Critique final build choices please! DD Commuter build.

[ivi_3]

Hi Endless-Sphere!

I've been leaning on you all for choices throughout this process while saving up the funds for this purchase. After this long time, I'm about to pull the trigger and just wanted to throw up a wall of information in the hopes that your collective experiences will idiot-proof my purchase.

Goal: Create a bulletproof and fun (aka potential for high speed) commuter bike to traverse my ~20mi round trip commute. I will always be pedaling heavily both ways as I enjoy the exercise. Commute has rolling and gentle hills, nothing above 6% grade and not incredibly long.

Donor Bike: Trek Marlin entry-level disc brake 29er.

This bike is basically non-negotiable as a foundation for this build. It's a good old bike that I used to commute unpowered to work when my commute was only 6mi one-way. With my current commute at a little over 10mi, it's been sitting unattended.

Motor: Crystalyte TC3080 with 7speed freewheel https://em3ev.com/shop/crystalyte-kit. Em3ev 12 FET IRFB4110 Controller https://em3ev.com/shop/12-fet-irfb4110-em3ev-controller-black/

I've chosen a more expensive and more powerful DD motor because of the ease of use and lower maintenance concerns. I want a motor that can handle my commute easily without the possibility of overheating while also having the options of a building a 72v or higher battery later for playing around with speed.

In my previous post (https://endless-sphere.com/forums/viewtopic.php?f=3&t=87009) a MAC motor was suggested for my commute and still isn't off the table persay. I gravitated towards the TC motors because 1) the absolute beefiness and bulletproofness of DDs generally, but this motor specifically, and 2) the possibility of building a future high voltage speed build.

I've taken some pictures of the rear dropouts and am hoping to get your thoughts. The spacing generally looks good to my untrained eyes, but please do idiot-proof me

http://imgur.com/NSHrNjo.jpg http://i.imgur.com/xykn2ZI.jpg http://imgur.com/YI2g4gT.jpg


Battery: a 50v Triangle pack (14s6p) in either 14.7ah 25r or 17.7ah 30q. Charger will be the togglable 52v mini charger from luna.

I plan on running this battery consistently from 80% down to 10-20%. Accounting for the natural degradation of the battery over time, will the the 14.7ah 25r last me hopefully more than 2-3 years commuting ~3-4 times a week? I'm hoping to get a battery that will be able to power a commute even well into 100-200 cycles. Here's the power degradation charts for the 25r and 30q: https://cdn.shopify.com/s/files/1/0674/3651/files/discharge-25r_1024x1024.jpg?7306674405146565693 https://sc02.alicdn.com/kf/HTB11NncLVXXXXX7XFXX760XFXXXS/225565083/HTB11NncLVXXXXX7XFXX760XFXXXS.png

Initially I was planning on building my own battery because it seems like a hell of a lot of fun! I still may build a future battery, but I decided against it for now. I'm a new homeowner with limited time at my disposal and after a spot welder, tight margins for battery purchase through fasttech, battery bros, and nkon, and purchasing accessories, building mine own was going to be expensive. Plus there's the possibility that I might mess it up and be out all that saved cash... Good old risk aversion strikes again.

Because I won't be building my own, I won't be buying a Cycle Satiator. The mini charger options through em3ev are weaker sadly. I'm not enthused at those limited options hence the Luna Charger purchase.


I've made the initial decision to purchase through Em3ev because they are one of the two places to buy a CA3, they have an impeccable record on this forums, they've been incredibly helpful in our ongoing correspondence, and are offering a nominal discount for bank transfer purchase. I'm open to ideas for purchasing elsewhere, but I'm totally comfortable paying slightly more for their reputation.


Tires and Rim: I'll be getting a set of 700x45c Marathon Pluses on both rims. What alex rim would you suggest I have the motor built into so that it matches my current bontrager rim? Pic of the rim with measurements http://imgur.com/4kdpbtq.jpg I'm thinking the Alex DH21 would do nicely: https://em3ev.com/wp-content/uploads/2016/08/DH21.jpg


Accessories: I'll be using CA3 with all the basics. In the future, I'd like to incorporate torque-sensing assist, but that's too much for me right now.

I'd love to pick your brain on adding fenders to this build. My mtb frame doesn't include chainstay or seatpost connections sadly. Any experience would be welcome!

--

Hopefully this post will become a build report and beyond ! Thanks in advance for any thoughts and assistance!

 

[rumme]

I sent you a PM, with some info that may help you.

 

[d8veh]

You need to think about your gearing if you want to pedal. Normal freewheel gears are 14T top gear which is too low. If you're going to build a 30 mph bike, you're going to need at least 48T/11T. With 14T on the back, you'd need 60T on the front. You can get DNP freewheels with 11T top gear from Aliexpress.

 

[rumme]

You need to think about your gearing if you want to pedal. Normal freewheel gears are 14T top gear which is too low. If you're going to build a 30 mph bike, you're going to need at least 48T/11T. With 14T on the back, you'd need 60T on the front. You can get DNP freewheels with 11T top gear from Aliexpress.

Agreed, also if he is looking for a battery pack that will offer the most charge/discharge cycles and be the safest option, Lifepo4 is the better choice.

 

[dogman dan]

Wrong bike for the crown in my opinion, but no reason you cannot use it. The TC 40 will be a very tight fit, but you can usually flex an aluminum frame out 5mm, but no more than that! If you need a spacer in there, you will really be pushing the frame flex to danger zone. No problem for the TC 30.

The crown, and the powerful controller that goes with it, will fairly quickly hammer your battery into dogshit. I would say 30 ah or so would be the right size for the crown.

Even if you tune the system down to 20 amps, it will still pull that 20 amps harder than a small motor will, so you still get a nice fat amps spike your battery will hate.

Change your plan for the battery to something that can handle the crown, then you will love the big hard pulling motor.


All in all, I'm still going to suggest the mac. 25 mph cruise is plenty fast for commuting, especially a 10 mile one way. And that speed is suitable for pedaling too, with the right gearing on the motor and bike. Its not a delicate motor,, its just not suitable for pulling a hot dog stand on a trailer is all. The 500w rated geared motors are really ideal for a commute.

 

[rumme]

ivi3, I sent you a private message with some useful info , did you get it ?

The build you are planning on doing, does not seem ideal for your demands. You may want to reconsider before spending money on the battery/ gearing ,etc. you mentioned in your post.

 

[MadRhino]

I agree with Dogman. You need a bigger battery, or one that can feed more power. Still, your plan is going to underfeed that motor in a 29er wheel. Large wheels like slower motors, fed higher voltage if you want speed. That is because a large wheel does pull more Amps on a hub motor, and feeding more Amps is much harder than feeding more volts.

Another solution is to build with smaller wheels, that is if your BB is high enough to let you. Smaller wheels are also for a big part in achieving your goal of building "bullet proof".

 

[ivi_3]

Dog and Rhino, thank you both for weighing-in! I think you're both right... I'm trying to do too much with this build and would be better served with a MAC.

Will the same class/size of battery serve this motor effectively? Should I aim for the 20, 25 or 30amp controller? Also, I'm thinking the 10T winding is the best bet for versatility but would love your input.

Thinking 25amp is the right choice from this blog post: https://www.electricbike.com/12-kit-power-levels-360w-to-8000w/

Rumme, thank you for reaching out. I'll definitely inform myself more about Lifepo batteries in the future. replying now

 

[MadRhino]

Your battery doesn't need to feed much power to a geared hub, and the geared hub would not survive much either.

The most reliable commuter has a big DD hub in a small wheel. This is making a long term bike, that can survive a lot of abuse, daily commuting at high power and speed.

 

[ivi_3]

Well, the bike that I've got is the one that I'll build around. I'm looking for the best solution to the problem wherein the only fixed parameter is the 29er. I'm hopefully buying from em3ev because of the CA3 availability. Which winding, amperage, and battery combo will serve my situation best?

 

[footloose]

With a small stable of ebikes now... my everyday favorite is a MAC 10 T with 48v 11.8Ah Samsung 30q. Rock solid, plenty of power, just works. Build is old steel mountain bike, 26", no suspension. With terrain and use profile you describe, think it might work fine for your 29er. Motor, controller, CA, battery and charger from EM3ev with zero headaches.

 

[dogman dan]

Mac 10 t will work fine for your commuting needs, and pair well with your battery choice. 20-25 amps controller is plenty for those who still pedal. Pedaling and cruising pulling 600-800w (12-16 amps) is the way to make your battery last, and extend range. 25 mph cruise, or less. The geared motor will perform ok in the 29 er. It will last fine, if you don't overload it with trailers and climb a huge mountain. But it can still run a large cargo bike, loaded to 300 pounds including you, easy.

But later,, you will get the addiction as many of us do, and then you will be spending on a more capable battery, big motor, etc. Essentially, a small motorcycle. For that, a more capable frame too is usually best. Stable of e bikes is where you are headed. One for commute, one for fun is a good start.

Again, nothing wrong with going for that right away,, it just going to conflict with some ideas you have, like a small, light, affordable battery that lasts a long time. Big fun powerful ebikes tend to need new battery sooner. I get about two good years from a pack of RC lipo myself. After that, its not much good for anything but riding low power, or running my mower.

 

[rumme]

For safety and longest lifecycles { at a fair price} , lifepo4 is hard to beat. A lifepo4 battery that is properly taken care of, can last 1000 complete charge/discharge cycles and still maintain a useable output of voltage/amps. For anyone new to this hobby, I think lifepo4 is often the best ,safest and most cost effective choice

 

[dogman dan]

Having had LiNiMnCoO2 burn my garage, Id buy that statement about LiFePO4 being safer.

I thought I had a safe battery, but clearly it was not safe enough.

FWIW,, any battery can burn your house down, if there is a short. so there is no such thing as perfect safety.

 

[rumme]

Having had LiNiMnCoO2 burn my garage, Id buy that statement about LiFePO4 being safer.

I thought I had a safe battery, but clearly it was not safe enough.

Yes, I'm not sure if there has been a catastrophic fire burn a house/garage down, involving lifepo4 battery that was discharged to low . This is what I was trying to convey to the OP in this thread. He is a newbie and it sounds like lifepo4 is the perfect battery for his needs.

 

[ivi_3]

No rumme, you've been trying to sell me on your own used battery/charger combo. I appreciate your enthusiasm at the tech and your own experience with the batteries. However, I will not be buying your used battery from you. Please let it alone and find another buyer.

EDIT: This response was in reaction to a series of escalating private correspondence and is not in keeping with the spirit of the ongoing conversation. I apologize for the poor tone and aggressive messaging. It was done in bad taste and is not reflective of the forum member I aspire to be.

 

[dogman dan]

Lifepo4 would not be likely to burn the garage, while charging, like my battery did. that is true.

I just meant that no battery of any type is perfectly safe, once something mechanical shorts it. Crashes, damage from how it was carried, etc. I had a 12v lead battery burn my truck when I was 19, for example.

 

[ivi_3]

Thank you guys for weighing in on battery safety as well! I've chosen a spot on my back porch that I think will serve! Should be easy enough to waterproof an area. The Luna Safe-Charge battery box (https://lunacycle.com/luna-charge-safe-small-size-lithium-battery-box/) has me gameplanning a DIY ammo box conversion. The hard part will be running the charge line from the Satiator to the box and keeping all parts waterproofed nicely.

The order I've submitted for invoicing to Em3ev could not emphasize more just how risk-averse a consumer I am. It's actually kinda surprising as I don't consider myself that risk averse in most consumer situations. I thoroughly research and try to maximize buying power which usually gives me a good amount of confidence. Not so with this new tech adventure however, even if it makes me pass on potential good deals like rumme's.

Motor: MAC 10T
Battery: 14.4AH triangle pack in 25r.
CA3 with all trappings (except torquesensing) including programming cable.
Grin Satiator

As you can see I've paid a premium for a battery from the most reputable source, with the best Ebike Computer that promotes safe use, and the safest charger that is also versatile enough to power any battery I may make in the future. It's hurts my inner Mr Money Mustache to pay almost as much as a fully loaded BBSHD Luna package, but It is what it is.

One more question: I have ordered the MAC built into at Alex DH21. I did this because it matches the rims that come with my bike, but I'm thinking this might just be an error. The rim sizes don't have to match... The tube I own (which I plan on filling with slime before I load it under a Marathon Plus) will work with a wider rim. The wider rim, either DM24 or MD35, both would work with my current setup correct? Would they be less prone to pinch flats? I've never had a pinch flat as I kept my tire pressure very high when commuting under my own power.

 

[rumme]

No rumme, you've been trying to sell me on your own used battery/charger combo. I appreciate your enthusiasm at the tech and your own experience with the batteries. However, I will not be buying your used battery from you. Please let it alone and find another buyer.

EDIT: This response was in reaction to a series of escalating private correspondence and is not in keeping with the spirit of the ongoing conversation. I apologize for the poor tone and aggressive messaging. It was done in bad taste and is not reflective of the forum member I aspire to be.

Apology accepted. Just because I sent you a few PMS about battery safety, and that I had a battery for sale, was no need for your snippy response. GL with your choice whatever it may be.

 

[footloose]

As you can see I've paid a premium for a battery from the most reputable source, with the best Ebike Computer that promotes safe use, and the safest charger that is also versatile enough to power any battery I may make in the future. It's hurts my inner Mr Money Mustache...

... The wider rim, either DM24 or MD35, both would work with my current setup correct? Would they be less prone to pinch flats? I've never had a pinch flat as I kept my tire pressure very high when commuting under my own power.

I've never regretted the purchase of quality tools from good vendors. On the other hand, I've cursed myself and the vendor many times when I "saved" a couple of bucks buying tools that turned out to be cheapo junk and really frustrating to work with. Not bike related, but I am working on a home deck project now. Decent tools make a real difference in result, and in the enjoyment of build process. Milwaukee Sawzall, DeWalt drill, Bosch jigsaw have repaid their couple extra bucks of purchase price many times over. What do they say, something like "buying quality only hurts once, buying based on price hurts every time you use it."

Re the rim. I think DM24 should work with your bike. I've found DM24 to be a great rim.

Enjoy!