How do I Tell If My Motor Is Dead?

[ralu99]

I used to play a bit of airsoft a few years back and then I recently found my old weapon again and was thinking about starting again. Unfortunately the gun doesn't work. I'm not entirely sure about what part is faulty. When I charge up the battery and sqeeze the trigger I can feel the motor giving a little twitch, but it doesn't spin. The battery is a 9.6v NIMH and was stock with the weapon (meaning the battery is about 7-8 years old) therefor i figured a new battery would likely solve the issue. But the thing is that when i measure the battery with a multimeter it reads 9.6v every time. When the battery is plugged in to the gun, the terminals at the motor reads about 1.5v when idling and almost exactly 9,6v when sqeezing the trigger. I remember back when i still played a bit, the weapon would occasionally do this, but when i unplugged the battery and put it back in, it started working again. I've been through most of the wiring, and everything seems to be intact. 2 or 3 times i actually did get the motor to spin for a few seconds from just fiddling with motor outside the handle and repeately sqeezing the trigger. although as soon as i put the motor back in, it wouldn't turn. The motor is called Golden Eagle Super High Power made by JG. The gun is an m4-type-something-idk and everything on it is stock. Hope you guys can help out Let me know if i've left out some crucial information. 

Cheers from Denmark. -Rasmus

 

[Adolf Hamster]

sounds like the battery is dead. nimh's don't age well and one of the things they'll lose is their current supplying capacity.

the voltage might read ok but it still can't supply the juice to crank the motor over.

the motor twitching at all means it still works, the only potential issue there is if the polarity is reversed it'll still twitch against the anti reversal latch no matter how good the battery is turning it.

the first thing i'd be looking at is a new battery, that'll eliminate one variable from the problem, of course there may be other issues but can't know that for sure just yet.

 

[EDcase]

Welcome back

Nixed by a Hamster ?

I would guess its most likely dead battery given the age without maintenance.  It can show 9.6v with no load but not have enough current to actually turn the motor.

Another possibility is the gearbox has seized.  Can you get hold of a good battery to test?

 

[ralu99]

Thanks for the fast replies! Unfortunately i don't have another battery but i think i'll order one right away. Even if the battery isn't the problem, a new one is probably about time anyways. I don't think the gearbox is seized because when i pull the motor out of the handle it still doesn't work. I will let you know when the new battery arrives

 

[EDcase]

....when i pull the motor out of the handle it still doesn't work. I will let you know when the new battery arrives

Do you have a 9v square battery you can test on the motor?  (With motor out)

Get a 7.4v LiPo

Highest mAh that will fit in the space.

 

[ralu99]

Sounds good. Do i need a new charger for that? I think my old one only supports NiMh. It isn't "balanced" or whatever it's called

 

[Adolf Hamster]

Sounds good. Do i need a new charger for that? I think my old one only supports NiMh. It isn't "balanced" or whatever it's called

yeah you're gonna need a new charger.

the skyrc s65 seems to be the current flavour of choice:

https://www.modelsport.co.uk/skyrc-s65-ac-charger-65w/rc-car-products/438918

of course you might want to try and find a local danish supplier rather than deal with whatever the export system for the uk is now.

 

[ralu99]

Thanks a lot. Ordered a 7.4v LiPo 2000MaH and a charger from a danish supplier. Hope that will do.