Battery technology as of 9/15 (Li-Ion, NMC, or what?)

[marcilla.smith]

Hello forum,

After switching to ICE bike motors for the past few years, I am returning to an electric hub motor conversion for a Trikke T12 project. I am unfamiliar with the current state of battery technology, and would like to solicit opinions on the subject.

I found a somewhat recent and thorough breakdown at https://www.electricbike.com/lithium-cobalt-manganese/ . Unfortunately, the article completely omits Li-Ion, so after reading, I am wondering about the benefits of Li-Ion versus NMC.

Then, I come to the forum, and I see the discussions seem to center more around LiPo and LiFePO4, leaving me really scratching my head.

Whatever is a poor little bicycle motorizer to do?

 

[Lungcookie]

some reading for you
https://endless-sphere.com/forums/viewtopic.php?f=14&t=26621

 

[marcilla.smith]

Thanks very much for the link =]

If I understand correctly now, "Li-Ion" is more of a generic or umbrella term that includes many different chemical formulas. Similarly, "LiPo" or "lithium polymer" can refer to different chemical formulas, so long as they are suspended in a polymer. So a battery could potentially be labelled Li-Ion, LiPo, and NMC, if I understand now.

I am considering this 36V 10Ah w/ BMS and charger for $169: https://bmsbattery.com/ebike-batter...og-ebike-battery-pack-ecitypower-battery.html

 

[FFV8]

Welcome Marcilla

In my experience most battery threads eventually degenerate in to a purse swinging contest.

Every application is different, and many times we are doing things way outside of the battery manufacturers design parameters...

I am far more interested in your application - the T12. You should do a build thread as this project gets started.

Since you are kind of limited to FWD, and a 12" OD wheel, it looks like a 250 Watt hub motor is the answer.

This is a very lightweight vehicle, so 250w should be plenty. I would work to keep the weight low & on the center line.

The next question is range. How long do you intend to ride it before charging? With a 24v 250w motor, 10.5 amps will run it wide open. A few hobby batteries would last a long time.

Good luck with your project.

 

[BarelyAWake]

In my experience most battery threads eventually degenerate in to a purse swinging contest.

...I don't think it's that simple FFV8.

SLA - very inexpensive but extremely heavy, low energy density, most tolerant of mistreatment but only about 300 charge cycles.

Li-Ion - the least costly of the commonly available lithium, thermally unstable if damaged or charged/discharged incorrectly, about 1000 charge cycles.

LiFePO4 somewhat more costly, no memory effect, thermally stable and about 2000 charge cycles.

...so, insofar as an investment/cost it's quite unclear which way the purse would swing as saving a few bucks may not be actually saving a few bucks.

For initial experimentation? SLA or Li-Ion is prolly a good way to go, but "cost effectiveness" is an awkward consideration when experimenting as sometimes smoke happens lol... for long term simplicity, reliability & ease of use? I'm very fond of LiFePO4.

In the end it's up to the user ofc

 

[Lungcookie]

To confuse things more.
Even in the 'Li' type batteries they have different max charge voltage levels.

LiPo=4.2v/cell
LiLo=4.1v/cell
LiFe=3.6v/cell

The long life cycle of the LifePO4 still requires the user to understand the battery limitations.
That would be not fully charging (90%) or discharging or pulling more amps than the cells or BMS are ratted for.

LifePO4 is most likely the safest easiest user friendly chemistry out now.

 

[marcilla.smith]

Well, I certainly don't want to start a battery chemistry war!

I have heard good things about LiFePO4. I am concerned it is more temperamental than other Li technologies, thus the BMS. I want something that is low stress and low maintenance.

I am figuring that a Li-NMC with BMS may be less finicky, but this is only based on what I've read. In the past, I only have used SLA for vehicular applications.

I would consider using SLA again, having used it before and this being something of an "experiment." However, it seems to me that the cost for a comparable setup would be more for SLA than the $169 36V10Ah Li-NMC I posted from BMS Battery.

As for the motor I plan to use, I found a 12" 350w hub motor that I have on order from: https://www.uumotor.com/12-inch-scooter-motor-brushless-gearless-or-geared.html

Where do build threads go?

EDIT: Sorry, Lungcookie, I did not see your thread until mine posted. You say that LiFePO4 is easiest, but also requires the user to understand the battery limitations. I have read that Li-NMC is better at staying balanced between cells

Thank you for the information, suggestions, and encouragement =]

 

[Lungcookie]

I don't want to start any wars either.
Its all good, we are here to learn and further our understanding.

Modern battery packs that you buy for ebikes should have a BMS (battery management system) to keep the cells in balance and hopefully keep the user from over discharging the battery below a useable voltage level and permanently damaging the cells. LVC (low voltage cutoff).

I will use myself as an example.
My first battery was a LiFePO4 cell pack. Great battery.
It was rated for 20a discharge w/BMS.
I didn't read the fine print on the battery information, new to the sport and all. I got used to the 20a.

This Magic Pie 3, I was riding went up to 30a so of course I turned it up to 30a.

Killed the BMS and the cells followed. 9 months
Complete user error, just didn't know what I was doing. DOH!

You can in fact add a BMS to LiPo, if one was so inclined.

 

[FFV8]

Marcilla:

When you get started, post pics an info in a new thread in this area:

http://motorbicycling.com/forumdisplay.php?f=36

Should be a wild ride with 350 Watts!

You really only have a little space on the upright to mount things. I would say SLA is not going to work out unless you sling the batteries in a backpack.

The battery you linked to would work. If the seat post clamp could be enlarged to fit the upright tube on the T12 it would mount hanging aft - if...

A $170 experiment. Probably not the place to start. This battery from the same source could solve some mounting issues:

https://bmsbattery.com/ebike-battery/463-36v10ah-li-ion-alloy-03-case-ebike-battery-with-a-carrier-rackr-battery.html

It could be mounted vertically to the upright and offers a place to put the motor controller.

If you are a good fabricator there are many options. If the li-xx battery stuff worries you, a packaged Batttery / BMS / Charger set may be the best option.

Don't laugh too hard about the backpack full of batteries. Here is Corbin running Mulholland on an e-bike. wearing about 35 pounds of Lithium batteries on his back

https://www.youtube.com/watch?v=QgOyDKrFZdc

 

[marcilla.smith]

Thanks!

I will sure I have a BMS. BMSBattery (confusing name) says all of their batteries include BMS.

The ride in the video looks fun, but yes, I think I will skip the backpack, if I can.

BMSBattery suggested this bottle battery at $159 https://bmsbattery.com/ebike-batter...bottle-battery-pack-with-charger-battery.html . It doesn't have the space for the controller, but I think the shape will look good when mounted to the head tube, and I haven't found a better price elsewhere.

I just got the motor, controller, and throttle in from UU Motor today. Having no battery, I can't test it, but I can tell you that everything arrived looking undamaged and of good quality. Tony from UU has been very helpful

 

[kevyleven007]

You might find this of interest http://www.batteryspace.com/Lithium-Titanate-Battery.aspx also. BMS battery seems to be one of the better values in ebike batteries. Keep in mind though that the shipping charges can be quite high. Still, I would go with them or conhis motors. Unless you want to do the RC lipo thing but that seems to be more for the hardcore/ not for casual rider.

 

[marcilla.smith]

Thanks. That LTO technology does look interesting, and maybe even more economical over the long term, but pretty expensive in up front costs.

In trying to learn more about using RC LiPo's, I read through most of the Turnigy threads. I see that Hobby King has 5.2Ah LiPo's in 11.1V and 14.8V. Mixing 4 x 11.1V and 2 x 14.8V, I could build them into a 37V 10.4Ah battery - perfect!

The cost of doing so, however, would already be >$200, and I would still need battery management system, charger(s), case, and mounting hardware. The 36V 10Ah bottle battery from BMSBattery would have all of this and be $259 with shipping.

I checked Conhis, but a comparable battery would be $230 before shipping, and doesn't include the USB 5V outlet (a neat addition, I think, on the BMSBattery model).

Going back to the subject of RC LiPo's... I was surprised to see people discuss using their LiPo packs for RC applications when not biking, or otherwise swapping packs in and out of their bike batteries. I have been under the impression that when building a battery, one is supposed to charge and balance the cells (or, in this case, smaller batteries of cells) before assembling them into the battery, then once they are assembled into a battery, only to charge (and discharge) them as assembled.

What gives? Maybe this was just an SLA thing, but I thought balancing was even more important with Li technology :: scratches head ::

 

[kevyleven007]

the easy way to go if you want a 37v lipo is get a 10s pack and charger. http://www.hobbyking.com/hobbyking/store/__11597__iCharger_3010B_1000W_10s_Balance_Charger.html and http://www.hobbyking.com/hobbyking/...=86&LiPoConfig=10&sortlist=&CatSortOrder=desc . Just use 2 packs in parallel . yeah its going to cost you more. Go with bms battery. conhiss has good 48v deals like this http://www.conhismotor.com/ProductShow.asp?id=459 . I personaly prefer 48v . almost forgot, if your looking for cheap, check out vpower http://vpower.hk/product.php?id=339 After looking up what your actually using- https://www.google.com/search?q=use...AcQ_AUoAmoVChMIoLOG_8CDyAIVCVaSCh1AjgiK&dpr=1 I would have to agree with your choice of battery. Frog type is a good idea.

 

[cannonball2]

M.smith. When using R/C lipos the BMS is basically replaced by the charger. It handles the balancing and basically all the battery maintenance such as charging, balancing, setting the packs storage voltage etc. No need for the BMS. You will need to be sure your controllers LVC is compatible with the Lipos minimum voltage.

This allows packs to be mixed and matched to vary voltage, AH, etc. One could use the same packs in an R/C application also. The 10s pack would be great except most less expensive chargers cap at 6s. The 10s capable are a bit more $$.

 

[Lungcookie]

In trying to learn more about using RC LiPo's, I read through most of the Turnigy threads. I see that Hobby King has 5.2Ah LiPo's in 11.1V and 14.8V. Mixing 4 x 11.1V and 2 x 14.8V, I could build them into a 37V 10.4Ah battery - perfect!

This ends up being a lot of work for anything but a weekend warrior.
I would not suggest this to any new user.
Many connection and charging of that many packs get to be a pain in the back side.

Going back to the subject of RC LiPo's... I was surprised to see people discuss using their LiPo packs for RC applications when not biking, or otherwise swapping packs in and out of their bike batteries. I have been under the impression that when building a battery, one is supposed to charge and balance the cells (or, in this case, smaller batteries of cells) before assembling them into the battery, then once they are assembled into a battery, only to charge (and discharge) them as assembled.

What gives? Maybe this was just an SLA thing, but I thought balancing was even more important with Li technology :: scratches head ::

We use BALANCE chargers that take each cell to the same voltage.

That bottle battery you linked would work fine for you, same similar in the Sonders.