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Battery basics questions for the Newbie

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I am hoping that the answers, corrections and verifications to the following questions for the Typhoon H plus OEM LiPo battery will not only help me but also those other newbies with similar questions. I use a RC charger rather the OEM charger (although I have read that the OEM charger does a good job at balancing the V for each cell).

Note: The OEM Battery specs are: 4S (4 cells), 5250 mA (5.25 A), 15.2 V (3.8V each cell) LiPo (Lithium Polymer) battery. No C rating is provided (Why?).

  1. Voltage
    1. Maximum battery V is 16.8. Is this correct? This would equate to 4.2 V per cell. Any greater is a risk to the battery bursting into flames.
    2. Lowest battery cell V is 3.2V (drone back at home and off). Is this correct? Voltage lower than 3.2 risks reduction of the life span of the battery.
    3. Preferred storage battery cell V is 3.8V . Is this correct? When time to fly, balance charge the battery from 3.8V to 16.8 V. Is this correct? How long after the last flight should the battery be placed in the storage state?. Ie, amount of days since last flight.
    4. See Beginners Guide to LiPo Batteries for FPV Drones for more information.
    5. The same V for each cell is preferred. However, It is common for each cell (in my case ... 4 cells) to fluctuate in V. Thus the need for balance charging (I read elsewhere that the OEM charger balances the V quite well). What is considered the max range of V between cells before I need to be concerned? 0.4 V?
  2. Discharge (C) Rating
    1. Why did Kuneec choose to not provide the C rating on their OEM battery? For that matter, there isn't a C rating on a recently purchased 3rd party battery (GiFi Power). Nonetheless, I understand that most batteries these days have two C ratings. One for steady speed (continuous) and the other for acceleration (boost). The C rating number assigned to the battery is used to determine the maximum sustained load you can safely put on the battery from the drone motor for either condition. The formula is simply C x V. As an example, If a 4s, 5000mA (5 A), LiPo battery has a C rating of 10/15, then the continuous load would be 10 x 5.0 = 50.0 A. The boost load would be 15 x 5.0 = 75.0 A.
    2. My question is where are the specifications of a particular drone located so as to check against the C ratings of a particular battery? In the case of the Typhoon H Plus, I noted an ESC (Electronic Speed Control) spec of 25 A. How does this relate to the C-ratings, if any? I can't seem to find any other specs for the Typhoon H Plus that could be checked against the C ratings of a compatible battery. To complicate matters, and as stated previously, both the OEM and GiFi Power batteries don't specify any C ratings.
    3. From some research, I did note that in charging a battery, it is wise to charge at 1C. In other words, the 5.25 A battery shouldn't be charged at more than 1 x 5.25 A. Thoughts?
    4. See What is C Rating of LiPo Battery FPV Drones for more information.
  3. Internal Resistance.
    1. Each cell in a multi-cell battery has an internal resistance (IR) measured in Ohms (O). The recently purchased GiFi Power battery has the following IRs per the RC charger: 7.4, 14.9, 7.4 , and 14.9 mO. Total of 44.8 mO. My first question here is why the large range of IR between the cells? Is this normal? And are these values typical of a new battery?
    2. My OEM battery, which is bad, has one cell at 0.0 Ohms. Not sure if this adds up, but given V (Volt) = I (A) x IR (Ohm), the equation is bust if V, I, or R, is 0. It is a mathematical impossibility. As this was only one of the 4 cells, however, and the other 3 cells have an IR greater than 0, does it really matter given that the overall battery IR (summation of the IR of each individual cell) is greater than 0? Does disparity between each of the cells matter in this case?
  4. The battery weight of the OEM is 565 grams. The GiFi Power weighs 605 grams. Will this cause any concerns? The new battery is rated 7900mA, 15.2 V. I am not entirely sure that a 7.9 A battery would make up the difference for the heavier battery. Ie, motor strength increased? Is this associated with the ESC A?
Thank you
 

Steve Carr

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I presume the batteries you are using are LiHV and not Lipo.
So they should be charged to 17.4 volts for a full charge.
I always plan to land when the voltage is at 30% with the H Plus. Discharging lower than that can shorten the life of the battery. When checked with the charger after a 30% landing, voltage should be close to 15.2v.

The IR readings you posted for the Gifi battery aren't great. I look for less than 10 on each cell with a new battery.
These are the reading for 6 LiHV batteries. Three are good and three are marginal.

Battery IR.jpg
 
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DoomMeister

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I am hoping that the answers, corrections and verifications to the following questions for the Typhoon H plus OEM LiPo battery will not only help me but also those other newbies with similar questions. I use a RC charger rather the OEM charger (although I have read that the OEM charger does a good job at balancing the V for each cell).

Note: The OEM Battery specs are: 4S (4 cells), 5250 mA (5.25 A), 15.2 V (3.8V each cell) LiPo (Lithium Polymer) battery. No C rating is provided (Why?).

  1. Voltage
    1. Maximum battery V is 16.8. Is this correct? This would equate to 4.2 V per cell. Any greater is a risk to the battery bursting into flames.
    2. Lowest battery cell V is 3.2V (drone back at home and off). Is this correct? Voltage lower than 3.2 risks reduction of the life span of the battery.
    3. Preferred storage battery cell V is 3.8V . Is this correct? When time to fly, balance charge the battery from 3.8V to 16.8 V. Is this correct? How long after the last flight should the battery be placed in the storage state?. Ie, amount of days since last flight.
    4. See Beginners Guide to LiPo Batteries for FPV Drones for more information.
    5. The same V for each cell is preferred. However, It is common for each cell (in my case ... 4 cells) to fluctuate in V. Thus the need for balance charging (I read elsewhere that the OEM charger balances the V quite well). What is considered the max range of V between cells before I need to be concerned? 0.4 V?
  2. Discharge (C) Rating
    1. Why did Kuneec choose to not provide the C rating on their OEM battery? For that matter, there isn't a C rating on a recently purchased 3rd party battery (GiFi Power). Nonetheless, I understand that most batteries these days have two C ratings. One for steady speed (continuous) and the other for acceleration (boost). The C rating number assigned to the battery is used to determine the maximum sustained load you can safely put on the battery from the drone motor for either condition. The formula is simply C x V. As an example, If a 4s, 5000mA (5 A), LiPo battery has a C rating of 10/15, then the continuous load would be 10 x 5.0 = 50.0 A. The boost load would be 15 x 5.0 = 75.0 A.
    2. My question is where are the specifications of a particular drone located so as to check against the C ratings of a particular battery? In the case of the Typhoon H Plus, I noted an ESC (Electronic Speed Control) spec of 25 A. How does this relate to the C-ratings, if any? I can't seem to find any other specs for the Typhoon H Plus that could be checked against the C ratings of a compatible battery. To complicate matters, and as stated previously, both the OEM and GiFi Power batteries don't specify any C ratings.
    3. From some research, I did note that in charging a battery, it is wise to charge at 1C. In other words, the 5.25 A battery shouldn't be charged at more than 1 x 5.25 A. Thoughts?
    4. See What is C Rating of LiPo Battery FPV Drones for more information.
  3. Internal Resistance.
    1. Each cell in a multi-cell battery has an internal resistance (IR) measured in Ohms (O). The recently purchased GiFi Power battery has the following IRs per the RC charger: 7.4, 14.9, 7.4 , and 14.9 mO. Total of 44.8 mO. My first question here is why the large range of IR between the cells? Is this normal? And are these values typical of a new battery?
    2. My OEM battery, which is bad, has one cell at 0.0 Ohms. Not sure if this adds up, but given V (Volt) = I (A) x IR (Ohm), the equation is bust if V, I, or R, is 0. It is a mathematical impossibility. As this was only one of the 4 cells, however, and the other 3 cells have an IR greater than 0, does it really matter given that the overall battery IR (summation of the IR of each individual cell) is greater than 0? Does disparity between each of the cells matter in this case?
  4. The battery weight of the OEM is 565 grams. The GiFi Power weighs 605 grams. Will this cause any concerns? The new battery is rated 7900mA, 15.2 V. I am not entirely sure that a 7.9 A battery would make up the difference for the heavier battery. Ie, motor strength increased? Is this associated with the ESC A?
Thank you
Voltage:
The H+ (520mm between opposite motors and uses the C23 camera) uses LiHV cells. Storage voltage is 3.85V/cell (15.4V) and full charge is 4.35V/cell (17.4V). Lowest cell voltage is 3.35V (many chargers will fault out with a cell lower than this on LiHV setting). A slight overcharge of the battery will not make it burst into flame (+0.05V or up to 4.4V/cell), but will shorten the useful lifespan of the pack (FPV racers do this regularly, but burn through batteries at an accelerated rate). Max deviation of cells would be more on the order of 0.04V and I personally become wary with a deviation of more than 0.015V. The weaker cell in the pack causes reduced flight time and poor high demand performance. @h-elsner posted graphs showing this in the other thread (in the TH Discussion forum).

C Ratings:
Who knows why Yuneec is so secretive with specifications for their aircraft and batteries? Most others are pretty much the same unless you are into building your own FPV stunt/racer drone. You stated the ESC rating for the H+ was 25A (I think it is fused for 20A) times six motors would give you 150A (120A) with all motors at maximum. I think you will find the firmware limits are much less than this (also secretive). By your own formula 150A/5.25=28.6C so a 30C battery (fused - 120/5.25=22.9 so 25C). Max charging rate is standard at 1C.

Internal Resistance:
IR should be less than 10 milliOhms per cell. Any over 20 milliOhms per cell are going to have reduced flight times.

The new GiFi battery should have all cells less than 10 milliOhms and fairly even between cells. It may take a few charge/discharge cycles on a new battery to break it in. If it doesn’t improve after 5 cycles you may want to go for an exchange or refund.

The OEM battery has really flaky readings and I would not fly with it. Use it for ground uses such as calibrations and GPS acquisition.

Battery Weight:
Higher battery weigh is no problem as long as you do not exceed maximum takeoff weight. Higher weight means less flight time.

Higher capacity batteries have greater weight so the flight times are usually less than what might be expected. This is due to energy density. Not taking the casing into account the OEM battery at 565g and 5250mAh is 9.3mAh/g and the GiFi is 7900mAh at 605g for 13mAh/g. This a bit off due to the casing on the OEM is a bit more robust than the GiFi, but if you were getting 9 minutes with the OEM you could expect about 13 with the GiFi under the same flying conditions.

BTW the GiFi is actually a 4S2P battery pack. I don’t know about the OEM as I have not seen one with the case removed.
 
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Very informative. Thank you much. And thank you for providing some calculations.
 
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I too have purchased a GiFi 7900 mAh battery back in Dec. I only bought one of them and it arrived quickly and was well packaged. It arrived on a very cold day and I removed it from the box ASAP and allowed it to warm to room temps for about 3 hours. I then checked the IR values of the 4 cells and found them all to be 7 or less in value. I then placed the battery on my charger and placed it into storage mode. Due to very cold weather where I live I have yet to fly with the battery. I have read in these forums that IR values can vary by 1 or 2 points as to if the battery is in storage or fully charged... I'm not sure and someone will correct me if needed. But, I do agree with all above posters that if you buy a "new" battery(LiPo or LiHV) all cells should have values less than 10.
 
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Steve Carr

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Yes, the IR should be less than 10 on a new battery.
After placing in storage mode I often see the voltage vary between cells by 0.01 to 0.02 volts. One that is in the charger right now reads 3.88, 3.87, 3.87, 3.86. It has an IR of 8,7,8,7. It's an older LiHV but still in good condition and was placed in storage mode a couple of months ago.
Does this answer your question?
 
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Voltage:
The H+ (520mm between opposite motors and uses the C23 camera) uses LiHV cells. Storage voltage is 3.85V/cell (15.4V) and full charge is 4.35V/cell (17.4V). Lowest cell voltage is 3.35V (many chargers will fault out with a cell lower than this on LiHV setting). A slight overcharge of the battery will not make it burst into flame (+0.05V or up to 4.4V/cell), but will shorten the useful lifespan of the pack (FPV racers do this regularly, but burn through batteries at an accelerated rate). Max deviation of cells would be more on the order of 0.04V and I personally become wary with a deviation of more than 0.015V. The weaker cell in the pack causes reduced flight time and poor high demand performance. @h-elsner posted graphs showing this in the other thread (in the TH Discussion forum).

C Ratings:
Who knows why Yuneec is so secretive with specifications for their aircraft and batteries? Most others are pretty much the same unless you are into building your own FPV stunt/racer drone. You stated the ESC rating for the H+ was 25A (I think it is fused for 20A) times six motors would give you 150A (120A) with all motors at maximum. I think you will find the firmware limits are much less than this (also secretive). By your own formula 150A/5.25=28.6C so a 30C battery (fused - 120/5.25=22.9 so 25C). Max charging rate is standard at 1C.

Internal Resistance:
IR should be less than 10 milliOhms per cell. Any over 20 milliOhms per cell are going to have reduced flight times.

The new GiFi battery should have all cells less than 10 milliOhms and fairly even between cells. It may take a few charge/discharge cycles on a new battery to break it in. If it doesn’t improve after 5 cycles you may want to go for an exchange or refund.

The OEM battery has really flaky readings and I would not fly with it. Use it for ground uses such as calibrations and GPS acquisition.

Battery Weight:
Higher battery weigh is no problem as long as you do not exceed maximum takeoff weight. Higher weight means less flight time.

Higher capacity batteries have greater weight so the flight times are usually less than what might be expected. This is due to energy density. Not taking the casing into account the OEM battery at 565g and 5250mAh is 9.3mAh/g and the GiFi is 7900mAh at 605g for 13mAh/g. This a bit off due to the casing on the OEM is a bit more robust than the GiFi, but if you were getting 9 minutes with the OEM you could expect about 13 with the GiFi under the same flying conditions.

BTW the GiFi is actually a 4S2P battery pack. I don’t know about the OEM as I have not seen one with the case removed.
My only feedback is that the ST16 uses a LiTon battery and the Typhoon H Plus uses a LiPo battery. Very good information.
 

DoomMeister

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My only feedback is that the ST16 uses a LiTon battery and the Typhoon H Plus uses a LiPo battery. Very good information.
Yes the ST16S uses a Li-ion battery pack anc the H+ actually uses a LiHV battery pack.
 

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