Batteries draining at a STUPID rate?! Not dead batteries either...

[Benjii]

Hey people!

I've just done out my ICS M4 to the max, and in the bunch of upgrades is an SHS high speed motor. Before I had the motor fitted, with a 9.6v 1600mah battery I could last the day.

But now with the identical battery, I get 40 minutes out of it max. It's wired to large tamiya, and I'm not sure what to do?! I've bought new batteries just incase mine started to lose there charge quicker, but no, still the same. I've tried using 3700/4600 mah batteries but it bumps up the ROF too high and the pre engagement with the piston begins to happen.

What should I do?

Cheers

Ben!


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[Darkmikey22]

Re: Batteries draining at a STUPID rate?! Not dead batteries either...

it sounds like a short somewhere and maybe snagged a wire. i could be wrong! but i had something similar a few years back and it turned out that i snagged a wire and cut into the protective layer while putting the motor back in and shorted it on that.

[Tom Andrews]

Re: Batteries draining at a STUPID rate?! Not dead batteries either...

If you have upgraded it 'to the max' would this include stronger spring, bushes etc as well as the motor?

Did you upgrade the wire as well? Chances are the motor draws more current, the spring (if fitted) is stronger and needs more power, the bushes/bearings may be tight. All this adds up to more power being drawn, hence the lower duration of the battery. Throw away the Tamiyas, fit thicker wire and you may regain a small amount of duration. Remember the extra power/fps has to come from somewhere, and that somewhere is the battery.

[original poster]

Re: Batteries draining at a STUPID rate?! Not dead batteries either...

Your ROF is increasing by using a higher mah battery?

[Benjii]

Yes that's correct, it increases by a lot. What wiring would you recommend? Also, as I can't do the wiring my self (have no soldering iron, and probably aren't capable!), can anyone recommend a cheap techie?

Cheers so far,

Ben.

[Snowdrop]

Re: Batteries draining at a STUPID rate?! Not dead batteries either...

For the price of a techie you could buy a soldering iron and plenty of vids on the web about how to solder. Don't forget heat shrink

[Crude Skinny B]

Re: Batteries draining at a STUPID rate?! Not dead batteries either...

Your current 1600mah battery does not have the discharge and possibly amps needed to run the shs high sped motor. Get rid of the tamiya and install deans as they have a lot less resistance. You may also want to think about going lipo. You may also want to exchange the high speed motor for the torque equilvant as it is more battery efficient.

[seansamurai1]

Re: Batteries draining at a STUPID rate?! Not dead batteries either...

On a NiMh battery (any battery I think) the MaH has no deciding effect on ROF, it's all about voltage/discharge rates. MaH is just the amount of 'storage' the battery has.

[original poster]

Re: Batteries draining at a STUPID rate?! Not dead batteries either...

On a NiMh battery (any battery I think) the MaH has no deciding effect on ROF, it's all about voltage/discharge rates. MaH is just the amount of 'storage' the battery has.

Exactly why I asked the question, didn't think it had anything to do with it!

[Clone1B]

Re: Batteries draining at a STUPID rate?! Not dead batteries either...

I think its simply a case of the battery you've got not being able to provide sufficient current. Consider getting a new battery that can deliver much higher current (usually a LiPo), rewiring the gun with better/thicker wire if the wiring job is shoddy, and replace the tamiya connectors with Deans or another high-current connector.

If you were using an ICS Turbo3000 motor before hand the needed current shouldn't of changed much, but older ICSs have notoriously shoddy wiring. How old is your gun?

[Crude Skinny B]

Re: Batteries draining at a STUPID rate?! Not dead batteries either...

I believe that Mah can affect rof, if the battery cannot supply enough amps to the motor then you will see a drop in rof. I was using a 800mah 20c lipo and comparing it to a 1600mah 20 c lipo there was a big difference in rof as it could supply more amps.
Thats why when he uses a bigger battery there is a noticeable increase in rof.

[seansamurai1]

Re: Batteries draining at a STUPID rate?! Not dead batteries either...

That's a Lipo though.
However between my lipos there is no difference.
You also haven't taken discharge rates into account either.
You have mAh which is the storage size, that's just how long a battery lasts under set circumstanses, then you have your discharge rate which is measured in amps.
I could have a 2000mah 9.6v battery that's slower than a 1300mah because the discharge rate of the larger battery is 15Amps whereas the smaller one could be 25amp discharge rate.
It's nothing to do with mAh which some may call the charge rate.

[caffin999]

Re: Batteries draining at a STUPID rate?! Not dead batteries either...

amps is calculated using mah and the c rating so yes mah does affect it. A battery can have a supidly high c rating but if the mah is too low it may not kick out enough amps to power a gearbox properly. Likewise if mah is really high and c rating is really low.

[Bachelarius]

Re: Batteries draining at a STUPID rate?! Not dead batteries either...

While normally I am more than happy to work on other people's rifles, I am normally a lot happier to teach a person how this stuff works so that they can pass on the knowledge themselves. There are also a lot of very poor techs around, far more than there are good ones, so please, take the time to take in the all of the following:

First of all the fact that the higher mAh battery is providing a higher RPS is not surprising. The SHS motors are Neodymium based motors. They are very strong but they eat up a lot of power, way more than your standard stock ferrous motor, so need the amps in order to run at the max voltage.

It looks like the 1600 was not supplying the current needed to run the motor. The 4600mAh battery will have a current ceiling of almost 3x that of the 1600. I haven't been able to find a concrete C value (max discharge rate before the cell becomes unhappy and voltage drops) for a generic nimh cell, but after a quick google numbers between 3C and 10C are thrown around. Lets assume that it's 10C for ease of math (its probably significantly lower), that means that the 1600 can only supply up to 16A, whereas the 4600 will be able to kick out up to a whopping 46A - which will run pretty much any reasonable setup without ever being over-stressed.

Lets assume that your motor is at it's healthiest at 15-20A on a reasonable setup (pulling a number out of my ass here, I think in reality it would probably be higher), that 1600 cell is still a bit underpowered, but not so much that it drains in minutes.

So, in short, something is causing your rifle to pull more than the expected amperage.

There are 2 possible issues here: Electrical and Mechanical.

Lets start with the more likely - Mechanical.

The more work a motor does, the more amps it pulls. ANY mechanical resistance in the system you have will add to this. The bevel to pinion gear method of shimming is fantastic because it not only does the usual gear-durability upgrade, but the positioning of the bevel and pinion gear with regards to one another is perfect for maximum power transfer (think back to moments from school and see how it applies here and just how badly a poor motor height can affect the force required to move the spring). The bevel-pinion gear method of shimming prevents poor positioning of the motor, where it pushes down on one side or the other of the bevel gear.

Good shimming and good motor height is a fantastic way to get rid of any excess wasted forces and drop the strain, both from removing slop and thus preventing the flat faces from ever rubbing and the aforementioned power transfer.

Next, good lubricant application is another good way to help stop things going wrong. Lubricant is actually used to stop gear wear rather than making it easier for the gears to mesh, but poor lubricant application actually much worse than a bone dry gearbox and is a surefire way to noticeably up mechanical resistance. The correct method of application is generally to slap it all on all over the gear, getting it into every crevice, then removing ALL of the excess, so that a very very thin flim remains, like a gleam of it giving the gear a bit of a shine. If you have grease thrown all over the place around your gears, that's bad and you're using too much.

Another thing to note during the lubrication process, make sure there is no crap in any of the teeth of the gears, e.g. bits of plastic from the piston or random crap like hair etc. It's really easy to miss and has a huge impact on motor stress, so clean your gears thoroughly during your service.

Next, electrical resistance.

The motor is not the only source of amps in the system. Any and all resistance adds up to wasted amps and thus wasted battery life/stress. It's normally really easy to spot a weak link because it becomes warm as you pass current through it. The obvious offenders are Tamiyas. They suck. Swap them for something that sucks less, if you can.

Next, the wire. 18awg is usually the stock diameter, I prefer to use 16awg silicone wire because it is cheap and does the job better than stock wire (and I have a load of it), others use teflon wire which is stiffer and thinner. Use whatever will fit in your gearbox. As mentioned above, If you DID have a nick in your wire as well, any shorts will be creating a huge power loss, so a rewire or just some insulation will sort this out. When soldering new wire on, be careful not to accidentally make it touch the case and plan the angle that the wire needs to be hooked up to a contact. I've lost count of the amount of times I soldered on wire, was happy with the lovely job, go to assemble the case and I can't get the wire routed because it's soldered on at the wrong angle! Gah!

Speaking of soldering, check your solder joins. Do some googling/youtubing around good and bad soldering as it's easier to demonstrate the differences than to explain what to look for.

Next, the trigger block. Check the contacts and gold tooth for corrosion. Don't know if ICS use an electrical safety or not, I think they do. I personally prefer to short mine by soldering on a piece of wire across the 2 prongs that touch the selector plate and removing the metal bit from the selector plate, as it's a REALLY inefficient part of the trigger circuit - I've burnt myself on it in the past, it got that hot. Alternatively, you can fit a mosfet, which will completely nullify any issues with the selector contacts AND the other inefficient bit - the trigger contacts themselves. You will then reap the benefits of much lower resistance from the contacts, so even less wasted power, and generally more win. And Billy Breach sells them for about £10, which have held up well so far for me.

The last inefficient part of the system is sadly one you cant do masses with on an m4 - the motor contacts. These are the last source of poor electrical contact and about the only thing you can do to them is use a pair of pliers to bend them a bit, so that they fit on tightly. Personally, I replace these with Ring connectors, which I hook up to the screws on the motor. Seems to work well, but I cannot guarantee it is compatible with every motor out there (if the screws are connected to a metal part of the can, then it will just short the motor and bad things will happen, but I've not yet found a motor that is built this way) . Also, the plastic that the screw actually screws in to can strip over time, so another thing to be wary of.

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Do all that, your battery efficiency will hugely increase. My guess is it's just motor height or shimming that is the main culprit, but it could be anything really.

On the subject of pre-engagement btw, that's also not good, esp with a 9.6, though I am not sure how you diagnosed the fact that it is happening. If it really is pre-engagement, try polishing your piston rails in the gearbox, checking if the piston can move smoothly and freely without catching on anything and then either lightening your piston assembly (look up swiss cheesing and remove any bearings or those stupid TM style spring-hook-'weight' things inside the piston). If all else fails - heavier main-spring is a good thing too - you can control fps using something like short stroking if it comes to it, but I don't tend to get overspin on 9.6v batts with a 330-350fps spring whereas I got it REALLY BAD with 270 fps TM for instance.

If in fact you are talking about over-spin and not pre-engagement, then a heavier spring will solve that as well. If all else fails, you could cheat and use an AB mosfet, but it's extra stress on the motor and another thing to go wrong in my opinion. Heavy spring + short stroking is usually a better solution.

Good luck! If you do end up getting someone to work on your rifle, do not accept any less than the above tbh...

[seansamurai1]

Re: Batteries draining at a STUPID rate?! Not dead batteries either...

To further add, I use a systema magnum high torque motor, which is neodymium magnet.
SHS 13-1 gears and on a 9.6v 1300 mAh battery I can comfortably hit 24RPS, it will last all day as well.

I'm personally not going to hedge bets but I'd say its a bit of both. Over shimmed gearbox with less than ideal wiring, if the battery is an old one that could also be an issue.