First build (BBSHD/Boris X9), some battery questions

[bigun]

Hi,
I'm planning to do my first ebike build on a Motobecane Boris X9.
Have been reading a lot and I think I'm settled on the following:

BAFANG BBSHD 48V 1000W MID DRIVE KIT
1000W, 30A
100mm (Fat Bike)
43V LVC for 50V (14S Li, 16s LFP)
42T Bling Ring (Black)
left thumb throttle (TYP2)
2pc HWBS (Cable Type) Ebrakes
GearSensor (deraileur)
DPC14 color display

I'm getting stuck on the battery choice though. Here are the bundle choices/costs:

• 47V 9.8Ah (4P-25R) Frame Pack ($360)
  47V 11.8Ah (4P-30Q) Frame Pack ($436)
  
  50V 14.7Ah (14S6P-25R) Triangle+Bag ($531)
  50V 17.7Ah (14S6P-30Q) Triangle+Bag ($631)
  50V 18.9Ah (14S9P-22P) Triangle+Bag ($518)
  50V 22.1Ah (14S9P-25R) Triangle+Bag ($751)
  50V 26.7Ah (14S9P-30Q) Triangle+Bag ($893)
  
  50V 12.3Ah (14S5P-25R) Rect Pack ($456)
  50V 14.7Ah (14S5P-30Q) Rect Pack ($542)
  50V 14.7Ah (14S7P-22P) Rect Pack ($423)
  50V 20.7Ah (14S7P-30Q) Rect Pack ($694)
  50V 16.8Ah (14S8P-22P) Rect Pack ($470)
  50V 23.6Ah (14S8P-30Q) Rect Pack ($784)

The above costs are special prices for the BBSHD bundle.
A few questions:
* I'm leaning toward the triangle 18,9Ah 14S9P-22P. It seems like the higher discharge cells would be a waste for a 9P BBSHD, which would draw 30A max. Are there other considerations? e.g, should i expect to get longer life (more cycles) from a 25R or 30Q variant?
* Question about the triangle packs. Since they are harder to remove, I'd assume most people leave them on the bike when commuting to work, or charging. Is there a good way to prevent theft of a battery in a triangle pack? Also, are these batteries harmed if left outside in > 100 deg F temperatures?
* For the charger, EM3EV has a 2A version for $30, and a 5A version for $60. If not concerned about fast charging, would the 2A version be better (I thought I read that charging slowly can extend battery life, is this true?). Can the 5A version be set to charge more slowly?

Thanks in advance for any input or ideas!

 

[Justins311]

I have the same exact question....found your thread while searching for an answer.

I am also leaning towards the 50V ~20AH pack range and can't find a good explaination for why some vendors offer 50V packs vs 52V packs, and why I would want one cell tech over another. It seems almost all the good packs are built with the 18650 cells, not sure if Panasonic or Samsung are the best but there seems to be a WIDE range of prices.

And finally same question on charger - I currently have a 3A charger that was sold to me by Hanebrink for their 48V pack. Every vendor tries to sell their charger with their battery. I wonder whats different between a 50A charger vs a 48V charger?

 

[induna]

The difference between the pack voltages is simply down to what nominal voltage you choose to specify for the cells. Paul at em3v always uses the more conservative 3.6 volts per cell, whereas Luna cycle, and many others, use 3.7 volts per cell. Which cell you choose is a matter of energy density, current capacity/requirements, and finances of course. You won't regret buying as much battery as you can afford, and fit on your bike.

 

[Justins311]

Thank you induna! That makes a lot more sense now - pretty much the same pack with the more conservative rating. Since you seem to know this stuff pretty well, can you help us both out with the OP's original question?

"* I'm leaning toward the triangle 18,9Ah 14S9P-22P. It seems like the higher discharge cells would be a waste for a 9P BBSHD, which would draw 30A max. Are there other considerations? e.g, should i expect to get longer life (more cycles) from a 25R or 30Q variant?"

I know I want to stick around a 20aH cell myself, but not sure I need higher discharge for the BBSHD. These are the three packs I am considering:

Luna: 52V Panasonic GA 18650 17ah 14s5p HIGH POWER + LONG RANGE = $599 + $30 ship + $45 3A charger

Luna: 52V Panasonic PF 18650 20ah 14s7p = $629 + $35 ship + $45 3A charger

Both are 50A continuous 70a max. Why is the 20ah only $29 more? What is the GA vs PF benefit?

em3ev: 50V Samsung 18650-22 (NCM?) 18.9ah = $545 + $60 5A charger

According to HIS website this pack is only good for 38A continuous 56A max burst. Is this him being conservative again or are the Panasonic GA cells better performers? Do I need more than 38a for the BBSHD?

Can my 3A charger that is charging 18650 cells now satisfy either of these batteries or do I have to spend the $45-$60?

And em3ev charges $71-$105 for shipping...so the cheaper pack becomes the more expensive pack! ugh.

So confused - thank you for helping with the voltage!

 

[Drunkskunk]

Lithium cobalt,lithium manganese, and all of the various hybrids of these combinations used to be rated at 3.7V nominal as this was the midway between the accepted full charge of 4.2v and eempty which is 3.0v. As the tech matured it was realized that this didn't really reflect the way the cells worked best, and some manufacturers began labeling the cells at the more accurate 3.6v nominal, which is more in line with their performance. It makes no difference the batteries perform the same, only the labels changed.

But some vendors and some manufacturers still quote 3.7v per cell, so you get different labeled voltages for the same tech.

As for charging, very slow charging is the death of Lithium. While slow charging [strike]old[/strike] ancient Ni-Cads was great for them, lithium works different. Ideal is somewhere between 0.5c and 1.0c, but this isn't super critical. 2A would probably be fine for a 10A pack, but 5A would be better for a bigger pack.

 

[bigun]

Thanks induna/Drunkskunk for explaining that.

I've read a bit more and answered a few of my original questions.
Here's a summary, in case it will help other noobs:

• Luna and em3ev are both very reputable 18650 battery pack vendors. They both sell similar batteries for 48V motors. Luna sells batteries from inventory, they are often out of stock on certain types. Em3ev builds to order, the batteries are built in Shanghai and shipped to the customer. Best I can tell, it typically takes over a week to build and over a week to ship to a typical US address. So maybe 2.5-3 weeks from order to delivery (this is a guess based on what I've read, I didn't email Em3ev to confirm this).
• Both vendors sell 'normal' voltage (em3ev 47V, Luna 48V), and higher voltage (em3ev 50V, Luna 52V) packs. See very good explanations above about how the vendors are labeling the same battery designs with different voltages.
• Internally, '13s' packs use 13 cells in series for 47/48V, and the '14s' packs use 14 cells in series for 50/52V. Battery packs have multiple 'banks' of these cells in series. A '9p' battery pack has 9 banks in parallel. A 14s9p battery has 14*9=126 individual cells.
• All things being equal, the '14s' packs are preferred for BBSHD, because they retain better performance when your pack has a low charge, where the '13s' packs will feel a bit sluggish as voltage sags. At least this is what I've read.
• It seems like em3EV sells only Samsung cells, and Luna sells a mixture of Panasonic and Samsung cells. Each cell has different characteristics (total stored energy, max sustained/burst discharge rate, and weight). Some of the newer cells (e.g., 30q), have both high energy and high discharge rate, but they are more expensive than older cells like 22p. The tradeoffs are: weight, cost, capacity, and max current.
• If you have a larger 9p battery, you will have no trouble meeting the max current requirement of a BBSHD, which is ~30A. At ~50V, this is ~1500W. So with a 9p battery, the BBSHD can't take advantage of the higher discharge rates that the new cells have. But the newer cells also have more capacity per cell, and that means means more total Ah, which means longer range.
• There are tables with specs for the different 9p triangle packs here:
  http://em3ev.com/store/index.php?route=product/product&path=35_51&product_id=123 and the 6p triangle packs here: http://em3ev.com/store/index.php?route=product/product&path=35_51&product_id=158
• If you run the numbers on the em3ev 14s9p packs, using the BBSHD bundle pricing above:
  [**] 22p cells cost $27.4/Ah and weigh 0.34kg/Ah
  [**] 25R cells cost $34.0/Ah , and weigh 0.29kg/Ah
  [**] 30q cells cost $33.4/Ah, and weigh 0.25kg/Ah
• The 30q cells look attractive vs. 22p (22% higher cost/Ah, but 26% less weight/Ah). The 25R cells don't make sense for my needs. Again, these numbers are based on BBSHD bundle costs for 9p triangle packs from em3ev.
• I wound up ordering a 14s9p 22p triangle pack from em3ev for $518, because this was by far the least expensive pack with high capacity, this is my first build, I'm already spending more than I planned, and hey, I'm cheap. Shipping is higher from em3ev but this is offset by sales tax from Luna since I'm in CA. It's a heavy pack though, and so maybe i will regret not spending extra for a 30q pack with similar range.

Hope that helps someone. BTW, I made a template for the 9p em3ev triangle pack. Looks like it'll fit nicely in my 21" Boris frame. Picture attached.

Some questions I still don't have answers for:

• How do people protect triangle packs from theft? I think it would be very inconvenient to disconnect the battery and take it with me whenever I park the bike somewhere.
• Beyond the published battery specs (discharge rates, weight, cost), what are the differences in cell reliability, longevity, etc. Which cells are more sensitive to high heat (being left in the hot sun), etc. Which are most/least sensitive to charge levels, charge rates, etc. I wound up ordering 22p cells, which are quite an old design. I wonder if they have been tweaked or improved in any way since they were first released. I know these are complicated questions, but does anybody really know?
• I gather that leaving a black triangle pack in the hot sun is a bad idea. But i don't know how much damage it will actually do.
• I'd like to understand a bit more about charge rates (not sure what 'c' is), and what is the optimal charge rate for my 22p batteries.

Please feel free to correct any misinformation above, and would love to hear any answers to the open questions. Some very helpful people in this forum, and the help is much appreciated.

 

[leelorr]

I carry my 12AH, 25R, 52v pack from EM3EV in my backpack when I ride as it won't fit in the triangle of my full suspension bike. That means that my battery just goes with me with I lock my bike up. My bike looks like a normal (non Ebike) bike while sitting there then. My pack only weighs 8.5 pounds though...

Pros of the battery in my backpack:
Doesn't get stolen from the bike
The bike feels completely normal and light handling
The battery can be moved to wherever I want to charge it easily
No one has ever even noticed that my bike is electric, even when I sit and talk to them

Cons of the battery in my backpack:
It weighs 8.5 pounds and the weight is noticeable (but not terrible)
I don't get to put too many other things in my backpack without making it too heavy

Good luck with your build, I have been thinking about the Boris X9 (with Bluto) as my next build....\
Leelorr

 

[Justins311]

Awesome input guys!

Question about chargers: does the charger care which type of 18650 cell is in there? I don't want to damage a new pack with my existing charger, but wonder if these companies just push their charger.

I assume there IS a difference in charger for LiFePO4? I have a 3a one of those. Could I use it on an 18650 tech Lithium based battery?

 

[leelorr]

I really like Paul's (EM3EV) 5A charger, it has 3 settings:
100% charge, 80% charge (for longer battery life), and 60% charge (for storage). He has them custom built to his specs.

It shuts off when the pack is charged to the correct level, and goes into balancing mode (if you charge to 100%). I bought two so that I would not have to wait for another one to come in from him in China if one died, but the same one has been working fine for a year now.

 

[Voltron]

LiFePO4 is a chemistry, and 18650 is a size, so you could if you got LiFePO4 cells in that size. But more likely, no, as the majority of high performance 18650s won't be LiFePO4, and will charge to a higher voltage, so your charger wouldn't go up high enough.

 

[Justins311]

Thanks Voltron. Absorbing as fast as I can lol.

So will an 18650 size Panasonic GA and Samsung 22r(?) use the same charger? Or do all chargers get built to the battery chemistry?

 

[Voltron]

Almost all of the new chemistry cells charge to 4.2v , and most nice chargers the final voltage can be fine tuned also, so not necessarily different chargers for every battery type.

 

[bigun]

Quick follow up.
I ordered from em3ev on 7/18. It took about 2-1/2 weeks to arrive.
Timeline:
7/28: received shipment notification (em3ev builds batteries to order)
8/2: received tracking info
8/4: first delivery attempt to my home in northern CA (received it on 8/5)
not sure if this was typical or not. There was a typhoon that impacted Fedex in PRC/HK, so that may have caused a day or two delay.

Here's what I ordered:
Bafang BBSHD 48V 1000W Mid Drive with Battery (~1500W Max)
- Ebrakes: 2pc HWBS (Cable Type)
- Display Type: DCP14 (TFT Colour Display)
- Battery Type: 50V 18.9Ah (14S9P-22P) Triangle+Bag
- GearSensor: Including GearSensor (deraileur)
- Chain Wheel: Lekkie 42T Bling Ring HD (Black)
- Throttle Type: Left Thumb Throttle (TYP2)
- Low Voltage Cut: 43V LVC for 50V (14S LI, 16S LFP)
- Bottom Bracket Size: 100mm (Fat Bike)
- Power/Current Setting: 1000W, 30A
- AC Plug Type: USA
- Charger: 58.8V 5A (50V packs only) 48VBBSHD_WBATT
Sub-Total: $1,335.00
Battery-Fed, USA (~7-10days) (Weight: 16.50kg): $156.90
Total: $1,491.90
For some reason, I was actually charged $1,530.95 via paypal. The $40 difference might be due to exchange rate.

I'm really impressed with the construction of the battery, and the triangle bag is great. I like that nothing has logos on it, so it's pretty stealth. The motor has a discrete Bafang logo but that's it. I haven't installed the e brake sensors or the the gearsensor yet, but will soon. I also haven't worked on wire management yet, but the triangle bag has a few cutouts for wires and it's simple to hide the slack. Very impressed with the triangle bag BTW, comes for free with em3ev's triangle batteries.

Just finished the build. The 100mm BBSHD and Lekkie Bling ring are a perfect fit for this bike (2016 Boris FS X9 LTD Rockshox Bluto - 21" frame). I did not use any spacers at all. The BBSHD seems to insert into the BB fully, but it does touch the chainstay, so maybe not quite. I tightened it down (bought the $20 Luna wrench), and I don't think this will be a problem at all. The bling ring is very close to the chain stay, but doesn't touch. Chainline is pretty much perfect. See pics.

Anyway, i think this bike and the 100mm BBSHD and Lekkie 42T bling ring are a great match.

 

[mrMikasa]

Ok to buy batt pack if first time.

But never again. Twice as expensive than to build your own.

I bought first 14s9p-22p.

Now I've ordered better cells 3350 mA. 200 pieces of them for half the price.

And they will be enough for two big batteries. One 13s5p (16,5 Ah) and one 14s9p (30Ah).

Skip the BMS. It doesn't even do the work.
Maybe put cell monitors with alarm. Also the motor controller shuts down at 43V.

Then only charge to 90%, 57,4 V with 5A.

 

[craneplaneguy]

I just completed an install of a 17 AH triangle Panasonic GA on my Sturgis Bullet. Unlike it's last install, and 3 others I've done, I decided to make it "permanent". Because of where and how I ride this fat bike, I don't need to charge the battery separate I decided. I also don't have to worry about theft, but if they tried, it'd take 10 minutes at least to get it out of the frame, and be a big hassle. It'd be easier to steal the entire bike. Once I fabricated the brake formed brackets (padded) and secured them using the water bottle mounts, I taped the hell out of it to the frame, using 2" wide tape. Then I cut apart a LUNA triangle bag and re installed it over the bike frame and battery and zip tied it altogether. Finish product looks like a frame bag, but ain't.