Using lipos without a mosfet.

[vialli]

Got an ics m4 and a jg mp5a4 and being about 10 years old they dont have mosfets.My old nimh batteries no longer hold a charge so i need some new batteries.Should i stick with nimh or use lios? Not sure what would happen if i dont have mosfets installed.

[Leonine]

I guess 7.4v LiPos won’t hurt right? ? As long as you use them correctly I guess they should be ok. Correct me if wrong though.

[Tackle]

Most of, if not all ?, of my guns are older generation kit, before mosfets became a "thing", & I run them all on 7.4 lipo's without any issues, did have an 11.1 but stopped using it as it spun everything waay to quickly for my liking.

[EDcase]

@Vialli, definitely get 7.4v Li-Po's [1300mAh or higher that will fit]

...and a good charger. (SkyRC S60)

 

Of my 16 AEGs, only one has a MOSFET.

All use 7.4v except the Lonex BAW which uses 11.1v because of the recoil system but it doesn't have a MOSFET.

 

The main downside of not using a MOSFET is arching on the trigger contacts will eventually damage the surfaces possibly to the point of not making good contact anymore but that would take a VERY long time.

 

Using 11.1v will obviously accelerate the process so I'll have to keep an eye on that but even so it will take a long time to have a noticeable effect.

 

Pulling the trigger slowly is worse for this situation.

 

[Nick G]

Not a single one of my RIF's has a mosfet ( more bloody electronics to go wrong , I hate tech ! ) and they all run 7.4 Lipo's . Biggest thing to be aware of is not over discharging the battery. If I use the same gun all day I change the battery at lunch time. 

[Tackle]

53 minutes ago, Nick G said:

Biggest thing to be aware of is not over discharging the battery. If I use the same gun all day I change the battery at lunch time. 

On that point, I have a lipo "alarm", essentially a little chip with a buzzer on it that will sound if the battery gets to the point it needs changing, hopefully before it does itself any harm, & itplug in to the batteries charging lead so easy to switch between gats 

[concretesnail]

I use 7.4 lipo in none mosfet rifs and keep an eye on the battery with a lipo alarm connected to the balance lead, works a treat.

[Rogerborg]

You can replace the trigger contacts multiple times for the price of the cheapest mosfet. It's not something to worry about.

[Nick G]

5 hours ago, Tackle said:

On that point, I have a lipo "alarm", essentially a little chip with a buzzer on it that will sound if the battery gets to the point it needs changing, hopefully before it does itself any harm, & itplug in to the batteries charging lead so easy to switch between gats 

I've got one of those too, must get round to actually using it ! Lol

[vialli]

Thanks for all the advice,7.4 lipo it is then.one to fit in the full stock of my mp5 and a crane stock version to fit the handguard in an ics m4 and that sky rc s60 charger.

[Druid799]

6 hours ago, Tackle said:

On that point, I have a lipo "alarm", essentially a little chip with a buzzer on it that will sound if the battery gets to the point it needs changing, hopefully before it does itself any harm, & itplug in to the batteries charging lead so easy to switch between gats 

Fun fact (not really but you’ll get it ?) if using a lipo alarm always remove it at the end of the day because if you don’t within a couple of days it will have killed your battery ! ?it draws a minute amount of power so if your Batt is depleted from use it’s just enough to end your battery  . Rather ironic really that the alarm that’s supposed to protect your batteries will kill them if left unsupervised ! ?‍♂️

[Tackle]

1 hour ago, Druid799 said:

Fun fact (not really but you’ll get it ?) if using a lipo alarm always remove it at the end of the day because if you don’t within a couple of days it will have killed your battery ! ?it draws a minute amount of power so if your Batt is depleted from use it’s just enough to end your battery  . Rather ironic really that the alarm that’s supposed to protect your batteries will kill them if left unsupervised ! ?‍♂️

Always do mate, all batts out too, just in case lol ???‍?

[Druid799]

58 minutes ago, Tackle said:

Always do mate, all batts out too, just in case lol ???‍?

Once accidentally left an alarm still attached to a battery after taking it out of the gatt , went to charge it the following Saturday ready for the next days gameday and discovered it was dead as a dodo AND ballooned up like a Bratwurst ! ?‍♂️

[EDcase]

First thing I do at the end of an airsoft day before even going home is remove all the batteries.

[shadowfacex]

Generally, no issues with 7.4v LiPos up to 25C discharge, however some guns have sensitive wiring; my G&G SG553 was a victim of this, and I had to fit a mosfet to get rid of it getting stuck in single fire. Every time this has been happening, I had to switch to auto, discharge, then switch back to semi.

 

Annoying, but made me send it for a full Titan v3 upgrade along with everything internally, and it’s now my most reliable weapon since 2018.

[vialli]

Ordered this

https://www.vapextech.co.uk/airsoft-7-4v-1300mah-25c-lipo-cranstock-battery-with-case-lp302-vapextech

[Leonine]

33 minutes ago, vialli said:

Ordered this

https://www.vapextech.co.uk/airsoft-7-4v-1300mah-25c-lipo-cranstock-battery-with-case-lp302-vapextech

I  have this, works fine without mosfet. So you should be all good?

[Rogerborg]

On 20/09/2021 at 14:38, shadowfacex said:

Generally, no issues with 7.4v LiPos up to 25C discharge

 

I'm not sure why you'd qualify it with "up to".  The sink (motor) should be the limiting factor, not the source (battery).  If you're relying on the battery to protect the motor, trigger or wiring then you're putting the strain on the one part that can fail catastrophically.

 

 

On 20/09/2021 at 14:38, shadowfacex said:

however some guns have sensitive wiring; my G&G SG553 was a victim of this, and I had to fit a mosfet to get rid of it getting stuck in single fire.

 

I'm a big fan of binning off stock wiring and going with the thickest that will fit, e.g. 16 or even 14 gauge.  And I do that before fitting a mosfet, as you'll want thicc wiring to take advantage of a mosfet anyway.

[shadowfacex]

@Rogerborg I understand where you’re coming from. My SG553 had shit wiring and overload on contacts was causing it to lock up. I’m not sure what batteries the motor or wiring was rated to but anything above 25C in G&G AEGs used to be problematic according to the guy who handled my upgrades.

 

Unless you know exactly what’s in your AEGs and you know what to do with that knowledge the above information would likely do the trick with a margin of safety. I doubt a lot of us here know enough about electrical wiring to play the game of “let’s put the biggest, beefiest battery and see what happens”…

 

What you suggested about rewiring has actually happened to my SG553.

[vialli]

https://www.ebay.co.uk/itm/Sky-RC-S65-AC-65W-LiPo-NiMh-Balance-Charger-and-Discharger-SK-100152-/273870621705?mkcid=16&mkevt=1&_trksid=p2349624.m2548.l6249&mkrid=710-127635-2958-0

Going for this as the s60 has been discountinued

[vialli]

So battery and charger have arrived,is it worth gett one of thoses lipo charging bags ?

[EDcase]

I haven't.  Just put the battery on a baking tray

 

 

[vialli]

Good idea ,didnt think of that,anything special they need to be stored in?

[concretesnail]

Lipo Storage, I use an ammo tin with the rubber removed. Works well as it clamps shut but if anything we're to go pop it doesn't become a potential pressure pot.

[EDcase]

Ammo tin is good and solid ?

Could use a biscuit tin perhaps.

Not something that is sealed so it can release vented gases in case of a fire.