3s Lipo

Lipo Batteries – Know How to Charge, Store and Dispose of them Safely

Quick Facts:

  • Long Term Storage Charge is Approx 3.8v per cell
  • Never Charge over 4.2v per cell
  • Never discharge below 3.0v per cell
  • Safest charge rate for most LiPo batteries is 1C or 1 x capacity of battery in Amps
  • C Rating is the Discharge Current the battery puts out
  • Burst is 2x the C Rating
  • Use with a low voltage buzzer when possible
  • Always use a lipo-safe bag if you have one when charging

If you are into Quadcopters and Drones then you know by now they run on Lithium Polymer batteries or just called Lipo batteries for short.
Did you know though that the incorrect use of Lipo’s could potentially burn your house or workshop down?

I didn’t know that about Lipo’s when I started flying and so I would leave a battery on charge in my house and go outside to work for a couple of hours before I checked on it. Luckily they were brand new and undamaged. Another way to damage your batteries and potentially cause a fire is to let them discharge too low and leave them in that state or leave them fully charged for too long.

Mine live in a big ceramic bowl on the wooden floor in my lounge. Not the best plan but 3 years later I’m still doing here. (touch wood)

Battery Charger

A Popular Lipo Battery Charger

Lipo storage tips

The storage charge is generally 3.8v per cell. The best chargers tell you the cell levels but the cheaper ones that come with an RTF (ready to fly) package are really basic and just give a green light as each cell reaches capacity.
If you are serious about this hobby then get a decent charger that can charge to storage levels as well as the ability to discharge.
Click on the picture to check out some chargers.

NB: Leaving batteries fully charged for too long can ruin them possibly even cause them to explode. Lithium-Polymer batteries can be damaged by sitting fully charged for as little as a week.
NB: Don’t leave your Lipo fully discharged either or an unwanted chemical reaction can happen and cause a fire.

Disposal Methods

Before you dispose of the battery. If it keeps its charge but just isn’t pushing out the Amps too well anymore then maybe you could re-purpose it.
They could run your Goggles or Transmitters or the lights on a pushbike etc. or even get some ELS wire (Electroluminescent wire) and make some fancy drone gates to fly through

The way I chose to dispose of my batteries was the Salt Water Method.

  • Mix a decent amount of table salt into some warm (not hot) water in a bucket or similar.
  • Run the battery’s charge down as low as you can then place the LiPo in the salt water.
  • Keep adding salt until it will no longer dissolve in the water. Ensure that the wires are all entirely submerged. The salt water is very conductive, and it will essentially short out the battery, further discharging it.
  • Leave the battery in the salt water bath for at least 24 hours.
  • Check the voltage of the LiPo. If the voltage of the battery is 0.0V, great! Move onto the next step. Otherwise, put it back in the salt water bath for another 24 hours.
  • Continue doing this until the battery reaches 0.0V.
  • Dispose of the battery in the trash. That’s right – unlike NiMH and NiCd batteries, LiPos are not hazardous to the environment. They can be thrown in the garbage with no problems.
  • Don’t forget to cut off the plugs, they can be reused on other projects.

Light Bulb Discharge Method

The light bulb is a very popular tool for discharging a LiPo battery because it’s relatively quick, cheap and effective. For a 3S Lipo, you can use a 12V light bulb, and just leave it somewhere fireproof. Here’s a good post on building your own light bulb discharger.

Parallel Charging

Parallel charging can be done safely but the risk increases.

Myth: You can’t mix batteries of different capacity on parallel charge. Yes, you can!
If you have 1600 and 1300 mAh Lipo batteries charging in parallel the nature of parallel circuits is the voltage will equalise. Think of pouring a bucket of water into a funnel that feeds a tube that splits in two. One tube feeds a 13-foot tube the other feeds a 16-foot tube, you would just keep pouring until both tubes were full of water.

How long can you run Lipo Batteries?

1300 mAh is also 1.3 ah (mAh = milliamp hours – Ah = amp hours) is a rating of how long you can run it for. The bigger the number the longer the charge.
1.3 mAh to 1.5 mAh is good for racing/freestyle drones even 1.8 Ah

3s or 3 cell lipo batteries was the norm when I started but everyone is getting into 4s and even 5s now.

  • 5s 18.5v not suitable for most equipment in 2018
  • 4s 14.8v becoming most popular for fpv racing and freestyle drones
  • 3s 11.1v was most popular
  • 2s 7.4v ideal for small indoor drones also goggles and radios can run on 2s but check manufacturer specs you have to make sure the equipment you have is right for the voltage of the batteries

Here’s a time to live chart I found online.

Battery Current (amps)Time to empty
2100 mAh1.05 amps120 mins
2100 mAh2.1 amps60 mins
2100 mAh4.2 amps30 mins
2100 mAh8.4 amps15 mins
2100 mAh16.8 amps7.5 mins

 

Best battery for your drone.

The best battery for drone racing changes as new models come out. The Turnigy Graphene 4S 1500 mAh 65C is considered among the top 5.
They can be found at Hobby King and Amazon Here and Here Respectively (Not Affiliate Links)

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