Building my first ebike - advice needed ;-)

[bruno_mac_douglas]

Hey Guys!

I'm actually studying to make my first ebike, and decided to register and ask your advice here after reading a lot of topics the theory is a good first part, but I want to share with you my plans before ordering because the experience is also very interesting and I don't have any yet!

BIKE

Here is the beautiful baby I just bought, a 2009 Giant XTC Hybrid 1.0 I found used in quite a good shape and at an interesting price, with a rock shox tora 318 fork.





BATTERY

My idea is to make the battery myself, after I'll have built my own spot welder with a car battery

I'm still hesitating which cells to use, for now I selected these but I'll keep investigating on it:
samsung inr18650 35e
sanyo 18650ga refurbished
If anybody knows a better site delivering original batteries in europe I'm defininately interested! (by better I mean cheaper, while still being originals)

So the idea is to have a battery with specs like 3.7v 3400mah with 10A max discharge rate
So if I can fit in 70 batteries
so I'd design a 52v 14s5p with a 16.8Ah capacity which would weight around 4kg with case and electronics.

I want to use this bluetooth BMS (review here)
the reason is that I can see on BT which cells is failing, and avoid having all of them dying if I have a problem with one.
I also like that I can set the overcharge voltage and undervoltage, which would allow me to have the BMS control my charge/discharge levels to go to 20%/80% (which if someday I need to extend for a longer ride I just can modify the values in BT apps).

I also plan to put a GPS tracker with sim card to find it back if it ever get stolen and kick someone's ass

For battery case I plan to use this jumbo shark pack

the 70 cells version, but will the BMS and GPS tracker have a chance to fit in ? I imagine the space available for more battery in "new version" is maybe the spot where was put the BMS ? Do you know of any triangle (bigger) case sold alone ?

CHARGER

As a charger, I'd like to use a Power supply like this one:

First of all I always wanted to buy such a power supply, because I like to do DIY electronic stuff and I will be able to use it in other projects. Also, I imagine with this I could set the voltage to charge up to a certain level (like 80%) if my plan to control it with BMS is incorrect, or if I decide to set it to 100% and limit the charge with the charger instead of BMS. I guess I could also change the amperage to be able to slow charge or fast charge depending what I need. I'm quite unsure about this part, so any feedback on similar experience is more than welcome.

ENGINE

I'm still looking in that part, not even sure if I want rear-hub motor or mid-range.
However I think I'm more inclinated for a classic a mid range bafang bbs02B 48V 750w

I wonder if I can use a BBS02V 32V 500w as 52V 750w ? I saw some post that the firmware needs to be modified but the electronics and motor is pretty much the same, is that correct ? I found a new 500w 32v for sale next to my place for cheaper than aliexpress, that's why it seems interesting option for me...

I also so some posts about TSDZ2 with open source firmware which seems nice and cheaper.

my biggest concern of mid range is the wearing of chain and other elements that people talk about in comparative between hubs and mid range, is that so big the wear induced by a mid drive compared to a hub ? how much kilometer can you make with a new chain ?


Thanks a lot for your feedbacks

 

[FarmerFpv]

After I priced everything out, I went with the Liitokala 26650 cells instead of the 18650. The price is about the same because you don't need as many and the power they put out is amazing. Have you gave those a thought? They pack some punch. I'm building my first ebike as well the problem I'm having is the bottom bracket can't figure out what I need to get the chain line correct, I'm actually building a bike from the frame up. Very intimidating compared to motorcycle, everything is so delicate, at least it is on my bike. Best of luck on your build, looks like she will be a fine ride.

 

[electric_nz]

I have an older giant xtc2 and that thing is solid af even at high speeds. If you’re going bafang may as well go for the bbshd and get the extra power. Pretty much any cell in 5P config will handle the draw. Look at a Luna charger that will allow you to charge at 90% and control the current.chain life is fine, might need to budget for a chain and cluster replacement every 2000km

 

[bruno_mac_douglas]

Hey guys

thanks for the answer

FarmerFpv I actually decided ordered a full GA pack in 13s6p from tumiche in this forum.
Seemed to me the best price/quality option to me, even if I wanted to do the battery myself, seems it will not be the case.

I ordered this BMS which has bluetooth, and seems to be small enough to maybe fit in the battery pack.

I also ordered this GPS tracker because it has glonass (better localisation) and support 9 to 75v input voltage, so ideal in an ebike battery.

I ordered this power supply to charge my battery with the current I want and to the level I want, as well as to use in other electronics projects. I might later get a small separate charge for bring with me if I travel.

Now I'm really hesitating between motors. The hardest part to make a choice for me.

@electric_nz great that this bike is good! Hope it will be stable and solid yes. I think BBSHD will be a bit expensive for me. If mid drive, will probably me TSDZ2 or BBS02

 

[HolgiB]

Just a side note: As I have seen you ordered all your stuff from China. Keep in mind that because of the Covid / Corona Lockdown all goods from China will have some serious delay.

At least that is what I experienced with the 14S BMS and charger I ordered well at the mid of January 2020 from Greenbikekit. I expect at least 2-3 month delay. I hope you are not in a hurry with your build. For myself I sourced a more expensive 14S BMS from within my country.