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I have a question or two about LiPo batteries.

I have a question or two about LiPo batteries.


Old 12-28-2016, 07:49 PM
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Default I have a question or two about LiPo batteries.

Hello, getting into more serious Quadcopters and I have a question about a new type of battery for me. The battery I have rn is a 7.4V 2200mAh 3 cell lipo pack, and as the first question about it is the "balancing"? I had just received this and haven't used it yet. Although I am wondering if I will immediately need a balancer, or if they come balanced and I just need to make sure it doesn't get unbalanced and get a voltage reader/balancer? Main reason why is because idk if my Quadcopter comes with a basic or balancer charger (Syma X8HW). I am aware ahead of time of caring for lipos and prevention of fire, so that's not an issue. Another weird thing is that a different battery needs a USB charger, but I have noticed that the USB side of the cable gets hot to the touch while charging. While the Lipo almost seems to be cold (although not puffed at all so I assume it isn't a problem). I would appreciate it if I can get these things cleared up a bit? And if possible, any tips on LiPo care that I may not know?
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Old 01-02-2017, 01:01 PM
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Hi. Not sure if you got your questions answered since you posted a few days ago.
First, I think you have a 2S or 2 cell lipo. You posted 7.4V 3 cell and it can't be both 7.4V and 3 cell. A 3S battery would be called an 11.1V battery. Note that when they label these lipos, they use the "nominal" volts per cell of 3.7. So 2*3.7=7.4. 3*3.7=11.1.

The fully charged cells are at 4.2 volts so your 2S battery will read 8.4Voltas total when fully charged.

I looked up your Syma but could not a see a good pic of the charger. It is probably a balancing charger. I also could not see what the battery looks like. A typical Lipo has two sets of wires; the main (bigger) red and black wires and the smaller balancing wires which usually have a white connector. You can tell the S-number by the number of wires to the balancing connector. A 2S battery has 3 wires, a 3S battery has four, etc.

There are two ways to balance a Lipo. Either during charging or by using a balancing discharger. It is far better to balance during charging.

It is a good idea to have a Lipo checker like this one

Those 3 in 1 Lipo checkers are very handy. There are lots of them on the market. The one shown is sold under many different brand names but it inexpensive and works great for me.

The toy grade things come with those little chargers but if you go much further, you will want a decent charger. You can get an inexpensive 80Watt charger like this one
which is fine for small batteries. beyond that, you should get one of the icharger combos from progressiveRC.com

It really helps to know how to solder so you can change connectors if a battery has a connector you don't have the charge adapter for.

As for your USB charger getting hot, that doesn't sound right. Could be a bad battery or a bad charger.
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Old 01-02-2017, 01:20 PM
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I downloaded the manual for your X8Hw. You have a balancing charger. The charger only connects with the balancing plug. It charges and balances through the one plug.

Most "real" chargers will require both the main power plug and the balance connector to be connected to the charger so you need a charge cable that matches your battery. The balance connectors are usually pretty standard JST type and the chargers either have a balance board or balance sockets on the charger.

Batteries do not always arrive well balanced. I just had a new GensAce battery the other day that has a low cell. Balancing current is usually much less that the main charge current so big batteries with a low cell can take a long time to balance.

You don't have to always have your batteries perfectly balanced but batteries that won't stay balanced are either defective to have gotten old. They will work but its better to replace or retire sick batteries.
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Old 02-17-2017, 11:23 PM
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you need a balancer right away
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