Ebike Conversion - My K2 Attack 2.0 w/ 48v 1000 watt front hub motor and 4x sealed lead-acid batteries

Kalashnikov
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Re: Ebike Conversion - My K2 Attack 2.0 w/ 48v 1000 watt front hub motor and 4x sealed lead-acid batteries

Post by Kalashnikov » Wed Apr 24, 2019 2:41 pm

This turned out pretty neat Dallas. The 2wd version would be interesting.

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5chn3ll
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Re: Ebike Conversion - My K2 Attack 2.0 w/ 48v 1000 watt front hub motor and 4x sealed lead-acid batteries

Post by 5chn3ll » Thu Apr 25, 2019 9:19 am

All of my engineer/contractor buddies have made the same observation - but dammit, I really want the look of the unsupported rack. One of the things I hate about most ebikes is how massive the frame becomes - I really want mine to look like bikes, not e-bikes.

Understeer: You will hit the wall with the front end.
Oversteer: You will hit the wall with the rear end.
Horsepower: How hard you will hit the wall.
Torque: How far you will move the wall.

Gone hunting with Alec Baldwin and Dick Cheney. Back soon.

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Re: Ebike Conversion - My K2 Attack 2.0 w/ 48v 1000 watt front hub motor and 4x sealed lead-acid batteries

Post by Kalashnikov » Thu Apr 25, 2019 11:04 am

Figure out how to stick the batteries inside the frame then. Get round rechargeable batteries, stuff them inside the bike frame with access points covered holes.

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gnat
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Re: Ebike Conversion - My K2 Attack 2.0 w/ 48v 1000 watt front hub motor and 4x sealed lead-acid batteries

Post by gnat » Thu Apr 25, 2019 11:50 am

Actually probably would be a pretty good idea if doable as it would allow the weight to be better distributed and even lower the center of gravity a bit by using the lower frame. I expect you'd need to use a custom frame though that offered some way to insert and remove the batteries as needed (e.g. bad cell).

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5chn3ll
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Re: Ebike Conversion - My K2 Attack 2.0 w/ 48v 1000 watt front hub motor and 4x sealed lead-acid batteries

Post by 5chn3ll » Thu Apr 25, 2019 11:53 am

There are loads of downsides to trying to stuff off-the-shelf cells into off-the-rack bike frames. I started to get all wordy - but the short version is: the battery in the middle of your downtube is the one that will eventually decide to catch fire, and it will mess up your day. Like Gnat pointed out, access is crucial - but you can't machine access ports into a bike frame without causing other issues. The chemistry and physics of a lithium cell failing are spectacular; you REALLY don't want to weld it into a bike frame (there's a common name for uncontrolled reactions taking place inside of pipes, but let's not go there).

There ARE a couple of companies who are designing composite frames that are more superlight motorcycles. This makes more sense to me - designing a monocoque around packs allows you to place the weight where it makes the most sense, and the frame can be more or less massive as the design requires.

Understeer: You will hit the wall with the front end.
Oversteer: You will hit the wall with the rear end.
Horsepower: How hard you will hit the wall.
Torque: How far you will move the wall.

Gone hunting with Alec Baldwin and Dick Cheney. Back soon.

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5chn3ll
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Re: Ebike Conversion - My K2 Attack 2.0 w/ 48v 1000 watt front hub motor and 4x sealed lead-acid batteries

Post by 5chn3ll » Wed May 01, 2019 2:57 pm

sh!t just got real up in here...UPS man is bringing a box of 100 LG HA1 batteries and a new 13s battery management board. Time for a real (13x5) bike battery...

LG_DAHA_EBAY_PIC_9eec3587-a3f5-4ff9-9b21-ca4f1a5acbe6_540x.png
LG_DAHA_EBAY_PIC_9eec3587-a3f5-4ff9-9b21-ca4f1a5acbe6_540x.png (504.2 KiB) Viewed 2427 times

Understeer: You will hit the wall with the front end.
Oversteer: You will hit the wall with the rear end.
Horsepower: How hard you will hit the wall.
Torque: How far you will move the wall.

Gone hunting with Alec Baldwin and Dick Cheney. Back soon.

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32wildbilly
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Re: Ebike Conversion - My K2 Attack 2.0 w/ 48v 1000 watt front hub motor and 4x sealed lead-acid batteries

Post by 32wildbilly » Wed May 01, 2019 7:16 pm

5chn3ll wrote: Wed May 01, 2019 2:57 pm sh!t just got real up in here...UPS man is bringing a box of 100 LG HA1 batteries and a new 13s battery management board. Time for a real (13x5) bike battery...


LG_DAHA_EBAY_PIC_9eec3587-a3f5-4ff9-9b21-ca4f1a5acbe6_540x.png
HOLY SHITBALLS! That frightens me and I live at least 1,500 miles distant!
Never gonna make you cry...

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gnat
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Re: Ebike Conversion - My K2 Attack 2.0 w/ 48v 1000 watt front hub motor and 4x sealed lead-acid batteries

Post by gnat » Thu May 02, 2019 1:22 pm

Mmmmm.... Fire...
1556828534592605511571583213452.jpg
Actually my first time seeing a 18650 in person. These things are massive!

Oh and some dumbass admin still need to fix the image rotation!

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5chn3ll
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Re: Ebike Conversion - My K2 Attack 2.0 w/ 48v 1000 watt front hub motor and 4x sealed lead-acid batteries

Post by 5chn3ll » Thu May 02, 2019 1:53 pm

The capacity they're getting from the newer cells is pretty amazing. I have some other modules for a project that I want to run 3x3, but I haven't yet found an affordable controller that can do 60 amps continuous @ 96 volts.

That project is going to use a single motor and the FWD drive train from my 996. :D

Understeer: You will hit the wall with the front end.
Oversteer: You will hit the wall with the rear end.
Horsepower: How hard you will hit the wall.
Torque: How far you will move the wall.

Gone hunting with Alec Baldwin and Dick Cheney. Back soon.

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gnat
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Re: Ebike Conversion - My K2 Attack 2.0 w/ 48v 1000 watt front hub motor and 4x sealed lead-acid batteries

Post by gnat » Thu May 02, 2019 2:01 pm

This is going to go in my not-quite-so-dry box running a esp32 and htu21d that will wake up every 10 minutes to post humidity/temp/voltage info to a little server I wrote. I figure at 9.8A I should have to swap batteries every 20 years or so :lol:

I'm glad I held off designing the case for the unit though. I was thinking these were AA size. That would have been embarrassing...

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