Given the number of crashes we have with mini quad and racing drones, we ought to do more to protect LiPo battery from physical damage. In this tutorial, I will show you the different ways of adding extra protection to your LiPo batteries.

The LiPo battery is one of the most unprotected parts on our mini quad. It usually just sits on the top or bottom of the frame which makes them completely exposed to impact in crashes or puncture by spinning propellers. The general recommendation is to throw away dented or bent for safety reasons. Damaged LiPo batteries can be dangerous and cause a fire.

Flying mini quads, crashes are inevitable, especially if you fly indoors, race and fly close proximity. This makes LiPo protection necessary, but it’s often overlooked.

Some LiPo battery manufacturers already started adding thin fiberglass sheets to their batteries. In case yours don’t have these sheets, or you simply want to play safer, I will show you some DIY ways of LiPo battery protection.

Heat Shrink for LiPo Batteries

The cheapest and easiest protection for LiPo batteries would be heat-shrink. When I was researching, I found two types of heat shrink for LiPo:

  • PVC Shrink Film
  • Rubberized Heatshrink Tube

PVC Heatshrink Film

  • Transparent from Banggood (70mm to 80mm for 4S 1300-1600mAh)

PVC Heatshrink film is commonly used in battery packaging, you probably have it already on your batteries.

This stuff is extremely lightweight, thin and stiff. In my opinion, they can be useful for taking scratches, but they add little to none protection for your batteries against impacts. You can buy spare to replace your old one or add extra layers for protection.

Added weight per pack: ~2g

Rubberized Heatshrink

  • 50mm Red from Hobbyking – One of the best
  • 50mm Black from Amazon – I haven’t tested this
  • 40mm Transparent from Amazon – Good for smaller packs (e.g. 1300mah)

On the other hand, rubberized heat shrink is a much better option. It’s thicker (~0.5mm), more flexible, more durable, and it sticks to your anti-slip battery pad much better. However, it will add some weight to your battery.

Added weight per pack: ~6g

Picking Heatshrink Size

For a typical 4S 1300-1800mAh battery, 70mm to 80mm flat-sized tubes should do nicely (equivalent to diameters of 45mm, 50mm, and 55mm).

There are two sizes shops use: diameter, the diameter of the tube; And flat size, the width of its flat form (half of the circumference).

You can convert between diameter and flat size using this formula:

Flat Size = 3.14 x Diameter / 2

You should choose a flat size that is larger than the total width and height of your battery (only two sides out of four). Most of these heat shrink has a 2:1 shrink ratio, so the maximum flat size mustn’t be larger than twice of that number.

How to Apply Heat shrink?

You can either remove the original packaging or keep it as an “extra layer of protection”. By removing it you can save a couple of grams.

Avoid using lighters or any form of fire, it’s a bad idea to “barbecue” your battery.

It’s best to use a hot air gun. If you don’t have one you can try a hairdryer, although they might not be hot enough. Keep rotating the battery and avoid applying too much heat at one spot as typical hot air guns are capable of melting through the plastics used in a LiPo battery.

I also prefer to peel off the label and stick it back on the new shrink-wrap so I know the capacity and cell count.

PVC films are not the best for physical protection, but they are useful for changing the colour of your batteries :D Great way to customize your battery collection.

PVC Corners

In case heat shrink isn’t enough, you can consider 90 degrees PVC corners. This stuff is available in hardware stores for close to no money. You can also find them online at:

  • Amazon
  • eBay

From my experience, most battery damages happen at the corners. Simply wrap these PVC corners tightly to the battery with fiberglass tape, will provide effective and strong protection to physical damage.

However these PVC corners are not light, you will add 10g to 15g of weight to your battery. I normally use two different sizes, 10mm and 15mm. 10mm is lighter, but 15mm protects a larger area.

  • Added weight per pack (10mm): ~9g
  • Added weight per pack (15mm): ~14g

You will also need some fiber tape to secure the corners, this type of tape is extremely strong and sticky:) You can also just use heat shrink film if you want.

Extra bonus: If you have a bottom mounted battery, the corners will help your quad stand up perfectly level on rough surfaces :)

I got this idea from a friend on Facebook, Vincent Offenbeck. Many thanks to him!

Bicycle Inner Tube

Be safe, put a rubber on.

So many people commented that they use inner tube from bikes for protecting their LiPo batteries, and have good results.

Bike Inner Tube for LiPo battery protection

Image Credit: ‎Idan Elefant

It’s not easy to slide the battery into the tube, but these tubes are much thicker than heat shrink and should provide better protection. The rubbery surface should also give good enough grip to the frame to replace your velcro.

I have not personally tried it, but I have been recommended to use 20″ tubes for 3S, and 26″ tubes for 4S. Probably a good idea to go down to your local bike shop and ask if they have any unwanted tubes :)

This is how you can fit the tube over the battery:

Cut it into sections longer than the pack, and slide over the lipo. Slip the tube over with a set of pliers, open them to stretch the tube, then start inserting the battery. Maybe even use 2 sets of pliers from both sides. It’s easier if you can get someone to help you

Added weight per pack: ~10g.

3D Printed TPU LiPo Protector & Landing Gear

This one is pretty cool because it requires no modification to your battery. You can print it yourself if you have a 3D printer and TPU filament, or you can buy it.

Added weight per pack: ~16g.

Conclusion

I hope the added battery protection in this tutorial can help you save a few battered and bruised LiPo batteries.

I really like the idea of applying a layer of rubberized heat shrink, then some PVC corners. A bit heavier perhaps, but these tricks have given me much better battery longevity, fewer dents, and punctures, most importantly the peace of mind when landing and crashing. :)

Source from https://oscarliang.com/protect-lipo-battery/