As FPV drone fans, we’re at all times looking out for methods to reinforce flight efficiency. One of many game-changers within the FPV neighborhood has been the introduction of LiHV batteries. On this weblog submit, we’ll discover what LiHV batteries are, why they’ve develop into fashionable, how they evaluate to conventional LiPo batteries, and the professionals and cons of utilizing them.
What Are LiHV Batteries?
LiHV stands for Lithium Excessive Voltage. These batteries are a variation of the normal LiPo (Lithium Polymer) batteries however with a key distinction within the chemistry and voltage. Whereas normal LiPo cells are charged to a most of 4.2 volts per cell, LiHV cells could be charged as much as 4.35 volts per cell. This increased voltage interprets into a number of efficiency advantages, making LiHV batteries a pretty possibility for sure sorts of FPV drone.
Why Are LiHV Batteries Widespread?
Improved Efficiency
Most motor RPM is proportional to the voltage utilized. LiHV batteries present a better voltage, which might result in elevated thrust and sooner speeds. For racing drones or high-performance acrobatic drones, this is usually a important benefit, providing faster response occasions and extra highly effective maneuvers.
Elevated Flight Time
For a similar weight, LiHV batteries affords extra energy capability, which doubtlessly interprets to longer flight time.
Compatibility
LiHV batteries are usually appropriate with most FPV drones that use LiPo batteries. This ease of integration makes it easy for drone fans to modify to LiHV while not having to improve {hardware}.
Evaluating LiHV to Conventional LiPo Batteries
Voltage and Capability
As talked about, the first distinction between LiHV and LiPo batteries is the utmost voltage. LiHV cells cost as much as 4.35V in comparison with 4.2V for LiPo cells. This increased voltage additionally gives increased power density, leading to increased motor RPM and longer flight occasions.
Weight, Dimension and C Ranking
As talked about, LiHV batteries are inclined to have a barely increased power density, which might imply they provide extra energy with out a important improve in weight or dimension in comparison with equal LiPo batteries. Subsequently, for a similar capability, LiHV packs are often barely lighter than LiPo. Additionally, as a result of increased voltage, the C score of LiHV can be barely increased than LiPo for a similar dimension battery.
This may be helpful for sustaining the drone’s steadiness and agility.
Charging Necessities
Charging LiHV batteries requires a charger that helps the upper voltage. Whereas many fashionable chargers do, it’s important to confirm this earlier than trying to cost LiHV batteries. You possibly can cost a LiHV with LiPo settings safely, however you gained’t be utilizing LiHV battery to its full potential.
Are you able to cost LiPo to 4.35V?
Completely NOT, it’s best to NEVER cost a typical LiPo battery to 4.35V per cell. Conventional LiPo batteries are designed to be charged to a most of 4.20V per cell. Charging them past this voltage can result in a number of critical points, together with growing the danger of overheating, swelling, and even catching hearth. Overcharging additionally reduces the lifespan of the battery, and even inflicting everlasting injury.
Are you able to cost LiHV to 4.20V?
Sure, it’s secure to cost LiHV battery to 4.20V per cell, as the utmost voltage you possibly can cost it to is 4.35V per cell. Nevertheless, you might be dropping round 10% of the capability.
LiHV Is Not For Everybody
There’s a priority in regards to the longevity of LiHV – its efficiency degrade sooner than typical LiPo. Additionally as you go up in cell rely the advantage of the upper voltage diminishes, due to this fact LiHV is generally fashionable inside micro drones, similar to Tiny whoops and 2S Toothpicks, the place the upper voltage can really make a noticeable distinction to make it value whereas. Anyway I plan to do some testing to verify if the longevity situation is actual, so keep tuned.
LiHV Batteries Testing
These Hyperion HVLi packs include normal XT60 Primary connectors, with JST-XH Stability connectors. The discharge lead is 14AWG silicon wire.
When evaluating to regular LiPo of the identical capability, LiHV’s are smaller and lighter due to the upper power per weight.
- Hyperion 4S 1800mAh 40C – 178g
- Turnigy Nano-Tech 4S 1800mAh 65C – 228g
And right here is the smaller 1400mAh pack.
- Hyperion 4S 1400mAh 40C – 142g
- Dronelab 4S 1500mAh 50C – 157g
So with the assistance of my KISS FC + KISS ESC 24A setup, I used to be capable of monitor voltage and present draw on the similar time whereas flying.
I examined and in contrast the Hyperion 4S 1800mAh and Turnigy Nano-Tech 4S 1800mAh. I ran the take a look at twice, the primary time I used to be simply hovering, and the second time I did some med-high pace cruising.
Hover Take a look at
Right here I hovered the quad at one place, and solely landded when “consumed mA” reached 1800mA – the required battery capability. (I eliminated the GoPro to get a bit longer hover time)
- Hyperion: 10:45
- Turnigy: 9:09
I used to be anticipating they’d land at about the identical time, given each are the identical 1800mAh capability, however curiously NO! The Hyperion lasted about 96 seconds longer than the Turnigy.
My guess is the burden of the batteries, the Hyperion is 50g lighter than the Turnigy, and the motors pull much less present when simply hovering. The ability graph confirmed this, as you possibly can see the quad has to work more durable (increased energy) to remain within the air when carrying the additional weight.
One other factor to note is the voltage of the batteries all through the entire discharging cycle. The voltage of the HVLi is increased than the LiPo initially, however in the direction of the second half of the method, it was steadily getting nearer to that of the LiPo.
Enjoyable reality: After we have now drawn 1800mA from the Turnigy Nano-tech, its voltage was nonetheless fairly excessive at 14.4V (3.6V per cell). That implies it really is perhaps bigger pack than specified by producer. (perhaps 1900mAh?)
Quick Flying Take a look at
On this take a look at I used to be flying round with 70% to 80% throttle always. The upper voltage improved the responsiveness and pace of the quad. You possibly can see that from the ability graph, the quad was capable of pull out extra energy from the LiHV than LiPo total.
Nevertheless I didn’t discover a lot enchancment on flight time in comparison with the Nano-Tech LiPo, most likely as a result of I used to be pushing the quad too exhausting.
Related consequence to the hover take a look at, the place we see increased voltage initially, however they converged in the direction of the finish. That implies the battery would give your motors increased RPM and fewer voltage sag, because of the increased preliminary voltage, however most likely comparable efficiency to the LiPo’s in the 2nd half of the pack. I feel that is one thing you must consider when doing endurance races, the place you must resolve when is finest to vary batteries.
*Be aware that the Turnigy battery I used to be evaluating towards with is practically a 12 months outdated so discharge price is worse than new packs. I don’t have any new 1800mAh LiPo packs in order that’s it.
Longevity Testing
Sooner or later I’ll take a look at the longevity of LiHV batteries and the way it compares to LiPo. Keep tuned.
testing methodology: absolutely charging at 2C, then discharge at 20C til 3.3V per cell. Repeat this for 50 cycles. Examine efficiency each 10 cycles.
Remaining Ideas
LiHV batteries have develop into a well-liked alternative within the FPV drone neighborhood for his or her capability to supply longer flight occasions and enhanced efficiency, particularly for micro drones. Whereas they provide a number of benefits over conventional LiPo batteries, it’s necessary to acknowledge the charging necessities and potential lifespan trade-offs. For drone fans seeking to push the boundaries of their flying expertise, LiHV batteries are undoubtedly value contemplating.
As at all times, when working with high-performance batteries, security needs to be a high precedence. Make sure you use appropriate chargers and observe finest practices for battery care and upkeep to get pleasure from the advantages of LiHV batteries whereas protecting your gear and your self secure.
