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  #41  
Old 15-05-2009
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No, you can charge them separately, but most prefer to charge them 'as one battery' in series (so it becomes a 4 cell). A custom balance lead would need to be made, but it's not that difficult. The only reason that people like to charge two at once is that two are required for the car at once. The charger cuts the Lipo charge off when the cells reach capacity, so it doesn't matter if you charge them separately. Even if they are both connected, the charging stops when one cell reaches full voltage, and the charger enters balance mode to bring the other cells up to the peak voltage. Therefore it is irrelevant whether you charge them at the same time or separately.

I can't see why using two Lipos of different ages is a problem, so long as they are the same cells (so have the same capacity and discharge rating (C)) there shouldn't be a problem. Unless one is completely knackered of course and the other is brand new or something. A couple of cycles different won't be a problem though.

4mm connectors are enough to run 1/8 Brushless. It's only when people run them in really high power applications that they start to really heat up and efficiency is lost.
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Old 27-05-2009
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Guys, as an update, ran my first meeting at the weekend, with the losi buggy and electrics, 2100kv motor, losi 4s 5000mah battery. It was at Sutton, a grass/dirt track which had what I'd guess is a long straight on it.

In 5 min heats was using 1800-1900mah. Pulled the car off 11mins into the final and can't be sure yet but as an educated guess had used around 3600mah, which I guess makes sense as you still only do one set of warm up laps etc. Depending on final drop off on the cells would guess maybe around 13mins is do-able. I was driving flat out at all times and made no effort to make the battery last. I didn't have a temp guage so not really sure how hot it was running, no thermalling though so presumably can't have done any overheating damage?

Speed wise the top nitro's had more top end (roughly the difference between using a 5.5 and a 6.5 in 10th) but nothing could touch the losi on bottom end or mid range grunt, it was awesome! I can't think of any tracks I've seen where more top end was necessary. Certainly was fine for Sutton, qualified 2nd and led from the start of the final till I pulled off! I think the electric has quite an advantage over the nitro's!!
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  #43  
Old 27-05-2009
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I think you should maybe gear up very slightly. What pinion/spur are you using at the moment?

The electric should be able to have the same if not higher top speed, yet still be soooooooooooooooooo much faster out of corners.

Glad you liked it though
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Old 27-05-2009
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Quote:
Originally Posted by Marvin View Post
I think you should maybe gear up very slightly. What pinion/spur are you using at the moment?

The electric should be able to have the same if not higher top speed, yet still be soooooooooooooooooo much faster out of corners.

Glad you liked it though
I'm using standard which is 15 pinion and I think 45 or 46 spur, not sure what final drive that would give though?

The straight was pretty long at Sutton and the top nitro's had more top end than at other tracks I've seen them like Oz, so think that may be the reason? Think they were only getting an average of 7 or 8 minutes per fuel tank from what I saw too?

I'll see how it goes at other tracks but want to play safe on temps where possible!
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  #45  
Old 27-05-2009
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I run a 14t on a 2650kv and have ran a 15t so you should be good to move up to a 16 to try, the lower kv motor wont be running as hot either so you should be good for a bit more top end.
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  #46  
Old 27-05-2009
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Nice one, will get hold of some pinions (and more batteries), gotta say really loved running 8th scale, and there seem a few championships that let them run so all good!

Hopefully more and more people will run them as time goes on!
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  #47  
Old 27-05-2009
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Stuart are you running the losi? If so what rideheight do you go for? Mine sits with quite a lot of plunge on the driveshafts at the moment?
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  #48  
Old 28-05-2009
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Differential Ratio: 3.3
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 46
Pinion Tooth Count: 15
Total Voltage: 14.8
Motor KV: 2100
Tire Diameter (inches): 4.5
Tire Ballooning (inches): 0.1
Motor Current Draw: 0
Motor coil Ω: 0
Spur/Pinion Ratio: 3.07 : 1
Total Ratio: 10.12 : 1
Tire Circumference (inches): 14.77 inches (375.04 mm)
Total Motor Speed: 31080 RPM
Vehicle Speed: 42.94 mph (68.98 km/h)
Effective KV Value: 2100
KT constant: 0.64 oz-in/A

Here are the results from THE calculator. Is Sutton an absolutely massive track or something? You are geared for a higher speed than I was with my Losi, and I was outpacing nitros down the straight (only just though).

If so, go with a 16T pinion and something like a 48T spur if possible. This should keep you as fast. The main problem with gearing up, is that, it heats up everything, and run time is reduced.

Differential Ratio: 3.3
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 48
Pinion Tooth Count: 16
Total Voltage: 14.8
Motor KV: 2100
Tire Diameter (inches): 4.5
Tire Ballooning (inches): 0.1
Motor Current Draw: 0
Motor coil Ω: 0
Spur/Pinion Ratio: 3 : 1
Total Ratio: 9.9 : 1
Tire Circumference (inches): 14.77 inches (375.04 mm)
Total Motor Speed: 31080 RPM
Vehicle Speed: 43.9 mph (70.51 km/h)
Effective KV Value: 2100
KT constant: 0.64 oz-in/A

Here are the results from the set-up I suggested. It's only 1mph more, but it should be enough. Try the 16T pinion on it's own first though.

I'm thinking it could be the Losi battery. The true C rating on those is only about 15C, so it won't be capable of providing the sort of current you're after. If you have another 4S lipo to try (like a Flightpower), give that a go instead, and see if there is any difference. I just can't believe you are outpaced down the straights by the nitros on that set-up.

Oh, and for ride height, start with arms level, and if that's not quite enough, go for driveshafts level.
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  #49  
Old 28-05-2009
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The top end was by no means a disaster, I mean I qualified 2nd and led the A final until taking the car off so it was plenty quick!! (and as anyone who knows me from 10th will say I ain't that good a driver!), just I'd say maybe a couple of the nitro's had a little more top end!

Hard to say how long the straight was, but maybe not far off double the length of the straight at the Oz BCL round? Also not sure what Nitro's normally get out of a tank, but they were only getting 7/8mins on it?

I'll get a pinion to try and see what heat difference it makes! I'll also check the rideheight later!
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  #50  
Old 28-05-2009
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the straights about 50 m long.
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  #51  
Old 28-05-2009
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Hmm, about the same length as the main straight where I go. I suppose if you don't feel it's a problem, then use the old adage 'If it isn't broken, don't fix it.'

7/8 mins is about normal to be honest. Some can get about 10 minutes at an extreme push, whilst others can barely get 6 minutes. It all depends on the engine and tuning (something we don't have to worry about, though something you never had to worry about).

Congrats on the excellent 1st result though! Plenty more to come too I'd have thought...
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  #52  
Old 29-05-2009
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Nope runnin an RC8, pretty much sticking with driveshafts level at the moment, occasioally just below.


Quote:
Originally Posted by DaveG28 View Post
Stuart are you running the losi? If so what rideheight do you go for? Mine sits with quite a lot of plunge on the driveshafts at the moment?
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  #53  
Old 29-05-2009
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My Hyper 9 (home made conversion) was awesome for battery life at the Neo. Even in the 10 minute semi (I was standing next to Maifield - awesome) I drew less than half capacity, so can easily hit 20-30 mins.

I am running a Neu 1512 2.5D, Tekin R1 Pro and two TrakPower 4900mAh (30C). The cells are awesome, 30C unlike the less powerful 5400mAh. I think being lower grip though Neo was kind. I have yet to try on a normal UK track.

Soon I hope
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  #54  
Old 29-05-2009
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Quote:
Originally Posted by glypo View Post
My Hyper 9 (home made conversion) was awesome for battery life at the Neo. Even in the 10 minute semi (I was standing next to Maifield - awesome) I drew less than half capacity, so can easily hit 20-30 mins.

I am running a Neu 1512 2.5D, Tekin R1 Pro and two TrakPower 4900mAh (30C). The cells are awesome, 30C unlike the less powerful 5400mAh. I think being lower grip though Neo was kind. I have yet to try on a normal UK track.

Soon I hope
Aren't the 4900mAh Trakpowers 25C, not 30C? Though they, like all Flightpowers, have a 35C climbout and a 50C maximum discharge, so it's all good.

Having seen the Neo track I would say on a normal UK track, you won't be getting 20 minutes, though I could be wrong (it has been known ).

The fact that the Hyper 9 is light also helps, it's good to see someone run a PROPER set-up. Good quality batteries, fantastic motor, and a capable ESC, lovely.

You'll have to post some pics on here. What did you do for weight distribution?
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  #55  
Old 30-05-2009
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Yup sorry you are right indeed.

25C with 35C peak and 50C burst. I've been looking at some FlightPower 30C cells for a new plane I am building so had 30C stuck in my head. Either way the 5400mAh is the lesser choice, I got one bit right at least lol.

TrakPower 2S 4900mAh - 25C Cont. (122A) - 35C Peak (172A) - 50C Burst (245A)

TrakPower 2S 5400mAh - 16C Cont. (86A) - 25C Peak (135A)

I believe I went for the best equipment for the job. The Enderland cells in the TrakPowers are awesome, and actually deliver close to their ratings, unlike a lot of these totally fictitious ratings others give their cells and people blindly believe. The Neu is obviously amazing. Very efficient and very quick! It made me chuckle last night watching RC Racing TV seeing Adam Skelding mentioning motor temperatures at the Neo. I don't think mine got warm?

The Tekin R1 Pro is awesome too. Without a doubt one of the best brushless ESC's ever made. It even out-rates the RX8 that Tekin have developed. Obviously it lacks the convenience of a nice heatsink and a BEC capable of handling the voltage, if the RX8 was out at the time I would have got one, but for a 1/10th ESC the R1 Pro is better than nearly all 8th ESC's, crazy.

I agree 20 mins on a higher grip track wouldn't be likely on a normal UK track. I will have to get racing it soon and find out for sure though! The Hyper 9 is great too. As you say, it weighs next to nothing. The diffs are smaller than normal 8th etc, it lends itself very well to leccy. The 9E came out a couple of weeks after the Neo, typical!

I will be doing a small project report on my website, until then though you can see photos of it here:

http://www.facebook.com/album.php?ai...4&l=8340b0d696

I realise cells aren't in the shots, but they were obviously put on the empty side of the chassis. Balanced very well

Oh I have to include a photo of it in cam-car mode though :

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  #56  
Old 30-05-2009
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Flightpower have announced a new range of LiPOs, to replace the Eon series. The EonX ranges. These can be charged at 5C safely, though there is no charger to charge at 25A yet!

I've recently got some Hyperions which have the 5C charge rate capability too (though they've been out slightly longer than the Flightpowers).

I think 2 or 3C is probably enough though!

The MMM is a great ESC too, though many people still run R1s, the MMs etc, as they are rated for 3S with BEC, so are capable of about 4-5S without.

I assume you've seen the 9E pics. I like the layout in your car, though Hobao's kit is nicer (the centre diff at the back is a good idea, as the electrics tend to be front heavy), though I would say that, as I have one!

Nice work on the motor mount though, much better than I could even conceive doing, I'm still a bit crude on the ol' CAD.

I recognised the shell straight away, I enjoyed your footage of the Neo, though the camara mount may need a Mark 2 made that doesn't fall down
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  #57  
Old 30-05-2009
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I agree the 9E looks awesome. The main reason I got a Hyper 9 was so I could convert it to the official 9E (at the time of the Neo the 9E wasn't out). However I was so very impressed with the handling of the car at the Neo I am not going to change.

MMM is indeed awesome. A little on the large side though, but if that's its only downside they have done great. I am glad to see Castle making it big in the racing scene (even if it is 1/8th). It's about time people realise some of their favourite "racing brands" mightn't offer the best electronics. My R1 Pro looks lost on an 8th though. Still, 48 FETs in such a tiny beast is still insane, the thing amazes me.

Oh yes, we do have much better video from on-board! The video we uploaded was one of the practice days and we hadn't got it working quite right. I just need to edit the video where the cam is working
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  #58  
Old 30-05-2009
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Quote:
Originally Posted by glypo View Post
I agree the 9E looks awesome. The main reason I got a Hyper 9 was so I could convert it to the official 9E (at the time of the Neo the 9E wasn't out). However I was so very impressed with the handling of the car at the Neo I am not going to change.
Having seen your conversion, I wouldn't have bothered changing it either, it's very similar to the 9E anyway.

Quote:
Originally Posted by glypo View Post
MMM is indeed awesome. A little on the large side though, but if that's its only downside they have done great. I am glad to see Castle making it big in the racing scene (even if it is 1/8th). It's about time people realise some of their favourite "racing brands" mightn't offer the best electronics. My R1 Pro looks lost on an 8th though. Still, 48 FETs in such a tiny beast is still insane, the thing amazes me.
Castle are actually releasing a Mamba Max Pro. Rated for 6S (I think, or maybe 4S, not too sure), 100A continuous (a real figure, not the inflated ones that LRP/Nosram etc use), sensored, and in a case the size of a normal 1/10 ESC.

Tekin and Castle appear to have the 1/8 market nailed between them. None of the other stuff comes close.

Quote:
Originally Posted by glypo View Post
Oh yes, we do have much better video from on-board! The video we uploaded was one of the practice days and we hadn't got it working quite right. I just need to edit the video where the cam is working
I'd like to see it. Looking forward to it!
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  #59  
Old 05-06-2009
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I have a couple of questions regarding my brushless car fellas, maybe someone here can help.
Ive built a Losi 8ight 2.0 E and its awesome, i race 8th scale nitro but have built a brushless car for practise and to see what all the hype is about. Spec is below.

Losi 8ight E 2.0
Mamba Monster Max speedo
Losi xcelerion 1700kv motor
6s 5000mah 30c Lipos
45t plastic spur
12t pinion
I initially built the car and fitted the 15t pinion, it was awesomely quick undriveable to be honest. However the motor seemed to be getting a little warm over 6 minute runs, speedo and lipos where fine though. I then changed the pinion to 12t which using the rc monster website converter gave the theoretical top speed just over 40mph which i though was correct. Ive ran the car since and im well happy with the speed (it will do any nitro car top end and smoke them off the bottom) the runtime is also excellent with 25 minutes the most ive ran it for and it was just starting to slow off ut wasnt anywhere near the lipo cut off. I do have one issue and that is still that of motor temp, theoretically the gearing should be right the lipos arent really getting warm and the speedo is cool too. Ive ordered a motor heatsink which should help but i think the motor is still getting too warm (it was 170 farenheit after a 15 minute run). Question is do i gear down to a 10t or 11t pinion or is it getting too hot as its undergeared ? Is there any sure fire way of telling ?
Jimmi.............
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  #60  
Old 05-06-2009
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Quote:
Originally Posted by jimmiprice View Post
I have a couple of questions regarding my brushless car fellas, maybe someone here can help.
Ive built a Losi 8ight 2.0 E and its awesome, i race 8th scale nitro but have built a brushless car for practise and to see what all the hype is about. Spec is below.

Losi 8ight E 2.0
Mamba Monster Max speedo
Losi xcelerion 1700kv motor
6s 5000mah 30c Lipos
45t plastic spur
12t pinion

I initially built the car and fitted the 15t pinion, it was awesomely quick undriveable to be honest. However the motor seemed to be getting a little warm over 6 minute runs, speedo and lipos where fine though. I then changed the pinion to 12t which using the rc monster website converter gave the theoretical top speed just over 40mph which i though was correct. Ive ran the car since and im well happy with the speed (it will do any nitro car top end and smoke them off the bottom) the runtime is also excellent with 25 minutes the most ive ran it for and it was just starting to slow off ut wasnt anywhere near the lipo cut off. I do have one issue and that is still that of motor temp, theoretically the gearing should be right the lipos arent really getting warm and the speedo is cool too. Ive ordered a motor heatsink which should help but i think the motor is still getting too warm (it was 170 farenheit after a 15 minute run). Question is do i gear down to a 10t or 11t pinion or is it getting too hot as its undergeared ? Is there any sure fire way of telling ?

Jimmi.............
the motor can get hot from undergearing (causing it to overev) and overgearing it. what pinions do you have? if you have a range from 10-15 just test to see what happens when you gear down/ up and measure the temps
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