Nano-tech "buffer tube" lipo

[Nec]

For those of us who use buffer tube lipos, there has always been the dilemma of finding a buffer tube lipo that fits.
As some of us know Hobbyking has recently released their airsoft line of lipos, not only are they geared toward airsoft guns but they are always nano-tech lipos which produce even more power in a smaller package than traditional lipos. I’ve always been a fan of hobbyking, I’ve bought almost a dozen lipos from them but never the airsoft versions. Well I finally did and I must say I was quite surprised! They are significantly smaller and longer lasting than the competition making them now my choice of battery for buffer tube application.
Lets compare them to other lipos:

I have four buffer tube lipos here I will compare:
Echo 1 1100mAh 11.1v 15C, $32 + shipping on AONW
Tenergy 1200mAh 11.1v 20C, 19.99 + shipping on All-battery.com
Turnigy nano-tech 1200mAh 11.1v 20C, $7.88 + shipping
Flame 1200mAh 11.1v 15C, $14.99 + shipping on KHmountain





“Height”

Echo 1 1100mAh 11.1v 15C


Tenergy 1200mAh 11.1v 20C


Turnigy nano-tech 1200mAh 11.1v 20C


Flame 1200mAh 11.1v 15C



“Width”

Echo 1 1100mAh 11.1v 15C


Tenergy 1200mAh 11.1v 20C


Turnigy nano-tech 1200mAh 11.1v 20C


Flame 1200mAh 11.1v 15C




As you can see the Turnigy nano-tech 1200mAh 11.1v 20C, was consistently the smallest. So with that being said it is now my Lipo of choice for buffer tube applications. I liked them so much I bought two more and was able to fit three of them in the crane stock of my JG CQBR. Triple the lipo, triple the fun. :twisted:

[Payback]

Great review, but i would like to know more about performance comparisons of the batteries.

[Matt]

Good stuff. Moved to accessories.

[Ivan Daylovich™]

I imagine the diagonal width of the battery would be the most restrictive. (At least in the stock I have it would.) Adding that info, or hell, why not all the dimensions (Length, width, height, and diagonal width) would be useful.

[Nec]

I imagine the diagonal width of the battery would be the most restrictive. (At least in the stock I have it would.) Adding that info, or hell, why not all the dimensions (Length, width, height, and diagonal width) would be useful.

I did not provide diagonal width because it is too difficult to measure with the calipers I have. And besides it can be found by using Pythagorean theorem A^2 + B^2 = B^2 (A being the width and B being the height).

[Ivan Daylovich™]

That'll give you a good approximation, but not exact since it's not a rectangle due to the rounded edges. How is it hard to measure with your calipers?

[Drtilgner]

Have 3 of the nanotechnology batteries for my dytac m4. Can play for 4+ hours on single charge without any decrease in performance.

[ogrejager]

Have 3 of the nanotechnology batteries for my dytac m4. Can play for 4+ hours on single charge without any decrease in performance.

This tells us nothing--how many shots do you fire in 4+ hours of play?

And, yeah, how's it hard to measure the diagonal with calipers?

Good information, though, thanks!

[Nocte]

That'll give you a good approximation, but not exact since it's not a rectangle due to the rounded edges. How is it hard to measure with your calipers?

Diagonal with perfect right-angle corners = 25.288mm. Now, we don't have perfect right-angle corners, they're rounded like this:


If we denote by x the little bit that is trimmed off each end of the diagonal when the corners are rounded, we can calculate x in terms of r, the radius of the rounded corners. At an over-approximation, w = 2r. This would give us the minimum battery diagonal (incidentally, old NiMH and NiCd batteries fit this profile). This isn't the case at all from looking at the picture, since Lipos are mostly rectangular. It's clear that w is much larger than r.

So at what point does r make the diagonal *meaningfully* different? To reduce the length of the diagonal by 10%, we have an r of about 3mm. This looks too big based on the photo. To reduce by 1%, r = 0.3mm. I don't think it's this precise, either, but it's close.

If we go with a value of r around 1.5mm, you get a 5% reduction in the diagonal.

OK NIC, SO bleeding WHAT?

95% of the perfect diagonal is about 24mm.

This gives the inner diameter of a military spec buffer tube as 1 inch (25.4mm). Commercial spec is "slightly larger" by some amount I didn't look up. Even if this battery had perfect squared corners, it would still (just barely) fit. If your airsoft replica's buffer tube has an inner diameter less than an inch it probably won't fit, but we generally assume the dimensions are the same since most real-steel stocks fit AEGs.

TL;DR -- Pythagorean Theorem is a good enough approximation of the diagonal.