Specialized Big Hit FSR with midmount

[toolman2]

0 to 110kph in 4 seconds is incredibly quick (do link us up with the info if you could recumpence, i missed that too) but yes lostrack that is well spotted, you cant really whiskey throttle a recumbent or a car, as you dont tend fall back and add more..
when, like you say you can just nail the throttle after 2 pedals, and 4 seconds later your merrily doing 110kph, then its clear you are not suffering from the affliction.
-good point also with the thumb throttle, they do seem to help.

[Beachcruzer]

Well, it's my birthday in a couple days and a Big Hit FSR came up on Craigslist for a good price. So now I own one. The nice thing about Tench's build is it takes the pressure off. The Big Hit Mona Lisa has already been painted, so I will be content to do a clean rear hub install and an Oatnet-style fork mount battery pack. Let the fun begin!

[recumpence]

0 to 110kph in 4 seconds is incredibly quick (do link us up with the info if you could recumpence, i missed that too) but yes lostrack that is well spotted, you cant really whiskey throttle a recumbent or a car, as you dont tend fall back and add more..
when, like you say you can just nail the throttle after 2 pedals, and 4 seconds later your merrily doing 110kph, then its clear you are not suffering from the affliction.
-good point also with the thumb throttle, they do seem to help.

This was achieved with two 4 turn Delta 3220 Astro motors. Each pulled a peak of 400 amps for two of those 4 seconds. So, 43 volts at 800 amps. It pulled so freaking hard that I found myself yelling each time I accellerated at that rate. I finally went down to a single motor in Wye termination because it was just too fast and way too tempting. It was also unreliable in that guise.

Anyway, I am hyjacking Tench's thread. Back on topic.

Matt

[Tench]

Dont worry about it Matt, we are all gobsmacked by some of your achievements and never tire of hearing more about them!

I dont know enough about the electrickery side of things yet to start pushing the boundaries so i am sticking to the mechanical engineering side of it for the time being.
There are so many motors, controllers and possible configurations that i am going to ride this bike through the summer to learn and give plenty of thought to how i shall do the next one, it will probably be another over winter build like this one was only i will try to be a bit more creative with a frame from scratch next time rather than trying to fit within the confines of an existing frame. A V3 CA will hopefully be available for that one.

[smudger1956]

Stunning is an understatement.....makes my Commencal build look real agricultural.....

All the best.
Tony

[Tench]

Martin, now stop reading this and get back to work, i need those parts !

When they are ready i will bring the bike with me so you can have a go!

[TopCat]

A very nice build indeed Tench
Not only are you top of the table in shooting, your also very high in the rankings of the best bike builds/builders on ES. Some people just have no end of talent

One small complaint! I see this on a lot of bike builds of various designs, and your bike (though stunning) falls into line with the others? Everyone takes great care and attention to detail - postioning motors/cnc-ing all there lovely shiny bits and bobs/securing all there wiring and batteries in a stealth like battery compartment. Then they go and plonk a controller on the down tube??? ---Wide open to all the elements. This is one thing that really bugs me Grrrrr

This is ok if you live in a dry climate but even then you never know when the next monsoons going to strike. With a little CF extension you could shield/conceal your controller a bit better, you could even cut slotted vents into the CF for air flow/cooling and have an orange (colour of bike) piece of fine mesh set behind the vents for that peekaboo bit of styling.

If this is what you hit us with on your first build I cant wait to see what you come up with next...? Probably some tyre shredding thing of beauty that looks like it just fell off of the back of the starship enterprise

Best of luck and fingers crossed for your upcomming shoot rounds.

Regards
Tom

PS....I and a few other members are still awaiting your wiring diagrams/battery charging setup tutorial with plenty pictures

[kfong]

Most controllers are pretty well sealed. I think that is a fine place for it. Keeping it exposed to rushing air will keep the contoller happy. Covering it up only creates thermal issues. Easy enough to add silicone sealant to any wire exit. I leave all my controllers exposed this way. Exposed wire or not having a drip loop is more problematic but heat is what will do your contoller in most of the time.

[Whiplash]

I have to agree with Kfong, I was caught in a total downpour with my controller right in front of the rear tire, it was flooded with water and was fine since I sealed it up with silicone...

[adrian_sm]

I agree. Controllers need cooling hence being out in the open. Just make sure they are sealed up, and you'll be fine.

I have ridden 3 winters daily to and from work, no issues having my controller out in the open.

[sn0wchyld]

+1 on keeping it exposed... ive ridden through creeks, in the rain, yada yada etc etc. no probs for the controller. Mine hasn't been specially sealed either other than the 'water catch' area formed by mounting it upside-down on the down tube. a good drip loop helps too.

Any chance we can get some more vids of this bike in action? its kind of the Lamborghini of the ES bikes right now... and we all love to hear that engine purrrrr.... or rather..._______........

edit
that's supposed to be silence. but its kinda hard to type the sound of silence .

[jtchoy]

WOW!

Beautiful build, looks absolutely professional! Very nice attention to detail!

[Whiplash]

+1 on keeping it exposed... ive ridden through creeks, in the rain, yada yada etc etc. no probs for the controller. Mine hasn't been specially sealed either other than the 'water catch' area formed by mounting it upside-down on the down tube. a good drip loop helps too.

Any chance we can get some more vids of this bike in action? its kind of the Lamborghini of the ES bikes right now... and we all love to hear that engine purrrrr.... or rather..._______........

edit
that's supposed to be silence. but its kinda hard to type the sound of silence .

AGREED!! Lets see it climb something steep!

[Tench]

I will see if i can get someone to film me climbing a few things on it over the weekend if i can.

[hotrod]

hi tench is possible to show me inside your series and parallel connectors, because there look very robust just what i am after for my bike. thanks

[waxman123]

What a build!!!

Question I have is what is your total reduction and how is your pedal cadence (speed)?

Again what a great build!!!

[Tench]

The motor has a 14t freewheel on it driving onto a 48t chain ring, the other front chain ring which drives the rear has a 44t driving a 13-34 7 speed cassette. In top gear, 14-48 and then 44-13 are virtually the same ratio so the motor is turning about the same speed as it would if it where in the wheel with the pedal cadence the same as it would be on any push bike with 24" wheels and this gearing, i would say it was just normal bike gearing. However the fun starts when the lower gears are used, at the other extreme in bottom gear 14-48 then 44-34 the motor is turning 3 times to one turn of the wheel, this is where the real advantage of the mid mount is found.

There are some pics of the series/parrallel changer plugs and an explanation of their construction somewhere in the middle of the build log, just been and had a look it is half way down page 5, read the text between the pics of the plugs for an explanation of how they are wired.

[Whiplash]

Any luck with the videos??

[Tench]

Sorry Whip, been peeing down here all weekend, i didnt want to get it dirty!

[Whiplash]

Lol come on! Get some mud on it!

[splad]

nice one tench cracking build,I no how you can save a shitload of weight and money,i built a mid drive with a golden motor 500w trike motor and ran it on that 72v stealth battery i bought off you stays cool even with me on it!I will post some pics when i can find my camera,seriously tho m8 you carnt go wrong with my setup ,72v 15 fet 4110 from zennid scooter parts uk £45 deliverd,500w golden trike motor £120 deliverd including import tax, you already no where to get your throttle you told me!petrol scooter uk about £15 quid deliverd,we can now get cheap lipo from robot birds in the uk also,same as zippy ect.i think these motors have been overlooked their about half the weight of that motor on your bike they also have a low rpm for easy direct drive or through the gears.i had mine way over geared 16t motor sprocket 52t on the wheel it did about 60 mph and im 15 stone and it still went up hills,it would not smoke tho even with that abuse,i think the controller was close tho!!quick question now sorry for going on!! Do you notice any enersha effects from the big spinning motor?? also sorry for my bad grammer

[Tench]

Hi Splad, glad you put the battery to good use, you should start a new thread about your bike or add it to the thread dedicated to pics and info of mid mount projects;
viewtopic.php?f=6&t=38553
I am sure other uk builders would like to know more about it and where you sourced all you parts etc.

Simon.

[Green Machine]

Hey Simon,

I really love the way you set up your charger and batteries....sleekest charging system i have ever seen.

What is the procedure to charge your batteries after you plug in the charging cables,in other words how complicated is the process to start up your charger? Are you confident enough in your system to charge in the house unattended?

How long does it take you to charge all your packs?

Did you customize the charger in any way?

How are you getting those led read outs?

Great build.

[Tench]

I have programmed the charge parameters for the main pack into one of the ichargers memories and saved it as "bike", When it is connected i select "bike" in the menu and press go, it balance charges and stops when all the cells reach 4.2v. The 2 meters in the charger housing are displaying the volt and amp output from the power supply to the icharger, the icharger can display these numbers but i have them visible all the time. the 2 meters are powered from a phone charger fed from the 240v input and i have a 50 amp shunt between the power supply and charger so i can measure the amps. The i charger is not modified at all. I am in the process of removing the dc/dc dropper off the bike and putting the lights onto a seperate battery, i will create another set of charge parameters in the charger saved in another memory as "lights" to charge this small pack seperately, i like to keep things very simple to ensure no mistakes are made, i am not fond of magic smoke! I have only done a few charge cycles on this pack, it has run without a hitch and as i am only charging at 12 amps with the pack for charging configured by my series/parralel changer as a 6s 48ah that equates to 1/4c so i dont see why i cant leave it unattended, i have not done so yet but my confidense is rising, nothing is getting warm other than the power supply. It is a 350w one, i have pushed it as far as 440w, it handled this for half an hour, it is back down to 350w now, i pushed it to see if it had power in reserve to ensure i was not thrashing it running it at 350w continuously. All my individual packs where charged seperately before the bike was assembled, none of the packs showed any anomilies and the balance has always remained perfect. The setup is basically as simple as the Lifepo4 battery and charger i have on the wifes bike. A full charge from bone empty would take around 4 hours.
I do need to rebuild the charger as the heat from the power supply is being pulled through the icharger by its internal fans, i need to partition the box so each has their own air flow and vents to prevent this.

Simon.

[hjns]

I read the whole thread and I continue to be amazed. Very professional work. Well done!
If you push the motor hard, does it get warm?