[ILLusion]

Ni-Cad is still the most robust battery technology out there in terms of charging error forgiveness and general abuse. It also provides the highest cold cranking power, which is why a lot of users still prefer it. It can also be charged at quite high rates, for quick charges.

Ni-MH is a bit more sensitive to temperature - it can be damaged at higher temperatures, and simply won't work at lower temperatures. However, they do not carry memory, which is a great feature for a lot of users, being able to just "set it and forget it." It is very low maintenance, besides care against temperature and slower charging rates. However, it's downside is the tendency to gain "memory."

Li-Po has huge cold cranking power as well, and also carries no memory, along with being able to work in very low temperatures - even lower than Ni-Cad. However, it is VERY sensitive to heat or shock, and can erupt violently if mistreated. So it's kind of a best of both worlds... with a major twist.

With all that said, users will make their own decisions on what technology to use, and I'm sure the OP has educated himself in this already.

In my personal opinion, if I were still using the original Crane stock, I would stick with the original Systema Ni-Cad packs. However, because my build uses a Magpul CTR Mil-Spec stock (and same for any other stock that can't hold a battery), I would switch to LiPo. I did a LOT of research to select the appropriate batteries for my different applications, and I suggest you do the same as well.

My current power setup is as follows:

- Custom machined buffer tube, with power plug cut-out
- Airsoft Surgeon miniaturized ECU (v2) (only fits 2008 models and newer) - allows me to collapse the stock almost completely with my current battery selection

Depending on the power cylinder I use, that choice will determine the battery I use. I'd spent my research comparing power output curves between varying Li-Po batteries versus the OEM spec batteries, and came to the following conclusions:

When using any cylinder that's M130 or WEAKER, use a 7.4v Li-Po, NO LESSER than 15C and NO GREATER than 20C.

When using an M150, use an 11.1v Li-Po, NO LESSER than 20C.

This research was based upon technologies existing at that time (2008-2009), and I've been using the following batteries:

- G&P 7.4v 1200mAh 15C
- G&P 7.4v 1200mAh 20C
- Intellect 11.1v 1200mAh 20C"+"

The reason why I set lower limit restrictions on the power (both in voltage, as well as in "C" rating), is simply so the pack can have enough juice to crank the spring. Due to the very sensitive nature of Lithium Polymer cells, demanding power output of them beyond their rating is a sure way to kill them and cause them to POTENTIALLY EXPLODE BESIDE YOUR FACE during use!

The reason why upper limits are set, is for the exact same reason why Systema implicitly states NOT to use their OEM spec 12v battery with the M90, M110 and M130 cylinders. It WILL provide too much power to the system in the long run, and can (and will) strip the expensive piston, gears, and potentially burn out the VERY expensive control boards. The PTW Users forum has quite a few users who've overpowered their guns which resulted in broken parts.

This setup has worked for me. YMMV.