Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

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Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by nickceouk » Jan 19 2020 10:16am

I have been exploring ideas on getting ebike touring logistics viable.

The obvious route from what's out there today is Lithium Titanate Oxide cells - LTO.

For example Yinlong cells as well as SCib cells rave about charging a 10ah to 40ah cell in 10 mins.

My Logistics dictate that I need a 48v to 72v LTO setup that I can recharge in 10mins and keep myself on the move rather than wait the several hours I currently have to on a lifepo setup.

To keep things civilised I would need to use the EVstreet chargers infrastructure.

Question is how to charge 72v 40ah setup at 10min or less?
Battery pack when in use would be x100 10ah Yinlong cells : 25s4p for a 72v 40ah battery pack.
To charge in 10 mins I somehow need to pump in 72x40x6= 17'280 Wh :shock:
Any charger of reasonable size is well under that figure and £££$$¥¥€€
One idea was that I can rewire the cells prior to charging so that the 100 cells become a 100s1p at ~240v DC. Perhaps flipping over the "battery pack" box cover coukd make this reasonably practical(reverse of box cover(top& bottom) would be different pattern to achieve 100s1p ...)

The question is what can I do to make myself life easier and EV Street charge an LTO ebike in 10mins!

If 17kw is too much than what's the best that can be achieved with the least extra charging hardware, weight ...

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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by John in CR » Jan 19 2020 3:36pm

Charging a 40ah pack in 10min requires 240A of charge current, which just isn't realistic.

Long distance trips by electric require a different approach to travel. That is to stop and do something interesting while your battery is charging. I used to take the drive straight through approach to trips...18-20hrs with only short stops for gas and food. It took a while to convert, but now my more relaxed approach, that requires a bit more up front planning to take in sites and do fun things as part of travel, makes trips far more pleasant.

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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by 999zip999 » Jan 19 2020 3:52pm

How many miles can you survive in a day on a bike ? 50 or 100 or more ?

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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by john61ct » Jan 19 2020 5:38pm

Yah talking 20kW public EVSEs, not too many of those along the way.

And have spec'd the volume and weight of LTO per kWh?

Much higher than LFP, which is twice that of the usual propulsion chemistries.

Probably right up there with old-school lead banks!

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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by amberwolf » Jan 20 2020 12:41am

nickceouk wrote:
Jan 19 2020 10:16am
To keep things civilised I would need to use the EVstreet chargers infrastructure.
what specifically is the capability of those chargers?

do they have a dc output? or ac only? what are the specifics of the output(s)?

i tried to find them on google, but all i found were references to them in various other sites, and not an actual site for them, or any specifications.

Question is how to charge 72v 40ah setup at 10min or less?
Battery pack when in use would be x100 10ah Yinlong cells : 25s4p for a 72v 40ah battery pack.
To charge in 10 mins I somehow need to pump in 72x40x6= 17'280 Wh :shock:
that's quite a lot of power. for example, i have four meanwell hlg-600h-54a led psus that make a pretty good totaly sealed, potted, weatherproof / vibration resistant charger that runs on either 120v or 240v (autoswitching) for up to around 58v at 48a, which is only around 2784w. together they weigh around 30lbs, iirc, and would be a block about 8"x12"x7", if I'm remembering the dimensions correctly.

to get 17280w out of that would need more than 6 of those blocks. so it would weigh nearly 200lbs, and be huge. i'd guess they generally cost at least $100 each new, so that's also really expensive, at least $2500. these aren't the right voltage for you, but you can use other versions that will give you the same capability; it'll still be about the same cost, volume, and weight, though.

i'm sure there are chargers that are more efficient and so would be smaller for the same capabilities, but probably not that much smaller. they could be a lot lighter, if they weren't sealed / potted, but that is what makes the ones i have more suitable for travelling. you might shave a third or perhaps even half (maybe not) the weight; the volume however will probably still be similar. dunno if they'd be any cheaper.


if i had to spend that kind of money, and take up that kind of weight and volume, i'd rather just carry more battery, and charge overnight whenever i had to stop to sleep anyway.


the question comes up....you have a battery with almost 3kwh of capacity. what is your wh/mile (or wh/km) expected to be? knowing those will give you your range. if you don't have enough range, but adding just a little more battery would give you the range you do need, then doing that will probably be cheaper and smaller and lighter than a superfast charging pack.

then use a standard charger for the overnight charge, and for opportunity charging along the way whenever you happen to stop for lunch or whatever.

One idea was that I can rewire the cells prior to charging so that the 100 cells become a 100s1p at ~240v DC. Perhaps flipping over the "battery pack" box cover coukd make this reasonably practical(reverse of box cover(top& bottom) would be different pattern to achieve 100s1p ...)
that kind of change means disconnecting and reconnecting all your high current connections every time you charge. this is virtually guaranteed to cause connection failures at some point, growing from minor to major over time. how bad a problem and how quick a problem develops depends on the actual connection method.... how the problem affects your system depends on exactly which interconnects begin to fail and how they do so.

people *have* done this sort of thing, usually using a connector block, like keyed andersons or the like, that simply wires out the cells individually (or groups of them, etc), and then a block "plug" that goes into this that is wired to hook them up as either charge configuration or dischare configuration. this type of system is relatively easy to fix by replacing conntacts when they act up, or the entire block if necssary.

my question is...where are you getting the 240vdc from?

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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by nickceouk » Jan 20 2020 5:14am

amberwolf wrote:
Jan 20 2020 12:41am
nickceouk wrote:
Jan 19 2020 10:16am
To keep things civilised I would need to use the EVstreet chargers infrastructure.
what specifically is the capability of those chargers?
do they have a dc output? or ac only? what are the specifics of the output(s)?
London, UK & Europe -
The rapid DC chargers use CCS & CHAdeMO (up to 50kw)

From batteryuniversity charging an EV website :

SAE J1772 Combo Charging System (CCS)
DC level 1: 200-500VDC, up to 80A (40kW)
DC level 2: 200-500VDC, up to 200A (100kW)

On Further research CCS allows for controlling the amps while charging through
HomePlug Green PHY and PLC protocol.

My basic reasoning is that by arranging the cells within the CCS: DC 1 charger voltage( 200-500 volts DC)
I can bypass on the bulk,mass etc of AC/DC mega rectifiers and keep to a minimum any hardware outside the cells themselves. If CCS DC level 1 can be set to 60amps at 240v DC with suitable electronic controller(Home Green Phy& PLC protocol) than its only up to the cells ability (<=1mOhm resistance from what I find) when connected in series Vs lab tested in single cell 10 min charge scenario.
It's a question mark whether 100 cells with <=1mOhm resistance hooked in series to 240v DC at 60 amps is ok. Everything points to amazing performance of LTO cells in fast charging so there is a good reason to believe this will work.

i tried to find them on google, but all i found were references to them in various other sites, and not an actual site for them, or any specifications.

https www osnpower com lto-lithium-35ah-titanate-oxide-battery-cell-for-sale_p16 html
Not allowed to post links yet hence the formmating :lol:
The link is of the 35ah cell...you can see the 10ah variant there too. The density and basic specs etc.

Question is how to charge 72v 40ah setup at 10min or less?
Battery pack when in use would be x100 10ah Yinlong cells : 25s4p for a 72v 40ah battery pack.
To charge in 10 mins I somehow need to pump in 72x40x6= 17'280 Wh :shock:

that's quite a lot of power. for example, i have four meanwell hlg-600h-54a led psus that make a pretty good totaly sealed, potted, weatherproof / vibration resistant charger that runs on either 120v or 240v (autoswitching) for up to around 58v at 48a, which is only around 2784w. together they weigh around 30lbs, iirc, and would be a block about 8"x12"x7", if I'm remembering the dimensions correctly.

to get 17280w out of that would need more than 6 of those blocks. so it would weigh nearly 200lbs, and be huge. i'd guess they generally cost at least $100 each new, so that's also really expensive, at least $2500. these aren't the right voltage for you, but you can use other versions that will give you the same capability; it'll still be about the same cost, volume, and weight, though.

i'm sure there are chargers that are more efficient and so would be smaller for the same capabilities, but probably not that much smaller. they could be a lot lighter, if they weren't sealed / potted, but that is what makes the ones i have more suitable for travelling. you might shave a third or perhaps even half (maybe not) the weight; the volume however will probably still be similar. dunno if they'd be any cheaper.
if i had to spend that kind of money, and take up that kind of weight and volume, i'd rather just carry more battery, and charge overnight whenever i had to stop to sleep anyway.
Yep, it's up there for consideration for sure :wink:
the question comes up....you have a battery with almost 3kwh of capacity. what is your wh/mile (or wh/km) expected to be? knowing those will give you your range. if you don't have enough range, but adding just a little more battery would give you the range you do need, then doing that will probably be cheaper and smaller and lighter than a superfast charging pack.

then use a standard charger for the overnight charge, and for opportunity charging along the way whenever you happen to stop for lunch or whatever.
I currently use one 13s4p(48v ~13ah) and one 13s3p(48v ~10ah) pack lifepo 18650s with 2-3 hours charging time each. Not sure on range at the moment and it's definitely changing both in terms of the build and battery setup etc.

Long distance touring(Europe to begin with) is my why I am exploring the LTO. It gives me that much more confidence knowing that wherever I am as long as I can get a DC CCS CHAdeMO charger I can be on my way in 10 mins instead of dancing around limited by the 2-3 hours charge time.
Charging in 10 mins is one of the issues...another would be if I can fit it all in a foldable built frame.
This would add the possibility of taking public transport along the way (may not be ideal but possible). For example the Eurostar train France- UK allows foldable bikes up to 85cm long.
The "mate X foldable ebike" (fat tires + suspension) is a good candidate at the moment...sorry not allowed to post links.
One idea was that I can rewire the cells prior to charging so that the 100 cells become a 100s1p at ~240v DC. Perhaps flipping over the "battery pack" box cover coukd make this reasonably practical(reverse of box cover(top& bottom) would be different pattern to achieve 100s1p ...)
that kind of change means disconnecting and reconnecting all your high current connections every time you charge. this is virtually guaranteed to cause connection failures at some point, growing from minor to major over time. how bad a problem and how quick a problem develops depends on the actual connection method.... how the problem affects your system depends on exactly which interconnects begin to fail and how they do so.
Yep, It's somewhat sketchy - it is however of a common interest with all electric vehicles(esk8, escooter,ebike, ebike, emotorbike,EV...) so worth investigating on that basis.
people *have* done this sort of thing, usually using a connector block, like keyed andersons or the like, that simply wires out the cells individually (or groups of them, etc), and then a block "plug" that goes into this that is wired to hook them up as either charge configuration or dischare configuration. this type of system is relatively easy to fix by replacing conntacts when they act up, or the entire block if necssary.
Thanks - need to look into this further.
my question is...where are you getting the 240vdc from?
Same place as the
1)Energica emotorbike : CCS/CHAdeMO rapid chargers(Street public access infrastructure)(50kw )
2)Harley's livewire model allegedly does 150 miles on a 35-40 min DC rapid charge(or thereabouts)
3) Lightning strike motorbike can also do level 3 DC rapid charging.

There will be more stuff to look for clues at from the emotorbike DC rapid charging street infrastructure
:D

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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by nickceouk » Jan 20 2020 5:35am

John in CR wrote:
Jan 19 2020 3:36pm
Charging a 40ah pack in 10min requires 240A of charge current, which just isn't realistic.

Long distance trips by electric require a different approach to travel. That is to stop and do something interesting while your battery is charging. I used to take the drive straight through approach to trips...18-20hrs with only short stops for gas and food. It took a while to convert, but now my more relaxed approach, that requires a bit more up front planning to take in sites and do fun things as part of travel, makes trips far more pleasant.
High amps or high voltage - CCS/CHAdeMO rapid chargers use both and DC charge.

Yes, the current state of logistics are dictating the multiple long forced stops approach...I can live with that ... yet the emotorbike Lightning Strike, Harley livewire and Energica have managed to use the EV public access infrastructure and that is a bit closer to ebike realms - so maybr( or maybe not) there are good synergys to be had ?
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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by nickceouk » Jan 20 2020 5:38am

999zip999 wrote:
Jan 19 2020 3:52pm
How many miles can you survive in a day on a bike ? 50 or 100 or more ?
On a good suspension with some careful setup and thoughtful build I would expect to at the least be on par with fossil fuel touring motorcycle I guess.
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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by nickceouk » Jan 20 2020 5:44am

john61ct wrote:
Jan 19 2020 5:38pm
Yah talking 20kW public EVSEs, not too many of those along the way.

And have spec'd the volume and weight of LTO per kWh?

Much higher than LFP, which is twice that of the usual propulsion chemistries.

Probably right up there with old-school lead banks!
It's not there everywhere and Street EV charging infrastructure demand is growing at a bubble industry speeds. It's a worthy investment of time & effort considering that perhaps.

Not happy about the energy density drop of LTO but will bite the difference easier knowing the trade-off 10 min full charge plus better safety aspects of LTO chemistry.
All that until some of those long promised speculation of next gen batteries materialize.

Lead banks :confused:

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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by john61ct » Jan 20 2020 6:13am


nickceouk wrote:Not happy about the energy density drop of LTO but will bite the difference easier knowing the trade-off 10 min full charge plus better safety aspects of LTO chemistry.
All that until some of those long promised speculation of next gen batteries materialize.

Lead banks :confused:
You remember lead right? Before the other chemistries, using deep cycling 6V golf car, even 2/3/4V cells, so heavy can barely lift one at a time!

Hence my question, have you actually spec'd the volume and weight of the LTO cells per kWh?

Yes we all know about LTO's benefits, fast charging being just one of them

but even for EV **car** builds rarely are they selected, just so much extra weight and space.

On a folding bike suitable for public transport? You're dreaming, do. the. math. you need to actually **know** the tradeoff before you can accept it!

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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by nickceouk » Jan 20 2020 6:51am

john61ct wrote:
Jan 20 2020 6:13am
nickceouk wrote:Not happy about the energy density drop of LTO but will bite the difference easier knowing the trade-off 10 min full charge plus better safety aspects of LTO chemistry.
All that until some of those long promised speculation of next gen batteries materialize.

Lead banks :confused:
You remember lead right? Before the other chemistries, using deep cycling 6V golf car, even 2/3/4V cells, so heavy can barely lift one at a time!

Hence my question, have you actually spec'd the volume and weight of the LTO cells per kWh?

Yes we all know about LTO's benefits, fast charging being just one of them

but even for EV **car** builds rarely are they selected, just so much extra weight and space.

On a folding bike suitable for public transport? You're dreaming, do. the. math. you need to actually **know** the tradeoff before you can accept it!
Lifepo is about 3 times the density of LTO and LTO is about 2 times the Lead acid ...so yeah quick charge option for a triple the weight & bulk trade-off.

My original calculations was on 48v 40ah LTO cells.
Cell spec :
1.25kg 40ah 2.4v nominal
66mm radius
202mm long(or heigh..)
48v /2.4v = 20 cells
20 cells in a 4x5 format (66mmx202mm each) can fit in a 30x35x21 cm container...a helmet box - size thing.
20 cells X 1.25kg = 25kg cells weight.

40ah 48v 40x35x21cm at 25 kg at the cell only level.

Then I realised that going up in voltage to what Rapid DC chargers natively charge EVs is desirable.
So for a 200 to 500 DC range I would need more cells rather than the bigger ah cells.
(arbitrary) 240 vdc / 2.4vdc nominal = 100 cells
So having the ability to switch between series 100 cells and then parallel them in 25s4p would keep the momentum of 10mins recharge on ebike going.

It's a departure from the 4x5 40ah cells but
more importantly is will the Street DC EV charger(CCS or CHAdeMO) be able to provide 240v dc at 60 amps direct to batteries (x100 10ah cells in series) in a reasonably small package to ebike with.
BMS is also non trivial with LTO

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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by john61ct » Jan 20 2020 7:06am

Yes, call it a coke can but longer, and 22 is 48V not 20, many would go to 23-24S

All the 40, 35, 30 and 25Ah capacities available are the same size, just QA grading give different Ah from the same production line, best to go for highest possible density.

Never seen LTO pouch style nor smaller cylinders, pretty sure practically speaking the 66160 form factor is it.

So, you see how going to 105S is five of those "helmet boxes"?

More like a 4m long trike design, not a bicycle, certainly not folding it, lifting it or even pushing it if your LVC kicks in, forget about carrying it onto a train 8-)

And even "just" on helmet box at 30+kg is **a lot** for just the battery pack.

Using the usual 18650's say 4000mAh NMC cells will likely be a third of the bulk and weight.
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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by john61ct » Jan 20 2020 7:08am

LTO BMS are widely available.

Even some of the good ones, $400+, are adjustable enough to deal with the lower voltage range.

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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by john61ct » Jan 20 2020 7:28am

Personally I'd rather be able to charge from standard 30/50A 240Vac outlets, those DCFC EVSEs may not yet be as easily available as you think just yet.

And different standards of course, Tesla's are proprietary, CHAdeMO I think is more USian rather than in Europe, CCS is the way to go for the future. . .

https://www.zap-map.com/charge-points/connectors-speeds

It is completely normal to use a 270~300Vdc "backbone" for power distribution in aviation and industrial applications, and then step down to ~48V, 24/12/5V whatever outputs at the point of load

using DCDC converters. Vicor is a leading civilian OTS vendor, secondhand even new units sold for pennies on the dollar on eBay.

Pretty high densities, but would still need to stack parallel modules to get up to 20kW, the total package will likely not be far off those HLG units.


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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by nickceouk » Jan 20 2020 7:52am

john61ct wrote:
Jan 20 2020 7:06am
Yes, 66160s call it a coke can but longer, and 22 is 48V not 20, many would go to 23-24S

All the 40, 35, 30 and 25Ah capacities available are the same size, just QA grading give different Ah from the same production line, best to go for highest possible density.

Never seen pouch style nor smaller cylinders.

So, you see how going to 105S is five of those "helmet boxes"?

More like a 4m long trike design, not a bicycle, certainly not folding it, lifting it or even pushing it if your LVC kicks in, forget about carrying it onto a train 8-)

And even "just" on helmet box at 30+kg is **a lot** for just the battery pack.

Using the usual 18650's say 4000mAh NMC cells will likely be a third of the bulk and weight.
23-24s is fine. I would actually work my way back from whatever setup I could charge seamlessly with the Street EV chargers DC CCS, CHAdeMO...)and slap a motor with suitable volts/watts etc. Tapping the 10min full charge on the go is where I am rooting at.

You can spec a good variety of LTO cells - prismatic including https : / / www . osnpower . com / lto-batteries_c10
There is even a 2.9ah prismatic cell there.

Pouch LTO video on YouTube as a safety demo of LTO chemistry - the pouch is abused :rol but pouch LTO do exist I guess
... likely not doing much to improve the 5 helmet boxes Vs 1 helmet box (at high ah ) scenario.

Well in the dream like situation of 30 kg cell weight we are talking a bag of cement stuff here 25kg. Some new designs on escooters have batteries as trolley to wheel for charging - 30 kg on a purpose built trolley like setup sounds just about doable.

Silence S01 by Silence urban mobility has this figured out. Just Google their detachable battery design - it's awesome.
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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by nickceouk » Jan 20 2020 8:06am

john61ct wrote:
Jan 20 2020 7:28am
Personally I'd rather be able to charge of standard 30/50A 240Vac outlets, those DCFC EVSEs may not yet be as easily available as you think just yet.

And different standards of course, Tesla's are proprietary, CHAdeMO I think is more USian rather than in Europe, CCS is the way to go for the future. . .

https://www.zap-map.com/charge-points/connectors-speeds

It is completely normal to use a 270~300Vdc "backbone" for power distribution in aviation and industrial applications, and then step down to ~48V, 24/12/5V whatever outputs at the point of load

using DCDC converters. Vicor is a leading civilian OTS vendor, secondhand even new units sold for pennies on the dollar on eBay.

Pretty high densities, but would still need to stack parallel modules to get up to 20kW, the total package will likely not be far off those HLG units.
The moment is towards quick charging ...that's the end game for EVs of all types. Yes it's not there yet and maybe even I would consider a backup lifepo with overnight charging - it's my current setup too.

This is interesting. The Vicor DC DC converter is 9v-450v input and 2-54v output at 600w.
Interesting options here :
1) 48-72v hub motor native voltage battery carried on the bike and 20 pieces of the DC to DC converters (what that is in bulk, weight and other ogistics )...dangerous springs to mind.
2) have a 240v dc battery carried on the ebike. This would be seamlesss to CCS Rapid charge and use Vicor type device at the motor - x2@600w would cover for my current 1000w hub motor for example

Edit :

Option 2 as done in the aviation...is looking better aligned overall. It's about fast charging( DC Street charger infrastructure) and slow discharging(hub motor, mid drive or other) hence matching the DC rapid Charger voltage on the battery pack voltage and DC to DC converter to whatever the hub motor uses (48v DC in my current setup). That seems to align all aspects of the chain to their respective strengths and optimal arrangement.
It's therefore interesting to compare full discharge of a 240v DC 10ah system with DC to DC converter to hub motor Vs 25s4p native discharge(no DC to DC converter) in terms of efficiency loss etc.
This way 100 cells used differently (with or without DC DC converter) can be checked for efficiency.

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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by john61ct » Jan 20 2020 11:11am


nickceouk wrote:The Vicor DC DC converter is 9v-450v input and 2-54v output at 600w.
That sounds like you only looked at one model?

There are hundreds, including those designed to parallel add-on modules for extra power.

______
The other way would be modular packs,

4 packs of 10Ah cells gives you 40Ah when these are paralleled

at say 22S for 51V nominal when discharging.

Put these temporarily in series to charge at 240V

-----
If occasional balance charging is needed, use 11S (standard 24V) sub packs rather than 22S, there are some hobby chargers around at 12S.

So 8S when charging, 2S4P while riding

No BMS used per sub-pack, just at full pack-level

LVC protection while riding set at 47V

HVC while charging set at 243-245V


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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by John in CR » Jan 20 2020 1:41pm

I still think you're making the same mistake as the big car manufacturers who are trying to maintain the status quo but with electric drives powering the same heavy wasteful cars. Electric transport should better meet the actual transportation needs while also making better use of the world's resources. The days of 2 tons of metal glass and plastic to move primarily just a 100kg of occupant needs to end.

Our ebikes are so much better in so many ways, that it's really no sacrifice to ride more efficiently on long rides, and for touring to have a big enough battery that charging while taking a leisurely lunch and while sleeping will get you as far as you can ride. Except for slow moving etrikes and other in town cargo carriers where extra weight can actually be a plus for stability and the longer cycle life drives long-term operating costs so low, I think it would be crazy to accept the 2X or more weight penalty of LTO compared to lithium. That's even before considering the weight and cost of a voltage converter to step voltage down from 300V that can output 240A, and the alternative of parallel/series connecting and reconnecting is the contrary to convenience as well as begging for failure.

If you really feel the need to go long distance, build a streamliner and achieve it through increased efficiency along with a nice big battery pack.

In 12 years of using electric transport I've been left waiting on a charger exactly once, and that was early on when I had only a sub 1kwh battery pack and a 300W charger.

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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by nickceouk » Jan 20 2020 2:57pm

John in CR wrote:
Jan 20 2020 1:41pm
I still think you're making the same mistake as the big car manufacturers who are trying to maintain the status quo but with electric drives powering the same heavy wasteful cars. Electric transport should better meet the actual transportation needs while also making better use of the world's resources. The days of 2 tons of metal glass and plastic to move primarily just a 100kg of occupant needs to end.
This is the precise reason why I am into ebikes now.
Our ebikes are so much better in so many ways, that it's really no sacrifice to ride more efficiently on long rides, and for touring to have a big enough battery that charging while taking a leisurely lunch and while sleeping will get you as far as you can ride.
Tempted to do both actually one bike(or more) that can do lifepo high density cells and the 10min recharge lto that way I will get to test in practice and have more real life value to share as well.


Except for slow moving etrikes and other in town cargo carriers where extra weight can actually be a plus for stability and the longer cycle life drives long-term operating costs so low, I think it would be crazy to accept the 2X or more weight penalty of LTO compared to lithium.
That's even before considering the weight and cost of a voltage converter to step voltage down from 300V that can output 240A, and the alternative of parallel/series connecting and reconnecting is the contrary to convenience as well as begging for failure.
Just had a second charger 48v pack. I wired it trusting the colour wires (blue neutral and brown live) and was sloppy not checking the polarity is correct. Two batteries and 1 new charger later (with reverse polarity) now looking at 2 new BMS replacements ... mistakes Ike this or other can happen.

On the LTO options to fast charge :
1) Have a 240v DC (100 lto 10 ah cells in series) and keep them like that on the bike( no rewiring).
I can the use the DC-DC converter suggested above to power the hub motor with 1-2 units (nothing big)
Efficiency is unknown here
2) Have a 240v DC (100 lto 10ah in series) and look into the hub motor itself. 240v DC hub controller is what should do the trick. On a given example of 1000watts hub motor 1000/240~5amps. That means I should be able to get the same efficiency by powering a hub motor with 240v DC 5amp hub controller. Hub motor may need more than 3 phases or it may be ok as is.. it's scratching the surface here

3) 240v DC to charge and rewire as needed to power hub - mechanical solutions do not need to be inferior - it could be as simple as pulling a lever up to charge in series and pushing the lever back down to use in parallel
If you really feel the need to go long distance, build a streamliner and achieve it through increased efficiency along with a nice big battery pack.

In 12 years of using electric transport I've been left waiting on a charger exactly once, and that was early on when I had only a sub 1kwh battery pack and a 300W charger.
What's your current setup like?
How do you go about charging?

My current 13s4p battery is about 13ah and it may be a stretch to have 8 of those for a 100ahs.
At that point I am at odds with suspension bike frame wheel size etc etc :lol:

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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by john61ct » Jan 20 2020 4:11pm


nickceouk wrote: one bike(or more) that can do lifepo high density cells and the 10min recharge lto that way I will get to test in practice
But LFP is **half** the energy density of what's used nowadays!

Light, low volume, tons of oomph is what's called for.

No one's using LFP for propulsion anywhere that I can see, not for bikes certainly, not much for cars, not even on those huge all-electric ferry boats in Europe. . .

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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by nickceouk » Jan 20 2020 4:32pm

john61ct wrote:
Jan 20 2020 4:11pm
nickceouk wrote: one bike(or more) that can do lifepo high density cells and the 10min recharge lto that way I will get to test in practice
But LFP is **half** the energy density of what's used nowadays!

Light, low volume, tons of oomph is what's called for.

No one's using LFP for propulsion anywhere that I can see, not for bikes certainly, not much for cars, not even on those huge all-electric ferry boats in Europe. . .
Actual cells Li-NMC, NCA ...so yes please scratch the LFP 💯

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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by Addy » Jan 20 2020 5:49pm

john61ct wrote:
Jan 20 2020 4:11pm
No one's using LFP for propulsion anywhere that I can see, not for bikes certainly, not much for cars, not even on those huge all-electric ferry boats in Europe. . .
They have been used in hybrid bus setups, you can see a datasheet of one example here: https://gettozero.com/pdf/bus/ESS-A123.pdf
Though in 2020 I don't know if anyone is still going this route.

I purchased a couple of these modules (12s8p of A123 cells in each) used on ebay and I was disappointed with them. I knew they were used, but they had been seriously degraded by the time I got the cells, they tested at about 65% of original capacity. Still worked for the starter battery I made with some of them, but just barely.

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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by john61ct » Jan 20 2020 6:24pm

Yes tons of buses from a long time ago, scrapped packs coming on the market.

Lots through a yard near Quebec, all crap afaict.

A123, top notch stuff when new but these well worn out in the streets of China I think.

Would be great to get NOS at scrap prices, but generally IMO secondhand is hardly worth the trouble.

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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by john61ct » Jan 20 2020 6:26pm

Don't get me wrong, LTO and LFP are fantastic chemistries, just not well suited for most propulsion use cases where energy density is critical.

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Re: Practical advice on achieving the 10min full charge LTO(Titanate) cells are meant to deliver

Post by john61ct » Jan 20 2020 7:52pm

Check out eBay auction # 143034247371

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