Recommediation for new build rc

[zibbby]

Hi!

I have build succesfully two ebikes using bafang motors.
My ebikes mostly are use for my camping trips with my Rv. I carry them on the rear hitch so the waight is limited, and the 12ah ping battery has to be remove every time.
I am looking to build rc friction drive for the trips with steep hills.
For last month I been reading all post in non hub motor drives because I did not know anything about Rc motors. Mechanicly I can do pretty good as I design and build Rv for my self.
I would like to be able to get speed 25mph but never use more then 20mph and I will be happy if I can get 10mph for hills .
The range 5miles and 10mil with pedaling.
I decided to start with not expensive parts for first time.
This is my parts list: most from hobby king
Motor : HXT 63-64-B 230Kv Outrunner
Esc : TURNIGY Sentilon100A or
Phoenix ICE 100
BEC: TURNIGY 5-7.5A (8~42v)
servo driver TURNIGY Servo Driver http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idproduct=8296
zippy battery : if use Turning ESc 2x 5s series 5000mah or if use iCE 100 2X 4S series 25c
BM-6 Cell Voltage Monitor 2-6S
iCharger 106B-plus 250W 6s Balance/Charger
Watt Meter & Power Analyzer (Watts up)
1.250" ROLLER DRIVE AND 26" BICYCLE
What would be your advice shuld I use lower voltage ice 100 or turning 36v setup?
Any commens about those parts ?

Thank you

 

[Grinhill]

Your motor will probably be happier running at 10S rather than 8S, however check what your no-load speeds will be for the two different voltages and see if you will be happy with that.

Also, you will find it more convenient to be able to charge your pack in one go, so consider going to an 8S or 10S charger.

 

[zibbby]

Thank you Grinhill
Would please help me calculate no load speed and how will that effect the speed of bike?
When I get 8s or 10s charger will I be able to charge and balance this two batteries at same time with one charger? What parts would I need to make harness to charge them at once and balance?

Thank you

 

[Metallover]

There are many programs you can use to calculate speed. I use one made for RC cars, and I'm sure there are better ones for ebikes, but this one works for me - http://www.scriptasylum.com/rc_speed/_top_speed.html

If you have two 10s batteries and one 10s charger, you can hook them up in a parallel with a couple adapters and charge them as a 10s, (2)Capaicty pack. Say your pack is a total of 10ah, 10a is the max you should charge that on 10s. You need a beefy charger and power supply, but it's possible.

I can only find balance adapter parts up to 6s, but you could get a 3s adapter and a 6s adapter and make it work. With the jst/xh type of plug, the first pin is negative and the next pins reflect each cell. If you had a 6s tap on then you'll have 4 more cells to go and a 3s tap has 4 wires on it.

There are a number of places to get adapters, but I like
http://www.cheapbatterypacks.com/?sid=2038161&pgid=connectors
and
http://www.hobbycity.com/hobbycity/store/uh_listCategoriesAndProducts.asp?idCategory=156

With either one, you might need to buy an adapter and cut off the plug you want. Make a Parallel adapter for the main discharge plug. Then once you get your 10s balance adapter worked out, connect neg to neg, cell 1 to cell 1, cell 2 to cell 2 etc until you hve a parallel balance adapter.

 

[E-Ride]

Assume you run at 36V

Motor spec says 230 kv (rpm/V).

Wheel speed is then:
=230*36/60*1.25*0.0254*PI*3.6 = 50 km/h

Assuming no load.

 

[zibbby]

Thank you Metallover

Does anybody have schematic how to make this balancer for 10s and 8s using 6s and 3s harness or anything like that. I would be affraid to do that on my own as I new with this.

Thank you

 

[zibbby]

Thank you E-Ride

Could you please explain this callculation? what is Pi , itc.

Thank you

 

[Metallover]

I'll whip one up using a 6s and 3s pack for 9s. It's pretty dang pracital setup. If you got 2 6s and 2 3s packs, you could run 9s2p, 12s1p, ane more...

6s chargers are easy to find, so I'll first make a charge diagram for 6s. Make sure to get one that's high wattage!

 

[E-Ride]

Thank you E-Ride

Could you please explain this callculation? what is Pi , itc.

Thank you

230*36/60*1.25*0.0254*PI*3.6
36 V divided by 60 sec to get seconds instead of minutes
1.25 inch for your roller times pi (3.1415) to get the circumference
times 3.6 to get from m/s to km/h

 

[Miles]

You could also play with this:
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=6892&p=119810#p119810

 

[zibbby]

230*36/60*1.25*0.0254*PI*3.6
36 V divided by 60 sec to get seconds instead of minutes
1.25 inch for your roller times pi (3.1415) to get the circumference
times 3.6 to get from m/s to km/h


What about 0.0254?

Thank you

 

[Metallover]

When it says cut or remove wire, you can connect it to the red wire if you want to be able to balance the pack without using the main discharge leads. The downside to this is that you can short the pack if you connect it the wrong way. That would be switching around the balance plug with the main discharge plug when plugging in the pack.

Let me know if anything is wrong or I need to explain anything. Praise is welcome. :lol:

 

[Miles]

Praise is welcome. :lol:

Awesome!

 

[E-Ride]

230*36/60*1.25*0.0254*PI*3.6
What about 0.0254?
Thank you

Inch to meters...

 

[Metallover]

Praise is welcome. :lol:

Awesome!

Thanks Man!

 

[Metallover]

Differential Ratio: 1
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 26
Pinion Tooth Count: 1.25
Total Voltage: 36
Motor KV: 230
Tire Diameter (inches): 26
Tire Ballooning (inches): 0
Spur/Pinion Ratio: 20.8 : 1
Total Ratio: 20.8 : 1
Tire Circumference (inches): 81.68 inches (2074.71 mm)
Rollout: 3.93:1
Total Motor Speed: 8280 RPM
Vehicle Speed: 30.79 mph (49.46 km/h)
Effective KV Value: 230
KT constant: 5.88 oz-in/A

This is what I got with my RC calculator. It has a nice export function.. Only thing I see is heat issues. IMO 36v too much voltage for 230kv to run cool. I have a 250kv motor on 24v on one of my rides. Temps are about 105fmotor/120fcontroller max.

 

[zibbby]

Now with the schematic I know what you talking about . Very nice diagram.
I would prefer not charge to the balancer only as it is slower and chance to go somthing wrong when you unplug wrong.
So with 9s battery I could use ICE 100, max V for ICE 100 34V.
Ice 100 is only little more expensive then TURNIGY Sentilon100A .
Can I limit current with ice 100?

Thank you

 

[Metallover]

The caslte creations controller will be twice as good as the turnigy controller. The only problem is that it's only rated for 8s, so you'll have to get a 8s pack. Not too bad though. A two 6s and 2 2s packs should do the trick, if you can find a 2s pack. Otherwise, four 4s packs is the way to go. All the cells in your pack must be the same.

The Ice will have tons of programming options and will probably handle more amps then the turnigy even though they are rated the same. The Ice has data logging and a switching bec onboard, which it makes it that much better. Whichever esc you choose make sure to have good airflow so you don't burn up the controller.

I would get the Ice controller if you don't plan on running more then 8s. If you plan on running more voltage, go for the Turnigy. Castle should be coming out with a HV ice in the future so keep an eye out for that.

I would get an 8s pack with your motor and run the Ice. That would by my personal decsion, but get some more views first.

 

[Metallover]

Don't ask my why, but I made two more diagrams. One shows a charging setup for 4s 20ah. It will take longer then 8s 10ah, but it will be easy to setup and it'll work. I also made a diagram for running an 8s 10ah pack with no BMS.

Does anyone think balancing each induvidual pack after charging is necessary? I can see one cell at 4.15v and one at 4.25v but it averages at 4.2v... Maybe charge mostly then balance induvidually then top off the pack?

I'll put the pics as thumbnails so they don't clutter up the thread. Just noticed on the "run" diagram you'll probably want to replace the two parallel adapters and one series adapter with the opposite. Then in the end, You'll have to make 3 parallel adapters and one series adapter unless you solder the packs together in a parallel without a connector.Then you'd just need one of each adapter.

 

[zibbby]

Than you once again Metallover
It makes much easer with those diagrams.
Yes , originaly I tought 8s with ice 100 is the way to go.
Do I need 10ah? or 5ah will be ok for 5miles no pedal and 8-10 with pedaling? (with some steep hills)

Thank you

 

[Grinhill]

The main reason for going from 5Ah to 10Ah would be to supply the current peaks without too much voltage drop, and to prevent your packs from getting warm.

My max amps with 8S and 230kV motor is 80 or 90A.

 

[zibbby]

Ok, I will go for 10ah , what about disccharge rate, will 20C battery be OK?
And what size wire would I need for parallel harness? and EC5 connectors will do the job?

Thank you

 

[Metallover]

20c will be great. Even 15c would work pretty good. The higer C rating the better. I'd definately go for the turnigy 20c packs.

I could use some help on connectors and wire size myself, but I would think 5mm+ bullet connectors or anderson power poles are good connectors paired with... 10awg?

I'm running deans and 14awg on my lil pocket rocket but I don't think the sla batteries are pushing out many amps.. :lol: Like I said, someone else should chime in on wire size/connector. Or else we could perform a few searches..

 

[Grinhill]

I get by by with 12 awg, but don't recommend it, 10 awg would be much better. Grab some from hobbycity if you are ordering stuff from there, it's great flexible cable and the silicone insulation doesn't melt.

I use both Deans-copy and the bullet connectors which come with the Turnigy batteries, both are good.

 

[E-Ride]

Guessing you're talking about these:

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=9672
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=9671

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=9283

Btw, why not pick this servo tester? ($5.74)