turn out good or bad. A lot of builders will be curious (along with me), and looking for a workable BMS solution...

 

[ElectricGod]

Please post up if these turn out good or bad. A lot of builders will be curious (along with me), and looking for a workable BMS solution...

At more than 7S these are NOT a BMS solution. Once you daisy chain 2 or more together, they are smart balancers only and you stop using P- and B-.

I'll post actual app photo's from my set up later. I've done some very limited testing so far so I can't really say how well they will work. They are cheap and they support LTO, LION, LIPO and LIFE so that is compelling to me.

Due to the nature of these BMS/balancers, the set up is pretty simple. The only relevant settings as balancers are in the left column. All settings get applied to all boards chained together. The android app is pretty rough and has lots of Chinese in it. Here's a translation I got. Sorry for the lo-res images. What I received was already low res and then I magnified those images a lot to present them here.

 

[ElectricGod]

Last night, I got around to messing with these 7S boards some more. I also had a BT module for one of the LION 20S smart BMS sitting on my bench. I plugged it into the open 4 pin JST connector on the 7S BMS and hoped I'd find a new BT device with my phone. 3 phones later and no BT device...what's the point of having a phone app if you can't use it? Maybe the pinout on the BT module doesn't match the pinout on the comms port on the BMS. I'll mess with this some more later.

 

[wiredsim]

So I bought a new-ish Kobalt cordless mower for a bargain- as a result I need to reuse my 24v LTO pack for a different purpose. That means I need to bump my voltage up to 36v. Does anyone have 6-10 of the 11ah cells they’d like to sell?

Thanks!

 

[ElectricGod]

So I bought a new-ish Kobalt cordless mower for a bargain- as a result I need to reuse my 24v LTO pack for a different purpose. That means I need to bump my voltage up to 36v. Does anyone have 6-10 of the 11ah cells they’d like to sell?

Thanks!

Talk to INWO...I think he still has some

 

[Deven]

Any one use yinlong 2.3v 40Ah lto battery’s

 

[SamRich]

Wanted to provide an update after 1100+miles (1800km) of riding over 5 months (>100 charges) with the LTO 11Ah Battery.

The battery performance is great!

IR of 113 mOhm so about 3.5 mOhm per cell - so within spec and pretty great for a 30S 11AH battery.

I opened up the case to make sure there wasn't any damage. Found a bit of chafing so added padding.

The other reason for opening it up is I wanted to add 2 cells to go from 30S to 32S.

What I realized is that although you charge 30S LTO at 30x2.8=84V there isn't much energy between 2.8 and 2.6 V.
I had thought the nominal voltage would be closer to 2.5V meaning that I needed 3.7V/2.5Vx20S=30S but in reality it is closer to 2.3V so 3.7V/2.3Vx20S=32S

So the battery quickly drops to 78V (less than 1/2 a mile).

Luckily I had bought 32 cells in case I need 2 for repairs or were defective.
My BMS can take up to 32 cells.
One of the two unused the cells was .1V lower voltage than the the others upon reception but I hope it is ok.
I had just enough room to stack 2 more cells into that box.

The only reason I didn't go with 32S before was that I didn't want to charge at 89.6V and have different chargers for my 20S li-ion batteries.
But I realise now that I can charge at 32S at 84V or 2.65V per cells without sacrificing much energy (Wh).

After balacing the pack it looks pretty good.
With the programmable BMS I changed the balance voltage to 2.6V instead of 2.8V (really love the programmable BT BMS!)

Even after two cycles and balancing, the last cell that I added is still the lowest (see Voltage 46), so there might be an issue with it. I'll keep an eye on it.
Now the bike feels more like a bike with a 20S li-ion battery. The 5-7% power and energy increase was worth the effort.

 

[Mandres]

Any one use yinlong 2.3v 40Ah lto battery’s

I'm wondering the same thing. Those look like a very interesting option. Any thoughts? https://m.alibaba.com/amp/product/60741696715.html

 

[kgasiorowicz]

I use LTO 20 amp hour Toshiba SCIB cells in my Honda hybrid car to replace the NiMH batteries. These things are really good. From my testing they really don't need to be balanced. They stay perfectly balanced to .001 volts and I didn't bother with a BMS. You are not using the Toshiba cells so they may not be as good.

These LTO cells will not go up in fire no matter what you do to them. You can also discharge them to 0 volts without much damage, can overcharge them, puncture them, they won't go up in flames.

I just found these on ebay for 350USD each. I bought two for an electric motorcycle project.

https://www.ebay.com/itm/32-4V-or-64-8V-20Ah-LTO-Titanate-Li-ion-1-1kWh-24cell-SCiB-cells/222782868762?hash=item33dee4cd1a:g:RgsAAOSwFO5aTs5x:sc:FedExHomeDelivery!53705!US!-1:rk:7f:0

 

[Mandres]

I looked at those same bricks, but for a motorcycle conversion I don't feel like their energy-density is good enough considering their size/weight. I could fit at most 3 of them in my frame and that's only 3.3kwh. Volt / Leaf cells give you almost double that capacity in a similar size package.

 

[kgasiorowicz]

I've been looking at buying and upgrading one of the electric grom clones that have popped up in the US over the past couple years. The SLA stock batteries weight around 65-70lbs, and two of those LTO modules weigh 64lbs. According to user accounts of the stock grom clones, the LTO upgrade should give me at least 20 miles of range @40mph or so, with a 65mph top speed. Because the cells stay so well balanced, I shouldn't need a BMS, so in total I'm saving a good amount over an equivalent 18650 pack, especially given that these Toshiba cells retain 90% capacity after 10,000 cycles.

Because I will only be using the egrom as a commuter, these batteries are perfect for me. However, you do have a point that for many EV applications, the energy density is weigh :wink: too low.

 

[Mandres]

Understandable. The positive aspects of LTO are very positive. I'm really tempted by those Yinlong 40ah cylindrical cells. They're about the size of a coke can, with threaded terminals, so building a custom pack will be relatively simple. You still get the massive C-rate and the incredibly long cycle life (claimed). I'm hesitant about ordering from China and the price seems to have jumped from ~$20/cell to $35/cell in the past month so I haven't pulled the trigger. I'm intrigued though, and watching for other projects to start popping up using these cells.

 

[kgasiorowicz]

Don't forget the incredible charge rate. The tochiba cells can be charged at 8C or 160A
This would require a 15-20kw charger, which would be prohibitively expensive, but in practice this means you can buy the most powerful charger you can afford without worrying about harming the cells. After 2kW, you kinda need a level 2 ev charging station though.

 

[Grantmac]

I am actively regretting going with the surplus Lipo packs I got instead of one of those LTO modules on Ebay for my bike build. 1.2kw/h in ~32# would be fine if the life of the pack is 5-10 years of commuting plus the enclosures should be easily mounted to a bike.

 

[ElectricGod]

I am actively regretting going with the surplus Lipo packs I got instead of one of those LTO modules on Ebay for my bike build. 1.2kw/h in ~32# would be fine if the life of the pack is 5-10 years of commuting plus the enclosures should be easily mounted to a bike.

LIPO per MAH is lighter and smaller, but life span/charge cycles, cold tolerance, discharge/charge rates, LTO wins. You will buy 10-15 sets of LIPO's before you use up one set of LTO's.

 

[marcorock2695]

hello what do you think about 96v 40ah LTO yinlong cilindral in 96v 1500w motor full load final range

 

[miro13car]

for me low terminal voltage of LTO is a big disadvantage.
you carry on your bike pack made from cells which dont even FULLY charge to 3.0V ????
it means you carry a lot of weight for a given Whs.
I would prefer to power my ebike with NMC chemistry cells from Chevy Volt, charge to 90% and discharge no more than 80% for longevity.
but NMC cell charges to 4.2V , big difference to LTO.
just like Sunders said LTO are great for stationary application like solar.

 

[john61ct]

The pro's and con's of LTO have been well covered already.

Let's assume this thread is now for people with use cases where LTO packs are appropriate, and people know already that is what they want to use.

So people that are not interested in LTO chemistry for **their** use cases, can just ignore the thread.

Would IMO help it remain much more useful.

 

[john61ct]

hello what do you think about 96v 40ah LTO yinlong cilindral in 96v 1500w motor full load final range

I am not sure what you're asking.

Could you put it in the form of an actual question?

 

[SamRich]

OP here.

After 1 year or so of riding LTO last year, I decided to look into 18650 li-ion cells instead.
The LTO worked fine for commuting, but I couldn't use it as much as I wanted for other uses due to limited range and at >100lbs it's not an easy bike to pedal.
I made the following chart to compare cells (based on early 2019 prices and available data)
Looking to build a 20S15P pack capable of 100A.

Compared to LTO, LG MJ1s seemed like a better long term solution.

The only downside was cost and not being able to charge at <0C.

Here are a few pics of the MJ1 20S15P build with ANT-BMS.

This battery can handle 100-150A bursts. The internal resistance of the pack is 0.050 Ohms, about half that of the LTO pack.

LTO was fun, but maybe not ideal for an ebike/emoped considering the low cost of long lasting cells like the LG MJ1.

 

[szczur333]

li ion is best choice - LTO has zero advantages - with my ebike frame for example I can fit max 20s20p pack built with HG2 cells - 4,3kWh and 60Ah

with LTO at the same weight and size I can do 20-24Ah

20P HG2 I can easy drive 150-180km and charge @ 30A in 2hours,

LTO range will be maximum 50-60km - even if I can charge it on 20minutes, this will be require 75A current charge, even if this will be possible probably only on car charging stations