Upgrading from a 1000W kit

[Leif.Ross]

Hi guys!
Brand new member here. And i'm looking for advice from you pro's!

I am currently running a 1000w brushless hubmotor, a regular 1000w motor controller and a 48v 16Ah battery mounted inside the frame triangle.
The battery is only delivering around 750w though. (low discharge rate)
So, i am looking into upgrading, and i figured, why not go for a real update instead of just adding in another battery.

What would be the best way of getting into the 3000-5000w range? (Without bleeding me dry of money )


If i add two 12cell 5Ah lipo batteries, and perhaps two extra cells per battery to compensate for the voltage, i would have around 26-28Ah, it would deliver enough power to drive a motor in that range considering the discharge rate of the lipo cells. They would also fit inside the frame triangle together with the old battery.
Could the hubmotor handle that kind of power? It is a 1000w dc brushless hubmotor bought brand new from ebay a year ago. Chinese manufactured.

Any recommended BMS for the lipo batteries?
Any recommended motor controller?

Current setup(Not the exact setup, closest i could find online):

- Bike: Specialized rock hopper M4 (2009).
- Battery: http://www.ebay.com/itm/48V-16AH-Li-Po-Battery-with-Slim-Aluminium-Case-BMS-and-Charger-for-e-Bike-/181178344746?pt=US_Rechargeable_Batteries&hash=item2a2f12252a
- Motor-kit: http://www.ebay.com/itm/2013-New-48V-1000W-Rear-Wheel-Electric-Bicycle-Conversion-Kits-with-LCD-Display-/231069787297?pt=Cycling_Parts_Accessories&hash=item35ccd524a1


What would you guys do in this situation?

Cheers!

 

[wesnewell]

You can't run that motor continuous at more than about 1500W without burning it up, but you can run it at 5000w for shorter periods of time. The big problem is the 13s battery pack. It's only rated for 16A continuous with 40A burst. I''d help if you gave an idea of what you want in the end.

 

[Leif.Ross]

A nice end result would be a bike with around 3000-5000w of motor power.
The bike also sits right next to me, in a 18m^2 apartment, so it would be nice not having it go up in flames while charging aswell!

Can replace any of the current parts, but i would prefer to keep the battery, and just add more cells, and a seperate bms for the new cells.

I was thinking of adding two of these: http://hobbyking.com/hobbyking/store/__26789__Turnigy_nano_tech_A_SPEC_5000mah_12S_65_130C_Lipo_Pack_.html

 

[wesnewell]

You don't want to add 12s packs in parallel with 13s packs as the 13s pack at 54.6V will overcharge the max voltage of the 12s pack which is 50.4V. If you're wanting more top end speed, then you have to increase voltage. If you just want more torque you have to increase the controller amps. That can be easily done with a shunt mod, but again, your battery pack is limited to 25A continuous. About all you can do with the controller you have now is to increase the voltage. And you can only increase it a little, because I'm sure it has a 63V limit. So you could add a 2S lipo pack in series with your current battery bringing max voltage up from 54.6 to 63V fully charged. That would give you 3-5 mph more speed and a small wattage boost. You might get away with a small shunt mod, but I wouldn't try for more than 40A out of it to meet the max burst rate of your battery pack.

 

[Leif.Ross]

I agree completely, it's bad enough that i run a 1000w motor on the current battery already.
So then the shopping list goes:

- Motor-kit: http://www.aliexpress.com/item/High-power-5kw-motor-wheel-electric-wheel-5kw-electric-bike-wheel-5kw/1502643380.html
- 96v battery, preferably lifepo4. Suggestions?

Thinking of this, and then manufacture a box to be able to fit it inside the frame triangle. Slightly expensive tho..
http://www.aliexpress.com/item/FEDEX-free-shipping-96V20AH-A123-3-3V20AH-32S1P-1920Wh-lifepo4-battery-pack-for-Scooter/703218355.html


Going to build up a new bike, then sell the old one, because i use it daily for commute.
Old bike paid for itself after 6 months of use, amazing things these bikes!

 

[dogman dan]

Back up a bit, and think it through. What will you need if you buy a big powerful motor some day?

Not your current battery + a bit of RC lico. Time to buy some real battery and a good way to charge it. That's where all the money will be spent.

When you have that, buy a 72v controller. While saving for your monster motor, you can still run your old motor at 2000w, or with a bit of restraint ( don't carry enough battery to go so far) run 3000w through it.

Once you have the cash, then get a big motor, but meanwhile you can have a lot of fun with some new battery, and a 48v 40 amps controller. Ideally, get a controller that can do 48v or 72v so you can see what 72v is like.