Adrian's 2nd Build - Giant AC Full Suspension

[adrian_sm]

Well I have now got my head around charging and wiring, so I no longer feel nervous charging up. Still a bit of a pain to have to disconnect wiring to charge up the packs seperately, and I really need to get a second charger so I don't have to carry it to work each day.

Just a small update. I replaced my wiring harness for the booster pack. It now has an extra parallel connection for the two 6s5000mah LiPo's. This means I no longer have to disconnect things when charging. I just plug in one charger for the main LiFePo4 16s pack, and one for the LiPo 6s pack. No more sparks, non more frigin' around with wiring everytime I charge.

Thanks for who ever it was that reminded me this was possible, as long as your chargers are isolated, which mine are.

- Adrian

 

[adrian_sm]

Battery Update #1

Well on cell in my headway pack has slowly been killing itself. To the point that I was running out of juice on the final hill going to work. Luckily Mark_A_W has built a tab welder, and I happen to have about a hundred headway cells with various states of abuse laying around. So I pulled out the old, welded in a "new". Checked the voltage drop on the ride to work, and the "new" cell sags about a third as much as the rest of my pack. I always wondered why I got so much sag from my pack compared to the spec sheets I have seen. Looks like I had crappy cells from day one.

Since I know now my recycled cells are good performers, I will probably just build a 24s pack out of them, get a new couple of chargers, and be back to a single battery pack.

Battery Update #2
When I fix the 16s headway pack, I took the opportunity to fix up some wiring, including hooking up my DC-DC converter to the LiPo booster pack to run my lights. Well when I got home from work the other night I forgot to turn off the controller, and now have the DC-DC hard wired to the LiPo pack, with a switch to turn it off. I plugged the packs in to charge, but forgot to hit go on the LiPo charger....

Anyway long story short, something drained my 2 6s5Ah LiPo to 0V. :x They now look a bit puffy, and ever cell in both pack is 0V. DEAD.

Looks like I'll be back to 48V, unless I steal the 5s packs off my friction drive setup.

Time to order those new chargers, and get my 24s pack built I think.

- Adrian

 

[Mark_A_W]

Oops.

 

[Stielz]

Hi Adrian,

This looks like a sweet bike!

I'm just curious as to how you manage the regen braking. The motor generates a back emf that is proportional to the speed. My question is how do you regulate this to a useful voltage for charging the batteries?

 

[adrian_sm]

Thanks, bike is great and still going strong.

As for regen, the controller does it all. But you have no control over the braking force that it applies when riding. The force is just proportional to the speed you are going. The controller must buck it up to greater than the battery voltage, to allow it to feed the battery.

Here is the controller I use:
http://endless-sphere.com/forums/viewtopic.php?f=31&t=18744

 

[adrian_sm]

Since I am no longer doing a daily commute on this bike, it sits idle a bit more often. This has been draining the pack.

So I removed the R203 resistor from the controller. This means that when I turn the controller off, it is no longer slowly draining my pack.

Schematic (See page 3 for R203, which normally drains the caps)
References to others that have removed this resistor.
Photo of board, with resistor gone.

- Adrian

 

[adrian_sm]

Well. The controller didn't kill my battery, but my BMS did. It slowly killed one of the cells I replaced a while back, after being left for months in the shed without a recharge. Since I can't be bothered welding in more cells, and I have LiPo lieing around, I decided to switch the bike over to LiPo. More specifically a small 2.8kg 20s5Ah pack for 370wh, at ~76V, all tucked away in Topeak Aero Wedge Large saddle bag. This pack can also be easily reconfigured as a 5s20Ah pack for my friction drive bikes. Or quickly removed to swap batteries, take the battery with me, or recharging duties. The old 16s Headway pack weighed 5.8kg, so this has shaved 3kg off the bike, bringing it down to ~26kg with battery, or 23kg without. Making it much more viable to put the bike on a bike rack, when I would never have considered it before.

Here is what she now looks like (with my GoPro mounted on a boom out the back)


And a quick video with said mount.
[youtube]emecNlHe-lI[/youtube]

Time to up the amps now. The headways never really liked more than 3c/30Amps, but the LiPo should be good for more.

 

[Mark_A_W]

Hey

How's tricks?

I'm in Germany right now - at Leica. I'm going to hire an ebike on Sunday to ride to a castle


Mark

 

[Chalo]

From the video, it looks like your seat is too low. If you put you heel on the pedal, the seat should be high enough that you have to lock your knee out to get to the bottom of the pedal stroke. Then when you pedal with the balls of your feet, your leg will have the right amount of bend.

Chalo

 

[adrian_sm]

From the video, it looks like your seat is too low. If you put you heel on the pedal, the seat should be high enough that you have to lock your knee out to get to the bottom of the pedal stroke. Then when you pedal with the balls of your feet, your leg will have the right amount of bend.

Chalo

Keen eye. Yep. I have the seat 1-2 inches "too low". But I did that intentionally for a few reasons
- I don't pedal as much with this bike
- due to suspension the bike has a high bottom bracket position, lowering the seat a bit allows me to still comfortably place the toes of one foot on the ground for stopping at lights
- easier to to let others have a go on the bike
- slightly reduced risk of hitting the jewels when jumping the bike.

 

[adrian_sm]

Hey

How's tricks?

I'm in Germany right now - at Leica. I'm going to hire an ebike on Sunday to ride to a castle


Mark

Hey Mark. Been way too long.

Tricks are good. The better half's work has been pretty nuts, so family life has been much more of a focus for me, which has been truely awesome but not what we originally planned on. Really good to be a bigger part in the kids life at this stage, but it has put the brakes on other ventures.

How long are you in Germany for? I might be there in a couple of weeks, down Friedrichschafen way. But that is probably about 4-500kms from where you are.

Hope you can get your hands on a bomber, as I can't see a little pedelec suiting your taste in ebikes. :lol:

- Adrian

 

[Mark_A_W]

Hey

How's tricks?

I'm in Germany right now - at Leica. I'm going to hire an ebike on Sunday to ride to a castle


Mark

Hey Mark. Been way too long.

Tricks are good. The better half's work has been pretty nuts, so family life has been much more of a focus for me, which has been truely awesome but not what we originally planned on. Really good to be a bigger part in the kids life at this stage, but it has put the brakes on other ventures.

How long are you in Germany for? I might be there in a couple of weeks, down Friedrichschafen way. But that is probably about 4-500kms from where you are.

Hope you can get your hands on a bomber, as I can't see a little pedelec suiting your taste in ebikes. :lol:

- Adrian

I'm coming home on Sunday.

It's going to be 38 degrees on Sunday - a little pedelec will get me where I want to go...slowly, carefully as it's all backwards and I can barely cross the street without being killed..

 

[adrian_sm]

6 fet reprogrammed.

Bike now power wheelies

 

[adrian_sm]

! ! ! SOLD ! ! !
So as of today it is with it's happy new owner.
http://www.endless-sphere.com/forums/viewtopic.php?f=9&t=47413

I was not using the bike much now that I am working from home, so decided to let someone else enjoy it.

 

[efergy kb]

Hi Adrian,
i know you sold your bike however can i ask the following if you can remember them..

Mudguards
what brand/model mudguard is that for the rear and how did you attach that; was there any modification to the bike?
Also what is on the front and how did you attach that to the forks?

Handlebars
Your handle bars looks quite clean.. its looks like you have right front brake only. SRAM trigger shifters?
And half twist throttle on the left? Why was that?

Controller
When you switched to the 6x4110 controller, what voltage and Amps were you running at and what speeds did you max out/ average out on the flats?'

thanks
@J

 

[adrian_sm]

Mudguards
- they were just the widest plainest looking things from a local big chain bike shop. Possibly BBB brand
- hot glue and cable ties was definitely how I attached the front one
- the back one I vaguely remember using the actual metal bracket that come with the guards,
- the front clip part was chopped of, as during suspension travel it just unclipped itself anyway.
- BTW the front one still allows water front the road to get flung forward, then blown back in your face when riding in the rain.

Here are some pics that might help: (from this post)

Handlebars
- On the right I had front brake, trigger shifters for the rear, and three speed switch.
- On the left I had half twist throttle, regen brake levers, and front shifter.
- This was to avoid having my right hand doing all the important stuff. Throttle, Front brake, and rear shifter
- Also I never got around to mounting a proper rear brake, and relied regen for the rear. Fine for commuting style riding, but not great for off-road.

Controller
83.6V hot off the chargers, but settles to ~78V once the surface charge is gone from the LiFePo4's
30 Amps
~55-60kph on the flat.

I think I ended up dialling down the amps a bit for my commute. I also had a 3 speed switch, that allowed me tame things down. Which was definitely a good thing for a bike that quick. I think I had it set to be about 30 kph on 1, 40 kph on 2, and all out on 3. I would always switch it to 1 or 2 when letting someone ride it for the first time.

Hope that helps.

- Adrian

[EDIT]
Since it looks like your are building your first ebike I might add a few comments regarding fast ebikes.
50kph + is way fast on a bike. You will need good brakes. I used Avid BB7s which are very good.
If your roads are rough, dual suspension will be on your shopping list. As soon as I started going over 40kph I started searching for a dual suspension frame to use.
At 50kph+ you start running out of gears, and can't pedal quick enough. I ended up getting a 52T chain ring, so I could keep pedalling. Well worth the money.
At 50kph you end up using a lot more power to get from A to B. So you will need a bigger battery. For my 15km commute I shaved ~5 mins off the travel time going from 40kph to 50+ kph bike, but ended up using twice as much watt-hours for the same distance. Halving my useable range.
Going this quick made me worry less about cars behind me, but made me worry a lot more about those in front of me. Cars don't expect a bike to be going that quick, so you need to be very alert for cars coming out of side roads etc.

I now ride ebikes that average closer to 40kph on the flat. I personally find this the best compromise between risk, efficiency, range and fun.