lipo charge - ToolkitRC M4q

[Rosssiiii]

Hello

today is just arrived that product, i would like to ask some info to see if i'm doing all well to charge my lipo battery Ovonic 1550mah 4C.

https://imgur.com/VGGoXXv

cells i let work in auto, because in manual it let me decide to use only 1or 2 S.

as Amper i have selected 1.5a :

https://imgur.com/RyA8Jk8

because unluckily don't let me select 1.55 !

and as mode i selected charge and i thnk will do in auto the balance:

https://imgur.com/Tc8jqT0

 

[droneguy]

@Rosssiiii ... You got it! Charging at 1C (1.5A in your case) with give you the most charge cycles and extend the life of your battery. When you decide to not use your batteries for a while, make sure you Storage charge them (StoChg in the mode) to charge them to 3.8V. You can also charge at higher C rating in a pinch to get out and fly more quickly, but you will degrade the batteries a bit quicker so it's better to charge at 1C if you're not in a hurry.

 

[Rosssiiii]

yesterday i used battery ending at 3.6-3.7-3.8v but today i find some difference in voltage per Cell:

https://imgur.com/o6mrB2t

https://imgur.com/iGlLIfK

https://imgur.com/yW5P9Vu

expecially the A battery have difference, maybe is the case to go in STOCHG mode and after do a charge ?

battery is not damaged

 

[droneguy]

This is completely normal. You will see a small difference in cell voltage after use. The current is pulled from each cell and the differing cell impedance will result in a small difference in cell voltage after draining. You can use your batteries down to 3.3-3.4v per cell safely. Once you get around 3.3-3.4v per cell the voltage will drop quickly so be careful and keep your throttle low when at the lower voltages. Your charger will balance charge your battery back up to 4.2v per cell. It will balance the cells so that when you get to 16.8V all the cells will be balanced to 4.2V. You can check your cell impedance during charging and the health of your battery depends heavily on the cell impedance staying similar between cells. Without a good smart balance charger, if one or more cells get a really high impedance (resistance) than the other cells will take on more of the voltage and pull more current when in use which can cause a fire. Keep an eye on your cells impedance and as long as they are similar then you will have no issues.

 

[Rosssiiii]

This is completely normal. You will see a small difference in cell voltage after use. The current is pulled from each cell and the differing cell impedance will result in a small difference in cell voltage after draining. You can use your batteries down to 3.3-3.4v per cell safely. Once you get around 3.3-3.4v per cell the voltage will drop quickly so be careful and keep your throttle low when at the lower voltages. Your charger will balance charge your battery back up to 4.2v per cell. It will balance the cells so that when you get to 16.8V all the cells will be balanced to 4.2V. You can check your cell impedance during charging and the health of your battery depends heavily on the cell impedance staying similar between cells. Without a good smart balance charger, if one or more cells get a really high impedance (resistance) than the other cells will take on more of the voltage and pull more current when in use which can cause a fire. Keep an eye on your cells impedance and as long as they are similar then you will have no issues.

ok, thanks

when battery are full charged i noticed that the resistance between the cells of the various batteries varies from 4 to 8 :dodgy:

1) what about the resistance, is it certainly a parameter to consider ?

2) when battery charger completed the process and back in standby can i remove the cable from the wall and later disconnect battery, i think yes ?

3) when is there to worry about the voltage difference between cells?

 

[droneguy]

ok, thanks

when battery are full charged i noticed that the resistance between the cells of the various batteries varies from 4 to 8 :dodgy:

1) what about the resistance, is it certainly a parameter to consider ?

2) when battery charger completed the process and back in standby can i remove the cable from the wall and later disconnect battery, i think yes ?

3) when is there to worry about the voltage difference between cells?

1) Resistance and impedance are similar. Many people use them interchangeably. In very simple terms, resistance exists with a static load and impedance exists when the load is active, inductive or capacitive (load can vary). Keeping an eye on your impedance (it will change over time) is very important as it is an indication of the health of your batteries / cells. It's normal for the impedance to vary between cell (it's an active load). The impedance should be close (ie. within +/- 4-5 milli ohms of each other) If you see a double digit difference then you should really pay attention to the charging cycles to ensure no cell is pulling excessive current or charging past 4.2v. It gets really dangerous if you have a large difference in cell impedance as the current will not flow evenly on charge or discharge during use and excessive current can lead to fire.

2) you can leave your batteries connected to your charger with the AC pulled from the wall, but it's not a good idea. Your batteries are attached to a load and depending on the design of your charger, your batteries will start to discharge (albeit very slowly because the resistance of the charger should be very high in the Mohms) but unless your charger has and output relay to open the circuit, there will be a load on the output thus slowly discharging your batteries.

3) Voltage difference between cells directly correlates to the impedance of the cells so excessive voltage difference +/- 0.3v is an indication that your impedance is starting to vary and you should start paying more attention to your batteries.