looking for input on my first e-bike build

[Neph Petrichor]

as the title says, I’m looking at doing my first electric build, and need some advice. I built two different motorized bicycles before- one chain drive, one friction drive- but both were gasoline-driven. the chain drive broke down in a way that couldn’t be fixed, and the friction drive got stolen, so I’m looking at going electric so that I can store it indoors, where it’ll be more secure.

I've read the "read before asking" post, and will answer the questions there shortly, but for the TL;DR people out there, I want to post the short version here

I have a long commute in a hilly area, so I want to trade speed for torque and efficiency. I'm looking at the typically-recommended MAC hub motor, but I'm concerned it won't meet my torque needs, so I’m also looking at the lightning rods mid-drive as a second choice, but they look much more difficult to install. also, the e3mv site has a lot of options, and I’m not sure what I need. I need a complete run-down about battery packs, and am aiming for a pre-made, reliable deal. in that regard, I care more about reliability and capacity than weight, so I think SLA is actually a good option for me, as Li-ion tends to… well, explode when handled improperly, and I don’t know how to handle it properly.

Spoiler: Desired max speed on level ground. mph or kph

don't care. I will be happy with as little as 5-10mph

Spoiler: Desired max range at what cruising speed. mph or kph

must be able to reliably go around 10miles on a charge with little to no pedaling. to my understanding, this is almost purely a battery issue- assuming an efficient motor

Spoiler: Preferred bike wheel size, or wheel size of bike you want to convert. Most common kits are for 26 wheels

26

Spoiler: Brake type of motor wheel. Disc or not.

I'm not sure. probably disc. I HATE typical bike V-brakes, as I'll rant about later

Spoiler: Rider weight.

around 200lbs. say, 50lb margin of error, which will likely be filled with battery XP

Spoiler: Terrain.

very hilly. no mountains nearby, but the entire city was built on sandstone and since settlement, it's been carved up every which way based on the whims of whoever happened to be living there. you can almost always expect some incline, with a rare extremely steep slope here and there.

Spoiler: Budget.

around 2k. 1.5k would be better, of course, and actually should be attainable, given the right options. the bikes are dirt cheap, the kits are around 1k, and the batteries are about .5k.

so, with basic questions asked and answered, I'm thinking of three different builds, each with their own pros, cons, and questions. I'm leaning towards the hub motor, which I'll post first, but as stated, I don't know if it will meet my torque requirements

cruiser bike with front-wheel mac hub kit from e3mv:

Spoiler: pros

cheap. even with ALL THE UPGRADES!!!, which I'm not doing, it's still only around .5k, without the battery.

easy to install. easy as changing a tire! ...well, and adding a brake line. since the cruiser doesn't have V-brakes, there's nothing to take off first.

coaster brakes. with the hilly terrain around here, you're forced to a) run headlong down a steep hill, just waiting for a pothole to send you flying over the handlebars, or worse, a car to turn in front of you without looking or b) tap your brakes at regular intervals to control your speed. even with a human-powered bike, I was replacing V-brakes every month. and I SHOULD have been replacing them every week, for safety's sake. coaster brakes, on the other hand, are much more robust. even my second motorized bike build, a friction drive on a cruiser, never needed to have its coaster brakes replaced, and could easily stop reliably (although not necessarily on a dime)

longevity. from what I gather, there's a whole 1-2 moving parts, and what parts are able to wear out are built more for motorcycles.

Spoiler: cons

may not have the torque I need.

may overheat on steep climbs, or even long but low climbs.

Spoiler: questions

I thiiiiink I want 12fet, 12T for max torque? maybe 9fet, 12T to avoid overheating? I have no idea!

what are those wheel types? ok, first value is diameter, that's obvious... second value is manufacturer, third value is... something? and last is brakes. speaking of which:

which brakes should I get with it? since I intend to put it on the front wheel, and have breaks on the rear, do I even need them?

and of course, the number one question on my mind with this build: will it have enough torque?

mountain bike with lightning rods small block kit

Spoiler: pros

gear shift. since it uses the bike's drive chain, it can change gears on the fly. I think it's 8-speed? plus, the idea of slowly shifting up to get stupid speeds on a long stretch of safe road sounds fun XP

super max torque. I thiiiink you can just ask the manufacturer to set the gear ratio low. that combined with the lowest gear on the bike's shift means omgwtfbbq amounts of hill-climbing power. of all three builds? this is the one I'm most confident can meet my needs.

hard to overheat. with its cooling fins and high capability, this thing isn't going to overheat any time soon

Spoiler: cons

frocking. V-BRAKES. see above rant.

most complex of all three to install. you'd have to swap the pedals- an ordeal in itself! move the brakes and gear shift somewhere, install the throttle, manage those wires... man, it's a mess.

gear shift might break. cheap bike. might not be able to take what the engine can dish out.

tough to buy. no online shop, would have to E-mail him, and... something? maybe he links to an amazon or E-bay shop? or just accepts payment through paypal? ughhh maybe I should just get a bafang... speaking of which:

Spoiler: questions

what's the big difference between this and a bafang mid-drive kit?

cruiser bike with lightning rods big block kit

Spoiler: pros

POWAH. undoubtedly the fastest of these three, maaaybe excepting the other lightning rod in high gear.

hard to overheat. see above

coaster brakes. see above

Spoiler: cons

most expensive option.

most battery-intensive. at 3k watts, this is gonna take a monster of a battery to power for very long.

tough to buy. see above.

looking over this, it seems like the MAC hub motor is my best bet… IF it has good temperature control and the torque I need.

as for the battery… I only know that I know nothing. I’d like to get something pre-made, high-capacity and reliable. probably two so that I have a backup. I’m ok with paying more to get that, and I’m ok with it being heavier than usual

 

[motomech]

Man, you have me going there for a minute. I'm thinking, "here's a reformed gasser like me, who has seen the light, who has been reading and studying, and you get to the SLA part and" LOUD BUZZER SOUND. Back to reality, epic fail. You drank some Kool Aid somewhere along the way.
Lithium batteries are reliable, or they wouldn't be used in cars and airplanes. The Ebike stuff is built to a price point(and In China, no matter what someone says, it's all from China)and some of the BMSs are a bit sketchy.
There isn't one experiened builder here is going to recommend chaining the SLA anchor around your neck, not for anything with 2 wheels. Dead end. Done. Peukert.
And FYI, while Lipo is a blast to use, it doesn't explode. It can combust into a really hot nasty fire if mishandled, the incidence is rare(there must be millions using it World wide).

If you need to cruise at a minimum of 25 mph and charge up hills, then you are probably perusing the right product sites(although a Mac on the frt. of a cruiser bike seems like a very bad idea to me). If you can make do with something a little slower, I would suggest you take a look at the big vendors in China like BMS Battery and Elifebike.
While 25 mph may not seem like it's fast on a gasser, it's a different goal on an Ebike. Most E bicycle riders have it in their head they want to pedal along and getting the gearing to do that over 25 mph can add expensive parts to the build. Not to mention, more and more battery needed to maintain range at 30 moh.

 

[dogman dan]

Actually a 7 speed cruiser with a few sweet modifications like dual disc brakes can be a decent e bike.





Since it's a steel bike, it's not terribly hard to weld disc brake mounts on to it. The one above did get lengthened too, but you could just modify the brakes.

 

[Neph Petrichor]

Back to reality, epic fail. You drank some Kool Aid somewhere along the way.

let me explain the situation you've put me in. I need help. technical advice for two or more completely new systems I've never handled before. my options in how to respond to this are:

let you insult me. (failure state)

explain my reasoning (you respond with yours. thread turns into an SLA vs. Lipo debate instead of any useful information for me. failure state)

criticize you for insulting someone who's honestly asking for information and admits that he doesn't know any better (risk of coming off as insulting. if so, flame war, failure state)

the only winning move is not to play.

If you need to cruise at a minimum of 25 mph and charge up hills, then you are probably perusing the right product sites

ok, so that (probably) means I'll have enough torque with the MAC. that's good. ...of course, that's just an assumption, you haven't explicitly stated that, but it looks that way.

how's the heat management? from what I read, you can have all the torque in the world, but if it melts into slag after two minutes of charging up a hill, as you put it, you're walking home.

beyond that, I'm still in the dark as far as most of my questions go.

(although a Mac on the frt. of a cruiser bike seems like a very bad idea to me)

why? is there some reason to rear-mount that I'm not getting? only thing I've seen on the subject is "less traction that way," and I don't think that'll be enough to matter. by putting it on the front, I won't have to mess with the bike's braking system at all, as it's all on the rear wheel; and in situations where I need a lot of traction, I can pedal for all-wheel drive.

as for cruiser, it's a notorious for being a great style for motorizing, regardless of method. it's steel-frame, cheap, simple, lots of room in the mid-frame for an engine or battery pack... what's not to love?

 

[mark5]

Neph. If you update your location maybe people can get an idea of how hilly it is.

Why do you want to use SLA batteries?

The Mac front wheel kit is 350W 14T or 16T vs. their rear wheel 500W 6-12T. There used to be a 500W front wheel kit but not any more.

The concern about using a front wheel hub motor is the possibility that your dropouts could fail like BiciMad's pictured here.

 

[wesnewell]

What country are you in?
https://endless-sphere.com/forums/viewtopic.php?f=3&t=66302

 

[oobagooba]

Lead is no good, your hills will run it down quick and you'll be fighting all that extra weight. There are safe lithium chemistries you just need to get the terms right then study up.

Don't confuse "lipo" with "li-ion." "Lipo" is the hotrod helicopter stuff that can burn your house. "Li-ion" is a generic seller term that doesn't really mean much.

What you want to look at is NCA a safe, light, hi-power, long lasting, affordable chemistry. Pay a little extra for a pack built with Samsung or Panasonic cells. Learn codes like INR and the different cells like 25R, 30Q, etc. Check the battery subforum, try a lot of light skimming rather than get bogged down in all the test charts and spot welding until you learn the basics.

Fyi the current cheapest decent NCA pack is probably $400 (shipped) from bmsb https://bmsbattery.com/ebike-battery/684-48v116ah-bottle-09-panasonic-battery-charger-battery.html I have that one, beat on it pretty hard, works fine for me on the hills, some pretty big ones where i live.

You could spend a little more from Luna or em3ev and get a better built pack with actual customer service and a warranty.

You can get an upgrade Mac kit from Paul for around 500 last I looked. A slow wind 48v hub should do fine on most hills if you can pedal some to keep the speed up. Heat isn't much of an issue on an upgrade hub if you can do 7+mph uphill and coast down the other side. Go with a rear hub for safety.

You don't need disc brakes if you have v-brakes or good cantis. You will need a couple torque arms unless you go mid-drive, but then you may have shifting or chain issues, keep studying you'll figure it out

 

[dogman dan]

Coaster brakes, and or internal gear rear hubs are the one really legitimate reason for going to a front hub. So if you want to keep coaster brake, then use a front hub for sure.

But again, what you really want is good disc brakes on both wheels. Coaster brakes are great though, if you want to lock up the rear wheel and smear rubber. But if you want maximum ability to modulate the brakes without locking up, I greatly prefer disc. Bear in mind, this advice comes from a lifetime motorcycle, moped, and bike rider, who has run electric bikes on a racetrack, beating the pants off 95% of the gas bikes in the race. So this braking advice does not come from a slow dude.

Even if you do keep that coaster brake, weld a disc mount to your front fork. That front brake is the one that really stops you, when you ride like a racer.

Front hub will have a heavy front wheel, poor traction causing the front tire to wear really fast, and you really have to avoid applying throttle in a turn in slippery conditions. While a rear motor is much easier to control, and gets much much better traction on the uphills. This traction issue really is not a problem until you are riding off road. So presumably, a cruiser won't do that much.

Re the Mac, that motor or similar size motors will climb a 10% hill easily, with a 200 pound rider. With heavy pedaling, I can crawl up hills that are short, but 25% grade with a similar motor. I'm 190 pounds.

When I sell similar motors at my online job, the company suggests a 300 pound limit for the larger geared motors. This limit will insure that you can get up nearly any hill, with pedaling, and no damage to your motor. That 300 pounds is you, the bike with motor, the battery, the cargo. If you ride a heavy cruiser, and carry 40 pounds of lead, you better weigh about 180 pounds. But the bike will climb a hill a lot better with a 10 pound lithium battery.