Given the amount of crashes we have with flying FPV drones, we ought to do more to protect our LiPo batteries from physical damage. In this tutorial I will show you a few ways how to add extra protection to LiPo and make them tougher.
Further Reading: How to choose LiPo Battery for Racing Drones?
Protecting LiPo Batteries from Physical Damage
LiPo battery is probably one of the most vulnerable part of an FPV drone, and yet it’s usually placed at the most unprotected place on our mini quad. It usually just sits on the top or bottom plate of the frame which makes them completely exposed to impact in crashes or get punctured by spinning propellers.
The general recommendation is to throw away dented or bent LiPo batteries for safety reasons. Damaged LiPo batteries can be dangerous and potentially cause fire. Do not risk your house over a $20 battery!
Pro Tip: How to dispose LiPo battery safely?
LiPo batteries are rated for over 300 charging cycles, if you had to dispose them early, you are not getting the most out of them :)
With flying mini quads, crashes are inevitable. This makes LiPo protection very important, but it’s often overlooked.
Heat Shrink for LiPo Batteries
Heatshrink provides basic protection to your LiPo batteries, it’s light-weight, cheap and easy to apply. Most LiPo already comes with a thin heatshrink but it doesn’t hurt to add an extra layer.
There are two types of heatshrink for LiPo:
- PVC Shrink Film
- Rubberized Heatshrink Tube
PVC Heatshrink Film
PVC Heatshrink film is extremely light weight (less than 2 grams per pack), thin and stiff, it’s commonly used in battery packaging, your batteries are most likely already wrapped with this.
In my opinion PVC heatshrink can be useful to taking a few scratches, but they add little to none protection to your batteries against heavy impacts. You can buy spare to replace your old one or add extra layers for protection.
- 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)
Compared to PVC heatshrinks, rubberized heatshrink is a much better option for protection. It’s much thicker (~0.5mm), more flexible, more durable, and it actually sticks to your anti-slip battery pad much better too. However it is quite a bit heavier, about 6 grams per pack for 4S 1500mAh for example.
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 normally use:
- diameter, the diameter of the tube
- 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 combined width and height of your battery (only take two sides out of the four). Most of these heatshrink has a 2:1 shrink ratio, so the maximum flat size must NOT be larger than twice of that number.
How to Apply Heatshrink?
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. And make sure you keep the label sticker for identification.
For safety, avoid using a lighter 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 (it might take longer because they are not hot enough). Keep rotating the battery, avoid applying too much heat at the same spot for long as typical hot air guns are capable of melting through the plastics used in a LiPo battery.
Now put the sticker back on so you know the capacity and cell count of that battery.
Heatshrinks are also a great way to customize the colors of your battery :D
This has to be the ultimate protection for your LiPo.
I get these 90-degree PVC corners and just stick them to my batteries. This stuff is available in hardware stores for close to no money. You can also find them online at: https://amzn.to/2J1FXfs (affiliate link).
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 the lightest, you could be adding 10g to 15g of weight to each battery (4S 1500mah). I’ve tried two different sizes, 10mm and 15mm. 10mm is lighter, but 15mm covers a larger area.
- Added weight per pack (10mm): ~9g
- Added weight per pack (15mm): ~14g
Extra bonus: If you have bottom mounted battery, the corners will help your quad stand perfectly level on uneven surfaces :)
Bicycle Inner Tube
Be safe, put a rubber on.
I have numerous people commented that they use the inner tubes from bikes instead of rubber heatshrink and getting great results.
It’s not easy to slide the battery into the tube, but these tubes are even thicker and more rubbery than heatshrink. The rubbery surface is ideal for providing strong grip to the frame / battery pad too.
It’s 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 so you can get them for free :)
Some simple instructions on how to fit the tube over the battery:
- Cut the tube 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 batteries.
Added weight per pack: ~16g.
Please consider supporting me on Patreon for more tutorials like this. I hope it helps you to save a few battered and bruised LiPo batteries.
I really like the idea of applying a layer of rubberized heatshrink, then some PVC corners. A bit heavier perhaps, but my batteries are certainly lasting longer! Most importantly it gives me the peace of mind when landing and crashing hard :)
A reader of mine made a video demo, how cool is this?!
- Apr 2018 – article created
- Jun 2019 – added a demo video, updated product links
- Mar 2021 – revisited post, updated product links