Remote's Heavy Duty Ebike

Hey ES, I've been trolling this forum for quite some time and now I'm ready to start my build.

Brief Bio:
College student in Miami
Battlebot builder
Name's Adam, online it's Remotecontact

Ok now the bike. I've got this motor from an old bot project that seems perfect.Average 84% eff (not bad for brushed) , 7.6hp@36v with managable 6k rpms all in a 12lb package. 5/8" shaft with standard keyway, Chain drive to a big sprocket similar to the 18hp monster build rear sprocket. This build is pretty similar to his just the cheap version using stuff I have already.



http://www.robotmarketplace.com/product ... 0-300.html

I also randomly have a crazy big Curtis (1204?) 36v and like 300 amps continuous beast controller, overkill but whatever.

As far as batteries go I plan to go LifePo4. My last Middleweight (120lb and EDIT Link: http://remotecontact.net/Coincidence%20V1.html ) robot had 6s2p A123 for the drive (4x 18v dewalt motors) and 20s42p 3.6ah sanyo nicd cells for the weapon. I ran the A123's really just to get a feel for them and they are quite lovely indeed. This bike will hopefully get to 10s5p. Balancing my 6s packs was easy with the astro blinky, is there a similar popular product the bike crew uses for 10s? Tppacks kit?

For mega fast and simple charging I'll get 2 more Astro A123 chargers (already have 2) and charge each 10s pack separately with a powerpole 4x2 block. Or maybeee just have one astro mounted on the bike for charge anywhere capability..? A123 can be parallel charged right? You guys have real world experience testing out all of the solutions to the various Ebike problems and I would appreciate any guidance.

Bahh maybe I'll just go with the KISS (keep it simple stupid) rule and go with 3x 12v hawkers or something. Advice?

Lipo is getting cheap too..... Can Lipo be parallel charged?

I don't have a bike frame picked out yet so it anyone can point me in the right direction towards a cheap steel frame hopefully with disc brakes and decent suspension I'd appreciate it. I'm not looking for any special frame materials, just something I can weld. Chromoly (4140-4130) would be nice but mild steel wouldn't be terrible either. Battlebots exp will probably have this bike being built very overkill so if anyone sees that getting out of hand please tell me.

This bike will hopefully act more like a small motorcycle and not a bike at all. No need for pedals type of ebike but still bike looking. Thanks! (Ppl use alot of emoticons here for some reason so I'll just continue that tradition)

Let me know how you go.

I have a C40-300 as well
But haven't used it for anything. See here: What to do w/ a C40-300 Magmotor & 4 Hawker 12v 13ah batts?

Perhaps I'll follow your footsteps if you succeed :wink:

One primary issue that came up was the fairly high RPM of the motor at decent power output. A multiple stage reduction would be required. The RC motor reduction drive being made might be one option: High power RC motor and drive unit production.

RemoteContact said:

Lipo is getting cheap too..... Can Lipo be parallel charged?

Click to expand...

Yes, rcgroups has some great threads on it. Personally its a bit over my head, but I know its possible.

Lol Voice, nearly identical posts.

Sweet, thanks Nomad. From reading around rcgroups, if I manually balance the cells every so often by discharging them individually then parallel charging should be alright. Anybody have some testimonial with this?

Note the leads in the picture.



This allows the parallel lipos to be tied together on a cell by cell basis. Perfect balance on all cells all the time.

I made these leads to link 8 packs together with a few hours of soldering and $10 in parts from hobby city.

Correct me if I'm wrong but I don't think that will cut it.

You're using one balancer for 8 packs.

So each cell input into balancer is connected to 1s8p correct?

That would mean that the balancer is detecting only the high end of that 8p spectrum. If the 8 cells connected together are out of sync the balancer cannot know that because it thinks it's 1 cell. If one of the 8 is low then it will likely still be low when the higher cells peak and the charging appears "done". The only way to fully balance and charge with this setup would be to discharge first to a common safe low voltage and then charge. Your setup appears to be only slightly than simply connecting the main leads in parallel into a charger. Youre essentially doing the same thing. I'm only about 80% sure on this so I very well may be wrong.

It ties every cell in P together directly via a wire. They all have identical voltages. It's also not just speculation, but something that has been done thousands of times, and definitely works. It's also very easy to do.

I looked through your photo gallery, awesome stuff!!! Now I'm thinking about making a battle robot

Best Wishes,
-Luke

RC,
Obviously weight is not too much of an issue, but stick with the A123's at least for the small footprint, if not for respect around here
7hp is a very solid performance, enough to rip some spokes and hubs apart. I would suggest building a custom rear hub using the SRAM 3 speed hub, some 14 gauge stainless steel spokes, and a nice double wall downhill rim. There are a few reasons for this hub, one being that you don't have to get the gearing perfect on the first try if you have three gears ( .66, 1:1, 1.33). As for a steel bike, A nice older GT or Specialized Stumpjumper hardtail should fit the bill, then just find an aftermarket fork that mounts disc brakes and buy components to fill in the rest. It will be much cheaper to buy a bike already setup with nice components, but good luck finding one that is steel with disc brakes. Full suspension, forgetaboutit. I am sure they are out there though, craigslist is your friend.

I say go with the controller you have, just try to find a bike with a big triangle to fit everything into, otherwise it will look more like an experiment than transportation. Just my 2 cents though. I look foward to seeing your build, and please post pics of coeds riding on it for me.:-D