Trike Build: 500w Geared Rear/9 or 12fet Controller/20" Whee

[dalfollo]

What a great resource this forum is!

I am looking to convert my Trident StowAway trike to an e-trike which I expect to weight ~250#/113kg total (including new wheel, SLAs, +rider).

I think I am a more conservative rider, where 20mph is a pretty good speed; bursts to 25 would be great (but short). I understand there would be a nice jump in speed when I move from a 36V/12ah SLA (to start with), to a 48V lithium (once i understand my riding habits and expectations).

Most of my riding will be bike trails and around town, though I have a lot of hills and even mountains I would like to put this to work on, so I think I would lean towards more torque than speed.

I love the idea of programming the controller for legal levels (if i understand I can do that). Then later reprogram to allow me to set the controller for hilly or flat terrain, or better utilize the various settings. I plan to pedal often, but will appreciate the motor leveling the playing field for me with hills, wind and friends in faster MTBs. I'd like to go bike packing with a trailer in the front range foot hills and some of the railtrails in Colorado.

From the EM3EV website I find their 500/1000w upgraded geared MAC motor and programmable controllers most intriguing. Paul suggested a 8T motor in a 20" wheel on 36V would provide close to 32km/h or 19.88mph max speed.

While I like that the max speed is legal, I would prefer to have 'extra power' and reprogram the controller to control speed to 20mph only when needed. Does it make sense, in the real world, to go with a faster motor (a 6T winding would be ~+4mph)...or should i just mosey along with an 8T on 36V, and then get some speed once I 'release the green' for a great lithium battery?

To match that motor is it too much to go with a 12fet controller, or is 9fet a better balance? This would be a programmable IRFB4110 controller, that I would likely tie to a CA unit. I want my gear to last, and want to take care of it.

Thanks so much for any clarification on matching the components, and helping me build this out. Hope it helps the next one working on a trike.

Stephen

 

[dogman dan]

http://www.tridenttrikes.com/stowaway.htm

Doesn't EM3ev also offer a three speed switch on the controller?. There's your slower and more efficient mode.

In a 20" wheel, a regular dd motor would climb well too. And could be given 2000w with no real danger of a meltdown. Still controllable by the CA, amp limiting to legal wattage for your area. Perfect match for a 48v 40 amps 12 fet when you want to let er rip.

Just saying, when the hill gets steep, more watts is more.

 

[dalfollo]

Thanks for the suggestion. I think I am looking at geared motors for the freewheel element, and somewhat lighter weight.

As I look around and see more info, I think I may need to rethink towards a 10T motor with more focus on torque, than on cruising with the 8T. The speeds appear to be in the window I expect, especially with 48V. Some of the roads, paths, and mountain roads especially, I would like to do are very twisty/curvy, and I think the 10T might be more appropriate.

A 10T appears to match to 6fet and 9fet, though the site recommends '10T – OK but can be very hard on gears and clutch'. So does that mean a 500W/10T w/ 9fet controller, a likely combo for these uses?

I can see the draw to upgrade to lithium!

 

[dogman dan]

In a small 20" wheel, a 10t should climb some damn steep hills. I would think that the smaller wheel would also lessen the strain on the clutch. But again, I'd be doing dd, because of my flaming climate. I don't pedal without the motor, ever. I have zero use for the freewheel. If I need to hypermile, I just ride using 100w. A decent size battery would last 8 hours at 100w.

Lots of emphasis on speed on this forum. I'm a bit kooky, and prefer a decent pull from a slower motor, wasting less of my battery into heat on the hills. 10T would be my choice, and 12t in a 26" wheel.

Not that I hate fast, one of my bikes for racing went 47 mph. 15 mph plenty fast on my local dirt trails.

 

[schosser]

You may want to call Tom at trident trike.

I had the opportunity to discuss the engineering behind the trident e-trike with him recently and was very impressed with his knowledge and experience regarding motorized trikes in general. He is more than willing to share his knowledge.
He indicated that trident may be offering a etrike retrofit kit in the future.
My experience with testing both a standard stowaway 2 and an E-spike was very positive. The e-spike really was easier to pedal with the motor off then my wife's standard terra trike rover 8. I believe pedal assist technology lets you have the best of both worlds. I can easily see 45 mile + range at a pedal assisted speed of 15-20 mph. Motor only at 15 mph would be 30+ on moderate terrain . And it's easy to transport!

The stowaway 2 surprised me with its build quality and handling. I'm now thinking about replacing my older catrike trail with a stowaway 2.

 

[dalfollo]

So...I have ordered the following via www.EM3EV.com:

Motor: Mac 10T 500w/1000w (upgraded)
Controller: 9 fet 30A (36-52V IRFB3007)
Other: 20" rear wheel install, 255 rpm, 255# total weight: rider, 3x12v SLAs, trike

I am planning to start off with a 36V SLA(s) (12-14ah), then move to a 48V lithium, once I understand better my riding habits and expectations, and can review the options.

My next question(s) is (I 'thought' I had some project batteries already available...):

What do i look for specifically, in the battery specifications, to maximize its potential for an e-trike use? Are there features/specifications I should avoid?

Here are a couple options I have identified on Amazon. These are running about $30/battery for 12V 12ah (or 14ah) SLA delivered to Colorado.

A) 12V/12ah, Model: UB12120, - $27.40 Linky
B) 12v/14ah, Model: AJC Brand - $29.43 Linky
C)12/12ah X-treme Scooter Battery 3-pack Model: $80 Linky
D)12V/12ah x3, MaxLife Battery/Invacare Zoom 3-Pack, $80 Linky

Do you have any suggestions regarding an online 12v SLA store or resource?

I will likely charge this with a 'Save-A-Battery', or will review any recommendations.

Thanks so much!

 

[GiantEV]

What is your battery budget?

How far do you want to go on a single charge?

 

[GiantEV]

I want my gear to last, and want to take care of it.

What a lot of people do, including myself, is start off with SLAs with the intention of upgrading after a while, and that sounds like your plan as well. When they finally upgrade to lithium they wish they would have started off with lithium and skipped SLA. If you look at 36V/12Ah of SLA you're almost at $100 for just the batteries, then you have the cost of the charger. That's a lot of money that could go towards a lithium purchase now. The performance of SLAs degrades quickly, and they have a lot shorter life than other batteries. The other thing is weight and space. The SLAs are going to be very heavy compared to the equivalent lithium battery capacity. They will also take up more physical space, so you're going to have to reconfigure how your batteries are secured to your trike when you switch out the SLAs. You mention that you want your gear to last, so if that's the case I'd seriously reconsider starting with SLAs.

I understand there would be a nice jump in speed when I move from a 36V/12ah SLA (to start with), to a 48V lithium (once i understand my riding habits and expectations).

Why do you want an electric trike? Where do you want to ride? What distance? These are questions you should be able to answer now, and those answers can help people recommend a good battery. From what you've said so far this battery would be a good place to start:

http://em3ev.com/store/index.php?route=product/product&path=35&product_id=128

This is for 50V/10.25Ah. It's $380 and is a good, reliable battery. If your budget is higher I'd go for the 14Ah option.

You should be able to tuck this behind your seat on your trike, or mount it to a rack over your rear tire. I put mine behind the seat on my trike and it handles much better that way.

If you're still stuck on the idea of SLA, just remember that they will lose power when sitting there a lot faster than another battery chemistry, and it's easy to beat up your batteries by letting them get low all the time. Then you get to explain to your wife why you need to buy another set of batteries and charger when you just bought these only a few months before that. She may even ask why you didn't just buy the lithiums in the first place.

I'm just speaking from experience and trying to help you out. If I could go back I'd personally start out with lithiums and skip the SLAs for all the reasons mentioned above.

 

[dalfollo]

Thanks for the feedback. Here is some follow up:

Schosser - I have spoken with Tom, and it sounded like his e-trike upgrade kit won't be available till later in the summer. I absolutely love my StowAway, and it has done everything I have asked of it. I have added some review info on www.bentrider.com; it really is a perfect trike for anyone that wants a reasonably-priced and very modifiable trike.

GiantEV - I do understand the math and what to expect from the SLAs. Lithium is just not happening right now. The battery you suggest is $380 + 100 SH = $480. Right now I should be able to get three 12v/12ah SLAs delivered for less than $100; with a top of the line 'Save-a-Battery' battery charger/trickle-er/anti-sulfur unit ($100). I already have the bag and connections.

With current timing and budget, the SLAs are buying me time to review options, understand better how i am using the trike (with power), and can then be used in the next two e-bike builds I have planned.

Thanks again for the feedback.