Jump to content
Jason1145

Tamiya Club Official Top 10 Fastest RC'ers List

Recommended Posts

54 minutes ago, Jonathon Gillham said:

Can't wait to see the result. I have 80amp esc running 17.5T and the people who sell Orion ESC's tell me one of theirs would make a difference but I don't believe them. In your case it sounds like it will, that 70amp ESC will be maxed out.

I don't think it would make much difference with a 17.5t, but I'm over it's turn limit by 1t, (well, I'm trying to run timing/boost on a 6.5 and the blurb says 7.5 is the limit for timing, 6.5 in stock tune). The 6.5 speed passion motor is quicker in the RB5, with the same esc, battery etc, and I'd of hoped for more out of a reedy motor.

Share this post


Link to post
Share on other sites
12 minutes ago, Wooders28 said:

@M 800STD

I paid £50 delivered for this one, maybe worth having a look for a 2nd hand one? 

The lipo I've gone for is 

https://www.modelsport.co.uk/absima-low-profile-shorty-lipo-7-4v-110c-3200-mah/rc-car-products/407612

Also tempted to get a pair of these, they are the size of normal 1s saddle, but 2s2p , giving potentially 4s in the space of 2s.

https://hobbyking.com/en_us/turnigy-nano-tech-ultimate-2600mah-2s2p-90c-hardcase-lipo-super-shorty-pack-roar-approved.html

How do you find the absima shorty? I want a couple more shortys mainly for practice, Gens Ace do a similar pack, rated to 60c but by all accounts as good as the higher c rating on chraper batteries, not sure how they compare to the expensive brands though. So could buy a couple of these

http://rc.franktonmodels.co.nz/index.php?main_page=product_info&cPath=13_697&products_id=117492

Or just get some secondhand ones for practice. I like the idea of the Gen Aces as they are lighter but should get through a race ok, so may replace the Orion packs for race day. But then some secondhand high MAH are probably better given I want them for max practice time, and the Orions were so expensive it feels wrong not to use them for racing!

Share this post


Link to post
Share on other sites
31 minutes ago, Jonathon Gillham said:

How do you find the absima shorty? 

I've only run one charge through them, so to early to give an opinion, plus I'm maybe not getting any benefit given the possible esc not pulling the amps.

I'm not sure what kind of amps a 17.5t will need, but I wouldn't think you'd notice any difference between a 65c and a 110c? 

Share this post


Link to post
Share on other sites
5 hours ago, Wooders28 said:

I've only run one charge through them, so to early to give an opinion, plus I'm maybe not getting any benefit given the possible esc not pulling the amps.

I'm not sure what kind of amps a 17.5t will need, but I wouldn't think you'd notice any difference between a 65c and a 110c? 

The story I got told is when the battery is running low then the higher C rating is more important as the battery can still deliver the total watts, as it can up the amps when the voltage drops due to sudden load. It sort of makes sense that it would work that way, and ran it past electrical engineer mate who though it could be the case. The guy selling the batteries also said that its more important in stock class as you can struggle to make the jumps, whereas in mod the cars are that much faster anyway that losing a bit of speed isn't so bad. I ended up buying the 110C 5000mag Orion batteries from him, but he races at my club and can supply spares etc (Kyosho dealer) so if I need to I can text him what i need and he will bring it to the race day. So my decision was political as much as anything. In practice the gens ace get rave reviews and they are rated 60C. I think there is a lot if C rating inflation going on.

I hope to call into a hobby shop in Hamilton (90min drive away but have managed to arrange some work visits...) on Friday and the guy there races stock and mod and uses the gens ace batteries so will get his thoughts. He even runs a 17.5T in mod and wins.

Share this post


Link to post
Share on other sites
21 hours ago, Phil_H said:

Plans? 

It's going to be a speed run car. I just ordered a 7700kv motor and a Mamba Monster X (Amain) for it and I'm deciding which Protoform body to go with at the moment.

I've spent more than Augusts RC budget already and it hasn't even started yet :(   But at least I have some projects to keep me busy!

20170731_173200

 

  • Like 3

Share this post


Link to post
Share on other sites

@El Dougo

6 minutes ago, El Dougo said:

It's going to be a speed run car.

How many lipos are you going to run, will you be using extra caps?

Don't forget to true and balance wheel/tyres, even when new.

Share this post


Link to post
Share on other sites

I think I'm right in saying @Jonathon Gillham that the C rating amps are equitable to the mah rating and an algebraic equation, so a 50c 5000mah would be the same amps as a 100c 2500mah.(50 x 5000 = 100 x 2500). 

So yes, a bigger battery will deliver, but I'm sure it'll only deliver what the motor demands, bit like fitting a 10mm fuel line to a moped.

Share this post


Link to post
Share on other sites
45 minutes ago, Wooders28 said:

I think I'm right in saying @Jonathon Gillham that the C rating amps are equitable to the mah rating and an algebraic equation, so a 50c 5000mah would be the same amps as a 100c 2500mah.(50 x 5000 = 100 x 2500). 

So yes, a bigger battery will deliver, but I'm sure it'll only deliver what the motor demands, bit like fitting a 10mm fuel line to a moped.

I was also referring to the 'too good to be true' C ratings you see on cheap batteries. There are a few sellers on facebook here that have brand new 100C lipos for around $80, but the batteries with 60C ratings from reputable brands like gens ace and turnigy perform better.

My motors have max current draw of around 45a from memory so 550amps should be enough!

  • Like 1

Share this post


Link to post
Share on other sites
2 hours ago, El Dougo said:

It's going to be a speed run car. I just ordered a 7700kv motor and a Mamba Monster X (Amain) for it and I'm deciding which Protoform body to go with at the moment.

I've spent more than Augusts RC budget already and it hasn't even started yet :(   But at least I have some projects to keep me busy!

20170731_173200

 

Lovely, will look forward to your results :)

Have I mentioned I have a TRF!!??

  • Like 1

Share this post


Link to post
Share on other sites

There's a good explanation of C here, which has been posted a few times.  I know @Wooders28 is aware of it:  https://rogershobbycenter.com/lipoguide/

The Turnigy Graphene packs have proven their worth and not too expensive.

I'm going to take a punt on these:  https://www.fantomracing.com/categories.php?cat=Li-Po+Batteries+Packs

If any of you guys are going to be running extra caps, aim for operating voltage plus 20 - 30%.

Also if you're going to run more than 4s, maybe incorporate anti-spark lead.

  • Like 1

Share this post


Link to post
Share on other sites

Those lipos look really high speced and really cheap! (Ok, maybe alot more expensive landed) I reckon I could do a full meet with that 2s saddle on one charge! 

7 minutes ago, M 800STD said:

If any of you guys are going to be running extra caps, aim for operating voltage plus 20%.

Guessing thats capacitors for the esc's? 

 

8 minutes ago, M 800STD said:

Also if you're going to run more than 4s, maybe incorporate anti-spark lead.

Never heard of those.

Share this post


Link to post
Share on other sites

@Wooders28

Yes, caps for the ESC.  Try and get them as close to the board as possible.

Basically a small diameter line, connected before primary.  Also there are connectors, such as XT90, available with anti spark.

  • Like 1

Share this post


Link to post
Share on other sites

Just had a look on Google images, the anti spark look easy enough to make, and will stop/reduce the 'ooo ya little stinker' (or words to that effect! 🙄) when the T plug doesn't go straight in, if I get to use 5s again.

Cheers.

  • Like 1

Share this post


Link to post
Share on other sites
32 minutes ago, M 800STD said:

With regards to connectors:

I see, half the surface area until it's fully connected.

The drawing is the one I found on Google images, looks easy enough to do. Not sure when I'll revisit 5s though.

Share this post


Link to post
Share on other sites

@Wooders28

I'm pretty sure that the XT90 anti spark version has built in resistor (I'll need to confirm), so this would make a cleaner installation, regardless of cell count.

 

..."The anti-spark connector allows a two stage connection to the speed controller. Initially the tip of the plug is connected to the battery, allowing it to slowly charge the capacitors in the speed controller via the resistor inside the connector. By the time the main body of the connector makes contact, the capacitors will be pre-charged to the battery voltage, avoiding any sparks."

  • Like 1

Share this post


Link to post
Share on other sites
22 hours ago, M 800STD said:

How many lipos are you going to run, will you be using extra caps?

Don't forget to true and balance wheel/tyres, even when new.

Just the one 3s to start with a 7700kv and I did go with the additional capacitor pack.  

I just looked at the data log from my Mamba X to see if I am getting any ripple in my RS4 (5700kv, 3s) as I don't have additional capacitors on it. It appears that I am getting some although it's my first time looking at the log and haven't done any research yet, so not sure whats normal and what the tolerances are.  If you or anyone else is able to shed any light on it it would be appreciated!    Also balancing the wheels never even crossed my mind, can you elaborate?

Capture

Edit:  Some interesting headline numbers! (shocked emoticon) :) 

Hmmmm

 

21 hours ago, Phil_H said:

Have I mentioned I have a TRF!!??

The Project X:)  Which model, a picture and divulge of plans would be nice :)  

Share this post


Link to post
Share on other sites
3 hours ago, El Dougo said:

Some interesting headline numbers!

Like max rpm 114060rpm on a castle 100k max limit!! 👍

Share this post


Link to post
Share on other sites
3 hours ago, El Dougo said:

 

The Project X:)  Which model, a picture and divulge of plans would be nice :)  

X being the clue. 

416X

Not made plans yet, was going to push the TA04 a bit more first. The TRF has only been used indoors....I'm a bit worried about binning it lol. No pic's, seem to have issues uploading at the moment. 

Share this post


Link to post
Share on other sites
10 hours ago, Wooders28 said:

Like max rpm 114060rpm on a castle 100k max limit!! 👍

I have now made sense of the data log, the big numbers came from the last run on the dusty road where it was most likely wheel spinning at 70Mph.  

The normal peak numbers from my usual running spot are: ESC 200f/93c, Motor 150f/65c and 70000rpm with a 170amp current draw. The ripple is a little on the high side peaking at just over 2 volts so I will be adding a capacitor pack but overall much less worrying numbers!   

10 hours ago, Phil_H said:

I'm a bit worried about binning it lol. 

It's gonna hurt seeing the 418 take the first tumble but I'm sure it will be worth it in the end :) 

  • Like 1

Share this post


Link to post
Share on other sites

Didn't realise the data logger would log everything, that's quite cool, and we now know the motors are good for some over rev 👍😁

I've been offered one for a good price from castle, as long as I send them my old max pro , and then I'll have import costs etc, so I'm still undecided.🤔

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...