By Joe Rich
Why do Lipo Batteries Swell Up
RC car racers are always looking for ways to improve their cars, but one of the biggest challenges is power.
There are many different types of batteries that RC car enthusiasts use. One type is a Lipo battery which has gained popularity due to its high energy density and weight-to-power ratio.
What does this mean? This means it’s lightweight, powerful, and easy to charge! But there’s also some downsides – like the dreaded “swelling” effect. What causes this? It can be caused by overcharging or undercharging, but most often it happens when you leave your battery on charge overnight after only charging for an hour or two.
Why does this happen? Well if your pack gets too hot while charging the chemicals inside the battery begin to break down.
But you still can’t be too careful when charging your Lipo pack! Our NiCD and NiMH packs don’t seem to swell much even when left on the charger for hours, but Lipos definitely do swell sometimes.
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What’s wrong with swollen batteries?
Well if you allow your pack to swell too much, it will expand and push the lid off of the case. This can lead to a fire as all those little cells are exposed directly to oxygen! In some cases the battery will explode as well which is even more dangerous.
So please make sure you don’t leave your batteries on charge overnight or while you’re away from your house. Also if the battery swells while you’re racing, get off the car track and stop driving immediately!
How do I keep my LiPo battery from swelling?
Well one way to reduce the chances of getting a swollen battery is to make sure it doesn’t get too hot during charge or discharge. Keeping your pack in a well ventilated area and using a fan to cool it down will help.
Don’t let your pack sit in the sun and avoid charging at high current rates. It’s best to charge at 1C or less if you can. This means that for a 2000mAh battery, you shouldn’t charge above 2A (2A x 1hr = 2Amp hours = 2000mah, etc). If your battery says it can handle higher rates (like our 2200 and 3300mAh batteries) then you can still charge at a slightly faster rate.
It’s also good practice to keep the balance plug connected when charging. This ensures that each cell is receiving the same amount of current and keeps the pack balanced. If a single cell begins to “puff” or swell, it will affect your entire pack and can cause damage as well as safety concerns.
What can I do to reduce LiPo battery charge time?
Well you can definitely use a higher rated charger if your budget allows.
The Tenergy TB6-B Balance Charger charger is a excellent choice for high current Lipo packs and have been specifically designed with safety in mind.
We have a review of the Tenergy TB6-B click here to view.
They even feature a “Lipo-SAFE” cutoff that will disconnect the power to the charge plug as soon as your pack is fully charged. This means you can charge at a higher current rate and still be safe!
You can also reduce charge time by choosing a battery with fewer cells (3S instead of 4S, etc) because the charge rate is based on battery voltage.
So please be sure to follow all safety precautions when using Lipo batteries. It’s always good practice to discharge your batteries completely before recharging (1C or less) and store them at about 40% capacity for long term storage.
Can you fix a puffed LiPo battery?
NO dispose of any puffed or swollen battery by taking them to a recycling centre.
Is swollen battery dangerous?
Yes very dangerous a swollen battery could cause damage to your RC car and could cause a home fire.
What causes LiPo batteries to catch fire?
Li-Po or lithium polymer cells are significantly more volatile than other types of rechargeable batteries.
The main reason for this is because there is no solid separator between the anode and cathode, so if there is any sort of internal short within the battery it can lead to a much faster release of energy that causes the cell (and potentially other nearby cells) to heat up and start to burn.
There are several factors that affect the likelihood of a cell’s catching fire, including overcharging, applying too much stress (such as physically damaging or applying too much pressure on it), and manufacturing defects. For this reason extreme precautions should be taken when dealing with Li-po batteries.
What happens if you over discharge a LiPo?
When a LiPo battery is discharged below its “low voltage cut off” (LVC), the discharging process continues and electrolytes within the cells may start to break down, leading to irreversible damage. If not detected and stopped early enough, this can lead to uncontrolled generation of heat and even fire.
How to safely charge a LiPo Battery
How to safely charge a LiPo Battery is a question that many newer modelers have, but few actually know how to do it. When charging a LiPo battery the number one step in keeping yourself, your home and others safe is to always follow these basic guidelines:
– Always charge your LiPo in a fireproof location. If you use a wooden workbench or other non-flame retardant surface, you run the risk of starting a fire.
Charging bags are available from amazon for safe charging of LiPo batteries click here to view.
– Always have a working smoke detector and fire extinguisher within arms reach when charging your batteries.
– Never charge a damaged LiPo battery. If it has been physically damaged stop using it right away and dispose of it properly.
– Always double check that your charger is set to the correct voltage for your battery. For example, if you are charging an 11.1V LiPo pack, make sure your charger is set to 11.1 volts and not 6 or 12 volts.
– Always double check that your balance connector is plugged into your battery properly before you start charging it.