noob questions for commuting/kid hauling/cargo bike

Hi everyone, I've lurked for 2+ years now and now I'm finally making my first post. First off, let me just say these boards are fascinating, I love learning from you guys.

I just got a long-tail cargo bike, I'm trying to decide what kit to put on it. here's the details:

me:

• 
  * i'd humbly consider myself a strong biker. I want whatever I do to continue feeling like a bike but I also want it to go fast.
  * weight: 190lbs

bike:

• 
  * Kona Ute cargo bike http://2014.konaworld.com/bike.cfm?content=ute
  * all stock, meaning:
  * 700c wheels
  * mechanical disk brakes

ride profile:

• 
  * the most common thing I will be doing with this bike is going to work and back. it's a 6 mile commute with some hills. here's a strava of me riding it on my road bike https://www.strava.com/activities/269162425/overview so you can get an idea of elevation profile & stuff.
  * I also want to be able to load it up with 2 kids (30 & 50lbs) on the back and one more (6 year old) pulled behind on a WeeRide Co-Pilot. while I'll put more miles on it commuting by myself, I want to make sure that the motor & battery can handle it as that is the main reason we got the cargo bike instead of just a normal bike and something we want to do often.

wants:
I'd like a desired max speed if I'm riding by myself with no cargo of ~27mph on a flat but anything above that would be great. I'd imagine I will be PAS 9-ing or full-throttling most of the time regardless of whatever the top speed ends up being, that's just how I am. The whole point is to get from point a to be asap.
range: with no hills or cargo at full-throttle (and by that i mean between 23-33mph) i'd like at least 14 miles (so I don't have to charge mid-day on my 6 mile commute)

questions:
I've narrowed it down to 3 options:

• 
  * BBS02 w/ 48V 12AH PANASONIC NCR18650PF 3C battery http://bafangusadirect.com/products/bafang-bbs02-750w-mid-drive-motor-ebike-kit-12ah-panasonic-battery $825 shipped
  * BBS02 w/ Shark 48v PF 11.5ah from lunacycle (https://lunacycle.com/bafang-bbs02-750w-middrive-kit/) for ~$950 shipped
  * or same bbs02 w/ 47V 11.8Ah High-Power (13S4P-30Q) battery https://em3ev.com/shop/bafang-48v-750w-bbs02-kit/?bundle_quantity_34=1&bundle_quantity_35=1&bundle_variation_id_35=1499&bundle_attribute_pa_display-type_35=c965&bundle_selected_optional_37=yes&bundle_quantity_37=1&bundle_variation_id_37=1091&bundle_attribute_pa_ebrakes_37=1pc-hwbs-sensor&bundle_quantity_38=1&bundle_variation_id_38=1252&bundle_attribute_pa_current-rating_38=25a-750w&bundle_selected_optional_42=yes&bundle_quantity_42=1&bundle_variation_id_42=1185&bundle_attribute_pa_preditor-l-battery_42=13s4p-30q&bundle_selected_optional_43=yes&bundle_quantity_43=1&bundle_variation_id_43=1205&bundle_attribute_pa_54-6v-charger_43=54-6v-2a&bundle_selected_optional_49=yes&bundle_quantity_49=1&bundle_variation_id_49=1250&bundle_attribute_pa_ac-plug_49=usa from em3ev for $960 shipped

which one should I get? I'm leaning towards the one from bafangusadirect because it is only $825 (~$125 cheaper than the other 2) but I assume people will mention that its from an less-known seller. but being $125 cheaper is a lot. I'm assuming the motors will all be the same, so is the quality of the luna or em3ev battery going to be more than $125 better than the no-name one? it says it comes with 48V 12AH PANASONIC NCR18650PF 3C CELL LITHIUM-ION batteries? are those $125 worse than what I'd get with the other 2?

Do I need to get the BBSHD over the BBSO2? it's not the added weight that's holding me back, it's the added price. Will hauling 3 small kids around town be too much for the bbs02?

Speaking of hauling kids, what size chain ring should I get? I guess I want my cake and to eat it too because I want to be able to haul kids but I also want to be able to have something that I can still contribute with pedaling while going 25mps+. and should I get a Bling Ring or one of those adapters so I can use it with whatever chainring?

how much battery capacity do you think I need for my 15 mile expectation? will an 11.xAH battery be enough or do I need 13AH?

do the 52volt battery packs make a huge difference over 48v? there is not a 52v waterbottle/shark option from em3ev that I saw. is it worth the ~$90 to upgrade? how much faster would it make things?

Thanks in advance for any help

Welcome!

As I started reading your post my first thought was "this sounds like perfect situation for a BBSxx setup with 48v battery". As I read further I saw you had reached same conclusion. Believe you are on the right track.

Thoughts:
- You only go through the pain of spending the money once. So don't begrudge yourself a few extra bucks up front, since you'll enjoy the benefits of good gear every time you use it. Lowest price is seldom best value on gear. And never the best value on customer service provided along with it.
- Get the BBSHD. I have BBS02 and love it. If it were only you, I'd say get a BBS02. But given that you are going to be joined by 3 kids sometimes... spring for the BBSHD.
- I have an 11.8Ah High-Power (13S4P-30Q) battery from EM3ev. Think it would be an ideal battery for the use you describe. More Ah is always nice, but not critical for your need. If you have to make a tradeoff on battery... go for higher quality over higher capacity. 12 mile roundtrip isn't really far, 11.8Ah should be ample. Even on windy days if you are willing to pedal if needed to stretch capacity, and it sounds like you are.
- 52v battery vs 48v battery... more voltage is generally nice, but the difference isn't really meaningful in this case. Would give you a bit higher top end in speed, but not much. 48v should get you in the 27mph ballpark. 27mph is actually pretty fast on a bike, not sure you'd find higher speed much real world value.
- Re chain ring. Do get the bling ring. And don't plan on adding much leg power to the system at higher speeds, it kind of just doesn't work. I find the leg power input is actually most valuable at low/medium speeds, like you'll probably be making when you are hauling the kids.

Enjoy!

My limited experience-

BBSHD on a long tail Yuba cargo bike hauling 50 pound kid up fairly steep hills, 52V 13.5ah battery. My friend up the hill has BBS02 on a lighter cargo bike, I'm glad I got the bigger motor, helps keep the RPM's up on hills keeping the motor cooler. Will do 30mph on the flats if I want it to, 30 feels pretty fast.

Brakes are mechanical BB7's, 203 front/180 rear, installed Big Dummy fork, you definitely want good brakes and fork with a motor combined with stopping lots of weight going downhill.

Though I'm well known for using hub motors on cargo bikes, you are on the right track. Go with a mid drive.

Buy the best battery you can. It's not mandatory that you get the motor and the battery in the same place. In general, vendors don't discount much for the bundle.

Happy owner of a BBSHD + 48V/12ah battery here
rock solid setup, but do not plan on pedaling too, the motor spins way too fast for your pedaling cadence (unless climbing loaded with your children)
Enjoy!

hey guys, sorry for going AWOL there for a bit.

I just wanted to post an update of what I ended up doing:

After a few test rides before I put the motor on the cargo bike with the kids on the back I got worried about the stability of having the kids up so high on the deck and what would happen if I ever were to lay the bike down. So I ended up going back on the idea of a cargo bike and just got a hardtail mtn bike with a burley bike trailer hooked up behind it. I figure it was safer for the kids in the bike trailer because there is nowhere to fall down off of. and it also has the added plus that for the majority of the time, when I am just commuting to work and back by myeself I don't have to haul the whole kit and caboodle with me like I would with a cargo bike. less hipster, but more functional :wink:

I ended up just ordering a bbs02 mid-drive kit and a 48v 12ah shark battery. works great! call me crazy but I do wish it was a little faster, maybe I should have got a BBSHD. and the motor does get pretty hot after the work commute ride (like if my leg touches the motor it is super hot, but does not leave a burn mark immediately). does anyone know how hot is too hot? is it safe to be in PAS 5 the whole time going up hills and stuff on a bbs02 as long as you are pedaling at the same speed you'd pedal normally?

ryankshaw said:

call me crazy but I do wish it was a little faster,

Click to expand...

Change the gear you ride in, shifted to the faster gears in back, if you're not already.

Or use a larger chainring in front for the drive to the rear.

and the motor does get pretty hot after the work commute ride (like if my leg touches the motor it is super hot, but does not leave a burn mark immediately).

Click to expand...

Are you shifting gears for startups, etc., so you get the right load on the motor for the speed/etc you're using?

With the mid drive, you do need to not start up in the high gear. But a hot motor if you run hard and fast is normal, if it won't burn you, actually blistering you, when you touch it.

Why not put the BB on the cargo bike, and still tow a trailer? Cargo bikes make great tow bikes. You still get the benefits of the nicer ride, moving your ass away from the back wheel.

That would allow a much faster, more powerful hub motor for the commute, but a much more powerful motor would need a better/ larger battery. Paralleling two batteries is possible.

amberwolf said:

ryankshaw said:

call me crazy but I do wish it was a little faster,

Click to expand...

Change the gear you ride in, shifted to the faster gears in back, if you're not already.

Or use a larger chainring in front for the drive to the rear.

Click to expand...

ya, I'm using the full range of gears in the back and starting up in low gears when I start out. I've just got the stock 44 tooth bafang chainring so that's probably what's keeping me from having the highest top end speed but I wanted it that low so, when paired with my 29" tires I could have the low-end torque to haul the kids & trailer up hills.

dogman dan said:

a hot motor if you run hard and fast is normal, if it won't burn you, actually blistering you, when you touch it

Click to expand...

good to know! sounds like that's the case for me, get's really hot but not to the point where it would burn or blister you if you touched it.

thanks for all the great advice guys!