Jump to content
Sign in to follow this  

Lipo, Wires and motor getting warm

Recommended Posts

I know there has probably been so many people asking this question but I simply cannot put my finger on the cause. So I have a version 2 gearbox that came stock in a Dytac Invader recon. The things that are not stock are: SHS 12:1gears, SHS high torque Motor, Pro arms motor connectors and an asg ultimate cylinder head. Now my problem is that after a couple minutes of on and off shooting the wires, motor and lipo are getting warm, the warmth never really gets to the point where its hot to touch but its like a phone that has been used for a substantial amount of time. But I know a lipo shouldn't increase in temperature at all. I am very confident that shimming isn't the issue as I have shimmed a few guns now and the bevel and pinion are meshing well. The wires that came in the gun I quite thin and crap, 20 awg i think and am thinking of re wiring to 16 awg but i don't think that will solve the problem entirely i have checked numerous times for shorts in the gearbox, oh and forgot to mention I am running a GATE NANO SSR mosfet that does not have active breaking. Besides this slight warmth my gun is running really well and the heat doesn't seem to effect performance whats so ever. The only thing i can think of is that the lipos I am running on this gun are 1450 MAH 7.4V 20 C and am thinking that this is not quite enough amps for the setup I am running, however am not really sure what the stock spring is in the dytac. It would be greatly appreciated if anyone has any suggestions ???

Share this post

Link to post
Share on other sites

Warmth is generated by resistance. If the temperature across all the parts is the same then I would start to suspect the wiring. If the motor is hotter and as you go further way the wiring cools a little bit then its the motor getting hot and translating that heat through the wiring (metal carries heat really well).


So the first test is to fire it rapidly and get one of the parts warm and see which it is. If its everywhere straight away then its your wire resistance, if its in the motor and then it spreads then you know the motor is getting hot. Unlikely to be the battery, its likely just soaking up heat from the other parts.

Share this post

Link to post
Share on other sites

Let's start with some basics. If something electrical is getting warm it's passing a lot of current. Possibly more than it should. Your gearbox sounds pretty far from standard, personally I think it's most likely the crappy thin wiring but even if you rewire with 16awg it's still going to get warm. If anything it'll get worse because the fatter wiring will pass more current. The wires might not get as warm but the motor still will. Ultimately you're running a high torque motor with high speed gears in an enclosure with little to no ventilation. It's going to get warm it's just basic physics.

Share this post

Link to post
Share on other sites

The wires that came in the gun I quite thin and crap, 20 awg i think and am thinking of re wiring to 16 awg but i don't think that will solve the problem



It will certainly help - it won't make matters worse and I presume you have got deans and not Small Tamiya

small tamiya, multiple breaks/joins in wiring, thinner stock wire, and the motor connectors needs a possible blob on 90 degree bend/elbow


You need the thickest wire from battery - fet & motor you can get in there

fet signal wires - tiny thin crap - heck 26awg is fine though wouldn't go any thinner

deans - least joins/breaks in wire etc.... - then motor connectors is next resistance

Sounds like a v2 - it was v3 I say consider solder wires to motor BUT only if all running 101% sweet

but that would be on v3 - if v2 don't solder wires direct to motor coz its a git to service gearbox later

(just try to blob the bends - or the connectors will just blow like a thin blade fuse under stress)


Your setup on 12:1 & high torque motor will unleash 30+ rps on a 7.4v - 25c to 35c battery

(if you are way below that it is coz there is lots or resistance/choking it)


That setup you are fitting together is quite a beefy setup - and I strongly advise:




No offense but doubt if you did all your homework coz 11.1v will go too fast and smash f*ck out of piston/box

12:1 gears might have been a little too much perhaps(12.65:1 ratio me thinks)

you have effectively increased cycle speed by 50% on gears & also the neo motor another 40 to 50%

so you have doubled the stock speed at least onm old gears n motor

but wiring is still stock - jeez


oh n spam on semi - keep firing on just semi say 2 shots per second for a minute

(120 single shots in a minute)

Then you will know what a warm gun is like - it is like a mega stress test some mosfet guy on youtube does to test his work

(the guy really knows his stuff - way more than I will ever know)

Actually don't do it for too long - actually don't do it at all until you have rewired and reduced resistance points like I said earlier

(your stock wiring will deffo not be able to cope)


SOZ - mega OTT reply but that is some serious oooooomphy setup - ya gonna get a bit of heat

especially if spamming - DEFINATELY WITH $HIT WIRE and only doing the job half done so to speak

Share this post

Link to post
Share on other sites

Yes I do have deans connectors. I wasn't planning on running an 11.1v I don't like the idea of that in airsoft guns also you said 25c - 30c and I'm only running a 20c would you suggest I'm putting too much strain on my lipo with this setup. Apologies with the lack of knowledge on batteries they do confuse me sometimes ?


Thanks for your suggestions though

Share this post

Link to post
Share on other sites

battery will be ok @ 20c - kinda of scraping it a little on the higher beefy setups

as I run 25c to 35c on my guns - some go nutz and run 45c+ batteries but c'mon.....


on that setup me thinks you may want 35c tbh but that is not the problem me thinks

its ya wire holding ya back AND it is a beefy setup for UK sites with our not so mental rof & rps as over the pond


it is capable of hitting 30+ on 7.4v or 40-heck 45+ on 11,1v and probably go BANG !!!!


@ 25rps you do start to get a risk of Pre Engagement creeping in on really heavy slow returning pistons

though it shouldn't occur until you go over 30 - but it could be getting close


Hence the PE warnings about pushing guns too far - trust me and plenty others on here

we have busted a few pistons along the way - well I've broke plenty of guns taking the mega pi$$


To be honest I think if box was rewired you should of got near 20 rps on stock 18:1 gears

and would of been fine for many people

worst rip off gears are in fact 16:1 gear sets - recently found out they are aprox 17.5:1

so htf can they call them 16:1 or 16.65:1 - jeez that ain't a 10% but only 5% gear ratio change over stock gears


it will still get warm coz it will be doing lots more work so even if motor/mosfet can keep up

it will be running at least twice possible a bit more than stock

30rps compared to say 14rps out of the box - so yeah it will get warm but hopefully we try to give it as least resistance as possible


You gotta rewire it first and see if she runs better - probably need to go up to 25c at least at some point

but depends on room available for battery I guess - but deffo rewire first n see

Share this post

Link to post
Share on other sites

Soz for double post but am trying to break it up a bit........




that is da $hit you want if fitting 16awg silicone wire is tight inside ya gearbox

I could link to the stuff I use but not giving all my secrets away and you have to buy my stuff in about 10m lengths anyway coz it ain't cheap


To anybody else reading this - it takes a fair bit of work to get ya gun firing faster n faster


You box will go faster....


it WILL f*ck up faster


it WILL wear faster


it WILL run hotter as more more heat is created - yup you guessed it - faster


So with all this in mind I strongly urge people to go slowly as you tweak your gun

and learn as you go - often you get to a point where in my opinion around 25rps is plenty

and a good balance of tweaking vs durability


to OP - rewire box and on motor connectors - hold upright and blob solder each side of elbow

don't blob solder on it coz it may run down into connector and not fit on motor contact

(I did that and had to cut/refit another connector - so hold upright and surplus solder runs back to wire - not connector)


If after all that and she is still running quite hot under normal use then I would suggest you check shimming...


YES your box may be running sweet but if the bevel gear is set low then as motor is wound inwards it pushes bevelm,

it pushes that poor bevel too much and it runs tight against the bushing/bearing - creating more strain/heat

This is not your normal schreechy sound but it deffo puts additional load on motor.....

On the motor - it is a very strong neodym torque motor and will just grunt along turning but strain/wear/heat is taking place


So ensure bevel is shimmed perhaps a smidge high rather than a smidge low

I say a smidge - and I mean a smidge - normally on quality gears you will not need hardly anything on top of bevel

the thinnest thinnest shim on bushings - max or maybe 2 x thinnest shims on bearings - max

any more and by my reckoning you are shimming bevel too low

You should check and really pay attention to bevel gear height in your gearbox - every box is different but check out some guides

coz this crap is important in high speed boxes - and not so fast boxes if you want them to run well


Think that just about covers it from me for the moment - but heck I'm still breaking n learning myself

soz if I went way way overboard and don't worry if some of this is just pure crap

99.9% of what I type is just that

Share this post

Link to post
Share on other sites

Wicked ! Thanks so much for your help will order the wire now. Hopefully this puts me on the right track. I am getting close to 25 rps which is my goal, I'm actually really happy with the performance, I just wanted to reduce the heat as much as possible but thanks again i appreciate your time I will post the outcome shortly !

Share this post

Link to post
Share on other sites

Yes they say SHS torque nd speed motors do run warm/hot

but my feeling is that these motors are running under more load/cycling faster etc.....


I bought some really cheap motors and they REALLY ran hot - even just on their own outside of box testing




magnets are mentally strong but think the build or assembly is pi$$ poor - even polarity on both long n short was labelled wrongly


the case was bigger and was too tight in an ak motor frame that motor height adjustment wasn't smooth

so I have strppied and rebuilt the short one into an old 28tpa ferrite to make a frankentorque which runs cooler than the cheapo one did

still to do a proper test on it but seems a beef of a motor and really really hard to turn by hand now....


Still gonna stick to my fav Big Dragon M160's and wait for shipping


To the OP - make sure piston is not all full metal teeth - you gotta have a few plastic teeth if going faster

if full metal piston is used and you get PE it will make a big mess coz no weak point to break/shred piston

(imagine all steel teeth/gears/pinion on motor smashing into each other - that mess will be costly - smashed 12:1 gears etc...)


As you go faster n faster it creates more n more issues to deal with

I have learned the hard way you can't just chuck in this n that - often stuff will bust unless you do other work etc.....


As you may go past 25rps once wired up - you "may" get two other things happen


Pre Engagement or get closer to the risk of it on a m100 spring setup


Double firing on semi also may start to occur, especially on a fresh higher charge or C rating battery


if these symptoms happen then you have to move onto more work like looking at a higher spring:

M110 or M120 spring and coz your over fps you have to shortstroke a tooth or two or three etc.....


Shortstroking is a bit of guess work for many often each tooth will reduce fps by aprox 6.5% - don't ask but I need to get out more

Airlabs highly recommend shortstroking a little on the more tweaked guns but like I said as people go faster it involves more additional work


therefore if people can be content with 20 to 25rps there shouldn't be a massive amount of work/problems creeping in

20rps should be do-able on stock - nearly 25 can be done on stock gears if you really really really use thick as f*ck wire soldered direct to motor on a v3

often stock gears are ok for most or perhaps use 14:1 or 13:1, 12:1 is maybe a too higher ratio imho and 16:1 gears are really 17.5 ratios so I got mugged


OP needs to check bevel height and ensure piston has some plastic teeth & AOE etc.... when rewiring the box

coz once it is rewired on thicker stuff you may gain a small percentage - up to say 5%

it probably will be fine but there is a very slight tiny risk of getting to say 27+rps and sailing closer to PE

more so if it is a fresh 7.4v off charge it will be pushing out 8.4v+ etc....


I'm sure new wire will greatly help but check a few things when you got your box open

Share this post

Link to post
Share on other sites

I actually have a guarder SP110 spring but wasn't sure if i should install it yet do you think it might be worth installing that when I re wire my gearbox.

Share this post

Link to post
Share on other sites

I actually have a guarder SP110 spring but wasn't sure if i should install it yet do you think it might be worth installing that when I re wire my gearbox.


Hmmmmm - tough one coz I personally haven't used guarder springs - only stock and/or shs & element


what is gun shooting at - has the AOE been done?


a m110 will put out aprox 365 - BUT if a box hop nozzle is perfect seal a m100 will get close to that instead of its

"supposed" 328fps or 100m/sec figure

Often to compenstate for slight - and I mean slight air loss a 105 or 110 can be installed to get to 350

trouble is sometimes springs can be pushing out a smidge more than say 110m/sec and good seals can take this to even 380fps+


when AOE is done you can expect a drop of 10 to 15fps but normally when this is carried out the seals in box are checked and improved upon

eg: good double o-ring cylinder head plus possible ptfe tape wrap, o-ring nozzle, new well lubed piston o-ring, polish cylinder etc etc......

so in effect though you lose15fps you claw back most of this with better seals

now if a bearing spring guide is fitted over a cheap std one then you can expect to add 10fps on top - so you could end up

with a great sealed box on say 105% of its original fps even though you lost 15fps doing AOE - if you really get it sweet


Still ain't finished coz if you fitted another nozzle with o-ring and didn't check/compare old & new

the new nozzle may be a smidge shorter and you no longer get a good or decent seal against hop bucking and so your fps can plummet

or too long nozzle and it may create feeding issues - jeez it is bloomin' nightmare if you don't take your time to check stuff


And all this stuff on springs n fps means nothing if you do not have a chrono to test your results

coz as I mentioned the final figure can really really vary a hell of a lot


I'd do the best possible checks you can on old spring first - really ensure your piston hardly moves once past the cylinder port

and I mean really hardly moves - big difference between a good seal and a great seal

AOE must be done - not should, it must be done if running a gun @ 20+rps

not a case if it piston will snap at pick up tooth - the very big first lug on piston

it ain't a case of if it will - it is a case of when it will snap off - so AOE must be done in guns firing into 20's imho


All springs will lose some of their tension over time - aprox 10% perhaps in 6 months

eg: gun fires 330 new but later on it is dropping to 300 - though some may also be wear on seals too


One day I'll get around to getting say a couple of m130's - get then shoved into an old shredded piston

using a few spacers to compress spring a little more inside piston say a further 5mm each end

bolt the spring into the piston with a 100mm M6 nut + bolt - with 2 x 5mm spacers so its really compressed

then leave it for a fortnight or month to lose some ooomph.....

this might lose a bit say 10% = a m117 spring power, short stroke a box/piston 2 teeth to arrive at aprox 350

coz spring has lost a bit of its initial tension then there is a good chance that m117 power will maintain its power

very reliable & for a longer period of time - well that is the theory one day I may get around to testing if it actually works out


Springs are a bit of a lottery there are different types but I tend to use the std consistent coil springs with a decent thickness of wire

some have more coils in centre so initial start of compression is easier and once piston is moving the tension escalates in the middle onwards


yeah soz can't say yes or no to other spring - get gun running ok and see what happens first is my guess at this moment

Share this post

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

  • Create New...