Lipo Battery Pack Tutorial | Forum

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adam
adam Oct 21 '21

So you want to go lipo?

 

Well you have made the big choice and now you need to know where to start. Well the first thing to look at is the condition on your gearbox. This is going to be one of those times where you have to be very truthful with yourself. Is this gearbox in the best shape it can be? When was the last time you shimmed the gearbox? When did you last grease the gearbox? If you have not taken the time to make sure you have no noise or play in your gears take that time now. You will pay later when a subtle oscillation turns into a spinning gear of death and takes out your AEG in the middle of sustained fire if you don't.

 

While you are in the gearbox there are some other things you should look at. What gauge and quality is your wiring? If you are not at 16 or 18 gauge wire then take the time now and change it so that you have a big enough and strong enough pipe to push the new sustained voltage.

 

The C rating of a lithium polymer battery denotes how much current you can draw out of a pack at a continuous rate. Example:

 

1600mah 10c battery 1600mah/10000mah = 1.6ah 1.6ah x 10c = 16 amps

 

1000mah 20C Pack 1000mah/1000mah = 1ah, 1ah x 20c = 20 Amps

 

1500mah 25C Battery 1500mah/1000mah = 1.5ah, 1.5ah x 25c = 37.5 Amps

 

So the higher your discharge rate (C Rating) the more amperes you can push out continuously. Resulting in your motor being able to pull as much as it wants/can for a longer time. Most NIMH batteries are 10c.

 

You may also want to do an AOE (angle of engagement) correction. This involves totally readjusting the timing on your piston head and should not be performed if you do not fully feel confident.

 

First remove the second to last tooth on the piston. Then shim the piston head so that the piston lines up exactly with the first tooth on the sector gear. We have a guide HERE. You may also want to upgrade all the other fun parts that require you to have the gearbox and gun body open.

 

New stronger spring

 

New piston

 

New Piston Head

 

New air seal nozzle

 

New bucking

 

New inner barrel

 

Now this is no small amount of work.

 

Taking apart a gearbox and replacing a spring can be a daunting challenge depending on your level of skill but with time and the wonderful world wide web you can find step by step guides to disassemble and reassemble your gearbox. See our guide HERE.

 

Then we can talk about MOSFET. MOSFET is a electrical switch that (in simple terms) regulates voltage to your gearbox. You can wire one in, but if you go for a 7.4v it is only necessary for ROF regulation, but if you are going for the 11.1 then you really should put one in. Installation and operation are part specific and come with detailed instructions.

 

Now that you have a new freshly shimmed tricked out gearbox now what? You need to look at your connectors. Deans are one of the most popular connectors because they have a lower resistance that the standard mini tamiya, and they are a soldered connection not a crimped, that is why many people switch to them. They do require solder but with a little time and patience that should be not problem for the average person. You can see a great guide HERE.

 

So now it comes down to the real deal 7.4 or 11.1. If you are confident in your work switching to a 11.1 is not a big deal but this is a higher voltage and a longer sustained amperage so this is for those who want the highest rate of fire. If you are just looking for a longer play time then 7.4v should get you a rate of fire in between a 8.4 and 9.6 and with the upgraded internals any AEG will handle a 7.4v lipo.

 

Plus we all know about air discharge. Nickel metal hydride batteries are great if you charge them the night before but you will have to charge them every time. There will always be a little "air discharge" but with Lithium you get nearly none.