Derka Posted April 23, 2015 Share Posted April 23, 2015 Hi, I have a Helion Dominus SC10 V2 with the Radiant Reaktor brushless system (See sig) I get about 8-12 minutes of run time (Lots of full throttle, large garden!) with the stock 3500 mah NiMH battery I fancy a bit more run time and more punch/top speed. Ive read that a 2 Cell Lipo would be similar to freshly charged NiMH for a few mins, but the power wouldnt tail off like NiMH. 3 Cell is more voltage, but im wondering if this would just make the truck uncontrollable? My ESC is rated at 30a, 35 a peak, (Supports 2s and 3S with optional fan which is installed) so I I dont think id need any higher C rating than 20C as that would supply enough amps and any higher would be wasted as the esc wouldnt ever need more than 35amp? If I got a 2/3S Lipo at 3500Mah I think I would get longer run times as I would be accelerating faster and wouldnt need to be at full throttle as much so a same mah rating would mean potentionally longer run times? I have been looking at 4000/4500/5000 mah 2 and 3 lipo batteries. Any advice? Thinking of buying from Hobbyking UK warehouse. Thanks Quote Link to comment Share on other sites More sharing options...
Gaz! Posted April 23, 2015 Share Posted April 23, 2015 Ideally buy 5000mah upwards packs with a minimum 30-35c discharge, might sound on top of what you want but if you buy another car, chances are that lipo could be used in that too.... 1 Quote Link to comment Share on other sites More sharing options...
Noj Posted April 23, 2015 Share Posted April 23, 2015 Motor draws current, not ESC. A pack must be able to provide a constant current greater than the motor demands, so that it can function effectively, and the pack can deliver the required current without being put under stress. Gaz stated the rule of thumb lipo rule, 5000mah/30c minimum, giving a constant current of 150a (5000mah = 5ah, x 30c = 150a) and a good level of punch when you bang the throttle hard. Your ESC is rated at 35a constant, the motor will draw less than 35a of constant current (being a combo, ergo matched to the ESC), so with 150a of constant available, everything remains happy and should work at its maximum efficiency.... as noted, you have a good lipo that could run an eighth scale set up (120a ESC) should the need for more powah grab you. If you choose to run 3s, you must drop a tooth or two on the pinny (gearing down) to compensate for the extra voltage. Another RC rule If you don't have one, buy a cheap, I/r temp gun from eBay. It is essential to monitor the temps of packs, ESC and motor when making any changes to a set up, in your case, lipo over NiMH. Hooning around willy nilly without making sure nothing is overheating leads to failing motors (magnets rebinding from the rotor) and venting escs....avoidable for the sake of five minute runs, temp checking etc for a packs duration. Hth 2 Quote Link to comment Share on other sites More sharing options...
Derka Posted April 23, 2015 Author Share Posted April 23, 2015 Thanks guys. I'll have to read up on gearing down then. All new for me! Quote Link to comment Share on other sites More sharing options...
Tug Posted April 23, 2015 Share Posted April 23, 2015 When you change the pinion, you'll need to learn the art of setting the mesh correctly, or you'll rip your spur gear to pieces. 2 Quote Link to comment Share on other sites More sharing options...
Derka Posted April 23, 2015 Author Share Posted April 23, 2015 I don't mind tinkering. I've read about the paper between the meshes to set. I need to read how to change gearing as that's not something I've looked into. In terms of 2s or 3s? Would a few 2s be better in terms of drivability? Quote Link to comment Share on other sites More sharing options...
Noj Posted April 23, 2015 Share Posted April 23, 2015 Simply put, yes. Less strain on the drivetrain too and lipos are a little cheaper To swap the pinny, you'll need to remove the motor...check the manual and the exploded diagrams to see what connects where, with a bit of luck and a fair wind, there won't be too many parts to remove to get access Quote Link to comment Share on other sites More sharing options...
Derka Posted April 23, 2015 Author Share Posted April 23, 2015 (edited) It looks fairly easy and I think the Helion website has different gears. Think if I get a decent rating 2s it should make things better as it's a brushless motor running nimh? The hobby king website lipo don't come with dean's connector. So that's something I'll have to get swapped at local hobby shop as they solder and my soldering isn't the best! Or I could pay a bit more and support the local shop and buy from them, save delivery charges etc. Edited April 23, 2015 by Derka Quote Link to comment Share on other sites More sharing options...
RCbutcher Posted April 23, 2015 Share Posted April 23, 2015 You probably know but check if you have to program the esc for lipo too. Quote Link to comment Share on other sites More sharing options...
Si Coe Posted April 24, 2015 Share Posted April 24, 2015 For a 1/10th scale like the Dominius the rule of thumb is 2S for all round driving, 3S if you want POWAAA!!! On a track, the 2S cars actually tend to lap better because 3S just can't put the power down well. Due to the lower internal resistance of the cells, 7.4V lipo's perform about the same as 8.4V NiMhs in terms of speed, but run cooler and longer. A 3500mAh lipo will give you around 20% longer run times than a 3500mAh NiMh. That said, its always advisable to get the best lipos you can, and personally I wouldn't buy anything less than 5000mAh unless its a shorty pack (and then not less than 4000). It can't hurt, you gain additional running time and there is minimal price difference. The better the C rating the more 'punch' (acceleration sort of) you get, and the less strain put on the pack. That means you'll get more cycles use out of a 50C pack than a 20C one in the same car, provided you don't do anything else wrong! Quote Link to comment Share on other sites More sharing options...
Derka Posted April 24, 2015 Author Share Posted April 24, 2015 Aye, I am learning more towards 2s. My esc has a lipo alarm and low voltage cut off. I just need an IR thermometer to keep an eye on things Quote Link to comment Share on other sites More sharing options...
Tug Posted April 24, 2015 Share Posted April 24, 2015 2S lipo and you shouldn't need to worry about temps. However, it's good practice to monitor temps whenever you make a change, even if you think it's only a minor change. Quote Link to comment Share on other sites More sharing options...
NuttyProfessor Posted April 24, 2015 Share Posted April 24, 2015 (edited) Agreed, id also if it was me, id strip the gearbox apart and re-lube everything, RTR'S tend to run lean on lubrication and shimming of the diffs, being a 2WD, it should be a lot easier to maintain as everything should be rear mounted light machine oil on the bearings too to keep those happy once in a while too. Edited April 24, 2015 by NuttyProfessor Quote Link to comment Share on other sites More sharing options...
Derka Posted April 24, 2015 Author Share Posted April 24, 2015 My dominus is 4wd... Quote Link to comment Share on other sites More sharing options...
NuttyProfessor Posted April 24, 2015 Share Posted April 24, 2015 Ok then, 4WD, dunno why I said 2WD, senile at 32! Quote Link to comment Share on other sites More sharing options...
Derka Posted April 24, 2015 Author Share Posted April 24, 2015 Ok then, 4WD, dunno why I said 2WD, senile at 32! Haha. No worries. My truck isn't well known. Just took the front diff cover off to inspect it. Wow. What a faff! Think I'll do the rear another day! Quote Link to comment Share on other sites More sharing options...
sparkysx Posted April 24, 2015 Share Posted April 24, 2015 2s lipo is like nimh with nos, I'll nevergo back to standard batteries, and looking after them isn't a big deal at all. Quote Link to comment Share on other sites More sharing options...
Bigoffroader Posted April 25, 2015 Share Posted April 25, 2015 Hi I'm new to the site and to electric cars. So any advise will help I've got a nitro hyper ST and hyper 9 I'm am in the process of converting the ST to electric, so far I have ordered losi battery box Exrun 4274SD brushless motor and exrun 150A-SD esc Spider centre diff Centre diff top plate I still need to order motor mount and batteries Any help on what would be best for this setup would be greatly received ( makes and place to order) Thank Tony Quote Link to comment Share on other sites More sharing options...
Noj Posted April 25, 2015 Share Posted April 25, 2015 Try reposting/looking for info in the dedicated Hyper ST owners thread Quote Link to comment Share on other sites More sharing options...
Derka Posted April 25, 2015 Author Share Posted April 25, 2015 Aye, I've seen a few posts about the Hyper. I'm new to all this also Quote Link to comment Share on other sites More sharing options...
NuttyProfessor Posted April 25, 2015 Share Posted April 25, 2015 When you took the diff apart, was it greased or oiled derka? Quote Link to comment Share on other sites More sharing options...
Derka Posted April 25, 2015 Author Share Posted April 25, 2015 Front diff was greased and looked ok from my limited knowledge. Gunna check the rear diff tomorrow. The dominus is full of various Philips screws which are not ideal! Just gotta get stuck in with and learn as I go Quote Link to comment Share on other sites More sharing options...
NuttyProfessor Posted April 25, 2015 Share Posted April 25, 2015 Its how I've always learned, buy a model and see how it ticks. Quote Link to comment Share on other sites More sharing options...
Derka Posted April 25, 2015 Author Share Posted April 25, 2015 Lost drive again to the front. I think the main centre drive shaft is not spinning Quote Link to comment Share on other sites More sharing options...
NuttyProfessor Posted April 25, 2015 Share Posted April 25, 2015 See if the front diff pinion is locked onto the centre shaft if its the grub screw style. Quote Link to comment Share on other sites More sharing options...
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