Best cell choice for BBSHD fat bike off-road?

[CCroft]

So...it’s time to add a 52v battery to the stable, something bridging the gap my current 8Ah ‘pocket rocket’ (Samsung 30Q cells) and 20Ah (Sanyo GA). I’ll be going with one of these options from Bicycle Motor Works:

• 12Ah (Ampace JP40)
• 12.5 (Samsung 25R)
• 12.6 (Molicel P42A)
• 13.5 (Molicel P45B)
• 15 (Molicel P50B)
• 15 (LG M50LT)
• 15 (Samsung 50S)
• 16 (Samsung 40T)
• 16 (Ampace JP40)

The price differences per Ah aren’t significant enough for me for that to be a factor, so I’m focusing only on cell quality/best performance for my needs. This battery is for my BBSHD fat bike (standard controller, with 30A limit), which I don’t ride very fast, but that does have some higher torque demands placed on it with riding offroad/off-trail with ~275lbs weight, and plenty of hills (and liberal use of throttle). Most of the time I've ridden this with 30T + 11-42 sunrace cassette, but long-term I'll going to be experimenting with a single speed setup with that same 30T ring + 24T cog.

I’m intrigued by the newer higher-discharge cells like the Molicels and Ampace, but I’m unsure how much if any benefit they would provide for my BBSHD/riding. I’ve read a couple of claims about their better low-temp performance (I bike year-round, but nothing usually below ~ 35F), lower running temp, and overall better longevity from only using a portion of a more-powerful battery rather than pushing the limits of a less-powerful one (?).

A final consideration that may be nothing: noise. A comparatively quieter motor is very important to me--a main reason I've stuck with the BBSHD over the years compared to motors that outperform it in other respects. Any idea whether higher-discharge/performance cells like Molicel or Ampace would result in more motor noise (assuming same motor controller settings/riding of course) than a more moderate discharge cell like the 50S or the LG? I realize the motor controller controls the amps pulled, but particularly under higher load/torque, it doesn't seem crazy to wonder about possible noise increase. But I have no specific info/experience one way or another.

Bottom-line, I’d appreciate any feedback/thoughts on these cell options for the BBSHD and the riding I’ve described.

Thanks!

 

[6zfshdb]

So...it’s time to add a 52v battery to the stable, something bridging the gap my current 8Ah ‘pocket rocket’ (Samsung 30Q cells) and 20Ah (Sanyo GA). I’ll be going with one of these options from Bicycle Motor Works:

• 12Ah (Ampace JP40)
• 12.5 (Samsung 25R)
• 12.6 (Molicel P42A)
• 13.5 (Molicel P45B)
• 15 (Molicel P50B)
• 15 (LG M50LT)
• 15 (Samsung 50S)
• 16 (Samsung 40T)
• 16 (Ampace JP40)

I've also been watching this company for possible replacements when my existing batteries give out. They are local to me so I can save on shipping by dealing direct. I like their construction standards and the cell chemistry does indeed look interesting.

The price differences per Ah aren’t significant enough for me for that to be a factor, so I’m focusing only on cell quality/best performance for my needs. This battery is for my BBSHD fat bike (standard controller, with 30A limit), which I don’t ride very fast, but that does have some higher torque demands placed on it with riding offroad/off-trail with ~275lbs weight, and plenty of hills (and liberal use of throttle). Most of the time I've ridden this with 30T + 11-42 sunrace cassette, but long-term I'll going to be experimenting with a single speed setup with that same 30T ring + 24T cog.

I ride my class 2 (throttled) bike in much the same way, carrying the same or more weight. I rarely use the throttle and sometimes ride on class 1 only trails. I'm therefore somewhat concerned about stealth. I don't use the throttle on hills and to avoid being obvious, I pedal at a normal cadence to match the conditions. A single speed setup using PAS would make this impossible.

I also don't like to advertise the fact that I'm riding an e-bike. I don't carry more battery than I need for a particular ride. On some occasions, I'll carry two or even three smaller batteries that I can conceal in a rear rack bag or pannier. Most trails I ride permit class 2 bikes though, and stealth isn't a concern. On those rides, I'll use a large main battery and keep a small one in my bag as a range extender.

A final consideration that may be nothing: noise. A comparatively quieter motor is very important to me--a main reason I've stuck with the BBSHD over the years compared to motors that outperform it in other respects. Any idea whether higher-discharge/performance cells like Molicel or Ampace would result in more motor noise (assuming same motor controller settings/riding of course) than a more moderate discharge cell like the 50S or the LG? I realize the motor controller controls the amps pulled, but particularly under higher load/torque, it doesn't seem crazy to wonder about possible noise increase. But I have no specific info/experience one way or another.

Following that same stealth theme, I also don't like motor noise. I know there are quieter mid drives out there but can't offer any specific advise on the BBSHD. In my case, I chose a hub drive which is nearly silent, even under full load.

Bottom-line, I’d appreciate any feedback/thoughts on these cell options for the BBSHD and the riding I’ve described.

Thanks!

Sorry I can't offer more help with your specific requirements.
Keep us posted with your progress and good luck with the project!

 

[CCroft]

It sounds like you and I may be kindred spirits as far as our riding values/goals! That’s very interesting what you say about the nearly-silent rear hub. At the time I started down the eBike road with my first BBSHD ~ 2016, I dismissed the rear hub idea for two main reasons: everyone I was reading (although I’m sure I wasn’t reading everyone) cautioned against them for riding like I do: off-road (and often off-trail/cross-country), hills, and significant weight (which for me often includes photographic and trail camera equipment). Second, I knew that a silent rear hub (without the freewheel pawl “click click click”) was non-negotiable for me, and I didn’t see any options for that with the hub motors I looked at. But if there are hub motor options that will handle my kind of riding and that have silent or very quiet freewheeling, that would definitely be worth checking out.

You’re right about the single speed being a non-starter for limited throttle/PAS riding. Single speed is attractive for me to avoid the inevitable mess I end up with riding where I do (off-trail through uncut grass and weeds) with a cassette/derailleur system. Last month I did several of my typical rides using only the 24T cog in my 11-42 cassette, and the Luna Mighty Mini 30T chainring I’m been riding/loving for years. There’s no way those rides would work without significant throttle use, and of course you do sacrifice a fair amount compared to what you get with that cassette—particularly if you’re wanting to more closely emulate a traditional non-electrified ride. But my goal—for this bike anyway—isn’t emulating a more natural ride, but getting out and doing wildlife and other photography over long distances in reasonable time frames…so the bike is more of a means than an end But who knows, the single speed may end up giving up too much compared to what is gained; luckily it's easily to revert back to the derailleur system if I need to.

I am cognizant of the stealth factor, not because I can’t eBike on the public lands I ride, but about what more obvious/unreasonable eBike use might mean for future land use decisions (“that guy is using an electric bike/motor…why can’t I use my ORV or 2-cycle trail bike?!”) And some kind of hub arrangement would definitely be more stealthy than that BBSHD hanging there. Some of the integrated motors/hubs/batteries look very interesting, but so far, don’t check the specific boxes I’m looking for (which probably isn’t very typical for most riders). Which hub are you using that is nearly silent?

 

[gromike]

Whatever battery fits, can deliver the current that the controller will pull, and has the capacity you need, but I'd also factor in weight.
I like high discharge batteries. I have a couple of packs built out of LFP A123 cells, cells that deliver 50 amps each. Great batteries, but big and heavy.

The quietest motor would be a direct drive hub motor, which also tends to be big and heavy. Also problematic at slow speed, which isn't all that much of a problem if you enjoy pedaling. I use a rear direct drive motor and ride trails all the time. Not all that technical, and no down hill racing for me, but the bike does great:

By using lighter motors in each wheel, a dual hub motor trail bike might be interesting.

 

[harryS]

I think the Samsung 50S is a good choice. It's a 5AH cell rated at 25A, so a 14x3 array will easily power a 30A BBSHD with minimal voltage sag. The P45B will also do that, but has a little less capacity,

I have batteries made with the Sanyo GA's, 30Q's. P45B, and M50LT. Think they're all quality cells.

 

[6zfshdb]

It sounds like you and I may be kindred spirits as far as our riding values/goals! That’s very interesting what you say about the nearly-silent rear hub. At the time I started down the eBike road with my first BBSHD ~ 2016, I dismissed the rear hub idea for two main reasons: everyone I was reading (although I’m sure I wasn’t reading everyone) cautioned against them for riding like I do: off-road (and often off-trail/cross-country), hills, and significant weight (which for me often includes photographic and trail camera equipment). Second, I knew that a silent rear hub (without the freewheel pawl “click click click”) was non-negotiable for me, and I didn’t see any options for that with the hub motors I looked at. But if there are hub motor options that will handle my kind of riding and that have silent or very quiet freewheeling, that would definitely be worth checking out.

You’re right about the single speed being a non-starter for limited throttle/PAS riding. Single speed is attractive for me to avoid the inevitable mess I end up with riding where I do (off-trail through uncut grass and weeds) with a cassette/derailleur system. Last month I did several of my typical rides using only the 24T cog in my 11-42 cassette, and the Luna Mighty Mini 30T chainring I’m been riding/loving for years. There’s no way those rides would work without significant throttle use, and of course you do sacrifice a fair amount compared to what you get with that cassette—particularly if you’re wanting to more closely emulate a traditional non-electrified ride. But my goal—for this bike anyway—isn’t emulating a more natural ride, but getting out and doing wildlife and other photography over long distances in reasonable time frames…so the bike is more of a means than an end But who knows, the single speed may end up giving up too much compared to what is gained; luckily it's easily to revert back to the derailleur system if I need to.

I am cognizant of the stealth factor, not because I can’t eBike on the public lands I ride, but about what more obvious/unreasonable eBike use might mean for future land use decisions (“that guy is using an electric bike/motor…why can’t I use my ORV or 2-cycle trail bike?!”) And some kind of hub arrangement would definitely be more stealthy than that BBSHD hanging there. Some of the integrated motors/hubs/batteries look very interesting, but so far, don’t check the specific boxes I’m looking for (which probably isn’t very typical for most riders). Which hub are you using that is nearly silent?

I chose a Pedego Platinum Interceptor as a starting point and modified it extensively to suit my needs. Due to the gear I sometimes carry, I wanted a bike that was rated at over 400#. The Pedego has a mag wheel option with a built in 500 watt hub motor that will carry the weight:

In addition to the extra weight capacity, the mag with motor is smaller than the largest cassette sprocket. It also doesn't transmit motor noise as much as the spoked wheel on my wife's identical bike. Two factors which contribute to stealth. There is no clicking noise when freewheeling and the bike pushes easily forward and backward with the motor off. This can be important if you have to walk the bike out of the woods. With the mag wheels, there are no spokes to get damaged by extra weight or underbrush

With a rear rack bag and panniers, you have to look twice to see it's actually an e-bike. Most people I encounter don't notice.

Since I ride in some remote locations, I also like the fact that a hub drive is immune to drivetrain failures. You can still get home with a broken chain or busted derailleur using throttle alone.

Yes, mid drive bikes are better hill climbers and, depending on the brand, have a more natural pedal feel. I don't do MTB trails or encounter many long, steep hills where I ride so for me anyway, a hub works best. Also if you want a throttle, there are many more hubs on the market than mid drives.

I don't dislike mid drives, I have one I ride casually, but for extended "outback" trips, I prefer the hub. It's really a personal choice and depends on the type of riding you do.

 

[m@Robertson]

I have purchased a number of off-the-shelf batteries from Bicycle Motorworks. The owner, Matt Bzura, has worked with me on a couple of projects getting some rather special custom batteries built (31ah and 35ah, with 100a continuous BMS') for a couple of my cargo bike projects.

So having been there and done that with this vendor over the years, and having spec'd batteries for BBSHDs dating back to 2017, I'll say there's no need to think on this so hard with respect to cell choice. EVERYTHING BMW sells is set up just fine for a BBSHD. Their battery management systems all have continuous output ratings well beyond the minimum necessary to handle a 30a BBSHD (the BBSHD's peak rating can be sustained indefinitely so there's no such thing as peak vs. continuous output on those motors).

@CCroft you are familiar with 30Q's and GA's presently. The 30Q is good for storage and high output, although it runs hot (which is ok for that cell). The GA is low output but high volume of storage... for a decade ago. With the right setup and BMS a GA pack could still handle a BBSHD just fine. I'm thinking of the Luna Wolf packs in particular when the GA cells were chosen. For batteries of that generation, the Samsung 25R bordered on legendary in that you could flog the piss out of it and it wouldn't blink, or even heat up. I bring this up because BMW sells a 25R pack with a powerful BMS and it is dirt cheap. 12.5ah IIRC and if you are OK with that amount of storage and the pack size, its a fantastic BBSHD battery that will last forever. I have two of them and they are a few years old and work great still. The 25R is an old cell design but it is still viable today, and inexpensive because its been around for so long.

Beyond that, just pick the one you can afford whose dimensions are what you consider optimal. Maybe that means pick the most capacity you can afford and that will fit in the space you have available. Either way the only things to really concern yourself with are size and price, since every choice from that vendor is going to handle a BBSHD just fine.

Also, forget about noise. That has nothing to do with the battery or cell choice.