Mini Tesla continued

[itsid]

Wow, those are huuuuge I like em

basically the same concept as headway cells (like the 38210 I mentioned)
large capacity cells, with high discharge capacity and screw terminals on either end.
easy to mount correctly, easy to maintain and replace...

LiPo and LiIon and LiFePo and whatnot are generally the same thing most of the time.
ALL Lithium cells need a cathode of course
most often it's Cobaltdioxide (what is commonly labelled LiIon, still passes as LiPo cell!)
sometimes Ferrophosphate (what's most often labeleld as LiFePo, still is a LiIon cell)
and sometimes it's some other cathode (manganese, titanate, graphite...) which often are just labelled LiPo (since it's some sort of polymer, which it ALWAYS is)

Newest and highest powerdensity are IIRC Lithium sulfur bateries... but IDK if they're available yet.

Anywhoo, prices are more often than not depending on powerdensity and size,
the higher the powerdensity the higher the price (and the lower the weight of the final batpack)

Anyways, cheapest bang for buck (at the price of high weight) is surely a lead acid cell,
it's also the safest thing you could handle (and it's still not exactly safe )
but it gasses out quite gently in case of over discharge and at worst you get a spray of acid
which is still a lot better than a 1300°C flame

Good choice are prefabbed cells from car manufacturers like the Chevy Volt pack FA got.
They're built to a security standard that is way beyond what any of us could satisfy in our home shop.

And lastly home made batteries from the biggest cells you can afford
(regarding discharge not size)
So that they're as safe under load as possible.
backed up with a good BMS installed in a secure and solid way
BONUS:
large cells like those TripleCellMagLite cans up there..
connected via polished copper bus bars tucked away in a clear acrylic container
even LOOK awesome!

'sid

Fun lingual fact: SAFT (which is in fact a french abbreviation here for Société des Accumulateurs Fixes et de Traction)
is also the german word for JUICE (as if someone picked the abbreviation for a reason )

 

[mr kart]

ok I've now started researching different approaches to motor + controller.

• e-scooter controller and motor
• VESC v4 and e-scooter motor
• VESC v4 and RC motor

advantages/disadvantages?
The e-scooter stuff looks heavy but simple and the RC / skateboard stuff looks light (possibly more efficient) but harder to use (mount and program).
I'm perfectly happy to program VESCs as its very similar to miniquad programming that i have done but i don't know if it is suitable. Also they only go up to ~10s. is that a problem? i know that would mean more amps for a given power and more amps is potentially bad...
this is the vesc i was thinking of:
https://www.rcmoment.com/p-rm10362....ZZ9vro2Phgz1oIrBH1LkbvshuUgxh3scaArquEALw_wcB

and i can put halls sensors on a RC motor if its better but i heard that VESCs have good startup torque.

 

[Functional Artist]

From my understanding
R/C & skateboard stuff is usually too small to power a (4) wheeled kart, with a full size person
...because of the bigger tires/rolling resistance, total weight etc.

IMO your best "bang for the buck" is either
...a 48V 1,000W MY1020 motor controller (~$125.00)
...a 48V 1,000W ZY1020 motor & controller (~$100.00)
...or a 48V 1,800W Boma brushless motor/controller (~$200.00)

I have built many karts using these motors.

http://www.diygokarts.com/vb/showthread.php?t=37442

Pair one of them up with (4) 12V 12AH batteries (~$100.00)
…you'll have a fun kart that can go ~15 to 20 MPH
...& you can usually ride it for ~30 to 40 minutes at a time.
(all for "well" under $500.00)

 

[itsid]

Vedder Controllers are GREAT.. but not for this application I'm afraid!

Benjamin meant to make a skateboard controller for RC motors,
and he did make the best one out there.

I have one on order atm.. but you guessed it: for a skateboard

for a kart, it's better to use controllers and parts in general that are MEANT for karts.
not a scooter, not a skateboard, not <put random other appliance here>

If you want reverse that is, otherwise there's no difference to a scooter controller really.

If you want a three phase brushless DC you come close to Ben vedders controller,
BUT:
You don't need to spend as much money to have a tiny footprint, you have a full size kart to mount a full size controller to it.
benefit: the larger the controller, the less problems you're likely to have with overheating)
bonus: since those tech is old and available it's more often than not cheaper than a well made VESC
a controller for a brushless 1.6kW EV motor is less than 50 bucks..
the vesc I ordered (cheapest I could find) is 80 bucks.

And NO, do NOT use RC motors!
those tiny monsters might (few do in fact) provide the power you need,
they're meant to move way less mass, and that small size comes at a price (structural weakness!) a 6mm shaft on a single bearing cannot provide the torque you need without deflecting (bending, snapping, catastrophic failure eventually)
stiffening it up is possible with a gearbox,
but that again costs money time and more money to make right.

Also: a 2kW RC motor is 2kW electrical power draw, NOT 2kW mechainical output power,
as an EV 2kW motor would be.

it's cheaper and more efficient to buy a large EV motor instead.

So yeah, the 1.8kW Boma FA was talking about for example surely outperforms my tiny
2.1kW brushless motor (270kV RC toy motor)
(the one my vesc is going to power either my kickboard or my skateboard we'll see).

'sid

 

[mr kart]

ok I'll do that then.
I mostly wanted to try the VESC was because it was very adjustable and it seemed cheaper than the scooter motor combo.
so for controllers, what should i use:
https://www.ebay.co.uk/itm/Control-...801932357?epid=2131766343&hash=item3d30374045
https://www.ebay.co.uk/itm/48V-2000...340738?hash=item5420311642:g:74UAAOSwR29ZCo7n
or is there any other option?

also how can i do accurate monitoring of the whole system? i've seen cycle analyst which looks good but is quite expensive. is there anything else and/or can i use something like a raspberry pi and some sensors to do that?

i have also decided to build a mini bike not a go kart as it will be lighter, faster and easier to transport as i live in the city.

 

[Functional Artist]

ok I'll do that then.
I mostly wanted to try the VESC was because it was very adjustable and it seemed cheaper than the scooter motor combo.
so for controllers, what should i use:
https://www.ebay.co.uk/itm/Control-...801932357?epid=2131766343&hash=item3d30374045
https://www.ebay.co.uk/itm/48V-2000...340738?hash=item5420311642:g:74UAAOSwR29ZCo7n
or is there any other option?

also how can i do accurate monitoring of the whole system? i've seen cycle analyst which looks good but is quite expensive. is there anything else and/or can i use something like a raspberry pi and some sensors to do that?

i have also decided to build a mini bike not a go kart as it will be lighter, faster and easier to transport as i live in the city.

What do you want to monitor?
...battery pack voltage?
...amp draw?

To monitor these I use an amp/volt meter (~$15.00)
http://www.diygokarts.com/vb/showthread.php?t=38583

...speed?
...distance?

Maybe try a bicycle speedometer (~$10.00)
http://www.diygokarts.com/vb/showthread.php?t=39441

As far as switching to building a minibike
...might...gonna have to...change your user name

 

[mr kart]

How do you change your username?

And is there a way of changing the thread title?

Ill have a look at monitoring after I've got it working. Ill see if using a Raspberry pi or Arudino for monitoring and controlling.

 

[landuse]

How do you change your username?

And is there a way of changing the thread title?

Ill have a look at monitoring after I've got it working. Ill see if using a Raspberry pi or Arudino for monitoring and controlling.

Changing your username can only be done by the site Admin Robertdjung. He has to do it in the database itself.

Thread title is an easy one. You cannot do it yourself though, but if you tell me what you would like it to be I will change it for you.