Baja 5b SS Brushless conversion
 

Hi everybody,
my dream of converting a big 1/5 HPI Baja to brushless is done!

Motor mount and pinion holder made by Serum (thanks!) :lol: :lol:

The photos

Motor: NeuMotor 1915 684 rpm/v
ESC: MGM 12018

At the moment, I run with little setup of 7s2p A123, but next weekend I will run with 9s lipo and Sentilon HV esc.

With 7s2p A123 the starting power was already enough, but the max speed was about only 62 km/h scryptasilum calculed (about 38 mph)

These are 2 video of the first on road run.
Video1
Video2

Eagle tree datas:
Max ampere 108
Max watt 1880
Max RPM 15200

I like it!

Very cool conversion.. Please make a video if you will run it on 9s LiPo!


- Patrick

Congratulation on this built and your succesful maiden run.

Interesting motor choice, as it is rather lightwheight for the wheight of the car. With 3KW peak not the most powerfull one but as one can see in your videos with 2wd too much power will only spin the car. Motor temp in your videos was around 49-58°C (120-136°F) right? I guess your outside temp was at 12°C / 52°F while you made this run. With a more agressive driving style, 9s Lipo, a more powerfull ESC and hotter outside temperatures your motor temp might become critical.

7s2p A123 are able to provide far more peak power then 1.9KW. I would assume up to around 2.8-3.5KW peak which also represents the rated motor limit.

Expect considerable more power with 9s lipo which is comparable with an 11s A123 setup.

Awesome build. I would love to see the Eagle Tree data you got from the run.

Very nice!!! I like!!! (said in Borat voice)

Any idea what your running weight with batts is? 7s2p a123 is not all that heavy and your motor is not that heavy either. The stock gas motor must weight at least 4-5lbs and a tank of gas adds a pound or so (6lbs to the gallon, tank must be around 20oz). You may be lighter than the gas model, which will always help performance.

I would go with a 10-12s setup with 2500mah lipos and a motor of around 550kv. Possibly an outrunner, but I do like your use of the 19 series Neu. I have been wanting to do a 5th scale, may make my own with lst components... Or buy a used 5b, they go for around 4 bills...

One question, does the 5b have any sort of 1 way bearing in the gear reduction? I know it is a single speed, just wondering if you could use motor brakes for the rear wheels? I would do mech front brakes anyway, so most likely use the rear mech brakes too. I could run a set of channel mixes so that I could have selectable reverse with a reversing esc, like Lutach's 10s 150 amp model....

Any chance of some close up pics of the motor mount installed in the 5b?

Weight RTR is 9,0 kg, I think about 2 kg less of nitro baja with full of fuel.
I'm sorry I don't have other pics of motor mount.

thats sick!. i was kinda thinking about making my baja brushless. but i dont know yet.

That looks real nice . :smile:

Sweet build. :yes: I think you could out-pull a diesel locomotive with that 8-pole Neu! :yes:

New Test:

9s lipo zippy 5000 mah 20-30c

Max velocity: 80 km/h (gun releved)
Max watt: 4.933 watt
Max ampere: 175 ampere

Eagle tree printscreen

Other photos

Video1

Video2

Nice speed! I like it! :smile:

Just one question, I want to buy a Eagle Tree system too. But I don't know which one to buy. Which one did you buy?

Thanks,

Patrick

Nice. Thank you for sharing pics and videos. The sentilon ESC seems to perform very well in your car. Motor start up is impressive.

At some point in your second video i think i have understood that your motor temperature was 58°C ... correct?

As Lutach i'm very eager to see your eagletree data. Maybe you can attach your eagletree logfile from this run to your next post.

to Byte:
I don't know which model of eagle tree I have used, because it is of my friend. I will ask him.


to Othello:
The sentilon works great (and is very cheap), you can see at about the third minute of the video2 the baja on 2 back road while starting at full gas.
Yes, max motor temperature was 58° (celsius) at about 16° of air temperature, sentilon was at a max of 50°.

I attach here the eagle tree log file.

My only doubt is about zippy lipos, they are rated for 20-30c, I got 172 ampere from them, that are about 35c. Do I risk to damage them?

http://lh5.ggpht.com/_GS-R7ugwb24/SV...204933watt.jpg

:surprised: That's a lot of amps!

I saw your videos the other day, Master Blaster has a thread on HPIBajaForum.com about his conversion and your vids are linked to a few times. Mike is working on a conversion for MB, hopefully he puts the finished conversion into production. I know I'd love to have a BL Baja but don't feel like custom-machining the motor plate.

EDIT: That's about 6.5 HP, stock 26cc engine out of an SS is about 3 HP I think :yes:

EDIT Again: What size pinion are you using?

I do like the use of a 19xx motor, a lot of torque and a 8 pole motor. Another motor that could be used is a Scorpion 4035...they have comparable performance to a Neu 19xx but a little cheaper

http://www.scorpionsystem.com/catalo...0/HK-4035-500/

hi!
nice conversion.
I have seasoning in BAJA.
Can you buy Motor mount and pinion holder?
Is there Motor mount and pinion holder usable elsewhere?
thank you^^

Ok thank you! :yipi:

it looks like the 172 amps were your burst, and with a 25c continous pack 35c burts are well within limits, Flightpower packs can handle 50c bursts, these bursts will be WOT from a standstill

Awesome build, very clean. I wonder if HPI are watching... (Savage > Savage flux, yada yada...)

@gyn77
Sorry for the late reply. Thank you for sharing your eagletree files. Very interesting especially since you also included a run with 12s1p A123.

Although a 12s1p A123 pack has a higher nominal voltage than your 9s zippy lipo pack, the A123 pack was only able to provide up to 3160 Watt or 100-120A due to its drop in voltage (especially at the beginning of your run where voltage dropped to 1.8V per cell as it obviously must have been relatively cold). With time (as it warmed up due to the load) the pack held its voltage better at high amp peaks - around 2.1V at 120A loads.

You were really pushing your A123 cells. If you want to get about similar performance to your 9s lipo pack you will need a 11s2p A123 pack. It has slightly less energy, wheighs around 400-500gr more but would be able to provide amp burts around 200-240A (up to 5.5KW). Average Voltage would be around 33V (comparable to your 9s lipo pack). But i don't know if the Sentillon would be able to feed as many Amps and if the motor would hold up to those high Amp peaks (efficiency can't be very good at those amp levels).

I think you were also pushing your lipos as they also dropped to 3.1V per cell when they had to provide around 170A. You might want to use a smaller pinion to reduce load on your lipos and motor.

Fantastic work, very inspiring. I feel a project brewing