use a step up module in 48v 1000w ebike

[iouhxm]

hi, guys
I dont know if it might be a noob questions!

if I have a 12v-48v 1000w step up module..... like this one http://item.taobao.com/item.htm?spm=a230r.1.14.16.sqHe5i&id=35339814693&ns=1&abbucket=19#detail (in chinese)

i know some guys use step up module to charge battery, but why not use in ebike ??

can i use this module directly connect to my ebike controller (48v 1000w system) with a 12v 20ah li-ion battery pack??

would this idea work??

Thank you !!

 

[Nobuo]

if it allows you to make a cc-cv charging phases it would work good, it it make only a constant voltage, it won't charge the cells in good condition

 

[Gregory]

Problems I see are

1. The 48V 1000W controller may pull 1200W or 1400W at start up.

2. 1000W on a 12V battery will be 1000W/12V =83A. Can your battery supply 83A or 4C?

3. There will be efficiency losses.

 

[iouhxm]

Problems I see are

1. The 48V 1000W controller may pull 1200W or 1400W at start up.

2. 1000W on a 12V battery will be 1000W/12V =83A. Can your battery supply 83A or 4C?

3. There will be efficiency losses.

how do i know my battery pack's current?
it was made diy from collected many different laptop batteries.

thanks

 

[Drunkskunk]

you'll need to get the manufacturer's specs on the cells used for those laptop batteries. You should be able to google the serial numbers on the cells for more info.

The efficiency loss will be a concern, but all that lost power is going to go out as heat, so you'll also need careful heat management of the device. Don't put this in a bag. If it could make an amazing 90% efficiency (Unlikely) it would still be burning 100 watts at 1000 watts input.


they list an input voltage range of 12-36 volts. that 12 volt limit may be a hard limit, in which case your battery might not be able to use it's full capacity. If you have 50% capacity when your battery is at 11.9 volts, you might never be able to use that if the DC/DC converter shuts down under 12 volts.

 

[Gregory]

Hi iouhxm. I'd only pull 0.5C from used laptop batteries, maybe 1C if I knew they were good. 4C will sag the voltage waaaaay down and damage them. I'm sure DrkAngel will have a thread on that somewhere.
Basically it's not a very good idea for this application. Sorry.


Also

4. how would the DCDC deal with regen currents (e.g. if using a Direct drive hub) or ripple current? Probably badly.

 

[iouhxm]

thanks for the reply!