Danny's Custom build thread

[dcastillo]

Thought I'd make a thread just for my build im thinking of starting. Havent been to active on here lately, just so much going on with 3 kids...
Attached is my current Kart, bought it used and modified it for electric... It works fine, uses a 2Kw 30yr old golf cart motor and 6 batteries. Surprisingly I can ride it with all three kids, very tight squeeze. But it wont last much longer without money, rear axle is a hack job, rims are welded to it... once the treads gone, its going to be 150-200 to redo the rear end, not worth it to me

My plan is:
-main driving is 70% pavement, 20% light trail/grass/dirt, 10% medium trail (ditches, mounds, roots, etc)
-something about 12" longer, and 6-10" wider then current cart
-I want a single seat in the front and two seats in the back
-to keep size down, back seats may need to be mounted over tires (putting them about 18" off ground (dont think its a huge issue since performance isnt key here and the batteries will be low and forward on the cart)
- Batteries mounted next to driver
-electronics between rear passengers
-solid axle with ~16" tires (similar to what I have now)
-front tires around 12-14" with manco style springed spindles
-steel frame with square tubing for easy welding
-disc brake
-etek motor (need around 4-6Kw, this thing will be heavy)
-reuse my current 200A kelly controller and 250A E-Stop
-will definitely need to add reverse on this beast

sadly, due to finances and time, this build may take 6months, but thats OK.

Just wanted to run this by some of the more experienced builders for feedback. Does my plan seem reasonable? Has anyone built a three seater like this?
I plan on starting the concept drawings in the next few weeks and will post them.

thanx
Danny

 

[firemanjim]

You do know that you can change the tires with out having to take the wheels off the kart, right? What it the little purple "racer"?

 

[dcastillo]

purple racer is a honda minimoto I bought off craigslist, then stripped it down and repainted purple/silver for my daughter. swapped out the slicks for larger offroad tires. Currently its a single wheel drive with 500W. But I may eventually modify it to a solid axle with 1000W...

As for the tires, there's just a lot of small things wrong with the kart on top of the fact its to small for the 3 kids and I, including the key slots on the axle are worn and the sprocket and tires can rotate about 30 deg on there own... Just too many things wrong with the kart to want to put any more money into it.

 

[itsid]

can't tell from the pics.. and cannot seem to be able to recall.. is this a 36V or 72V set up?
the latter will work nicely with 200A for 4-6kW, 36V might cause a bit of a problem though.

if the kelly doesn't allow for a higher voltage it might not allow for a constant amperage of more than 100 Amps maybe even less that that (IDK, but that's easy to check with the manual) so a 4kW motor might already be stretching it.

as long as the kids are small enough, having them in front of you might be the more thrilling riding experience to them, plus you can keep an eye on them while you drive the kart, keep them away from a battery, any electronics even powered wires, and the weight distribution might even be better than the other way around
Only downside, the kart needs to be wide enough to have your legs between the front seats, since "long enough" isn't exactly an option I assume

Or you can do an 'adult' two seater but instead of one passenger seat you can mount two in a row slightly offset perhaps, the smaller kid can sit in front or in the back depending on how you set up the leg room, seat sizes etc.
Still a good weight distribution and no need to make an extra long or extra wide kart,
just a little longer and a little wider should do.

depending on how old your kids are and how "evenly" their spaced age-wise you could even have the biggest kid sit slightly behind you and line up all three in a single row next to you, each sits between the thighs of it's bigger sibling (that'd need custom seats of course) but it'll result in a relatively compact kart in the end

'sid

 

[dcastillo]

my current setup is a 36V, but the controller can do 48V which is the plan. If i remember correctly it does 80A continuous and 200A for a minute which should be fine for a 4KW watt to start with (upgrade the controller later) I dont need the full 4KW of power anyway, just driving the kids around mostly.

Interesting though on putting the kids in the front... I will ponder that a bit, only down sides I see are the cart may need to be wider since my legs will be between their hips, I can compensate by moving the pedals far forward so my legs are straight and under the steering wheel, but then they couldnt drive... but it would allow them to be lower to the ground (not over the back tires). If i did go that route, the only plac for the batteries would be over the rear axle, which I dont prefer..
(decisions, decisions)

And because im building from scratch, I will have a full safety cover over the motor, battery and electronics...

as far as stacking them, thats how we ride now, 7 yr old sits next to me, 5yr old in front of him and 1yr old on my outside leg... its one crammed Kart!!!!!

thanx for your input, thats exactly what I want..
-Danny

 

[dcastillo]

After thinking about hte options, I think Im going to stick with the kids in the back, jsut adds more room for everyone, puts the batteries in the front and keeps the cart size down since they will sit over the rear tires.

below are some rough concept drawings... (been awhile since I used that tool)

I started out trying to make it in the proper dimensions but it didnt work..
my plan is about 6" wider and 10" longer then my current cart...
15" rear and 12" front tires
back seat will be set just above the rear tires, and around 40" wide should fit 3 kids easily (with lips on each end so the dont fall out )
Rear seat will mount with larger tubing over smaller with locking pins to easily remove
front seat will have angle iron welded to it and slide along square tubing (not shown yet) and use locking pins to easily move the seat forward and back depending on the driver
controller/electronics probably right behind the driver seat since middle passenger will always be the smallest
probably standard brake setup with solid rod to a disc brake


let me know what you guys think
Remember this isnt a performance cart...just want something fun to drive the kids around on and to the park. Although I will be fishtailing on loose ground without the three kids on the back


next questions: material
-Im thinking 1.5" tubing for the main parts and 1" for the rest... not sure the wall thickness though
-Also, my current cart has 3 bearing hangers, should I add a third to this one as well do to all the weight?

thanx
Danny

 

[OzFab]

Im thinking 1.5" tubing for the main parts and 1" for the rest... not sure the wall thickness though

Material size sounds ok, wall thickness in the range if 0.065-0.085"

Also, my current cart has 3 bearing hangers, should I add a third to this one as well do to all the weight?

It couldn't hurt; in fact, it's a good idea...

Speaking of weight, if I may suggest, move the rear seat forward a tad; sitting over the axle may make the steering a little light; sitting a tad in front of the axle will improve handling...

 

[dcastillo]

thanx, I was thinking of moving the axle further back towards the rear of the frame as well..
Once I get the main part of the frame welded, I will lay the seats in to get a better idea of leg room and stuff.... i will try to get the back seat as far forward as I can

 

[dcastillo]

hoping to finally start laying out the frame soon..
Question:
whats the best way to figure out the width of the main frame to fit it to the axle?


Im thinking I will need something like this

http://www.bmikarts.com/Deluxe-Flexpruf-Steel-Step-Down-Axle--1-to-34-Standard-_p_3264.html

which is a 42 or 44" x 1" axle with 3/4 step down, threaded.

If I understand correctly, this would allow me to just slid the the hubs on the end with keys and tighten the nut on.

What Im not sure is how to determine the width of the frame, do I need to buy the axle/rims/tires first and assembly them to get the inner dimension?

thanx
danny

 

[itsid]

Not really.. the Azusa flexpruf have two inches of step down per side.
SO a 42" axle has a shoulder to shoulder width of 38" and the 44" of 40" ..

substract another three inches (for spacing) and you know where your pillow blocks would be and work from there.

'sid

 

[dcastillo]

awesome, thats what I wanted to know
just to be clear, is that 3" per side or 3 inches total
(meaning for a 44" axle, 40 inch shoulder so should the frame be 37" or 34" wide?)

thanx again
Danny

 

[itsid]

I'd say 3" in total should be sufficient, just to clear the wheels enough,
4" maybe to have a bit wiggle room in case you need it (and you'd have a nicer number)

three per side would be a bit much if you ask me, it's a flexpruf axle alright,
but it's still a lot of weight on just 1" of material, so the pillow blocks should be as close to the wheel as possible if you ask me

'sid