Adrian's 2nd Build - Giant AC Full Suspension

adrian_sm

1 MW
Joined
Feb 22, 2009
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2,429
Location
Melbourne, Australia
Okay time for build number 2.

I have racked up about 5,500kms on my first ebike by commuting to work everyday on it. This was just electrifying the bike I had, an Avanti hardtail. But as I am riding it everyday, along some pretty average roads, I started thinking a dual suspension bike might be a better idea. Especially after a couple of my mates have built some pretty nice examples.

Mark_A_W
Mark_A_W.jpg
full_throttle
full_throttle.jpg

After cruising ebay for quite some time trying to find a good candidated I finally found this. A Giant AC, pretty much a full bike minus the wheels. Placed a bid on impulse, and won it. Woo hoo.
Giant_AC_Frame.jpg

I haven't got it yet, so don't know what is wrong with it, but will soon find out. I think I should be able to get my headway pack in the frame, just, and possible strap the controller below the down-tube, assuming I just transfer my current set-up across to the new frame.

But then I started thinking, maybe I should keep the old bike in one piece, and build a new one from scratch. This will still be my commuter, so I don't need crazy off-road strength just wanted to smooth out the roads, and gutters. I don't want to be going much more than 50kph, but would appreciate a bit more pull up the hills than I currently have.

Options I am entertaining so far are:
1) Use what I have.
- Crystalyte 408 motor
- Crystalyte 36-72V 35A controller
- 48V10Ah Headways

2) Replace 408 with Bafang BPM (fast wind)
- would need to get it with sensors, or get a new controller
- this will help with a bit more torque for the hilss, and up top speed

3) Upgrade the battery voltage
- 60 or 72V headways
- existing controller can handle it, but new chargers & BMS.
- would require a custom built pack to fit the bike

4) Go to LiPo
- 18-20s Zippy LiPo's
- existing controller would handle it
- need new cahrgers, balancers, BMS etc etc etc
- this might be easier to fit in the frame

Hmmm. Options.

- Adrian
 
$285. It is getting delivered to work. I'll give you a bell when it arrives.

Then you can laugh at me when I realized it is a POS that has had as hard a life as your bikes. :)
 
Nice frame, good choice for stepping up to dual suspension :)

I vote you keep the 408, maybe upgrade phase wire gauge close to the axle, and go lipo!

The 408 should go really nicely on 18-20S hobbyking lipo. A couple things:
Of course higher voltage means higher speed but also, the higher C rate lipo holds a higher voltage longer then lifepo4 during its discharge and also sags less under load. So...you accelerate quicker to your top speed and maintain a higher top speed towards the end of your ride.

If you went for a higher voltage lipo setup but stayed at 10Ah like your 48v headway pack, you'd be carrying more total energy which would help offset the fact that at higher voltage you're likely to be drawing more current then you are presently.
 
Mmmmm. LiPo.

Looking at the price of these, it is pretty appealing.
ZIPPY Flightmax 5000mAh 5S1P 15C $39.99
5000-5-15.jpg

That would be 20s2p for $320 + shipping, giving me 74V 740Wh.

Then I just need to sort out all the extras.
- BMS - maybe a v4 GGoodrum will be available soon.
- Chargers - ebay Meanwell 350W's @ $60 each
- don't know what else

Anyone want to school me on LiPo setups?

- Adrian
 
I'm using the same packs you've linked to above (15S2P in my setup) they seem good but the Turnigy packs in comparison do have silicon balance tap wires which are a bit nicer.

Here's what I'd suggest:

* Four of these: http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=10952 (they'll beep to warn if of any cells going too low)
* One to four of these: http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=10328 (they let you balance all the cells in a pack down to the voltage of the lowest cell in the group, very handy!)
* Some of this: http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=9672 It's just such nice high temp wiring!

You can skip a BMS all together if you're careful.

John @ E-MTB can order good chargers set at any specific voltage at a variety of set currents. You could conservatively charge to 4.1v/cell to extend the life of the pack and get a charger that outputs 82v for a 20S pack. You could get a 600w one if you need to charge fast (~7A) or a 400W one if you needed more portability (~5A). Meanwells are another option although I haven't used them myself yet.
 
@voicecoils

Thanks for that. I just order one of the logging cell-log 8's, as I bought a RC plane. Do they come with the JST-XH 9-pin cable, or am I going to have to source that myself?

Might have to tag on to a digi-key order at work.
 
Did you get SOAKED on Friday night?

408 on 72v looks pretty similar to a MAC on 60v...except it won't break. Torque appears lower, but apparently the simulator isn't accurate for geared motor torque.

My prediction is your battery won't fit, so you'll be up for a new pack, or major surgery.


Lipos are great, I think most of the issues I had when I used them as boosters have been sorted now (but GET SILICON BALANCE LEADS, I had endless trouble with balance leads) the only downside is they are made out of nastier stuff than Headways.

Our Headways have always sagged more than they should (more than reviews say).

Full-throttle, what batteries are on your Hardtail? They don't seem to sag much at all.


And...if you don't run some sort of cell monitoring, you will probably end up in tears at some point (like AussieJester). I have had a good run with my 4 Headway boosters, but the main pack does have a BMS, and it protects them to some extent (current, and overall LVC). I check mine with RC cell monitors every few days.

Be very interested to see how you go with your rear mudguard. Mine is FUGLY and it ruins my bike. But it's essential....grrr...

It you don't recycle your old bits...you'll be up to $2k before you know what hit you ;)


Cheers

Mark

(PS "Candidate has a bonus d in your first post).
 
Mark_A_W said:
Did you get SOAKED on Friday night?
Bit damp, but wasn't cold so I don't mind.
I assume the Subi kept you cosy warm on the way home. :)

My prediction is your battery won't fit, so you'll be up for a new pack, or major surgery.
My packs cells are in a 5x3+1&BMS configuration. So I am hoping all I have to do is move the BMS.

Lipos are great, I think most of the issues I had when I used them as boosters have been sorted now
Maybe I should just try a Zippy LiPo booster with the pack. My Hobbycity order hasn't shipped yet, wonder if I can add a LiPo pack?

Our Headways have always sagged more than they should (more than reviews say).
I would love to know why. That is one of the reason I got the celllog8.
I want to know if:
- each cell is sagging more that the spec sheets say
- if I have a rogue cell
- if the BMS or wiring is to blame.

And...if you don't run some sort of cell monitoring, you will probably end up in tears at some point (like AussieJester)......... I check mine with RC cell monitors every few days.
Agreed must have cell monitoring with LiPos.
I really like my current set-up that just requires a single plug, walk away and peace of mind I will have a full balanced pack when I return.
Hope I can keep it pretty simple if I go to LiPo.

Be very interested to see how you go with your rear mudguard. Mine is FUGLY and it ruins my bike. But it's essential....grrr...
Hmmm. Never really thought about it. Looks like there is a cross member at the top of the rear frame, should be able to put a similar rear guard as I have on the Avanti.

It you don't recycle your old bits...you'll be up to $2k before you know what hit you ;)
That's what scares me keeping the old bike running. But I am sure I can justify it. Now that I don't have a car, the old bike has already paid itself off. So as long as I can hold out a getting 4 wheels again, I should be able to get it past the finance police at home :lol:

- Adrian
 
Got the frame today, and no major suprises.
Looks like it has been sitting unused for a few years. There are a few rust spots, a small ding in the chainstay, usual scraps and scratches. But all in all very nice for the price.
Managed to get it home and build it up to a ready to ride bike, so I can find any issues before I make the conversion. My seat post was even the right size. :D

The biggest concern was if the battery wouldn't fit in the frame. After a little persuasion, and an adjustment of the rear shock mount..... she fits... just.
:lol:

Anyway here are the pics.
DSC_9135.JPG
DSC_9141.JPG

I decided I will just use all my existing ebike bits initially for the build, so hopefully I won't take too long to get her running.

- Adrian
 
adrian_sm said:
@voicecoils

Thanks for that. I just order one of the logging cell-log 8's, as I bought a RC plane. Do they come with the JST-XH 9-pin cable, or am I going to have to source that myself?

Might have to tag on to a digi-key order at work.

it only comes with a usb cable...JST-XH 9 pin you have to fabricate yourself...
 
Gees...that's a tight fit...

Is there enough room for the arm to swing?


Doesn't take you long to throw it together! Did you get all the stainless screws that you needed?
 
Mark_A_W said:
Gees...that's a tight fit...

Is there enough room for the arm to swing?

It will be close, depends on how I fix the baterries in there. I moved the shock to the 6.6" travel mount from the 5.3", to give clearence between the battery and shock/spring. But the end of the shock lever arm is still looking too close. I'll take it for a ride, and see if the suspension is too soft before I do anything drastic.

Mark_A_W said:
Doesn't take you long to throw it together! Did you get all the stainless screws that you needed?
I haven't swapped the screws over yet, I really just threw things together to get it rolling, and find out what is wrong with it. Then I'll strip it all down and do things properly.

I was going to try riding it in to work today, but I pulled up crook this morning. So will have to wait.

Looks like I could use your 48t chainring if you want to part with it. I put my 44t off the Avanti for the moment, and looks like there is enough clearance for something a bit bigger. Which reminds me I still owe you $$$'s for the freewheel.
 
Well there are a few things I will need to buy/steal/make for the bike. Here is the list so far:

Must buy:
- brake cables front and back (need to route them away from the inside of the frame)
- shifter cables, front and back (need to route them away from the inside of the frame)
- rear derailuer hanger (bent/broken during transport)

Can steal from other bike, or buy new:
- chainring ~48t (only came with granny gears)
- front wheel (disc compatible + decent tyre)
- seat + post
- new chain

Must make:
- torque arms
- rear disc + mounts for frame and 408
- battery + controller mount
 
adrian_sm said:
Mark_A_W said:
Gees...that's a tight fit...

Is there enough room for the arm to swing?

It will be close, depends on how I fix the baterries in there. I moved the shock to the 6.6" travel mount from the 5.3", to give clearence between the battery and shock/spring. But the end of the shock lever arm is still looking too close. I'll take it for a ride, and see if the suspension is too soft before I do anything drastic.

Mark_A_W said:
Doesn't take you long to throw it together! Did you get all the stainless screws that you needed?
I haven't swapped the screws over yet, I really just threw things together to get it rolling, and find out what is wrong with it. Then I'll strip it all down and do things properly.

I was going to try riding it in to work today, but I pulled up crook this morning. So will have to wait.

Looks like I could use your 48t chainring if you want to part with it. I put my 44t off the Avanti for the moment, and looks like there is enough clearance for something a bit bigger. Which reminds me I still owe you $$$'s for the freewheel.


I would LOVE to swap my 48t for a 44 or 42. It's too much for a normal pedal bike, which is where it is being used now.

Oh, and you can borrow my spare MAC axle (same size M14x10 as your 408) if you want to get torque arms sorted without stripping the other bike.


Shock lever arm could get a haircut, if you aren't ever going to use the outer position....
 
Damn. I didn't realize you were using it. I still need my 44t for the Avanti so can't trade.

Guess I'll have to find my own.
 
Wow. Manage to take the bike out today in pedal only form, and damn.

6" of travel front and rear is so plush. I immediately started looking for things to ride up/down/through. It just soaks them up.

Putting the hub motor on my old hardtail flattened out the hills, now this frame will flatten out the bumps. Getting closer to ebike nirvana. :D
 
And I thought you were sick?

:wink:


Did you have any brakes when you took it for a spin? (I think you had a BB7 left over?)
 
NAh still crook, some weird flu thing. But I go mad sitting still for too long. Only pedaled like 200 m so not much of a test, as I realized my body wasn't upto it.

Only BB7s on the front at the moment. Don't know what I'll do for the rear. What sized disc did you use on your front hub when you bolted it on to the side cover?
 
203mm
 
Okay, new brake and shifter cables installed.
And temporary battery mount complete..... and this ones for you mark_a_w ..... with duct tape.

Bike wieghs in at 10.9kg on the front, 18.5 kg on the rear for a grand total of 29.4kg.

Haven't taken it for a spin yet... :( :cry:
Still looks a bit tight for clearance on the suspension pivot to batteries, might require a bit of surgery.
View attachment 2DSC_9148.JPGDSC_9150.JPG

- Adrian
 
Got my old torque arms on, but only the one on the right is doing anything. I will need to work out something better soon.
DSC_9166.JPGDSC_9168.JPG
 
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