# Has anyone tried a LIPO battery?



## Francis Cebedo (Aug 1, 1996)

It seems like all ebikes I've seen use Lithium Ion batteries. They use these 18650 cells that are in steel cases and they put them in a heavy case.









They work but they are heavy. The Shimano battery weighs about 6 lbs.

Iphones, RC cars and drones all use Lipo batteries because they are smaller and lighter. Most drones for example will have little chance of lifting these Lithium Ion batteries for long periods since weight is critical.

So my question is, has anyone thought about or used Lipo batteries in ebikes? The battery will weigh half is my guess. The batteries will have to be protected and charged carefully of course.









Lipos are measured in mah (milliamp hours). Ebike batteries are in Wh (watt hours). Found a conversion here: https://www.rapidtables.com/calc/electric/mah-to-wh-calculator.html

Looks like 10,000 mah at 48 volts is 480Wh.


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## Guest (Sep 22, 2018)

fc said:


> It seems like all ebikes I've seen use Lithium Ion batteries. They use these 18650 cells that are in steel cases and they put them in a heavy case.
> 
> View attachment 1217424
> 
> ...


Why would I need batteries on a mountain bike? :???:


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## ninjichor (Jul 12, 2018)

I hope not. Those things are prone to thermal runaway (fragile, easy to short from damage) and don't last for as many recharge cycles. Glad the engineers picked the more sensible option, rather than succumb to weight weenie demands. Hate to see what happens when non-engineers, such as copy cat Chinese, take this idea and try it out and create a load of extra controversy (e-bike fires), due to stupidity/ignorance. I wouldn't be surprised if this becomes regulated, as I'm sure some spec-sheet shopper would optimistically buy it thinking it passes some safety standard...

Plenty of more hopeful battery tech to come. Solid state perhaps? Higher energy density and more safety are big pluses. I wouldn't expect these any time soon, likely beyond 2025.

For now, if you want lighter batteries, you just have to pay extra for the packs with higher capacity cells. There's 3800 mAh cells, for example. Or just opt for lower capacity, like the Lapierre eZesty, which is ~38 lbs. Something like this is perhaps more suited to a fellow of your stature and fitness, while the more common offerings will appeal more to 180+ lb riders. The new Levo uses 21700 cells, which perhaps has more energy density for the size and weight (haven't looked into it that deeply yet).


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## Francis Cebedo (Aug 1, 1996)

ninjichor said:


> I hope not. Those things are prone to thermal runaway (fragile, easy to short from damage) and don't last for as many recharge cycles. Glad the engineers picked the more sensible option, rather than succumb to weight weenie demands. Hate to see what happens when non-engineers, such as copy cat Chinese, take this idea and try it out and create a load of extra controversy (e-bike fires), due to stupidity/ignorance. I wouldn't be surprised if this becomes regulated, as I'm sure some spec-sheet shopper would optimistically buy it thinking it passes some safety standard...
> 
> Plenty of more hopeful battery tech to come. Solid state perhaps? Higher energy density and more safety are big pluses. I wouldn't expect these any time soon, likely beyond 2025.
> 
> For now, if you want lighter batteries, you just have to pay extra for the packs with higher capacity cells. There's 3800 mAh cells, for example. Or just opt for lower capacity, like the Lapierre eZesty, which is ~38 lbs. Something like this is perhaps more suited to a fellow of your stature and fitness, while the more common offerings will appeal more to 180+ lb riders. The new Levo uses 21700 cells, which perhaps has more energy density for the size and weight (haven't looked into it that deeply yet).


Great points!! I don't think manufacturers will turn to lipos as they require more care. I still want to know the knowledge and experience with them though. They are used in drones after all and those are pretty demanding conditions.

The 21700 cells on the Specialized are cool for compactness but they are 700 grams heavier than the normal battery. Would be interesting to put a put a best-in class battery on that bike with half the capacity and save... 4 lbs. (250 Wh, lipo, Carbon case)


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## PierreR (May 17, 2012)

Battery technology that is prone to fires must be avoided at all cost. I don't see anything that would offset this.


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## Francis Cebedo (Aug 1, 1996)

PierreR said:


> Battery technology that is prone to fires must be avoided at all cost. I don't see anything that would offset this.


I get your point.

It's in gradients though. Virtually every single one of us has lipos in their pockets/cellphones and laptops.

And lithium ion which is on ebikes is prone to fires, per Tesla... and those bike lights.


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## ninjichor (Jul 12, 2018)

Those things are lightweight. Not much mass/inertia being swung around. Plus they're encased by armor that is heavier than the cell itself.

Tesla had to resort to reinforcing their battery packs with the titanium plate. Think that could've been done better, with external shaping to deflect, like what's going on with mtb tire sidewalls.

I'd be hesitant to even run LiPo with bike lights, based on the fire hazard. The LiPo compatible chargers, that are specialized for minimizing damage related to balancing packs made with multiple LiPo cells, are pretty pricey too. You get into new standards with XT60 and XT90 connectors too.


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## Bigwheel (Jan 12, 2004)

"So my question is, has anyone thought about or used Lipo batteries in ebikes?"

Only for the last 15 years or so. Very popular with the Endless Sphere set that adopted them from the RC world. Always too much of a risk, Weir's garage for example, for me to subscribe and you will certainly never see the industry go that route. Think Hoverboard. 

Li Ion is a much more stable chemistry yet can still catch fire if the BMS does not do it's job correctly but with the amount of Li Ion cells in use it is a very small percentage seemingly acceptable to the electric industry in general. 

And all cells have a mAh rating, which times the amount of cells at a given mAh rating configured in series and parallel the Voltage and Ah rating of the battery. Wh's are the result of Ah x current allowed by the controller resulting in wh's.

The 2170 cells weigh more per cell than 18650 it just takes less of them to get the same amount of V/Ah's. If the Levo had used 18650 cells to get their 700wh battery it wouldn't necessarily weigh more but need more space. 

There is a lighter weight option that can be used as a safety measure against fire. It is a silica impregnated cloth, similar to Nomex which is good up to 750 degrees, that will withstand temps up to 1000 degrees which is where Li Ion and LiPo type chemistry will end up to if they do go wrong. It can be used as a sleeve and doesn't even add much cost.


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## KenPsz (Jan 21, 2007)

Lipo is used extensively in the RC world and they do come with serious limitations, but do have a great power to weight consideration.

I don't think there are ESC's built around there for e-bikes and the notion you could have a puffed cell that could lite on fire between your legs does not sound appealing. But put lipos into a fireproof charging bag and put those on your bike that would be good. But you can't abuse lipos in amp draw or temp.


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## Francis Cebedo (Aug 1, 1996)

Bigwheel said:


> "So my question is, has anyone thought about or used Lipo batteries in ebikes?"
> 
> Only for the last 15 years or so. Very popular with the Endless Sphere set that adopted them from the RC world. Always too much of a risk, Weir's garage for example, for me to subscribe and you will certainly never see the industry go that route. Think Hoverboard.
> 
> ...


Great info. Thank you.

fc


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## Guest (Sep 26, 2018)

^^^you should just hit the gym instead...


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## Bigwheel (Jan 12, 2004)

fc said:


> Great info. Thank you.
> 
> fc


I have to admit to a bit of mis-info to see if anyone here is on the ball with e terminology.....I posted this above:

Wh's are the result of Ah x current allowed by the controller resulting in wh's.

This is not correct as Wh's are the result of V x ah = wh's. V x A (controller current) = Watts.

I think that as time goes on the EU based manufacturers will up the voltage from 36v to 48v as it just makes sense as it allows a small electric motor to run more efficiently at a higher output. Personally I am running 52v which isn't as much about power but adds to available wh's for more range.


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## KenPsz (Jan 21, 2007)

Bigwheel said:


> I have to admit to a bit of mis-info to see if anyone here is on the ball with e terminology.....I posted this above:
> 
> Wh's are the result of Ah x current allowed by the controller resulting in wh's.
> 
> ...


The whole voltage = efficiency does get really weird. I look more at amps since that is direct heat and load.


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## Francis Cebedo (Aug 1, 1996)

griz said:


> ^^^you should just hit the gym instead...


Stop trolling griz. Just having a discussion here.


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## BCsaltchucker (Jan 16, 2014)

lipo are a problem because they have LOW energy density compared to li-ion. This is why your cell phone does not have lipo as you claimed earlier in the thread, it has li-ion cell technology.

I am big into RC flying (FPV flying) and am moving to li-ion because it is much better for endurance, providing more than DOUBLE the range of a similar weight lipo. On one plane it can get about 20min on a 1800mah lipo, but 60 minutes flight time on a 3000mah li-ion pack which weighs nearly the same. So the 'heavy steel case' of the li-ion cell is actually not a problem - the typical lipo cell are still much much heavier than the typical 18650, per WH.

and now that we have higher amps-rated li-ion cells for a while now, ebikes and RC planes can both use li-ion cells for great performance and great range.

Only reason for lipo is for devices that need a TON of amps draw. So racing miniquads, sport planes or some kind of franken-ebike with 5000 watts might benefit from going to lipo cells. But in those cases the endurance will be poor, albeit on a bicycle you can just load it up with more heavy batteries I guess unlike an aircraft. 

Also lipo come in much more sizes and amps-ratings while the more commonly available li-ion are mostly 18650 cells which limits the usefulness for fitting into model aircraft. Not an issue for bikes.


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## Francis Cebedo (Aug 1, 1996)

Looks like Lithium Ion is best. Huh!


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## KenPsz (Jan 21, 2007)

BCsaltchucker said:


> lipo are a problem because they have LOW energy density compared to li-ion. This is why your cell phone does not have lipo as you claimed earlier in the thread, it has li-ion cell technology.
> 
> I am big into RC flying (FPV flying) and am moving to li-ion because it is much better for endurance, providing more than DOUBLE the range of a similar weight lipo. On one plane it can get about 20min on a 1800mah lipo, but 60 minutes flight time on a 3000mah li-ion pack which weighs nearly the same. So the 'heavy steel case' of the li-ion cell is actually not a problem - the typical lipo cell are still much much heavier than the typical 18650, per WH.
> 
> ...


We need flat pack cells without the steel shell like lipo's come in.


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## Francis Cebedo (Aug 1, 1996)

KenPsz said:


> We need flat pack cells without the steel shell like lipo's come in.


exactly. That was my main issue with it. A case within a case... when weight is a key factor.


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## BCsaltchucker (Jan 16, 2014)

KenPsz said:


> We need flat pack cells without the steel shell like lipo's come in.


can only agree. and more variety in shapes like lipo come in. But still li-ion chemistry is for me. I've had lead acid, LiFePO4 and li-ion on my ebikes over the years. my god li-ion towers overt those others!

although, perhaps the spaces left in between the cylindrical 18650 cells allows for more cooling than we get with flat lipo cells. And the steel casing might help to wick away the heat more quickly too?

It might be telling that Tesla is sticking with cylindrical cells for their latest and greatest 2170. Maybe it is the best shape/construction we know of to date?


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## KenPsz (Jan 21, 2007)

BCsaltchucker said:


> can only agree. and more variety in shapes like lipo come in. But still li-ion chemistry is for me. I've had lead acid, LiFePO4 and li-ion on my ebikes over the years. my god li-ion towers overt those others!
> 
> although, perhaps the spaces left in between the cylindrical 18650 cells allows for more cooling than we get with flat lipo cells. And the steel casing might help to wick away the heat more quickly too?
> 
> It might be telling that Tesla is sticking with cylindrical cells for their latest and greatest 2170. Maybe it is the best shape/construction we know of to date?


I run LiFePO4 for the number of potential cycles which is much higher that Li-ion

I work in energy storage so know a bit about how we put together battery racks in the kW and mW power ranges

The space does not need to be much to get cooling so small spacers would work for that

Keeping the batteries in the steel case is a great safety concern where flat pack is great for a small form factor. On our bikes we are not real worried about running over something at 60mph and puncture the cells, so flat pack would work with an outside protective shell.

Here's the thing there is a flat pack cell in those round cells. They roll up the flat cell in to a tube and put a steel case round it.

The company I work for moved away from flat pack and to round cells since they are cheaper to get. I am sure Tesla does it much for the same reason.


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## BCsaltchucker (Jan 16, 2014)

Tesla makes their own cells now with Panasonic in Tesla Factories. they could have chosen any form factor they wanted IIRC


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## KenPsz (Jan 21, 2007)

BCsaltchucker said:


> Tesla makes their own cells now with Panasonic in Tesla Factories. they could have chosen any form factor they wanted IIRC


Yeah sure and the steel case is the safest form factor that is overkill for e-bike usage.

Panasonic sells those same batteries around the planet so which form do you think Panasonic would prefer to make.

I don't want to argue, if you want round use them I would prefer flat for the reasons above.


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## BCsaltchucker (Jan 16, 2014)

I'm not saying it's best for MTB use, just that it was the best choice for Tesla! In fact I said flat and varied shapes makes lipo easier to shape into tight spaces. I work with lipo all the time, making my own packs for RC plane uses, FPV systems etc. And recently started making my own 18650 packs for flying too


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## Bigwheel (Jan 12, 2004)

KenPsz said:


> The whole voltage = efficiency does get really weird. I look more at amps since that is direct heat and load.


Running a 52v battery @ 20A is more efficient than running a 48v @ 25A due to my experience with both systems on similar bikes that I track with a CAIII. They both give me all the assist I need in a hard to tell by the seat of the pants if either is actually better way. I do get more range with the 52v system in general. Temp is about the same, they are DD motors which are notorious for generating heat, and rarely get near the 90c threshold.

But the 52v holds the 17+mile local rural pavé loop record of 30mph/30 wh/mi vs. 29.8 @ 32 wh/mi.. Both bikes have gearing enough for effective pedal input at speed and was active the whole time also.

My mid-drive mtb is 52v/16A and is good for any hill in eco and up to 4 hours of fun and games with a 520wh battery. An effective torque assist and the right gear selection is crucial to "keeping it on the pipe".


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## KenPsz (Jan 21, 2007)

Bigwheel said:


> Running a 52v battery @ 20A is more efficient than running a 48v @ 25A due to my experience with both systems on similar bikes that I track with a CAIII. They both give me all the assist I need in a hard to tell by the seat of the pants if either is actually better way. I do get more range with the 52v system in general. Temp is about the same, they are DD motors which are notorious for generating heat, and rarely get near the 90c threshold.
> 
> But the 52v holds the 17+mile local rural pavé loop record of 30mph/30 wh/mi vs. 29.8 @ 32 wh/mi.. Both bikes have gearing enough for effective pedal input at speed and was active the whole time also.
> 
> My mid-drive mtb is 52v/16A and is good for any hill in eco and up to 4 hours of fun and games with a 520wh battery. An effective torque assist and the right gear selection is crucial to "keeping it on the pipe".


Like BCsaltchucker I used to do electric RC and there you really see the magic of voltage vs. amps.

Give a brushless 36volts or more and magic happens for performance and duration.

Electrical systems are some cool tech and I do like the fact it has made its way into this hobby.


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## jesse101 (May 23, 2011)

ninjichor said:


> I hope not. Those things are prone to thermal runaway (fragile, easy to short from damage) and don't last for as many recharge cycles. Glad the engineers picked the more sensible option, rather than succumb to weight weenie demands. Hate to see what happens when non-engineers, such as copy cat Chinese, take this idea and try it out and create a load of extra controversy (e-bike fires), due to stupidity/ignorance. I wouldn't be surprised if this becomes regulated, as I'm sure some spec-sheet shopper would optimistically buy it thinking it passes some safety standard...
> 
> Plenty of more hopeful battery tech to come. Solid state perhaps? Higher energy density and more safety are big pluses. I wouldn't expect these any time soon, likely beyond 2025.
> 
> For now, if you want lighter batteries, you just have to pay extra for the packs with higher capacity cells. There's 3800 mAh cells, for example. Or just opt for lower capacity, like the Lapierre eZesty, which is ~38 lbs. Something like this is perhaps more suited to a fellow of your stature and fitness, while the more common offerings will appeal more to 180+ lb riders. The new Levo uses 21700 cells, which perhaps has more energy density for the size and weight (haven't looked into it that deeply yet).


I disagree with the above mentioned, we have been using LIPO batteries on equipment/UAVs/Ground based vehicles for a long long time, not to mention the model airplane and RC Car community has been using them for years as well. As long as you have these batteries regulated with automatic shutoffs, and charged equally, they are just as safe as any other battery powered systems and perform very well. They have the ability to produce more power through the entire range and do not degrade with charging cycles as with most other batteries.

and yes they are lighter..which DOES play a factor when you are using batteries as a energy source to power a motor for extended periods. I personally would like to see LIPO batteries induced into the E-Bike Community, one that is well protected, water proof, with the appropriate regulators installed. You can currently purchase your own set, wire them accordingly if it be series or series parallel and apply associated connector with a regulator to automatically shut off when battery reaches 15% of its capacity. I am down with it


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## E. Bryant (Jan 25, 2018)

I think that there is some confusion in this thread between cell chemistry (what materials are used to construct the cell - specifically, the anode and electrolyte) and cell construction/form factory (how the cell is structured and contained). 

Cell chemistry is a trade-off between energy, power, cost, and safety. E-bikes would appear to favor energy density over power density, but there is still the issue of finding a chemistry that offers acceptable safety and affordability. There are chemistries that are "intrinsically safe" (meaning that they will not go into thermal runaway if damaged or abused), but they typically do not offer competitive energy density. Such is life. 

Cell construction is a matter of manufacturing cost, durability, cooling, and pack assembly. Prismatic or pouch cells can be packaged more densely, but are often more expensive to manufacture and can be damaged more easily depending on the material used for the housing (plastic film is typical for consumer electronics and hobby applications, but more robust materials are used for industrial and EV applications). 

The auto industry hasn't sorted out any of this yet; there are a large variety of chemistries and packages that are being tested in the marketplace right now and in the next few years. I suspect that once things settle down in that market, we may see some trickle-down effects. For now, I suspect that run-of-the-mill 18650 cylindrical cells with LCO or NMC chemistry offer the easiest design path for most manufacturers. 21700 cells will become more popular as they are adapted in the auto and power-tool industries. An e-bike with high production volume could make good use of a prismatic or pouch cell that is properly sized to the battery pack, but that would take some investment and I suspect that the e-bike market is still too young (although this assessment will rapidly change).

Also note that, when it comes to safety, the battery management system needs to be on-point! 18650 cells are reasonably robust from a mechanical standpoint, but that isn't going to stop a cell from going into runaway if it is mistreated during charge or discharge (and if one cell goes up in flames, it's probably going to take its neighbors with it).


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## Bigwheel (Jan 12, 2004)

As noted a properly configured BMS is the safety feature built in to a LI eBike battery. This feature is not used with LiPo batteries in general until a properly executed charge cycle via the aforementioned methods that prevent thermal runaway.

The BMS can also be configured for CAN/BUS protocols that enable it to send other information around the system in regards to the bikes operation.

The element missing from this conversation is C rating. A larger mah battery will have a higher power density but also allow for a longer run time if not used to its full capacity due to less strain on the cell to produce the voltage required. I am not sure what mah rating the 2170 cells in the new high end Levo's are but I would suspect the max 5000mah ones. The highest 18650 rated cells are around 3800mah so based on individual cells the 21700 has a higher C rate. While each cell weighs more as mentioned it takes less to make up to the series and parallel config required. But according to my calcs it will still weigh a bit more per given config but offer higher energy and power density to more than compensate.

Some infö to get you going on C rate here: w w w.power-calculation.com/battery-storage-calculator

Here is a shot of a 2170 Samsung 5000mah cell in comparison to the 2500mah cells at the top of this post.









They don't look all the much different but due to the size difference will take some redesigning to get into a case or to integrate which going forward will happen but at the usual slow pace the industry seems to like to follow.


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## BCsaltchucker (Jan 16, 2014)

jesse101 said:


> I disagree with the above mentioned, we have been using LIPO batteries on equipment/UAVs/Ground based vehicles for a long long time, not to mention the model airplane and RC Car community has been using them for years as well. As long as you have these batteries regulated with automatic shutoffs, and charged equally, they are just as safe as any other battery powered systems and perform very well. They have the ability to produce more power through the entire range and do not degrade with charging cycles as with most other batteries.
> 
> and yes they are lighter..which DOES play a factor when you are using batteries as a energy source to power a motor for extended periods. I personally would like to see LIPO batteries induced into the E-Bike Community, one that is well protected, water proof, with the appropriate regulators installed. You can currently purchase your own set, wire them accordingly if it be series or series parallel and apply associated connector with a regulator to automatically shut off when battery reaches 15% of its capacity. I am down with it


just one note - You suggest that LIPO are lighter than li-ion batteries, This not the case at all. LIPO are HEAVIER than Li-ion batteries, generally speaking. But it gets complex when accounting for C ratings, of course, because most lipo in RC are multiple times the C rating of even high discharge li-ion cells. But when the application can be efficient and utilize low-C rated cells, the rewards are much much better duration+range using li-ion instead of LIPO.

I also do RC flying and have recently started using li-ion packs in some of my long range planes. I can achieve approximately double the duration with a li-ion pack compared to the LIPO of the same weight. The energy density is nearly double that of LIPO. While a flight on my nanogoblin gets about 25 minutes max using a 1300mah 100 gram 2S LIPO, I can easily get 55 minutes with a 100 gram 3000mah 2S liion pack (LH HG2 cells). Same weight, double the duration. Of course this airframe is super-efficient and lighweight (and quick), while many many other kinds of RC planes, quads need much higher C-rating, thus li-ion can be difficult to integrate.

With ebikes, unlike planes however, we do not have to lift the batteries into the air so can have heavy banks of li-ion cells to achieve high amps draw. This makes it a good match for our ~1hp output limits like eMTB. The folks who really need LIPO on their ebikes are the folks going ludicrous (and illegal) speed, lol. I've seen the videos, going 100kph on an ebike with LIPO. And no BMS!!


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