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Lipo C ratings and Airsoft - Sunday, September 12, 2010

Lipo C-ratings and Airsoft

We get many questions asking us what does “C” mean in “C” ratings. Then the other questions is why do some gun manufacturers limit the “C” rating a particular gun can use.

Both of those are very important and we will attempt to simplify both here.

What does “C” in “C”rating mean?

“C” simply stands for “Capacity”. As in the capacity of the battery pack. So if you get a 1100mah 11.1v lipo pack then “C”is 1100. That is it. Simple as that. So when you see a pack rated as 15C, for example, it simply means 15 x “Capacity”. Take 1100mah x 15 = 16500ma. (note we drop the “h” of “mah” andnow call it “ma”). So that is a large number but it is also talking about milliamps not amps. So divide by 1000 to get amps (ordrop off the right most 3 digits). In this case we get 16500/1000 =16.50amps (note: 1000ma = 1amp).

So take the capacity x number in front of the C and divide by 1000 = max constant discharge rate.

I know what a math lesson. Some examples below:

20C 1000mah packs max constant discharge = 20 x 1000 = 20,000ma/1000 = 20amps

45C 3300mah packs max constant discharge = 45 x 3300 = 148500ma/1000 = 148.5amps

Simple as that

Why do some manufacturers limit the “C” rating I can use.

This is another great question and we can really only speculate why. First off it is important to know that a “C” rating of a pack does not mean the pack will always discharge that max current. It simply means it is the max rating. What determines the amperage your pack outputs is your motor, spring tensions, and pinion. Those 3 things will tell the battery how much energy to release and how quickly (amperage). So a 50c battery pack can also discharge at 10c if that is all it is going to take.

So why then would it matter? In a word it should not matter if you use a 50c pack on a gun that says to only use a 15C pack max.

But there is a reason. The reason is the higher “C” packs will maintain a higher average voltage but not exceed the nominal voltage(3.7v per cell) for a given pack. So if a manufacturer states to not use anything over 25c then in means they need you to use a pack that will have lower average voltage so it does not damage the motor. In a sense they are telling you to use a lessor battery simply because using a better battery is too much power. What? Really? YES! So the question is why use a lipo at all in this case? Perhaps nimh isjust as good? In some cases it is. In others no.

The truth is a very good nimh pack, like the Elite airsoft batteries, really are a great high power Nimh product for your airsoft gun. Many people are seeing poor performance from stock packs that come with their guns and think all nimh is the same. That is not true. Far from it. Nimh can also provide higher “C”types and don't suffer the same issues as Lipo does. So keep that in mind when selecting a pack for your airsoft needs. Sometimes lipo isthe best choice. Sometimes it just does not make sense. We are here to help you decide what the better choice is. That is what we do.

Thanks for reading our short bit of info. If any of this is still unclear or you have more questions please send your emails to us. Please go to contact us area to send us an email. In an attempt to keep spam to a minimum we do not use our emails in blogs.

Thanks,

EAB Staff.

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Quick Battery Guide By: Chris The Battery Man - Tuesday, September 07, 2010

Quick Battery Guide By: Chris TheBattery Man

Forthose of you who don't know me, My name is obviously Chris I have been buildingand selling Batteries with CheapBatteryPacks.com for a little over 8 years now.I have almost 7 years experience hand making Lipo packs, and am a avid RC'ist.Feel free to contact me with any questions you may have at:chris@eliteairsoftbatteries.com

In my light endeavors into airsoft, I have noticed, thatthere are quite a bit of you, that aren’t fully informed on batteries. So I amhere to help you a little bit. Below is a little info that you may findhelpful. I can answer any further questions you may have, but this should coverquite a bit. You may know some or all of these facts, but this is to the newguy, or the mis-informed guy.

Voltage:

Pretty simple. The more voltage(ie 7.4v pack) the higherrate of fire

Capacity:

The capacity(ie Mah) will give you more runtime. This islike your fuel tank. The more Mah, the longer you can shoot people

Neither of these will effect your accuracy or FPS.

Battery Chemistries:

There are a few Chemistries that the electric hobbyistuses. The most common is Ni-Mh, or Nickel Metal Hydride. Li-Po, or LithiumPolymer is big in RC applications, and is beginning to take off in the airsoftcommunity also. A lot of stock guns come with low quality Ni-Mh, or Ni-Cadbatteries. Ni-Cad’s, or Nickel Metal Cadmium batteries are an older technology,and have become inferior to Ni-Mh, and Li-Po packs. There are also a lot ofvarious forms of the Li-ion chemistry.

For airsoft, Ni-Mh is the best bet. Very powerful if youbuy the right cells, and affordable. I know that there is a larger demand forLi-Po packs also, but your only real gain besides rate of fire, is some weightloss. Li-po’s are much more needy, and have less configuration options. Also,in most cases, you don’t get as much capacity for certain packs. Li-po is agreat performing chemistry, but would not be my first choice. They require moreto be happy. Such as some type of low voltage detection, to keep the cells fromdropping below 3v each. And a special charger/balancer.

Ni-Mh batteries are 1.2v per cell

Ni-Cad batteries are 1.2v per cell

Li-Po batteries are 3.7v per cell

Li-Ion type cells vary from 3.3-3.7v, depending on thespecific chemistry.

Battery Quality/Performance:

One thing I fight with a lot, is informing people thatnot all batteries, are living up to what their label says. There are a lot ofbatteries that come out of really cheap Chinese factories, and are of a verylow quality. Generally, these are stock batteries that the gun comes with, orare no-named looking cells. This is bad for 2 reasons. 1: Low quality cellswill have a short cycle life. Which means you will get a lot less charges fromthem. 2: they do not deliver enough power. And even though airsoft guns aren’ta high current drawing applications, the cells can’t be bottom of the barreleither.

Now when it comes to good cells, there are 2 differenttypes basically. 1 being a low drain cell, and the other being a high draincell. The difference is that the low drain cell is meant for low currentapplications such as cordless phones, RC transmitter packs, and so on. Whilebeing able to offer a good capacity, and offer plenty of cycles before theyneed to be replaced. High drain cells can handle way more current, and take amuch larger beating. These are most used in high performance RC applications.Airsoft, although, not a really high current application, rides between lowdrain cell, and high drain cell needs. So naturally, you guys need high draincells.

Right now there are plenty of decent brands on themarket, but the only 3 I recommend at the moment, that have proven in my 8years of experience, to be good, are anything from GP, IB, or Elite. Eliteseems to be the most wanted cell in the airsoft world.

Plugs:

All of these guns come with the crappy little whiteplastic plugs. Weather it be the “Large” or “Small” type, both aren’t worth adamn. There is only 1 easy option. Deans Ultra. There are a few other goodplugs out there, but Deans is the most widely used, and has proven it’s qualityfor years.

Why, might you ask, does it matter what plug to use.Well, the reason is, that the pins inside the stock plugs, are made from areally thin tin, that over a very short period of time, begin to wear out, andcause a faulty connection. This will cause the gun to not fire at times, andthe battery to false peak on a charger. Plus, the plugs are crimped, whichisn’t necessarily a bad thing, but Deans are a solder style, which is muchbetter.

When you go to a better connecting plug, you reduce yourresistance dramatically, and free up some power that you didn’t have before. Ihave showed people many times, how my gun with the same batteries, at the samevoltage, has more power just from having a Deans plug. And they can’t believethat a little plug will restrict so much power.

Chargers/Charging:

First and fore-most, wall wart, or trickle chargers areworthless. I can’t tell you how many times I have a guy spend a lot of money onsome batteries, just to skimp on the charger. You can’t have a good battery,without a good charger. Good doesn’t mean you have to spend a bunch of money,but you won’t get a good one for 20 bucks. Generally, most of the good chargerscost around 50 bucks, and higher. You’re going to want something that has avariable charge rate(amp’s) and is a peak detection charger. Those are theminimum. If you’re getting a Li-Po pack, then you want something with avariable current setting, in at least .5 amp increments, and has a balancerbuilt in. Most of today’s chargers do all of this, in 1 package. There are somany chargers out on the market today, you can’t hardly go wrong as long asthey do what I mentioned above.

You want to set your charger to the appropriate cellamount, chemistry, and charge current. Charging at 1C and below is the safestbet for any pack. Example: 1C of a 1500 mah pack is 1.5 amps on a charge. Sofor a 1500mah pack, anything at or under 1.5 amps is safe. Another easy way tofind the C, is to take the first 2 digits of the Mah( if it is a 1500 mah, takethe 15) and put your point between them. That will be 1C.

Some chargers may have a Mv setting. This is your deltapeak. You want that to be between 3-5mv per cell. This is for Nimh packs. Butthe majority of the newer chargers out there, do this for you.

If you’re charging a Li-Po pack, and the charger has a balancer,or you have an external one, you use that every time you charge. In fact, Itell ALL my customers to ALWAYS use a balancer. We don’t warranty packs that wecharged without one. It is un-safe to charge without one. You charge Li-pos at1C also. Charge all Li-Po’s, away from anything flammable, in the event theycatch fire, so they don’t catch anything else on fire.

I hope this is helpful. Feel free to ask me anyquestions you may have…

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