[MadMax]

I realize in a recent upgrade discussion that many airsofters are unaware of the actual current specifications of their electrical connectors.

Having taken some introductory courses in electrical engineering and perhaps more importantly having some experience in electrical R/C helps one appreciate why a range of connectors exists to the hobby market.

There are two connectors in wide use in airsoft:

-small Tamiya
-"large" connector (basically a scaled up Tamiya type connector)

both connectors have white or yellowish/cream natural nylon bodies and are 10mm and 13.5mm wide respectively. I believe the smaller connector is actually a Tamiya properietary connector which has been adopted by airsoft because of it's wide availability and compactness. The larger connector resembling a scaled up Tamiya connector is more commonly referred to as a power connector made by Molex/Waldom in the electrical industry.

The Tamiya connector is typically rated for 9A continuous current flow. The larger Molex connector is rated for 15A of current flow. The continuous current rating specifies the maximum current flow that the connector is designed to pass on a continuous basis. I would guess that this assumes a 20C environment of unmoving air.

This means that a large connector can pass 15A continuously in still air (no forced air cooling) for hours or days without melting down. Whatever voltage drop occurs over the connector at 15A can cause the connector to warm, natural convection will remove heat fast enough that the connector will not fail.

This does not mean that the connector is working efficiently. It only means that it will not completely fail. Some voltage drop occurs over the connector (which warms it) so a reduced voltage is applied to the final load (the motor in the case of airsoft).

A relatively new connector style is becoming more popular with technical airsoft enthusiasts: Deans Ultra connector. The Deans Ultra plug is rated for around 40A of continuous current transmission. It features gold plated flat contacts which make firm large area contact between connections.

In the R/C world, the constant current rating of connectors is very important. Model electric aircraft or cars are expected to run their motors continuously for minutes at a time. In the case of planes for perhaps even tens of minutes. Because of this, it is very important that their connectors don't fail from the heating caused by sustained current flow.

In the case of airsoft, we don't have such stringent requirements. Typically airsofters fire in relatively short bursts lasting seconds. We can accept a degree of connector heating as there is often a period to allow cooling between bursts. However, a warming connector means that we are not supplying full voltage to our AEG motors. Some voltage drop occurs over switch gear and various connectors and within the battery itself.

If we are to expect optimal performance from our AEGs, series resistances between the motor and the battery should be reduced. In some cases, the series resistances are not very high. In others, they are significant.

I will address a few different situations:

-stock AEG, mini battery
-mid upgrade AEG (~330ish fps), large battery
-high upgrade AEG/LMG (~400fps), large battery

Stock AEG, mini batt

-low current requirements due to low stiffness spring
-relatively high battery internal resistance

The low current requirement for driving a stock spring don't really stress the mini plugs typical in stock AEGs. If you fire your AEG for a long burst you may note a bit of connector warming, but nothing particularly interesting.

Minipacks typically have a considerable internal resistance so removing every connector resistance is not hugely effective as the int' resistance of the battery pack is considerable compared to the resistance of the rest of the AEG components. Since the total resistances in series with the motor are added, eliminating connection resistances may not affect the total sum all that much.


Mid upgrade AEG, large battery ~1700mAh and higher

-med/high current requirements to drive upgrade springs
-lowish internal resistances in the battery pack
-AEG typically owned by someone who likes to shoot a fair bit

Usually in mid upgraded AEGs, the 15A fuse is removed or at least changed to a 20A or 25A fuse. This indicates that the current req's of a mid upgrade AEG are actually higher than the rating on the large Molex connector.

When firing short bursts this is not a particularly bad issue as the Molex connector can pass higher surge currents than the continuous current rating. However you do incurr an appreciable voltage drop over the connector. Enough to warm it up anyways.

If you've got a Tamiya connector up close to the mechbox, you've got a 9A rated connector in the series which is probably heating up a fair bit more than the Molex connector.

If you plan to use a very high capacity battery (say 3000+ mAh) the pack resistance will be quite small. The resistances of the mini plug and battery connector start to become considerable.

If you plan to use high end battery packs and upgrade springs, consider splicing around the ditzy mini connector at the rear of the mechbox. This is certainly feasible with fixed stock AEGs. It can be a bother with MP5's wired to the foregrip through a mini coming out the back of the mechbox.


High Upgrade/LMG AEGs:

-AEGs typically used for long bursts (LMGs)
-heavy upgrade springs used
-high voltage, high amperage packs with low resistance

Sustained current flow can really warm up crappy connectors. Definitely solder around the mini on your mechbox.

Consider switching all temporary connections with high amp Deans style connectors. If your aim is high ROF and you've gone through the expense of a big heavy pack, remove as many series resistances as you can.