How to Charge and Parallel Charge Lipo Batteries

The batteries, the most boring part of the FPV hobby, unfortunately it's also one of the most important, especially for those of you guys just starting out.

In this blog, we're going to be talking about how to charge your lipos, both efficiently and safely .

First, let's talk about charging a single battery at a time. The process is really simple, first, plug in your charger, then you want to plug in your XT60 connector first which looks like this.

And then your balance port, make sure your pins line up with the balance port correctly, starting with pin number 1 which is usually on the right hand side.

Moving to the left, this should give you a reading of the voltage of your battery and each individual cell. Now my charger automatically detects that a 4s battery has been plugged in and it'll configure to charge to the correct voltage.

Now remember that whether or not your charger has this feature, you always want to double check and make sure that you're charging to 4.2 volts per cell. And you never want to charge over that or else you can have some serious problems. I'll also include a chart right here for reference

so that you know what your entire Lipo should be charged to based on how many cells it has.

So it's easy to know how much charge to give your batteries because you always want to charge them up to 4.2 volts per cell. However it's also important to determine how quickly you're going to charge them. Now a lot of chargers are capable of charging your battery at a variety of speeds,. However faster is not always betteries. the safest way to charge your batteries is at 1C or at one times the capacity. So if I want to charge this 1500 milliamp hour or 1.5 amp hour battery at 1 c. I would charge it at 1.5 amps.

This is a 850 milliamp hour or 0.85 amp hour battery, so I would want to charge it at between 0.8 and 0.9 amps.

Again, this is the safest way to charge your batteries. However there's a downside because it takes a very long time, no matter what size your battery is to charge it from fully empty at a 1C rating, it would take a little bit under 45 minutes. I currently have 8 batteries, so if I was to charge them all separately at 1 c, if each one takes 45 minutes, altogether it would take me around 6 hours even if you have a charger with two ports where you can charge 2 batteries at a time, it would still take you 3 hours.

Luckily there are two ways you can speed it up. First you could try to increase the current and instead of charging your battery at 1c, you could try charging it at 2c or twice the speed of the capacity, which would charge it twice as fast. If you're really pressed on time, some people might even say that it's okay to charge once in a while at 3C or 4C, but the higher the speed you charge your batteries at the more dangerous it becomes. Even if nothing happens while you're charging the battery, the more often you charge at higher C ratings the more your battery will degrade over time. Therefore I would recommend that you stick to a 1C speed whenever possible. Maybe if you're really pressed on time, you could boost that up to 2C, however, I would never go over that unless it's an emergency, your batteries are away from anything flammable, and you're also willing to risk the possibility of a Lipo fire.

The other option if you don't want to boost the current is to parallel charge. The parallel charging refers to the use of a parallel charging board like this one below in the image, which lets you increase the amount of batteries that you could charge on one charger at a time. 

Instead of charging one battery per port, this board would allow me to charge up to 6. Now just like charging your battery at higher speeds, parallel charging could also pose a little bit of increased risk if done incorrectly. This is why there are a few preliminary steps that must be taken every time before you charge. First, in order to parallel charge both successfully and safely. You want to make sure that all your batteries are the same cell count, you never want to charge a 3s battery with a 4s or a 4s with a 5s, if you're charging 4s LiPo batteries, you want to make sure that they're all 4s. Otherwise, the charger is going to try to distribute the amps equally amongst all the batteries, and the smaller battery will end up getting overcharged, which is incredibly dangerous. To be extra safe, usually I'll only parallel charging batteries that are the same brand and the same model. Different brands of batteries could have a slightly different composition and also just by seeing that all your batteries are identical, it makes it really easy to avoid making a stupid mistaken.

Next, you also want to make sure that all the batteries you intend on charging together have a similar voltage. Ideally, when you plug them into this board, you would want all of these batteries

to have the exact same amount of volt within them. Like I mentioned before, the charger is going to think that it's charging one big battery and not four little ones, so it's going to try to distribute the amps equally and charge them equally. If the voltages vary, some of the batteries might end up getting overcharged, and again that's really dangerous. Luckily for you, there is a little bit of leeway, and you can charge batteries together that differ up to 0.1 volts per cell. Again this is per cell so these 4s batteries their entire voltage could differ up to 0.4 volts.

So I have 8 of 4s batteries here and their voltages are as follows.

These batteries could be safely charged together in parallel, and these could be charged in a separate batch. Each of these two groups has a maximum difference of 0.4 volts between them, which means they're safe to charge. This last battery should be charged separately as its voltage is too far from the others. Otherwise if this battery was charged with the others, the same risks apply of possibly overcharging one of the batteries.

Now let me show you how to actually do it. First plug in your balance board.

When plugging in your batteries into the balance board, it is recommended to plug in the XT60 connector which is this one before the balance lead. However if you have already made sure that all the batteries are at a similar voltage, this isn't a big deal either way. When plugging in your balance lead, make sure you are plugging in to the correct port, and in the right direction, one side of the connector will have little guides to show you the direction, but a tip for most boards is that the red wire from your battery will most likely always be on the inside. Pluging these in slowly to avoid any mistakes and causing a short.

Also your parallel charging board will probably have bounce connectors on each side, which one you plug them into doesn't really matter as long as it has the right amount of pins. After you plug them in, I would let them sit for a little bit. If you have a charger that can show you this, you'll notice that the voltages between each battery start to regulate even more and balance out at closer voltages than you had before. So after a few minutes after they settle, that's when you can start to charge. When it comes to parallel charging, I would never charge over a 1C speed, however, 1 c for a single battery is very different than 1c for 4 batteries.

As I mentioned before for this 1500 milliamp battery, we want a current of 1.5 amps, however if we were to charge 4 of these batteries using 1.5 amps, the power would be split amongst the 4 batteries, and we would actually be charging them using 0.375 amps each. This is no longer 1c but actually around 0.25c, this means if we're charging 4 times the amount of batteries at once, we can also quadruple the amperage at which we're charging at, and we can charge these 4 batteries with the charger set to 6 amps. The charger will then split those amps amongst the batteries and provide each one with 1.5 amps, and it's as easy as that. All the batteries will charge at the same time and after they finish charging, the charger will also balance all the cells within the batteries. I also wanted to add one other note in case it wasn't clear before that some chargers have 2 separate ports or channels that can perform 2 different and completely separate tasks, anything plugged into channel 1 will not affect anything on channel 2. In fact you could treat them as two separate chargers built into one, therefore even though I wasn't able to charge this 4s battery with the rest of them, I could plug this one into a separate channel and anything that happens on channel 1 will not affect what's happening on channel 2, I could even plug in a 3s battery into channel 2 and it will not affect, the 4s batteries parallel charging on channel 1. The only thing you have to keep in mind is that both channels will share the amount of amps that they can draw from your power source. So there is a limit, your charger will have a maximum of amps that it can draw from the power supply, and the charging that's going on in channel 1 and 2 together can't surpass that amount.

That’s all for this blog. If you feel like you Learned anything from this video, please give it a share.