Hardtail, On/Off-Road - 4.2KW - First Build

I'll grab a snap of the torque arms when I get home. Hose clamps aren't perfect, but they certainly work and I'm not worried about the motor falling off. I wouldn't be stressed about condensation in the motor, just don't ride through slush that's up to the axle. I would be concerned that you're not going to get the power/range you need from Headway's in those sorts of temperatures. Capacity drops WAY off.

Heating the controller is probably not required as long as you're starting your journey with the bike at a livable temperature and it never gets cold soaked. Otherwise I suspect you could have issues with capacitors if the internals actually reached -30 degrees. So far as I'm aware there's no electrical reason that a very cold motor wouldn't work fine. However you might experience issues with bearings, electrical insulation on wires, adhesives on the magnets. Just in general it seems pretty damn crazy to ride in -30, especially on something that could very well leave you stranded.

There's no way I would be running those cells with no BMS.
 
I think I'll design something that can clamp with bolts to the frame, rather than hose clamps but curious to see your design. I tend to ride in very deep snow... but can avoid the deeper bits if need be, I mean it won't be 'slush' ever up to the axle, but fresh powder which probably wouldn't be as bad, especially with some grease/silicone in the axle opening there.

Are headways really that bad in cold? Even with some electric heating pads and insulation?

Maybe I won't ride in sub -20 very often with the e-bike, save it for the pedal bike which I can fix basic things on the road/trail and won't leave me stranded.. but I'll see how it fares once winter comes around, too many people just hide indoors all winter here but for me that's impossible when it lasts 7 months!! Cold is nothing if you are prepared.

Hopefully the bearings are good quality, supposedly upgraded in the H40 series vs H30 crystalytes.

Hmm, a lot of people seem to think BMS is a good idea, but the seller I'm dealing with convinced me I could care for these sells fine without a BMS as long as I treat them properly. Supposedly he charges and balances all the cells before he ships them out, and is supplying a charger that will stop at the exact high voltage. I can set a low voltage cut-off with the CA, I will get a single cell charger as well, and top off the cells from time to time. Perhaps get a set of individual cell monitors too to keep an eye on them.
 
Could you name this seller? I would parallel them in 6P config first and charge them all to 3.65 before I did anything. The voltage below that doesn't really tell SOC.
otherDoc
Then I would use either a BMS or a 12S charger to charge after a ride. LVC either with BMS or Cellogs with a buzzer at about 3.0 volts.
 
Kyle201 said:
Yup, the seller is Maxwell. Seen him on here selling stuff and whatnot.

Here's the info he gave me on caring for headway cells with no BMS, anyone feel free to check it out and tell me if it seems proper and accurate! Seems pretty comprehensive.

http://sleekupload.com/uploads/5/no_bms.txt
Click to expand...
I just read through that little "treatise" on no BMS and I don't accept it. I have used Signalab BMS for years and they do the job. dnmun has some even better ones cheap. I would not trust the APM at all. I would use either a good BMS or a RC charger with balance and a good meter like a Cellog for LVC with alarm set. LiFePO4 like headways really need to be balance charged. They do not work like LiPo.
otherDoc
 
Alright... thanks for the input otherDoc.

Anyone else have any opinions on going without a BMS with this setup, or opinions on this set of guidelines I was given for going no BMS..?
 
Lithium batteries of all types need to be balanced. You can live without a dedicated BMS is you become the BMS yourself, checking the balance of every cell before and after every charge. It gets tedious, but some of us do. I do, for good reasons, but I wouldn't recommend it. BMS are cheap enough and make life easier.

Anyone who suggests you can use a lithium battery without balancing it at least occasionally should be ignored as a fool.
 
Drunkskunk said:
Lithium batteries of all types need to be balanced. You can live without a dedicated BMS is you become the BMS yourself, checking the balance of every cell before and after every charge. It gets tedious, but some of us do. I do, for good reasons, but I wouldn't recommend it. BMS are cheap enough and make life easier.

Anyone who suggests you can use a lithium battery without balancing it at least occasionally should be ignored as a fool.
Click to expand...

I figure that's basically what I would do.. maybe a BMS would just make life easier, but how hard is it really to balance yourself. I'm pretty new to all of this, batteries, electricity all of the electrical aspects...

So I've heard of some other people running headways with no BMS, what does a self balance require, basically just get a single cell charger, and a multimeter.. top each cell off and check the voltage.. every month or so?

What about some individual cell monitors hooked up, is that a good idea, make balancing and keeping the pack healthy easier right?

My seller has me really convinced I can run it without a BMS, supposedly he charges tests each cell and rejects any defective ones before he ships them out, and says that once in this state they should stay balanced a while.
Maxwell said:
because the headway cells are very large capacity cells at 15AH each, the batteries literally balance themselves, so in the case of a 72v pack the charger is pumping 87.6v throughout the whole pack, when any one cell has more electrons then the other, to a certain extent those electrons will transfer over to the cells that have less electrons thus balancing each other out. it also helps that it is a straight series configuration as opposed to a series/parallel configuration. (that being said it is no problem to have a series/parallel configuration using the headways 15AH cells without the use of a BMS for EBIKE SETUPS,,,for the much smaller AH cells at only 3ah it is problematic as they are simply too small and cannot withstand much of an imbalance)
Click to expand...

Seem accurate?
 
Not really. I run AMP 20 A123 pouches and they are high quality. They must be balanced every charge. I believe Headways are also high quality, but also must be balanced at first, and then at every charge or they will get out of balance and be damaged. It is easy to balance them automatically with a good BMS or a good 12S charger like the Thunder. To not do so will cause a short life. Also why waste time hand balancing when for 30-40 bucks you can get a good BMS. Or 90 bucks for the Thunder charger.
otherDoc
 
Kyle201 said:
Maxwell said:
because the headway cells are very large capacity cells at 15AH each, the batteries literally balance themselves, so in the case of a 72v pack the charger is pumping 87.6v throughout the whole pack, when any one cell has more electrons then the other, to a certain extent those electrons will transfer over to the cells that have less electrons thus balancing each other out. it also helps that it is a straight series configuration as opposed to a series/parallel configuration. (that being said it is no problem to have a series/parallel configuration using the headways 15AH cells without the use of a BMS for EBIKE SETUPS,,,for the much smaller AH cells at only 3ah it is problematic as they are simply too small and cannot withstand much of an imbalance)
Click to expand...

Seem accurate?
Click to expand...

Nope. His statement is 100% wrong. Lithium batteries can not self balance, they won't share electrons with the other cells the way NiMH, NiCAD, or SLA do.

Balance must be checked every charge. With good matched cells, you won't need to make any major adjustments very often, but you will need to make them from time to time. There is a real danger of large fire if your pack is charged while imbalanced. The voltage tolerances are tight. Max charge is 3.65 volts ± 0.05v. Get one cell a little off one time because the pack wasn't balanced, and it's a potential fire risk every time you recharge it, regardless of whether it ever gets overcharged again.
 
Agh! I hate getting conflicting information.

Looks like I might just go for the BMS and be safe.. thanks for the advice guys.

Anyone have some input on oil cooling? Type of oil, volume etc?
 
Fellow Albertian here.
I ride in Calgary year round , all winter except days after snowfall and when temperature dips below minus 20 C.
But I ride Tidal Force ebike - legend for reliability, USA-designed and built in USA built to last.
In cold choice of cells in your battery is crucial, my Tidal Force is powered by A123 12S 36V battery, no need for crazy voltages here.
TF is my winter ebike which gets a lot of beating in deep snow, salt, gravel, ice, etc.
Tips for riding in winter?
You better have RELIABLE ride in winter conditions, I cannot stress it enough.
Reaching speeds in winter where?, on icy roads? gravel spread? So speed is not really my concern in winter, but how to avoid salty mist, how not to ride close to cars.
Again reliability is a must, in -15C , example?
IN minus 20C I cannot stop and push shoddy cheap connections, because they got "loose" , there is not such thing like "loose" connector on reliable ebike.
To give you idea about reliable hub motor here are the pictures inside my TF motor after 24,000km of riding in winter conditions.
Grey plate you see is the heatsink - yes controller is built into motor for rock solid reliability.
 

Attachments

  • Tidal Force ebike motor 005.JPG
    Tidal Force ebike motor 005.JPG
    76.4 KB · Views: 1,527
  • Tidal Force ebike motor 002.JPG
    Tidal Force ebike motor 002.JPG
    78.3 KB · Views: 1,527
Hi Mate,

My 2 Cents,
Some easy ways to get the torque arms done, is get the frame dropouts removed, and get two flat laser cut dropouts welded or glued together, that way they are about 1cm thick solid steel. Paragon steel works and nova cycles sell them.

I've got a 4080, and 4060 on 84 Volts... IMO The 4080 is too fast, It went 58 MPH on a 26 inch rim. The 4060 is just as silly but a little slower, but it still pulls harder than a moped or electric motor. I doubt you would have time to change gears fast enough to keep up with either of these motors, unless you going up Everest

On the flat. 300-400 Watts acceleration you can put some human effort in, but no way 4 kw.

I think 600-800 Wats is probably a good trade off of range, high speed, hill climbing, etc...

Good luck!
 
Thanks for the input dachopper.

I only have a removable dropout on one side of the frame.

But now I have decided to go with a new controller.. I was very interested in the adaptto setup, but they don't even respond to emails apparently, plus I cant imagine they will have as good of support as Grin in Canada. So I'm probably going with the grinfineon 40A controller with proportional regen now.

Thinking instead of the effort of making custom torque arms, with <3KW now, I'm going to go with just 2 Grin torque arms, and also a third arm that bolts onto the brake mount.

I also probably want to go with a BMS now.. but I'm not sure what one will be best. Do all BMS's have to be soldered on, or can they be connected in less permanent ways? Looking also at something like a cell checker: http://www.hobbyking.com/hobbyking/...al_Battery_Checker_With_Balance_Function.html, otherwise what is the best BMS for LiFePo4 /headways?

Would something like this be okay instead of a BMS, assuming I use well matched cells and keep an eye on everything..?
 
Sorry but those cell checkers only make sense if the cells were balanced in the first place. That still means either a BMS or a Balancing charger. The less costly way is a BMS. Check with dnmun and see if he has one to sell. Otherwise for 12S use a Thunder 1220 for about $90. A BMS should be around 40-50 USD. Then, to make sure these products are working (particularly the BMS) splice another set of balance cables in to check with your Cell checker. There really is no way out unless you don't care about early failure of the battery.
otherDoc
 
docnjoj said:
Sorry but those cell checkers only make sense if the cells were balanced in the first place. That still means either a BMS or a Balancing charger. The less costly way is a BMS. Check with dnmun and see if he has one to sell. Otherwise for 12S use a Thunder 1220 for about $90. A BMS should be around 40-50 USD. Then, to make sure these products are working (particularly the BMS) splice another set of balance cables in to check with your Cell checker. There really is no way out unless you don't care about early failure of the battery.
otherDoc
Click to expand...

Well, my cells are supposedly balanced by the seller, he told me he does this before he sells any of them, and also removes all the B grade and defective cells..

and did you look at this particular cell checker, it has a 'balance' function.. though I will likely still get a proper BMS in any case.
 
Yep I have some Battery Medics that work similarly. They will balance but it takes quite a while. They also only balance "down" but don't charge. Again, useful but not something to replace a BMS or a 12S charger.
otherDoc
 
Hey guys. So I've been waiting forever for my vendor to get his stock in, but I should have all of my parts soon. I will be using a BMS.

Started trying to plan my battery box with a quick coroplast mock-up.. Going to attempt to build the final version with ABS plastic.
I can only fit 18 cells inside the triangle, and want to put the other 6 below the bottom tube for good center of gravity.

Seems like I can go about only 3 cells wide in order to have the box fit between the crank arms. Max width between crank arms is about 5 - 3/8", with 3 cells wide being 5", That leaves me about 1/8th or 1/6th for the side covers. I was hoping to be able to insulate or even install heating pads in the box for winter at some point but I feel like there won't be too much room for that now with only a 1/16th to 1/8th max space between the cells and side covers. Anyone have insulated or heated boxes?

So I want to use the thinnest ABS that I can get away with without it being too weak, suggestions? I was thinking 1/8th thick for all the horizontal panels, and then 1/16th for the side covers. Thoughts on ABS thickness?

I've never done anything electrical before so please offer me suggestions on anything at all about what I'm doing!!
 

Attachments

  • 123.jpg
    123.jpg
    150.3 KB · Views: 1,391
if you have never done anything electrical how can you decide that lifepo4 cells will balance themselves or that you can balance them? what a waste of good batteries. and they cost a lot more than a BMS but you got all kinds of EXPERTS here to tell you how you don't need them.
 
Kyle201 said:
I've never done anything electrical before so please offer me suggestions on anything at all about what I'm doing!!
Click to expand...

These batteries hold a lot of charge, and you can get quite a shock if you're not careful, not to mention damaging batteries and other components, so be careful.

The good news is that most people on this forum are helpful and can walk you through wiring up your batteries and bms. Just post some pictures and ask if it looks right. At these voltages you can't safely experiment if you aren't absolutely sure about what you are connecting.
 
Good advice.. I'm a tad worried to be honest with no experience wiring... but it seems pretty straight forward with the headway stuff, especially when using the connecting blocks and bus bars. Is there special types of rubber gloves or something to protect against shocks or burns in case something did go wrong?

Will post progress on battery box and wiring once my ABS plastic and BMS arrives.. I've seen people connect BMS and other devices to the battery terminals with either ring terminals or solder, which is better?

Anyway, I have most of the parts for my build now.. slowly making progress, but already running into some issues.

Built up the wheel myself, with some nice Sapim 12g spokes, laced to a beefy 700g 24" crystalyte rim with 30mm inner width. Had to bent the spokes a lot to get it laced, thinking they would straighten right up like a normal bicycle wheel.... but as you can see they're still pretty bendy. Anyone think that will be an issue?

Also swapped my narrow light XC front rim with a nice wider DT Swiss DH rim.

Here's two of my nice faaat mountain and road 24 x 3.0 rear tires, they just fit with no rubbing! :) tread clearance is huge, but the sidewall clearance is tiny.. I'll have to see how they ride first and if they rub from bike flex, but thinking I might want to file back the protruding welds a little bit, but not sure if that will compromise frame strength significantly. Anyone see a problem with doing that?





I also purchased one of those torque arms that bolts onto the rear brake adaptor mount, but it seems the angle is completely off from my drop-outs. Seller ignoring my email about it.. Thinking it might be worth it to file down the one side of the hole, to match my dropout.. and that way at least one side could have full contact, with almost none on the other side. Should still add some security that way, yes? I'll be using two Grin torque arms on top of this, but want further security. Thoughts?

 
Crap. As I should have suspected the slick 24 x 3.0 tire shown in the previous pic stretched a little wider just from holding air, and now slightly rubs on my seat stays.

Looks like I should just file the protruding welds down a little bit, anyone think this would weaken the frame much???

 
Nope, if you look at the pics I just posted you can see that the tread has tons of clearance, but it's the sidewall that's rubbing there.. bit of a bummer.
 
You must log in or register to reply here.

Similar threads

M
Cassette recommendation for hardtail MTB (off-road)
Replies
5
Views
350
Nomadstealth
N
ColinC
Unicorn search? Off-road fat step-through + internal hub?
Replies
8
Views
358
ColinC
ColinC
Tplayer42
29" DD hub with 150mm dropouts
Replies
0
Views
209
Tplayer42
Tplayer42
jetzki
    • Like
Help me choose a motor / battery set up :)
2
Replies
26
Views
738
jetzki
jetzki
Cyb0rg d3ck3r
New Fat Tire BBSHD Build From Scratch! Need HELP Selecting Components!
Replies
16
Views
539
Bullfrog
B
Back
Top