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Need to know LiPo info

Whether you are new to the hobby or have been in it for years. Knowing LiPo saftey and maintence is critical. Not only will this help reduce the risk of a fire. It is also going to prolong the life of your batteries.

I’ll be starting off with a TL;DR that sums of what i will be going over in this article. These are the key points when it comes to LiPo’s


  • Never charge out of sight
  • LiPo
    • MAX: 4.2 per cell
    • MIN: 3.2 per cell*
    • STORAGE: 3.85
    • Charge at 1c. AKA 800Mah Battery will charge at .8A
  • LiHv
    • MAX: 4.35 per cell
    • MIN: 3.3 per cell*
    • STORAGE: 3.9 per cell
  • Li-ion
    • MAX: 4.1 per cell
    • MIN: 2.4 per cell**
    • STORAGE: 3.8
    • Charge at .5c - 1c

*Be aware of voltage sag, this could bring you below your min voltage

**Check the spec sheet of your Li-ion. There minimum voltage may be higher or lower.

In case of fire

Lithium fires are very hard to put out completly. You best bet is to isolate them, remove flammable items away from them, and let them burn them selves out.

  • Water can put out a fire. But it can come with other risks. Water can help stop the fire by cooling the cells enough so they dont autocombust. But if the inner cells are exposed to water they can react with it producing some toxic fumes. It will also take a significant amount of water to proper put it out. There will still be the risk of it re-igniting after it is put out the first time too
  • Sand/Dirt is exreamly good at smothering the fire.
  • Class D fire extinguisher ideal. ABC is next best
  • Fire proof container like a ammo tin for storage. Make sure it does not seal!

Any links in here for products are affilate links. I frequently buy from race day quads, pyrodrone, and sometimes getfpv. getfpv is the only palce with a affilate program. feel free to find these else where.


Getting a good setup for charging and storage of your LiPo’s may seem like a no brainer. But there are several things to keep in mind. We are not just plopping them in a drawer and forgetting about them untill we need them. We need to take into account the what if’s? What if it catches fire? What if something falls on them? what if there is a flood? etc. etc. etc.

For your storage place you want something that is away from combustible items. Is going to be safe if something were to fall on them. And can avoid getting wet.

There are several options when it comes to preping for a fire. First and formost is having a appropriate fire extinguisher. The ideal fire extinguisher is going to be class D. These are specifically made for metal fires. These can be harder to find and a bit expensive. Your next best option is ABC fire extinguisher. Amoung other things this is rated for electrical fires. It is important to remember lithium fires are hard to put out. Isolate them, prevent spread, let them run out. Having a bucket of sand around is perfect for this. Charging/storage on a non flammable surface and if you have a fire dump all the sand/dirt on it. Messy yes, but this will prevent it from spreading and is going to contain the flames.

At this point we are going to assume we are prepared for a fire. But what else can I do? So far this has just been what to dump on them to contain the fire. But there is more we can do!

  1. Ammo tin: is a perfect storage container. It is sturdy, made of metal, and water can not get into it easily. If there is a fire it is contained to the metal tin. Its not going to be easy to crush either. one thing to keep in mind is these tins usally have a seal, you want to remove this to prevent pressure build up. (link)[]

  2. Bat safe: These are specifically made for lipos. They have holes for venting, made of metal, and have flame retardent materials. Keep in mind cheap knock offs exsist. (Link)[]

  3. Soft sided lipo bags: These bags are flame retardent, they will burn but take a lot more heat. These are good for storage and seperation of your batteries. (Link)[]

  4. proper battery maintenance and care (we will get to this next)

lipo care/charging

All batteries have a finite number of charges, they will be trash at some point. But with proper care we can make the most out of these charges and have them last a long time. All batteries also have a min and max voltage. going below or above this will cause damage to the cells.

First and formost is the subject of charging. You are going to want a smart charger like ToolkitRC M7 this is going to give several functions. First this has presets for LiPo, Li-ion, LiHv. It it going to know when to stop charging for each of these. Second this is going to balance your cells while your charging. Lastly this also allows you to plug in a battery and get voltages for individual cells. There are tons of other smart chargers, this is just the one I use. One note, most of these do NOT come with a wall plug this will have to be bought seperately.

But lets back up for a second, what the hell is cell balancing?

The short is, cell balancing is ensuring the voltage between cells is as close as possible to the same.

When a manufacture builds the battery. They are going to select cells that have as close as possible discharge rate, internal resistance, etc. This way when we pull power from the bat, we are pulling equally from all cells. This loops back to the min per cell voltage. If one cell is draining faster than the others it could go below this min voltage, damaging the cell. Same thing goes for charging, we want to make sure all cells stop charging when we hit the maximum voltage. So we balance the voltage between the cells while we are charging.

Over time and with use your cells will become unbalanced. This is normal and gets worse as the cells degrade.

Min voltage? Max voltage? For every battery composition there is going to some variation on what the max, min, and charge rate is. For this we are going to be assuming LiPo. For other popular battery types check the TL;DR at the top.

LiPo batteries are in their happy place when they are at 3.85v. This is their storage voltage. Any time your battery is not in use it should be charged/discharged to around 3.85v per cell. You may ask why? Chemistry, the truth is im not a electrically engineer or a chemist. Thats the best I can say.

Well what will happen if I store them at full charge? sure you can do this, but this greatly increase the build up of Internal Resistance. the higher the IR the harder it is to pull the volts out. AKA a 40c pack with high IR could act like a 5c pack. If you try and pull out 15 amps itd still do it, but its going to have a lot of voltage sag. Possibly enough sag to pull the cells below their min.

Voltage Sag

Voltage sag is a occurs when the voltage level of a battery temporarily drops below its nominal or expected voltage during a sudden increase in demand. It can be particularly noticeable in batteries, especially when high currents are drawn from them.

Here’s a breakdown of the key points related to voltage sag:

  • Load Increase: Voltage sag is often triggered by a sudden surge in electrical demand, commonly referred to as a load increase. When a device or system requires more current, the internal resistance of the battery or power source can cause a temporary drop in voltage.

  • Internal Resistance: Every battery has internal resistance, which is the opposition to the flow of electric current within the battery itself. This resistance causes a voltage drop when current flows through the battery.

  • Impact on Performance: Voltage sag can affect the performance of electronic devices. For example, in electric vehicles, voltage sag during rapid acceleration can lead to a momentary reduction in power, affecting the vehicle’s speed and acceleration.

  • Voltage Recovery: Voltage sag is usually a transient event, and the voltage tends to recover once the high-demand period subsides. However, the extent and duration of the sag depend on factors such as the battery’s capacity, internal resistance, and the magnitude of the current demand.

  • Battery State: The state of charge and health of the battery also influence the degree of voltage sag. Older or degraded batteries may experience more pronounced sag compared to newer, healthier ones.

Proper charging

As mentioned proper charging is crutial to battery health and fire prevention. for lipo’s we never want to go over 4.2 per cell. Charging should be done at 1c. For example a 800Mah battery would be charged at .8 amps. 1c = mah / 1000 => 1c = 800mah / 1000 = .8Amps

Can we charge at a higher rate? yes, yes you can. 1c is what is generally considered safe. Most LiPo’s even have on the battery to never charge higher than 1c. Some times 1c doesnt fit neatly into what is on the charger. Ex 850mah battery should be charged at .85A. But the charger only shows .7, .8, and .9. charging at .9 would be just as safe as charging at .8.

Some people do charge at a higher rate. Might be rusing to get out or are at a race event. Just remember the higher you go over 1c charge rate the higher the chance of a fire. Higher charge rate also euqals higher degradation of the battery with every charge

Proper usage

lastly when using our lipo we never want to go below our minimum voltage percell of 3.2v. Anything below 3.2v per cell will cause permanent damage to the cells and will cause puffing, cell death, degraded battery status. I mainly fly drones, I dont fly below 3.5v per cell. 1 this gives me a bit of a buffer of before I hit 3.2v. 2 some cells are going to sag more than other cells. We dont want a cell to sag below 3.2v

Every time you use you lipo you should inspect it. Check for rips/tears in the foil and puffing. Some puffing will come with age, this is pressure building up in the cells from them off gassing. Dangerous yes, but if it is minimal the battery is still good to use. If its looking like a pillow OR has some serious squish to it. Then it is time to dispose of the battery


Their are several different ways to dipose of a battery. They all end the same, bringing it to a recycling center and they take it away. Batteries and Bulbs is a good place. You do not want to bring them to best buy and drop them into the boxes upfront for battery disposal.

  1. bring to recycling center let them deal with it.
  2. cut off power leads (clip only a singl wire at a time) and drop it into a bucket of salt water for a few days or a week
  3. connect a car light bulb to the battery and let it drain it
  4. get a LiPo Killer
  5. use the discharge function on your charger

What option should you choose? well it depends, if the battery isnt safe to transport. Get it discharged some way, then bring to the recycling center. if you close to a recycling center just drop it off reguardless of charge. I always like to give them a heads up tho.

It is nice snipping off the power and balance leads to have extras. BUT a lot can go wrong very fast if you dont know what your doing.

Published Nov 11, 2023

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