Need battery recomendation for 52V TSDZ2

[uraberg]

I am adding a TSDZ2 motor to my wife's Cannondale treadwell bike. This bike will be used on moderately hilly terrain (100ft/mile elevation gain) for around 50 miles/ride, at 17-18mph average speed. I have looked around for batteries mostly on aliexpress, but there are some batteries advertised that I am suspicious about (52v30aH for $250 surely sounds too cheap?) Firstly, I'd like to get an idea of the capacity I would truely need, and secondly, I need some advice on where to mount it. She likes the low standover height of the frame, and I'm not sure she'd be comfortable with mounting a battery on the bottle bosses. I don't like the idea of a rear carrier mounted battery for fear of making the bike top heavy, which leaves the underside of the down tube. Have people done this? Am I missing any options?

Thanks.

 

[tomjasz]

EM3EV or @Jenny Mao

 

[uraberg]

Thanks. I've seen her name pop up here and there. I wonder how many 21700 cells I could squeeze between the upper and the lower down tubes. It would be a funky form factor for sure.

 

[harryS]

I'm in the midst of converting an old Raleigh Mixte to a TSDZ2. Going to start with a 48V7AH battery in a real water bottle. I can just about fit the 26 cells in there, making it a little longer if needed, It will be about 350 WH.

I usually burn 10WH/mile on my cadence sensor 36V bikes, and 30 miles is enough for local riding.



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[JRA]

At 17-18 mph target you will be using more like 15wh/mi so to be safe you would need a 17.5Ah, 910wh battery but may be able to get by with a 15Ah, 780wh? Going to be tough to mount any of the standard Hailong style case batteries to that down tube and not interfere with the space. Not sure of the dimensions of that triangle above the bb but you might fit a triangle battery in a bag in there but probably not. Won't be an easy conversion but anything is possible.

 

[uraberg]

Yes, the standard case is just not going to work anwhere on the frame. I just laid out 42 nickels (same size as 21700), and it looks like I can get that inbetween the two down tubes. (Not quite in the triangle though). With 5000mAh cells, that should give me 15Ah, which ought to work. Barely....

HarryS, are you building your own battery?

 

[kevinmccune]

Why must you have 21700 cells and why do you need a 52 volt battery,? there is a 48 v 10 AH( RATED) small triangle soft case battery called a "Hailong" I have one and surprisingly enough it seems to have what it is rated for, for $200 I took a chance and I was pleasantly surprised, the full suspension bike had barely enough room near the BB to fit it in if you are trying for a cheap e-motorcycle save yourself time and frustration buy a "Sur Ron" I started out building what I thought was going to be fast powerful ebikes, reality bit Me in the Donkey, I finally saw the logic in the type of builds "Pedaluma" does, if you are willing to pedal and roll back the speed a bit you can make a satisfactory conversion,I found out 10-12 mph is a comfortable cadence on fairly steep grades. Remember going up may be hard, going down is easy.

 

[uraberg]

The Bike is for my wife to ride with me on my analog bike. The 21700 cells are just to optimize for capacity since there is so little space available.

 

[harryS]

Pedaluma seems to do a lot of TSDZ2 conversions using small bottle batteries. Which is why I'll try a little pack first. Maybe it won't suit our riding style, or maybe I've gotten too soft to ride a T/S bike. .
.