As FPV drone fans, we’re at all times looking out for tactics to boost flight efficiency. One of many game-changers within the FPV neighborhood has been the introduction of LiHV batteries. On this weblog put up, we’ll discover what LiHV batteries are, why they’ve develop into widespread, 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 will be charged as much as 4.35 volts per cell. This greater voltage interprets into a number of efficiency advantages, making LiHV batteries a lovely choice for sure varieties of FPV drone.
Why Are LiHV Batteries In style?
Improved Efficiency
Most motor RPM is proportional to the voltage utilized. LiHV batteries present the next voltage, which may result in elevated thrust and sooner speeds. For racing drones or high-performance acrobatic drones, this generally is a important benefit, providing faster response instances and extra highly effective maneuvers.
Elevated Flight Time
For a similar weight, LiHV batteries gives extra energy capability, which probably interprets to longer flight time.
Compatibility
LiHV batteries are usually suitable with most FPV drones that use LiPo batteries. This ease of integration makes it easy for drone fans to change to LiHV without 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 greater voltage additionally supplies greater vitality density, leading to greater motor RPM and longer flight instances.
Weight, Measurement and C Score
As talked about, LiHV batteries are inclined to have a barely greater vitality density, which may imply they provide extra energy with no important improve in weight or measurement in comparison with equal LiPo batteries. Subsequently, for a similar capability, LiHV packs are normally barely lighter than LiPo. Additionally, as a result of greater voltage, the C score of LiHV can be barely greater than LiPo for a similar measurement battery.
This may be useful 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 making an attempt to cost LiHV batteries. You may cost a LiHV with LiPo settings safely, however you received’t be utilizing LiHV battery to its full potential.
Are you able to cost LiPo to 4.35V?
Completely NOT, you must NEVER cost an ordinary 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 severe points, together with rising the danger of overheating, swelling, and even catching hearth. Overcharging additionally reduces the lifespan of the battery, and even inflicting everlasting harm.
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’ll be able to cost it to is 4.35V per cell. Nonetheless, 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 widespread inside micro drones, resembling Tiny whoops and 2S Toothpicks, the place the upper voltage can truly make a noticeable distinction to make it value whereas. Anyway I plan to do some testing to verify if the longevity subject is actual, so keep tuned.
LiHV Batteries Testing
These Hyperion HVLi packs include normal XT60 Major connectors, with JST-XH Steadiness 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 vitality 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 in a position to monitor voltage and present draw on the identical time whereas flying.
I examined and in contrast the Hyperion 4S 1800mAh and Turnigy Nano-Tech 4S 1800mAh. I ran the check 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 desired 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 apparently 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 facility graph confirmed this, as you’ll be able to see the quad has to work more durable (greater 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 greater than the LiPo initially, however in the direction of the second half of the method, it was progressively getting nearer to that of the LiPo.
Enjoyable truth: After we’ve drawn 1800mA from the Turnigy Nano-tech, its voltage was nonetheless fairly excessive at 14.4V (3.6V per cell). That means it truly could be bigger pack than specified by producer. (possibly 1900mAh?)
Quick Flying Take a look at
On this check I used to be flying round with 70% to 80% throttle consistently. The upper voltage improved the responsiveness and pace of the quad. You may see that from the facility graph, the quad was in a position to pull out extra energy from the LiHV than LiPo general.
Nonetheless 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 outcome to the hover check, the place we see greater voltage initially, however they converged in the direction of the finish. That means the battery would give your motors greater RPM and fewer voltage sag, because of the greater preliminary voltage, however most likely related efficiency to the LiPo’s in the 2nd half of the pack. I believe that is one thing you should have in mind when doing endurance races, the place you should resolve when is greatest to vary batteries.
*Notice that the Turnigy battery I used to be evaluating in opposition to with is practically a 12 months previous so discharge charge 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 check the longevity of LiHV batteries and the way it compares to LiPo. Keep tuned.
testing methodology: totally charging at 2C, then discharge at 20C til 3.3V per cell. Repeat this for 50 cycles. Evaluate efficiency each 10 cycles.
Closing Ideas
LiHV batteries have develop into a well-liked selection within the FPV drone neighborhood for his or her capacity to supply longer flight instances and enhanced efficiency, particularly for micro drones. Whereas they provide a number of benefits over conventional LiPo batteries, it’s vital to acknowledge the charging necessities and potential lifespan trade-offs. For drone fans trying 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 ought to be a prime precedence. Make sure you use suitable chargers and comply with greatest practices for battery care and upkeep to get pleasure from the advantages of LiHV batteries whereas conserving your gear and your self secure.