My fast road DH Comp - 2.5kwh 18650's/Mobipus/QS V3

Ohbse

10 kW
Joined
Dec 26, 2013
Messages
886
Location
Auckland, New Zealand
Hey all

Been lurking and learning for some time now and have actually built a couple of bikes over the last year or so. Thought it's about time I had a thread where I can concisely record my experiences and hopefully help others looking at the same type of bikes.

My current every day ride is a Giant DH Comp from 2005:



It's made up of (running left to right)

Pelican 1300 mounted to Marzocchi 888 CR fork (ride height adjusted all the way down) with ballast clamps (purchased from eBay)
Battery is 20s 25ah assembled from LG HE4 cells, a total of 1.8kWh. Isolated by a breaker as suggested by Allex, monitored and protected by Adaptto BMS. Cells terminated with full mesh of 0.3mm Nickel strip welded with my custom lead powered MOSFET switched spot welder. Battery output all 8ga Turnigy wire back to Adaptto Mini-E currently, but will shortly be back to Max-E once it is returned from repair in Russia. Phase wiring all 8ga.
Half twist throttle on the right grip, thumb throttle on the left to control variable regen (currently configured for 30a battery or ~2.2kw, I rarely use physical brakes)
Shimano Saint brakes on front, older M375 on rear. 205mm rotors front and rear.
Manitou 6 way Swinger(original equipment on the DH)
150mm standard swing arm
Kiwi-designed dropouts manufactured by Scott from ES (Thanks Scott!)
Cromotor v3 in a 24" Sun rims Kingpin with 12ga Sapim spokes
26" front and 24" rear hookworms with DH tubes

It gets used every day to travel 35km return commute. It has done 4,500km since it was built with near flawless reliability. Top speed reached while testing Max-E of 91km/h, however this is not even close to true maximum. Once Max-E is back I will find a suitable road and re-test, I expect ~105km/h will be possible with this new battery and suitable space.

My daily ride to work, very little traffic this day as it was a bit later than usual:

[youtube]9_zyrhziacU[/youtube]

Riding like this (e.g much faster than traffic) consumes a long term average of 26wh/km for a return journey total of about 900wh and a total range of about 70km on a charge.

I charge at both ends using on-board Adaptto charging function with an 1800w Lineage power CP1800AC52 (I bought two). I tend to run the PSU at its rated 1800 watt and bulk charge the pack to 81v or 4.05v/cell shortly before I am due to depart. This minimises the time spent at 'high' state of charge (I realise 4.05v is very conservative anyway). This should result in a long and happy life for my 18650 pack while allowing for a hefty bump in potential range for when I want to cover some real distance. My pack has a total cell voltage spread of <8mv and has maintained that for several weeks since I built it.

Currently set for the maximum battery/phase current the locked mini-e latest firmware will allow, it delivers 5kw HOC. With the big brother controller in place it will happily deliver 10kw and is acceleration is geometry limited (e.g wheelies everywhere)

With about 8,000km of high speed 'ebike' commuting under my belt over the last 13 months I have had zero issues with police or anybody else on the road (beyond the occasional angry person who's angry in general). In New Zealand the legal limit is 250watt continuous, I am obviously a whole heap higher than that but nobody seems to care so far. I have had positive interactions from countless people who all ask the usual questions, plenty ask where they can buy one.

The bike as it stands owes me something in the region of $5,500 NZD all up. While that scares a lot of people off, it's very possible to achieve similar performance for a whole lot less. In my case I spent more for smarter solutions that were under-stressed and over-specced in the interest of reliability. I don't NEED 10kw or 1.8kwh of capacity - but it sure makes life easier sometimes.

Any questions? Anybody want me to expand on anything?
 
Nice clean build, you sure get lots of mileage out of it. Can you link to the type of ballast clamp you used? Can you elaborate on the Pelican build? Do you ride this in the rain, is it water proof? Controller is just zip tied? No derailleur shifter?
 
exe said:
Nice clean build, you sure get lots of mileage out of it. Can you link to the type of ballast clamp you used? Can you elaborate on the Pelican build? Do you ride this in the rain, is it water proof? Controller is just zip tied? No derailleur shifter?

Clamps can be found Here or search for "Accessory Clamp 1.375". Nice machined billet clamps that are as light as can be. Note that the later model Marzocchi 888's have larger diameter stanchions and as such will need larger clamps! These are 35mm, newer ones are 38mm or 1.5" which has a similar clamps available.

I went with the Pelican after reading about a few other builds on here and the prettty consistent praise for the feel. That and coming to the realisation that the 2005 DH frame with the kink in the top tube excludes most other battery options. Not to mention I've got the external reservoir for the rear shock to contend with. I simply drilled four holes on the back of the Pelican after removing its 'feet' to ensure the surface was flat. Bolted on the clamps loosely with large panel washers to distribute the stress of carrying the 10kg worth of battery, bolted onto the fork and then tightened everything up once it was all aligned. It definitely has an impact on steering, particularly at low speeds - however I got used to it very quickly and have no difficulty balancing at slower than walking pace through gaps only a few inches wider than my handlebars (which I have cut down considerably from their full DH spec length). Wiring has another pair of holes in the rear and then connects to the breaker and battery internally. No bulkhead fittings or anything complicated. Plug for the BMS simply gets passed through a hole the exact same size the BMS plug.

I ride rain or shine, I have the luxury of slightly flexible work hours so can work around the worst of the weather. I think in the last year or so I've probably opted for the bus only 4 or 5 times, not once for the past 8 months or so. Everything is pretty water resistant, I wouldn't go so far as to say waterproof :) I got pretty wet the other day riding in constant light rain, I just keep a spare set of clothes at work.

Controller is indeed just zip-tied, initially as a temporary measure but it hasn't moved so I haven't been bothered to build new 'proper' mounts for it given that the Max-E is going back on soon and doesn't fit in the same location.

No shifter as I have a single 16 tooth rear freewheel. Derailleur has been hacked up to clear the face of the Cromotor, removing the cable clamp portion and is manually adjusted to give a good chain line. It's just a chain tensioner at this point which it does very well. Bike weighs 42kg all up, so while it is certainly pedal-able you wouldn't want to go far and you can't go fast. I hit the pedals hard off the line for about one revolution and then it's all motor. Sometimes I use them at slow speeds but if it's tight I'm just on the throttle as it's a lot easier to balance.
 
Looks really good, nice soils build with top of the line components.

Impressive mileage you've had without issues. Do you do much off road riding?

You mentioned that you sent your e-max back, what was the problem with it?

My Alien powered systems controller crapped itself during some bench testing so I'm looking for a new controller. The e-max sure does look impressive, stacked with features. Are you happy with how it goes?
 
Stielz said:
Looks really good, nice soils build with top of the line components.

Impressive mileage you've had without issues. Do you do much off road riding?

You mentioned that you sent your e-max back, what was the problem with it?

My Alien powered systems controller crapped itself during some bench testing so I'm looking for a new controller. The e-max sure does look impressive, stacked with features. Are you happy with how it goes?

Virtually no off-roading, it's not really ideal for it. My Max-E failed in a bit of a strange way, blew one phase of fets while stationary and unattended - possibly water intrusion? Unsure until I hear back from Adaptto. Other than that weird failure I'm hugely happy with the Adaptto products, mini and max. I wouldn't buy anything else at this point. Charging/BMS and easy adjustment of every setting is worth its weight in gold.
 
Thanks for the eBay link, going to come in handy for me. So you put the panel washer inside the box and put a bolt through it and through the box and into the clamp? I assume it is 1/2 inch diameter bolt and however long/ thick your box is plus a little more to thread into the clamp without going through the stancions?

Since it is a 2005 bike, did you refurbish any of the parts like the shocks, forks or bearings? Are you familiar with 888? I have an old 2007 bike with 888 and the stancions are 35mm but I cannot find it on Marchizzi's website, what I have matches the 2008 models in picture but from 2008 onwards they are 38mm. Maybe mine just has newer boot color/graphics from 2008 but are still 2007 forks due to it being 35mm?
 
exe said:
Thanks for the eBay link, going to come in handy for me. So you put the panel washer inside the box and put a bolt through it and through the box and into the clamp? I assume it is 1/2 inch diameter bolt and however long/ thick your box is plus a little more to thread into the clamp without going through the stancions?

Since it is a 2005 bike, did you refurbish any of the parts like the shocks, forks or bearings? Are you familiar with 888? I have an old 2007 bike with 888 and the stancions are 35mm but I cannot find it on Marchizzi's website, what I have matches the 2008 models in picture but from 2008 onwards they are 38mm. Maybe mine just has newer boot color/graphics from 2008 but are still 2007 forks due to it being 35mm?

You are correct on all counts regarding the clamps and the forks. Mine is a 2007 as well. Graphics appear to change frequently as mine also didn't line up with images I could find online.

The previous owner of the bike had renewed the linkages and bearings for the rear suspension. I have not felt the need to freshen up anything else but the suspension is definitely the next area that will be getting attention with a full rebuild for shock and fork. I do have replacement bushings for the shock already as there is a tiny amount of vertical play in the bottom bush. The only other thing I know is worn out are the pedals!
 
Thanks for posting video,i really like seeing local road travel,especially NZ rds. the bike is balanced nice with the pelican box.
 
How much does the completed bike weigh? Are there any notes kept breaking down how much each major component and/or subsystem weighed?

Please describe its suspension and any confidence of its safety at high speeds.

What have been your scariest experiences while riding it?
 
The Toecutter said:
How much does the completed bike weigh? Are there any notes kept breaking down how much each major component and/or subsystem weighed?

Please describe its suspension and any confidence of its safety at high speeds.

What have been your scariest experiences while riding it?

As above, completed bike weighs 42kg.

Battery weighs 10kg
Cromotor weighs 12kg
Controller 1kg
Bike in standard form weighs 17kg
couple of kg for wiring/box/brackets/fender sounds about right.

You can obtain more precise weights for all of the other components such as fork, shock, frame etc via google.

Suspension is adequate, however the fork has quite a lot of stickiness in its travel. It needs new seals and a good cleanout internally. Static air pressure is set relatively low and progressive using the second air volume above the cartridge. Dampening set relatively hard for a stable high speed ride, however this does result in a loss of the bomb proof isolated feeling of a conventionally sprung DH fork. I bomb over speed bumps at 60+ km/h constantly but it does transmit quite a bit of shock through the bars.

Handling is great on smooth roads at speeds well in excess of the speed limit. Top speed in the video I posted earlier is ~75km/h. I have pushed much harder than in the video at times with higher cornering speeds and deeper lean angles, however I haven't approached the limits of tire adhesion so I don't know what handling is like beyond the limit. I suspect very unforgiving. Frankly I don't need to push harder as I'm already substantially faster than traffic and don't have the requirement of travelling on roads with higher speed limits. This bike is first and foremost a tool for transportation, not a toy :)

Video is sped up a lot, I believe total journey time in reality that trip was about 26 minutes over 17.5km.
 
ridethelightning said:
:lol: lets just see how you feel about"adequate top speeds" in a month or so....

What's going to change in a month? I've been riding this for 6 months now ;) Previous bike was a Specialized HardRock with an HS3540, Mini-e on max settings with lipo pack which was slower but not by much, rode that every day for 8 months before that.

NZ is not like majority of the US or lots of australia, all the roads I ride are 50 km/h speed limit, narrower than would be considered legal in US and infested with idiots in mini vans and hundreds of diesel belching bus's. Despite what the youtube video above shows (that really was a good day for traffic), the majority of the time I'm battling through near stationary assholes en masse. Faster than 75 km/h wouldn't do me any good other than making it harder for them to put me back together after a taxi driver takes me out.

More acceleration is definitely welcome though - I am looking forward to putting the Max-E back on and upping the phase current a lot. I do miss the warp speed ohshit i'm going to fall off the back of this thing and fighting to keep the front wheel on the ground, that's quite a lot of fun.
 
i like to affectionately call it sweet jesus speed.

i find one you are accustomed to 80+kph, going at 70max just doesnt cut it anymore, but yeah also its the accelleration.
we have similar situation here with a lot of 50kph limit areas, and i get your point about safety in taffic. i guess im more talking about those open road occasions that happen sometimes, when its ok to unleash the inner dickhead 8)

actually i use my upmost self controll and usually stick to 40kph round town to avoid the wrong kind of attention. it can be very hard sometimes, and stupid car antics sometimes sometimes prompt some spontaneous warp incidents....
 
Hi Ohbse,

Great build.
Very interested in your mention of variable regen.. that's a feature I am planning to use for my build. I have a right hand twist grip throttle for "go" and a left hand thumb throttle for "slow". Any comments / advice from your experience so far?

I'm about two weeks from finishing my bike.. that's where I have been for a couple of months and will be for a while longer.. really annoying but another project takes priority at the moment. I'll probably get it going for midwinter.. Oh well, I guess there's always another summer coming, just need patience.

I probably won't be riding on the road much (especially as I have lost the pedals along the way, so it clearly isn't a "bicycle") but good to hear our Kiwiland police don't seem concerned about your rocketship.

Regards,
Dave
 
Drum said:
Very interested in your mention of variable regen.. that's a feature I am planning to use for my build. I have a right hand twist grip throttle for "go" and a left hand thumb throttle for "slow". Any comments / advice from your experience so far?

Hey Dave

Variable regen via thumb throttle is the business. At this point with a 30a regen limit (which it rarely gets close to) I'm using physical brakes only for occasionally stop from 5km/h to stationary or during really hard braking if somebody did something dumb. After a few days of wet weather I got a bit of a shock when I arrived home the other day and when stopping outside my front door the brakes made a grinding sound. I realised that at no point in either journey in or home had I actually used them and they had a little bit of surface rust that was getting skimmed off.

I just went for a fast ride on some bush roads, narrow wet and sketchy and I never touched the brakes then either. Unfortunately I did get a nail right through the rear tire just as I was arriving home. The variable bit is absolutely essential, fixed regen can't be strong enough for rapid stopping without it being irritating to use at other times. I used a thumb throttle but there's others that have tried out either magnet and hall sensors mounted to levers or Arlo's solution which was a lever with integrated strain gauges to provide a more natural hydraulic like feel (e.g small travel, variable effort). Thumb throttle works well enough that I can't bring myself to sink the time into getting the other options to work. It also leaves me with both front and rear physical hydraulic brakes which I can use independently of the regen.
 
wuxing thumb throttle is awesome. also very cheap, iv seen em go for around 14usd but iv also seen them in boxes of 200 on alibaba for around 4usd each. they work super well with addapto controllers so yeah, i basically never use brakes except for final stop at low speed or emergency stops, which i did the other day when a car just pulled right out infront of me to change lanes, while stopped at the lights :shock: no warning at all. the regen combined with the shimano saint m820s front and rear, did the job, locked up the back wheel real good :D
 

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I can only shake my head when I see builds like this were the battery is on the front fork I know you say it handles great , If you put the battery anywhere Elise you would feel a big improvement . More thought should be used when choosing a frame for a E bike project remember you got to put the battery somewhere.
 
You're welcome I'm happy to help!

Nice build Ohbse! That's some very impressive range. I'm currently designing an electric bike at my college and we plan to have similar battery capacity (actually the same 20s 5p (25Ah)).

The road quality in NZ looks amazing, I wish the roads were that nice here, there is only one near me and its 32 kph :roll: .

Do you have any pictures of your battery pack?
 
Scott said:
You're welcome I'm happy to help!

Nice build Ohbse! That's some very impressive range. I'm currently designing an electric bike at my college and we plan to have similar battery capacity (actually the same 20s 5p (25Ah)).

The road quality in NZ looks amazing, I wish the roads were that nice here, there is only one near me and its 32 kph :roll: .

Do you have any pictures of your battery pack?

You know I was sure I took some photos on my phone as I was assembling the pack, but apparently I imagined that... I'll get some photos when I next pull the battery but that might be a little while. I subscribed to the high density offset row, hot glue method of construction with 10p strings welded in parallel and then each individual cell bridged to the next. 6 spot welds per join, 4 joints per cell including P and S connections makes for 4000+ spot welds and quite a lot of 0.3mm nickel. Between the hot glue and the welded strip it's a very cohesive, dense unit. I then insulated the cell ends with some high density plastic in the form of thin cutting boards from the hardware store, affixed of course with some more hot glue. This is abrasion resistant, highly insulating and cheap. Battery is then surrounded with high density closed cell foam for vibration isolation and just to pack out the volume. Pack is built in two 10s10p layers and connected in series and terminated to the controller with 8ga Turnigy wire and XT150 connectors. 4s JST balance connectors were from 4s extensions I purchased from HK and lopped off the female end. Connectors are all reinforced with some more hot glue to ensure pins don't pull out or vibrate loose. Total pack resistance is ~40mOhm according to the controller, that compares favourably with my previous pack built of 20c lipo which came out at around 70mOhm. Whole pack cell delta is 0.0009v according to my 0.02% 500,000 count meter.

Regarding hatorade for the fork mounted battery - eh, everyone is welcome to have an opinion. You are probably right. I chose this option because it was easy, waterproof and a known quantity. I may end up rebuilding and mount the split pack hanging from either side of the top tube as close to the head tube as I can get while maintaining steering range. This removes the mass from the steering axis - however it also moves it rearward which ultimately I think will slightly reduce straight line acceleration. It may improve handling at high speeds, definitely will at low speeds. Frankly I don't think it will make a world of difference, just fractional improvement so it's not a huge priority. Other than maintenance and lighting (which I need to get onto as the days are getting shorter already) this bike is 'done'.
 
lighting is as easy as a ac/12vdc switchmode psu from a laptop or lcd screen. runs 12v lights nicely. cheap,compact, easy to get and install.
just need to make sure the polarity of the dc input is round the right way, wont harm anything if you get it wrong, just no show..
 
So I got hit by a car. It was inevitable considering the amount of cars I pass every day that someone would do something that couldn't be anticipated.

I was in the bus lane, car in the outside lane stuck in traffic decided to make a last minute trip to the restaurant on the road side and hooked left right in front of me. Only a few meters to brake, but shaved off a bit of speed before colliding with his rear door. Ended up continuing along the side of the car and he'll be needing two new doors and a wing mirror. I ended up on the ground with the bike nearby and rapidly drew quite a crowd from people that had pulled over, people from the restaurant and people who lived nearby. They were all quite surprised that after a couple of minutes to collect myself and check all my limbs I was able to stand up.

Ambulances and Police attended pretty quickly, they got called within seconds because the first person on the scene was convinced I was going to be pretty severely injured. Thankfully all the armor and layers did the trick and I had no broken bones, just extensive bruising on most of my extremities. The police and ambulance staff thought the bike was awesome and were very impressed with how well both me and the bike had come through considering how frocked up the car was, they definitely got a pleasant surprise when they arrived and couldn't immediately tell who was the cyclist instead of finding a bloody mess.

The driver was a really nice guy in his early 20's, we ended up getting on really well. After some fiddling I managed to remove the very taco'ed front wheel and we put the bike in the back of his golf and he gave me a ride home, very apologetic and hugely relieved about how well it ended up considering what might have been. Fully insured and eager to make things right, I don't expect I'll end up out of pocket.

Later that evening as adrenaline wore off and things settled I was feeling pretty crippled but now a little over 48 hours later I'm back to fully mobile with only mild pain when I tense my ribs. Fortunately for me but unfortunately for you there's almost nothing visible as I really don't bruise much, so no carnage pics of injuries. I did grab a snap of the taco wheel which I'll put up later.

Bike came through well! The metal bar end rode along the doors of the car and obviously absorbed a lot of the energy of the impact. Front wheel took the rest and is quite bent but no dramatic failures. Front fork appears fine and everything else is straight from what I have measured so far. No damage to drivetrain, there's a little bit of road rash on one corner of the Pelican as it slid the last few meters on the pavement and the grips/barends will need replacing. I will take this opportunity to get the suspension all rebuilt by a pro. I have ordered a new front wheel from CRC - Hope Evo 2 hub, Mavic EX729 36mm rim, double butted spokes, brass locking nipples. This should end up looking a bit better and have a wider tire footprint than the old relatively narrow rim.

With the long weekend I expect I'll only be off the bike for a couple of days next week. Doesn't put me off in the slightest.
 
I'm glad to hear that you are still alive and were able to pretty much walk away from that!

I agree and would definitely have a pro take a look at the fork. One thing you can do when you get a new wheel is to hold the front brake and push the bike to see how much play there is in the fork. Your fork "should" have almost no play at all.

I had a guy come into my shop a week ago who got run over by a car (he is ok) and the driver stopped to check on him then drove off. He was getting a new bike at my shop because his was ruined. He had a front hub motor so he bought a new one and we were helping him convert the new bike.
 
sory to hear this . glad you are ok.
thanks for posting the incident in detail as it is a great lesson for others.

had a vey similar thing nearly happen not long back. stationary car at the traffic lights in a que, decides to pull out into the empty lane next to them(which i was coming along in) giving no warning or indication and diddnt see me in the mirror, even though i had 2 ultra bright lights on the front.

i mannaged to brake hard and all was ok but a second later and not so good...

just cant be too careful out there. its a crazy world sometimes and the stakes are too high.

glad to hear your keen to get back on the horse though :D
 
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