Against-all-odds budget ebike for delivery

[Y0z64]

I love this forum and have been lurking for a while now, you all are extremely helpful.
I'm an engineering student from Mexico, I require an ebike since food delivery in a traditional bike is my main source of income, but for the same reason my budget is really low.
Thankfully, I live close to the USA, and I'm able to get some components that are otherwise extremely expensive or unavailable in my country.
For the same reason, my budget is under $600-700, I was planning on going even lower but after getting informed it seems to be very unrealistic to aim any lower, specially for an investment.

I was planning for a ~20mph bike with as high range as I can possibly get, since it's going to be mostly used for long daily trips and constant stops, but with an overall decent motor since my city also has some pretty step hills.

I was planning on buying the kit: Voilamart EBike Conversion Kit 26" Rear Wheel 36V 500W Electric Bike Conversion Motor Kit
One of the 48V 19.5ah battery packs posted in the "Items for Sale" forum.
And finally a generic charger that fits the specification, with an adapter of course: 54.6V 4A / 48V 4A AC Adapter Power Supply Lithium Battery Charger for 13S
Which should get me everything I need until I find a fitting bike for the kit and the battery, which will probably be in a used local marketplace.

I would appreciate any help given, I'm very new at this as it probably shows
If this post is unfitting, feel free to remove it.

 

[docw009]

I've built a few low budget ebikes, but I put in secondhand geared motors that I bought on clearance ($50 USD) and the electrics were new at around $100. I also put in used 36V scooter batteries two 36V10AH packs for $30 each. So we're talking about a relatively slow (18-20 mph top) bike that relies on me pedaling a lot for mild hills.

I think the key to a low cost bike is obtaining a decent battery with good cells and safe construction. The used scooter packs were made for a large rental fleet, and were constructed far better than the typical ebike packs sold to consumers, They used brand name LG or Panasonic cells and have about 90% of original capacity. You just cannot go online and find them when you want them. I just happened to see a post either here or on another ebike forum that let me know there were deals available. It's a matter of luck.

I have no experience with gearless direct drive motors, as they don't fit my usage which is low speed recreational riding.

Buena Suerte (high school spanish from 50 years ago)

 

[electric_nz]

Geared hubs are lighter and more efficient at low power and speed levels. Look for a bafang hub laced into a wheel and as big a battery as you can afford

 

[lnanek]

A plastic body charger like that overheats easily. Last cheapo generic I bought had a metal case, like this 14S one I bought:

https://a.co/d/1QQqR4d

 

[CONSIDERABLE SHOUTING]

Welcome to the Forum! Couple questions:
1. How hilly of a region of Mexico are you in? There's a chance you might have to do a mid-drive just because of topography.
2. I know you're in engineering, but what is your skill level with fabrication, welding ect? What do you have access to, in the form of tools and raw material like metal stock? Do you have sources of free metal that you've already been taking advantage of, like trashed appliances?
3. How much is it to ship parts to you from trusted sites like Battery Hookup?

Aside from that my only opinion so far is, it might be prudent for you to wait until you get your hands on a good bike chassis to start with before we commit to battery packs and parts for it. Always a small chance that something you bought that shoulda woulda coulda worked, didn't. No sense in throwing good money after bad!

 

[amberwolf]

I was planning for a ~20mph bike with as high range as I can possibly get, since it's going to be mostly used for long daily trips and constant stops, but with an overall decent motor since my city also has some pretty step hills.

I was planning on buying the kit: Voilamart EBike Conversion Kit 26" Rear Wheel 36V 500W Electric Bike Conversion Motor Kit
One of the 48V 19.5ah battery packs posted in the "Items for Sale" forum.

How hard is it for you to ride the same conditions, routes, terrain, and speeds with your present pedal-only bike?

If it is not possible to pedal them at anywhere near the necessary speeds, it may take more power than the kit you are thinking of can supply.

There is a motor and trip simulator at ebikes.ca that you can experiment with to setup your conditions and a similar motor/controller/battery setup to see how much power it will actually take to do the job you need it to do for you under your conditions. It will also give you a guesstimate of Wh/mile, to then multiply by the miles of range you need, to see how big a battery you require at minimum.

Then you can see if the amount of power you require is available in an affordable way to you, or one that will even fit your bike, along with a battery large enough for the required range.


Also, note that the kit you link is for 36v, so it's LVC will be too low for a 48v pack. This means you will need to manually watch it's voltage to ensure it does not overdischarge the pack. If the pack has a working BMS, it will shutoff at it's emergency limit that will prevent cell damage, but it will wear out faster and become unbalanced easier (requiring much longer charging times) than if you use a "normal" LVC like a 48v controller would use.

Note also that there are 48v (13s) and 52v (14s) packs, and controllers that are setup for LVCs for each of those. If you get a 48v pack and a 52v controller, the controller LVC will shut off the system when there is still usable capacity in the pack, which reduces your available range. Ifyou get a 52v pack and a 48v controller, then like with the 48v pack and 36v controller, the LVC will be too low and the packs' BMS will have to do the protecting, with the consequences above.

So make sure you match the controller to the battery.

 

[Y0z64]

Hello again, and sorry for the late reply!

1. How hilly of a region of Mexico are you in? There's a chance you might have to do a mid-drive just because of topography.

I live in the north-west region in the capital of the Sonora state. My city in general does not have a lot of step hills, but there are a lot of differences in elevation. For example, my daily commute to my school is about 8 miles but according to google maps is almost an uphill trip. (I'm leaving the elevation chart attached)

2. I know you're in engineering, but what is your skill level with fabrication, welding ect? What do you have access to, in the form of tools and raw material like metal stock? Do you have sources of free metal that you've already been taking advantage of, like trashed appliances?

Admittedly I don't have a lot of experience in fabrication as I'm in my first year, I do have some experience in welding, but it's very limited, again I can learn if necessary as there are tutors and equipment in my school for welding and wood working, but I'll have to ask around to see if they are available to use. My experience goes mostly to electronics and programming, I also know the basics of 3d-printing and CNC, but I'm self-taught, so I don't know if that is enough.
I do have access to a lot of scrap aluminum sheets, but I can look for more scrap materials as necessary around my city.

3. How much is it to ship parts to you from trusted sites like Battery Hookup?

They don't ship to Mexico as far as I'm aware. I do have a contact in Phoenix that can receive shipping and send them my way, though.

Thanks everyone for the incredibly useful information, it seems that I'm better off investing in a good bike chassis for now, there is a very prominent second hand bicycle market where I live, so I'm going to see if I can find something worth the investment locally, or I could look online for a used bike available near phoenix, but again my budget is very limited, so most probably I'm going to have to make with what I can find.
Any recommendations when looking for a good second-hand bicycle?

 

[amberwolf]

Any recommendations when looking for a good second-hand bicycle?

That depends on your specific usage, riding conditions, and riding style, as well as the specific motor assist you're adding to it and how much battery you need for the range and performance required to do the job you need it to do.

Various mixed thoughts to inspire you to decide how you will use it, what you will use, etc.:


What bike are you using now for your commute, deliveries, etc?

Does this bike already do what you need it to do?


If you can fit the battery you need into the triangle, it will handle better and leave you room for rack and panniers on front and back for your deliveries...but many bikes with good suspensions for poor road conditions don't have much if any triangle space.

If you have poor roads you may require good suspension to go at any reasonable speed, much less up to 20mph, without damaging your deliveries.

Suspension forks sometimes preclude using front hubmotors due to design or materials without significant DIY.

Some modern bikes have dropouts even on the rear that preclude hubmotors of any kind without significant DIY and/or frame modification.

Some modern bikes have BB's or frame designs/materials that preclude many of the common middrives.

If you have great smooth roads everywhere you can use a non-suspension bike, which greatly increases the number of suitable bikes available cheaply via used bikes.

Used bikes will often require significant maintenance to get them read to be reliable as a daily work bike and commuter...but the same is often true of new really cheap bikes.

 

[nicobie]

Any recommendations when looking for a good second-hand bicycle?

Be sure to check out Pink bike. I have gotten a few great deals there. (will ship to Phoenix)

 

[CONSIDERABLE SHOUTING]

Any recommendations when looking for a good second-hand bicycle?

I would ask soon about the welder, they really are game-changers depending on what type you can use. There's a chance with a used bike you might have to repair it, or build torque plates for a motor that demand some kind of metal cutting and shaping. Nothing wild.

I'm a total newbie too so I have few things to add, other than:
Bring a magnet so you know if it's a steel or aluminum frame
Check local shops what sizes of tires and tubes they stock, and what eBike specific parts they might have. For example, Jump eBikes were offloaded up here in the USA in droves a few years ago so there's a few 26 inch wheels and nice schwalb tires from that, and frequently the next common sizes are 700c and 29 inch for us in the USA.