1 shot per 1mAh?

[DanBow]

I was going to ask a question about how many shots would you expect from a battery, as I only got one mornings worth out of a 7.4v 1300mAh 25C 9.62Wh, but is the above right? Obviously in general term!

 

[Asomodai]

Impossible to know. That idea was formed back when we all used NimH batteries with Tamiya connectors. Now we use all sorts of batteries and connectors with less resistance. 

If your replica is badly shimmed, motor height incorrect or a heavier spring is used, it effects the amount of shots you get. Also using semi auto over auto actually uses more energy per shot. 

Also temperatures can effect power draw. 

So 1 Mah per shot is likely a very inaccurate baseline. 

 

[The_Lord_Poncho]

To echo the above, I have one particular replica - bought on this forum second hand that shoots great (at AEG limits), is really snappy, and doesn't sound like the gearbox is badly shimmed. But I always need to take a spare battery into a game with me when i use it - for some reason it gets through a battery (to the point where the gearbox locks up) in under an hours skirmish - whereas other 350fps rifs I use will happily run off the exact same battery for 2-3 hours.

But ultimately, if we can afford a spare Lipo to bring with us (and lets face it, these days they are pretty cheap - especially with Hobbyking having reopened in the UK), it's possibly a bit of an academic discussion!

 

[Leo Greer]

As stated, this is heavily subjective. I'd suggest establishing an approximate baseline for your own build through testing and work off that.

For example, I run my primary off a single 2200mah 11.1v pack, which lasts me for approximately 5,000 shots before I hit LVC ranges. (brushless, well shimmed, etc, etc) Other builds are a lot less efficient...

 

[DanBow]

For example, I run my primary off a single 2200mah 11.1v pack, which lasts me for approximately 5,000 shots before I hit LVC ranges. (brushless, well shimmed, etc, etc) Other builds are a lot less efficient...

5000 shots!!! Jesus!

What started me looking in to this is the last time I played i got through a fully charged 450mAh in a morning and estimated that id only shot about 500 shots. That figure came from google and i thought that if its right, then a full battery in the morning was about right.

 

[Sewdhull]

Have a look on Reapers Air soft, he has a table he has done for various motors and their mAh per shot.

Go to 43 mins to see that table, but long story short around 1mAh a shot is the highest. Depending on the motor you may get from 900 to 5800 bbs for each 1000MAh. There are lots of            variables tho, and data measurement can vary with method so it's going to be ballpark.

You will get more shots from a good ( low IR) battery of the same capacity and a good battery running at a fraction of it's current giving ability will give you more shots than a smaller one running closer to it's limit.

 

[The_Lord_Poncho]

What started me looking in to this is the last time I played i got through a fully charged 450mAh in a morning and estimated that id only shot about 500 shots.

To be fair, 450mAh is tiny - which gun was this in? I can happily (well, reasonably happily - it's a squeeze) get a 2200 7.4v nunchuck battery in the front handguard of my Cyma MP5 - which looking at your list might have the tightest battery space of your current guns..?

 

[DanBow]

To be fair, 450mAh is tiny - which gun was this in?

It's the MP5. I've just checked the battery and I got it massively wrong!!! it a nunchuck 1300mAh 7.4 25C 9.62Wh God knows where I got 450mAh from!!

So I'm guessing 500 odd shots from a fully charged one of those isn't good?

What does the 9.63Wh mean?

 

[Pseudotectonic]

Wh is just the total energy capacity, literally, mAh x Voltage = Wh

Let's say there are two batteries, one is 7.4 V and one is 11.1 V, both are 1300 mAh, the 11.1 V one will have more total energy in Wh than the 7.4 V

 

[Skara]

So I'm guessing 500 odd shots from a fully charged one of those isn't good?

Your system draws a lot of current then.

I run 7,4v 1450mAh 30c batteries in my M4s and my average BB consumption per game day is about 2000 (say 5/6 fully depleted Lonex Flash Mags).

The battery tester I use says that with the above conditions I get my battery from 99/98% charge down to 30ish, now I don't know that the percentage refers to, but all things considered I think my builds are at okay efficiency..

All this in full auto for the most part.

Also keep in mind that semi auto fire draws way more than full auto, the current required to get the motor going is much higher than the current needed to keep the motor going once it's already spinning.

It's not hard to imagine that thirsty motor + semi spam will deplete an average sized battery in a short time, but 500 shots is definitely a sign that something needs addressed in your gun.

p.s. I'm confident I have butchered every electrical term and principle with this comment, sorry, I build houses and survey the land, not an electrician/electrical engineer 

 

[Sewdhull]

Using larger capacity batteries is better all round, if they fit the space.

 

[The_Lord_Poncho]

The other thing to be mindful of is of course the condition of your battery. An old, or poorly made battery that has been left to drain below it's lowest recommended voltage previously will not be holding the capacity it says on the sticker.....

I have bought a few aliexpress batteries as I'm a sucker for such things, and had very mixed results.

But if the battery gives you good performance in other guns, or swapping in a similar capacity battery into the mp5 gives the same results, then might be the gun. 

I tend to swap my 1300mah batteries out after each 1hr game in most of my guns that use them, whether they run down or not - that's probably anything from 300 to 700 shots for me.

 

[DanBow]

They're new batteries in a new Cyma Blue MP5 so i would have thought its set up well. I was mostly shooting on semi though.  Ill take a bit more note of how much im.shooting next time i play.

 

[Leo Greer]

I should add, all this is discounting the strong tendency of airsoft battery manufacturers to lie about the capacity and discharge ratings they advertise. You could very well be using a battery that has only 60% of it's advertised capacity and 50% of the discharge, thus skewing the apparent performance of your RIF far away from accurate.

My personal pack I spoke of in the above post (Kypom 3S butterfly 2200mah) has actually been tested at 2106mah, so the capacity is pretty close to advertised by airsoft standard. And this is by far one of the best packs in this range, which may contribute to a higher apparent "shots per man" rating.

 

[Lozart]

They're new batteries in a new Cyma Blue MP5 so i would have thought its set up well

That right there is a dangerous assumption to make. It'll be set up adequately at best.

 

[DanBow]

That right there is a dangerous assumption to make. It'll be set up adequately at best.

Yes, quite true. Im ordering shims for my G&G so the MP5 might get done too.