First time build thread 36v 500w bafang /36v 20ah

[iain85]

Cheers Dave, I assume there would be no battery degradation with this method? Or you just throwing caution to the wind and 'just' using it /like it should be!

 

[Old_Dave]

The amount of extra degradation caused by small charge cycles should be less than that caused by full discharge / charging, battery ageing also plays a part... Don't forget that batteries are consumable items that normally only last a few years anyway.

So in answer to your question, it's a bit of both


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[iain85]

Right, thought an update was in order!

So I've been using my bike for about 6 months now I think it's absolutely the best thing since sliced bread! I've only put 500 miles on but it's only used for fun. Apart. From the spokes becoming loose and leaving me stranded it's not missed a beat

Unfortunately the seat mounted rack sheared off recently but I suspect that's down to using it off road. I've got a replacement foc from halfords, however I'm really interested in fitting the battery in the main frame to lower the C.O.G as I feel this really would be the ultimate set up for me ala D8vah Kracken conversion.

Now, I've offered up the battery and in its current state it's about 1 cm too big to fit in the frame.
Does anyone know if I can remove some of the packaging to make it fit? I'm not overly sure what's inside and don't want to ruin what is a expensive battery pack. If this is a no-go any other ideas ? The battery is wrapped in some form of blue plastic shrink wrap.

T.I.A

 

[Deleted member 4366]

You didn't say which battery you have other than 36v 20aH. They sell 3 different ones. Only the Headway one can be adjusted for size. If you got the shrink tube one, it looks like this inside, so no chance, and you have to be careful not to damage the corners, so don't risk it being a tight fit:

 

[bilabonic]

I was LUCKY that the secondhand Kraken bike i bought was a 20", it was stated as an 18" or i would of been in trouble.

My battery is literally wedged in the frame and has been fine so far !!!

My rear wheel is an absolute pain though, loose spokes all the time and had to remove rear break as it was constantly on after playing/adjusting for weeks.

I have seen batteries on ebay with seperate BMS that you perhaps could use ?

 

[iain85]

You didn't say which battery you have other than 36v 20aH. They sell 3 different ones. Only the Headway one can be adjusted for size. If you got the shrink tube one, it looks like this inside, so no chance, and you have to be careful not to damage the corners, so don't risk it being a tight fit:

I believe it is this one:- 36V 20Ah Li-Ion Shrink Tube EBike Battery Pack - BMSBATTERY
However its blue shrink wrapped and has more of a rounded edge.

 

[Deleted member 4366]

It's the same as the one above then. That one had black shrink-tube. It has a thin coating of foam rubber under the shrink-tube, which gives it the rounded appearance.

 

[iain85]

I was LUCKY that the secondhand Kraken bike i bought was a 20", it was stated as an 18" or i would of been in trouble.

My battery is literally wedged in the frame and has been fine so far !!!

My rear wheel is an absolute pain though, loose spokes all the time and had to remove rear break as it was constantly on after playing/adjusting for weeks.

I have seen batteries on ebay with seperate BMS that you perhaps could use ?

Hi,

What have you used to support/secure your battery?

I guess il have to get a bigger framed bike if this battery can't be made smaller.

It's a shame about the spokes. I'm fairly lucky as the rear has a disc brake fitted on my bike. That being said my spoke tightening skills are coming along well!

What is a BMS? I'd prefer to stick with this battery as it wasn't cheap and would have no use for it other wise.

Thanks,

 

[iain85]

It's the same as the one above then. That one had black shrink-tube. It has a thin coating of foam rubber under the shrink-tube, which gives it the rounded appearance.

Thanks, would it be a big no-no to rearrange the cells into a different shape and re-shrink wrap it?

 

[Deleted member 4366]

They're probably fixed together with very strong double-sided tape, which makes it virtually impossible, with a real risk of damage.

 

[103Alex1]

I guess il have to get a bigger framed bike if this battery can't be made smaller.

It's not only the frame size it's the frame geometry that matters most. A lot of the newer bikes I've seen for sale seem to have downtube angles which are very unhelpful.

I've a smallish-medium sized Trek frame (being only 5' 7") and managed to incorporate that same battery, KU123 controller, 3 DC-DC converters, charger socket, charging outlet and masses of wiring in the triangle along with extra padding for the battery - although it was very tight to make battery and controller independently removeable and I had about 1mm clearance left in the 2 key insertion points.

 

[iain85]

That's a shame. thanks

 

[bilabonic]

Hi,

What have you used to support/secure your battery?

I guess il have to get a bigger framed bike if this battery can't be made smaller.

It's a shame about the spokes. I'm fairly lucky as the rear has a disc brake fitted on my bike. That being said my spoke tightening skills are coming along well!

What is a BMS? I'd prefer to stick with this battery as it wasn't cheap and would have no use for it other wise.

Thanks,

It just sits in my Falcon EV triangle bag, no support, nice fit.

See my build thread.