Taking Care of Your Lipo Battery

First of all, even though it can be a sign, A PUFFED LIPO DOES NOT ALWAYS EQUAL A BAD BATTERY; the inner resistance is a better way to see if the cells have gone bad. Some lipos, especially high discharge ones, will puff no matter what. It’s simply the nature of the chemistry; high discharge cells tend to be thicker and more volatile. Thicker equals less space in the casing for it to expand towards thus the swelling becoming more noticeable. Add to that the more volatile nature of it and you get yourself a battery prone to swelling. With that out of the way, we can start on how to take care of your lipos.


Charging your battery for use

First, make sure your charger is lipo capable and is capable of balance charging.

  1. Power on your charger.
  2. Making sure the polarities are correct (positive (+) to positive (+) and negative (-) to negative (-)), connect the battery to the charger’s output and the balance lead to the balance port.

     

  3. Select the program/option “BALANCE CHARGING”. You can set to “CHARGE” but that would mean no balancing happening and risks one cell being overcharged.
  4. Set your charge current (A). For the best life span of your batteries and for the most capacity, charge current should be set to 1C. This means setting the charge current the same as your batteries capacity e.g. 4A charge current for a 4000mah battery, 5.5A for a 5500mah battery so on and so forth. You can set a higher charge current but that has a higher risk of puffing and/or damaging your cells. I’ve seen someone charge at 70amps on a 2800mah LRP battery, a whopping 25C charge current. Charge was done after 2 minutes but the battery was thrown out after the race since the cells were so puffed and damaged.

    C = \frac{(CHARGE CURRENT, A)}{(BATTERY CAPACITY, MAH)/1000}

  5. Start the charge. Most chargers allow you to monitor the charging of the individual cells as well as other parameters by pressing the left/right or up/down buttons.
  6. Wait for the battery to be charged. For fully depleted batteries, this may take anywhere around 45 minutes to 1 hour. Going over an hour isn’t a problem.
  7. After charge is complete, disconnect battery from charger. If you are using bullet/banana plugs, disconnect the balance plug first then the main power leads.

Note: Always turn on charger first before connecting the battery. Some older chargers got damaged when the battery is connected before turning on the charger. 

 


Storing Battery After Use

Believe it or not, this is where most of the puffing and damage happens. Improper storage of batteries. I am not talking about storing in cold or hot places. I am talking about the state at which you store your batteries. Some get lazy (EHEM EHEM) and some simply do not know that you’re supposed to store your batteries within a certain voltage range. SMC suggests storing your battery around 3.4v to 3.9v per cell with the best being 3.8v to 3.85v for long storage times (more than a week). You can use lower than 3.8v for short term storage. Most chargers will terminate the charge at 3.85 volts per cell or anywhere around that. If after playing, your battery is around that voltage then you can store it. If it’s higher or lower then you need to STORAGE CHARGE it.

  1. Turn on charger and connect battery including balance lead.
  2. Select “STORAGE CHARGE”.
  3. Set charge current to 1C.
  4. Start the charge.
  5. After charge is complete, disconnect battery from charger. If you are using bullet/banana plugs, disconnect the balance plug first then the main power leads.

USING YOUR BATTERY GUIDES, TIPS, ETC.

Extending lifespan 

  • Set your low voltage cutoff (LVC) to 3.6v per cell or 7.2v in total or to whatever value so that after immediately tripping the LVC your battery’s voltage is around 3.6v per cell. This will most likely be higher than 3.6v especially when using a lot of boost/turbo because of the voltage sag that high boost/turbo incurs. This will shorten your playtime if you usually set your LVC lower but your battery is gonna last longer.
  • Setting your charger’s max charge voltage to below 4.2v per cell will extend the battery’s life immensely. Depending on your boost levels and how much you squeeze your throttle, a 0.02v difference might give you just a few seconds of playtime. It’s a matter of a few seconds lost vs a shorter lifespan. Personally, I would set it to 4.18v per cell.
  • DO NO CHARGE BATTERY IMMEDIATELY AFTER USING. Let it cool off to room temp first.
  • Charge at 1C.
  • Always store at the correct voltages. The best being around 3.8V for long storage times.
  • Always balance charge.

Determining if your battery is not fully health or damaged.

  • Discharge isn’t symmetrical. You can see this by checking your cell voltages after your LVC kicks in. If the voltages are very far off like a 0.2v difference:3.4v, 3.2v.
  • Big difference in internal resistances (not all chargers can measure this) between the two cells e.g. cell 1 = 2 mΩ, cell 2 = 4 mΩ. Even a 2 mΩ difference can affect the end voltages greatly.
  • Cannot hold full throttle especially when using high boost levels; throttle modulates or falls off after a few second.
  • LVC kicks in even if the battery voltage after is way higher than the set LVC. Means the battery has a very high internal resistance and the voltage is sagging a lot.
  • Battery gets unusually hot while in use.
  • “Abnormal” puffing. 

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