Be careful with “cheap”. Quality costs. A year later you might find expensive repairs.
Bafang motors are costly but good quality. Good batteries are expensive, there’s no way around it and most fires seem to be from the cheap ones.
But a kit is the way to go if you have mechanical skills. And it’s easy to go overboard on estimating “needs”. What’s your goals? It’s ok to not know or wanna go fast or just commute to school.
FWIW, I bought a “kit” from california-ebikes.com. There was a slight shipping snafu, mixed up boxes, but they were great, it’s all fixed, got all my stuff only a couple days late and now, who cares. They’re fine people to deal with. I think overwhelmed with business.
I live in LA, I have a sports car if I wanna go stupid fast and a thousand miles of desert to do it in. In LA I wanna explore, go to lunch, minor shopping, go down town, etc. 25 mph in traffic is scary in a bicycle, on urban roads. I’m old, I don’t want to die right now thanks. I want to have a basket and a dog carrier (in front of me, that’s the next project). I’m light, 140 lbs, pretty rugged, don’t mind pedalling.
My base bike is a Trek 930, 26", we bought new in the middle 1990’s (!) that got little use, but had been to burning man so it needed full disassembly (every screw and bearing, except the one-way clutch thingie in the rear wheel). New cables, new chain, soaked the cassette in citric acid and water to get all the rust off, etc. Sanded and repainted it. New tires, tubes, wheels were fine, new brakes… I was afraid this was gonna cost so much I would have been better off buying new, but no, probably $400 all told to take the bike to like-new, mechanically and I wanted to paint it myself anyway (crazy Montana colors and hologram spray). And also kept pretty much all of it out of trash and recycling.
I’ve done electronic engineering and software most of my life and extreme reliability is my thing. The magic word is: DERATE. Get more capacity than needed and don’t use it, lol. Well I went a bit overboard… I’d already decided Bafang for the mid-drive motor because it hasn’t changed radically in design for some time yet has received incremental improvements. That’s the sort of shit I wanna see… parts are available, and the kinds of things that fail are reasonably well known.
TBH I wasn’t finding reddit /r/ebikes very useful. Too much noise about trying to buy stupidly cheap stuff that was obviously a crock and kids just wanting to go real fast. But I figured out that middrive is the best choice above 250 watts, that 500 might have been adequate, 750 is not much more cost than 500. Gearing matters, I’ve spent exquisite months with spreadsheets gearing my underpowered sports cars, it matters hugely, but, lol, when it came time to order only 44-teeth was in stock so that’s what I got.
At order time I impulse-bought the BBSHD. It’s 1000 watts, and heavy, but endurance was the goal. And 17 AH battery.
Very specifically I stuck with 48V, not 52V. Stay away from electronic component ABSOLUTE MAXIMUM ratings. Larger margins decreases some failure probabilities. Most of what “mil spec” means IRL is testing and derating. I don’t know what chips/MOSFETs Bafang uses, but 60V is a common rating, and 48 is close enough, with inductive spikes’n’shit that’s close to ABS MAX. Not interested in finding out.
It all went together by-the-book – except the bottom bracket which was 68 x 100 didn’t allow directly bolting on the torque lever so I had to make two 5mm spacers for the two 6mm bolts, but with that it’s perfect. I bought the extra-long torque lever.
The power wiring wasn’t totally satisfying to me but probably exceeds most consumer quality. The Bafang uses a yellow plastic two-pin (common, I just forget the name) and the battery a paired red/black slide connector (also common, also can’t remember name) and the kit came with a 24" jumper to connect them. Slightly annoying, but I get it. I chopped the jumper to 6", soldered heatshrink, enclosed in spiral wrap and cable tied to the upright. Ugly hack but electrically fine.
I don’t trust those connectors long term. Short term, I’ll buy replacements to have on hand, and watch for temperature rise in use (I can put a finger on them – if they even discernably warm, remove and replace ASAP).
So the Trek was 21 speeds, now 7, since the Bafang middrive replaces the crank setup. The chain line is OK, but 1st gear looks like it wants to jump off, so I’ll watch that and I suspect chains won’t last long on an ebike anyway.
I got it up to 30 mph; it will do more, not interested. The rim brakes are not really adequate; I’ll put a disc on the front later.
It will also climb a fkn tree – we have an 18-percent (!) grade, and this climbs it! Umm that’s crazy. A steep grade on a freeway is 5 or 6 percent, in Western mountains. Here in LA, I climbed up and down Echo Park streets around Elysian Park, not that many miles total (15) but man, lots of grades! I used 12 percent of the battery. I have achieved overkill!.
About $1400 for the Bafang kit and california-ebike.com battery. I got new brake levers, throttle, the dumb LiPo charger it comes-with (ordered a smart charger separately), new crank levers, the DSP14? display.
Ask me in a year or two, lol… I just built an ebike and my local shop pointed out that Abus comes out with most of the good designs that kryptonite sells. I bought a 130 buck combination folding bar U lock.
A $20 kryptonite cable through the front wheel to the lock around frame wheel and parking meter etc.
Front wheel is cheap enough to replace.
Also gonna paint the motor and battery horrible colors so the quick -buck fuckwit theivesoght avoid it.
I put a Bafang BBSHD motor and a dolphin type 17 ah battery on a 30 year old Trek 930 we had. Probably 300 to completely renovate the trek. Bought the lot from California-ebike.com. I recommend them.
I don’t intend to go fast. I wanted overkill for reliability. Only 100 miles so far, first couple trips pf adjusting etc, now it’s just great.
I have an Aventon Aventure with a battery blender & swappable 20 ah LiFePo4 with a 35 ah arriving this week. I’ve got an ebikeling 1200 motor watt & controller running through that battery blender ( so I can run both controllers with any 1 battery or 2 at a time. )
For cargo space I have the Topeak MXT rack & EXP trunk bag, and a Burley COHO XC single wheel trailer with their paniers & rack.
I don’t know what I would recommend except to someone else my weight ( I’m heavy ).
I would feel comfortable telling anyone in my family to pick the Aventon that meets their needs pretty comfortably - ( cargo bikes, folding , etc ).
So apparently there’s no such thing as a 750w bbshd, what happens is they take a 1000w motor and lock/throttle down to 750w, maybe for legal/regulation purposes?
So what people do is the other way around, they purchase the ones sold as 750w and unlock to achieve full 1000w potential!
I guess in your case, are you sure it’s unlocked to 1000w? If so, you could in theory get the programming cable and lock/throttle it down to 750w yourself
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