48v grampa trike build

oobagooba

100 W
Joined
Sep 16, 2014
Messages
138
Location
us
Updated the title as the parts are in and it's moving forward. Will post the progress even though i'm probably the only one building a mobility trike for use around the yard...

I'm looking to propel my adult trike around a 1/2 acre with a few short, steep grass hills.

Looking for cheap, simple, rugged, max climbing at 48v. It is an old granny trike & i don't care if it tops out at 5mph long as it climbs strong.

Will this kit work? Any stronger/cheaper/more reliable options out there?

BPM front 201rpm no halls https://bmsbattery.com/ebike-kit/340-bafang-48v500w-bpm2-front-driving-hub-motor-ebike-kit.html
KU123
Torque arms + throttle
$250 shipped


Trike has 24" rims I can build the front wheel.
I have a battery 13s4p 25a bms 5c 18650s
Trike + rider= 250lbs.
Trike is geared down but minimal pedal input
 
The 201rpm motor should provide plenty of torque and top out close to 15mph in a 24" rim.
 
Thanks i meant the verb sense as in go, as in will this thing go up hills with a ku123 and last for a while at 48v,
I like that it all comes shipped for $250 just wanting to know if there is anything better out there for the price?
 
Front wheel drive up grassy hills sounds like a literal no-go.

2 x 24V MY1016z3 350w gear reduction motors = $110
2 x spoke mount 32T fixed sprocket = $40
24 - 36V 28A controller = $12 (can upgrade to 40 - 50A controller if needed)
410 (415?) chain = ~$10
Throttle = $13
Angle iron for motor mounts & bolts etc. - $15 ?

$200 .... (Batteries extra)
24V gets you 700w dual rear wheel drive @ 10 mph
36V gets you 1050w dual rear wheel drive @ 15 mph - (speeds are rough estimate)
48V through motors in series gets you 700w dual rear wheel drive @ 10 mph

Sprocket sizes available 28 - 56T ... can be geared lower for more torque!
Gives you posi-traction and motors act as moderate brakes going downhill = not freewheeling!

24V or 36V controllers available with reverse!!!

Should have enough power to pull trailer up hill ... with treaded tires!

Gear as low as possible if you decide to mount a plow!
 
Oops!
Sorry, missed that you had already had 48V battery.

Use a 48V brush controller with the 2 - 24V motors run in series!
 
Don't forget that you need a LCD with the S12S. If you don't want PAS, the KU123 would be cheaper.
 
I'm just curious what brand of trike that is. Looks identical to the half a trike that went into Amberwolfs St Bernard Cruiser.
Because of my job, I need to learn as much about all kinds of trikes as I can.

A slower wind motor like that one is a good choice, but for the most power the largest motor you can get would pull a lot harder. But no way be cheaper. Put some big knobs on the front tire to help with the slippery grass.

Modifying the fork so the trike took a 20" wheel would be the way to really maximize your torque, with limited power.
 
oobagooba said:
Yeah, it's one of these.
file.php
Looks like rider weight is >75% on the rear wheels.
Front drive might be OK on level pavement ...
Any hill might leave less than 10% of weight on front wheel and "steep grass hills" should prove front wheel drive to be totally useless!

IMO Rear drive looks to be your only workable option.
Dual rear drive and mountain bike tires being ideal for traction.
 
As usual, dogman dan has a good idea. However, if you do put a 20" front motor wheel, you may run out of ground clearance. It will put the front end 2" lower, unless you modify the fork as he suggested. You will need a longer fork. The torque gain may be worth it.
otherDoc
 
DrkAngel said:
Front drive might be OK on level pavement ...Any hill might leave less than 10% of weight on front wheel and "steep grass hills" should prove front wheel drive to be totally useless! Rear drive looks to be your only workable option. Dual rear drive and mountain bike tires being ideal for traction.
The weight of a front hub motor would add some downforce for traction. Mounting the battery towards the front could add some more if you can do so without interfering too much with steering ability; possibly a front basket, panniers, handlebar bag or combination thereof. :wink:
 
Drk Angel. that sounds like a good idea. More work than i want at present, for now it is quick and easy. I will keep rwd as a backup if the front spins out.

Dogman. The pic is from the Internet for quick reference, i was searching Columbia i believe. the frame looks like mine but not the drive. Mine is a Ted Williams 3 speed. I will take some pics

D8veh I'm just using a throttle no pas. also no halls if possible

Does anyone know is the ku123 a good match for the bpm2. No stuttering or cutout, etc. It looks good 12fet and 201 rpm but i have had trouble matching motors to controllers in the past
 
Here are some pics
sears.JPG

3 speed rear w/some kind of "live axle" it drives both wheels
searsgears.JPG

Some notes. It has a long wheelbase with a lot of weight up front.
The rear diff will spin either wheel in the air. The back wheel is probably spinning in the pic, a lot of fun to ride.
I got the gears working with a hose clamp, got most of the bolts and nipples freed up to make it rideable.
It has grease fittings on the bb and shimano hub but not the rear diff.
Sears/Columbia/whoever tried to make the frame stiff with the double down tubes and rear structure but it still flexes. Even after snugging spokes and bearings.
Not bad for gas pipe 1970, nothing like a wal-mart schwinn but 1/4 the price of anything local advertised. I found it at a thrift shop. Next up electrics
 
FWIW, the flexing of your frame is a good thing, as it gives you a little "suspension" vs just jouncing you all over the road on every little deformation of the surface. I originally intended to stiffen the SB Cruiser's frame to prevent twisting, but I probably will not after having ridden it a few hundred miles and felt how it works vs the road surface, and the way it would probably feel without that flexibility would really suck, without full independent rear suspension.


You might want to look at my SB Cruiser cargo trike thread for some other trike-building info; link in my signature.


One note:

I used a heavy (x5304) hubmotor in front, and it had traction, but nothing like having it in 20" wheel on the rigth in the back, with a 9C 2807 in a 20" wheel on the left in back. That gives loads of traction and also minimizes tipping even in high speed (for me) turns, 10-15MPH (maybe more). ;)


Unfortunately it required major modifications to the dropouts, and probably will not work directly like that with your axle/wheel design. It would probably require adding double-ended dropouts behind your existing axle ends, and putting sprockets on the axle ends, then driving the motors via short little chains (see my thread for how mine works). It'd be a lot of work to do that, to keep pedal power while using the "standard" bike hubmotors.


But even just changing to 20" wheels in back will get you a whole lot less tippiness, if you have 26" right now.

If you then put all the weight you can of battery, controller, etc, under the basket forward of the axle, as far out to the sides as possible, it will also help a lot.
 
dogman dan said:
Looks identical to the half a trike that went into Amberwolfs St Bernard Cruiser.

It's basically similar, but unlike mine that uses regular bike wheels in dropouts, his has "single ended" axles that go to a differential, whcih makes doing what I did a lot more complicated (though still possible).

His also does not have full frames around the wheels, just stubs for fender mounts. So those would also have to be built and added, to do what I did.
 
A mid drive would certainly reduce all the efforts to adapt the read end.
A 'side mount' motor might even be an option if it could drive the transfer hub.
http://www.gngebike.com/350w.htm

Then again GNC has trike kits but most of those look like they are designed to drive a live rear axle.
http://www.gngebike.com/trike-conversion-kits
 
The first picture is the trike I wanted a brand name. Tx.

Even if his front wheel spins a lot, he may still make it up the hill. But yeah, bike or trike, anything much steeper than 5-8% will be much harder to do with a front hub only. More pedaling to power the rear wheel has to take up the slack if the front spins too much.
 
I hear you guys on traction and rwd.

Amber as you note my rear hubs and axles are propietary and flimsy for motor driving. The hub is a thin sleeve with a through bolt, one wheel is already getting loose. The rear diff is some kind of sealed limited slip and probably wouldn't last long at 1000w. Good to know the frame flex will help with ruts.

Lew the gng kit looks good. Just more work than i can do, for now i want to get this bike going quick and easy

The new front rim is coming so will proceed with the bpm. I have enough flat ground for a running start uphill. If it doesn't work i know someone wanting a road kit. Then look for a better trike for rwd.

For now this will get me around most of the yard and off my "mobility riding mower" which pretty much sucks. My 48v mtb gets up the grass fine but with my disabilities the trike is a lot less painful not having to fight for balance, etc.

Dan I am gearing the trike way down like my other ebikes, 1st gear is already pretty low so should be able to pedal just enough to keep it moving, at least that's the plan for now. Ebay is great for old $5 chainrings and sprockets. Thanks for the help,
 
dogman dan said:
The first picture is the trike I wanted a brand name. Tx.
I think i found that pic searching for Columbia trikes. I tried finding it again after you asked about it. Of course now i can't find it, sorry about that.
 
IMG_0138.JPG2015-03-21 14.15.43.jpgYou can make it like these and they will climb hill very good but I am not sure it will climb dirt hills very well, it will spin the front wheel a lot on dirt hills.
 
So the parts arrived from bmsb in under a week. I was impressed that most of the connectors fit together as i picked out this kit myself with no questions asked of the vendor. Here is what i got, also the new ebay cog for the 3spd hub at the bottom.
DSCN1924.JPG
With bmsb i got 4 items in the box for the same shipping charge. So i kept it to 4 items, going as cheap as i can with this.
The 22t cog was 10 bucks shipped and worth it, my low gear is 23 inches, same as the triple on my mtb, a big difference over the old 70s clunker gearing that came on this trike.

The extra motor cable wasn't mentioned on the bmsb site, so bonus. Also the display which turns out to be necessary for the controller to power up. No directions but the controller ad page has a diagram, which i needed. Only issue is the cruise wires on the throttle don't fit the controller plug.

Anybody know where i can get one of those little black 3-wire connectors?

Dropouts filed
View attachment 1

It lives
DSCN1938.JPG
Motor is a code 13, which i think is around 230 rpm, not the advertised 201, also the hub is black, not silver like in the ad. Oh well when feeding off the bottom if it works I call it good.
 
You can find those connectors on Ebay. Type in "JST 2.5" to the search.

I'm not sure that the switch on the throttle is suitable for the cruise. IIRC, you need a non-latching (momentary) switch. Don't consider the cruise function unless your brake cut-offs work.

You don't need that LED control panel if you don't require the PAS. You can replace it with a simple switch between the red and blue wires, for which that red throttle switch is ideal. Wire the yellow and brown from the throttle cable to the red and blue, and the green wire to the blue as well. That way, the throttle LEDs will come on when the power is switched on.
 
Thanks for the info i will try doing that, don't want to depend on that cheesy display too long. And i was hoping the throttle leds would light up. good info

Meanwhile i'm waiting on the spokes, so put the old wheel back on. 09 dolphin pack just fits in the front basket
DSCN1940.JPG
The weight up front doesn't hurt the handling of course i'm only doing 5mph


More ebay schwag
tires.JPG
The rim is pretty wide and double wall. The tires are the 1.95 variety, fits the new rim but not the old back wheels on the trike. The trike rims are the 1-3/8 variety, quick trip to google shows the old fractions don't fit the new decimal tires. Back when i was a kid i would get frustrated trying to mix and match old tires and rims, funny it comes back to me now. All this time i just thought it was a schwinn thing but the old sears wasn't immune either
 
How wide is that white saddle and where did you get it?
 
Back
Top