As FPV drone lovers, we’re at all times looking out for tactics to boost flight efficiency. One of many game-changers within the FPV group has been the introduction of LiHV batteries. On this weblog publish, we’ll discover what LiHV batteries are, why they’ve develop into in style, 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 customary 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 larger voltage interprets into a number of efficiency advantages, making LiHV batteries a pretty possibility for sure varieties of FPV drone.
Why Are LiHV Batteries Common?
Improved Efficiency
Most motor RPM is proportional to the voltage utilized. LiHV batteries present the next voltage, which may result in elevated thrust and quicker speeds. For racing drones or high-performance acrobatic drones, this generally is a important benefit, providing faster response occasions and extra highly effective maneuvers.
Elevated Flight Time
For a similar weight, LiHV batteries presents extra energy capability, which doubtlessly interprets to longer flight time.
Compatibility
LiHV batteries are typically appropriate with most FPV drones that use LiPo batteries. This ease of integration makes it easy for drone lovers to change 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 larger voltage additionally supplies larger vitality density, leading to larger motor RPM and longer flight occasions.
Weight, Dimension and C Ranking
As talked about, LiHV batteries are inclined to have a barely larger vitality density, which may imply they provide extra energy with out a important enhance in weight or dimension in comparison with equal LiPo batteries. Due to this fact, for a similar capability, LiHV packs are normally barely lighter than LiPo. Additionally, because of the larger voltage, the C score of LiHV can also be barely larger 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’ll be able to 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, it’s best to 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 critical points, together with growing the chance 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 protected to cost LiHV battery to 4.20V per cell, as the utmost voltage you possibly can 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 concerning the longevity of LiHV – its efficiency degrade quicker than typical LiPo. Additionally as you go up in cell depend the advantage of the upper voltage diminishes, subsequently LiHV is usually in style inside micro drones, akin to Tiny whoops and 2S Toothpicks, the place the upper voltage can really make a noticeable distinction to make it price whereas. Anyway I plan to do some testing to verify if the longevity concern is actual, so keep tuned.
LiHV Batteries Testing
These Hyperion HVLi packs include customary XT60 Important 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 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 similar 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 velocity cruising.
Hover Check
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 might 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 load 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 possibly can see the quad has to work tougher (larger 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 larger than the LiPo initially, however in direction of the second half of the method, it was regularly getting nearer to that of the LiPo.
Enjoyable reality: After we’ve got drawn 1800mA from the Turnigy Nano-tech, its voltage was nonetheless fairly excessive at 14.4V (3.6V per cell). That implies it really could be bigger pack than specified by producer. (possibly 1900mAh?)
Quick Flying Check
On this check I used to be flying round with 70% to 80% throttle continuously. The upper voltage improved the responsiveness and velocity of the quad. You’ll be able to see that from the ability graph, the quad was in a position to pull out extra energy from the LiHV than LiPo total.
Nonetheless I didn’t discover a lot enchancment on flight time in comparison with the Nano-Tech LiPo, in all probability as a result of I used to be pushing the quad too laborious.
Comparable consequence to the hover check, the place we see larger voltage firstly, however they converged in direction of the finish. That implies the battery would give your motors larger RPM and fewer voltage sag, due to the larger preliminary voltage, however in all probability related efficiency to the LiPo’s in the 2nd half of the pack. I feel that is one thing you must keep in mind when doing endurance races, the place you must resolve when is finest to vary batteries.
*Word that the Turnigy battery I used to be evaluating in opposition to 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 check 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 preferred selection within the FPV drone group for his or her capability to offer longer flight occasions and enhanced efficiency, particularly for micro drones. Whereas they provide a number of benefits over conventional LiPo batteries, it’s essential to acknowledge the charging necessities and potential lifespan trade-offs. For drone lovers trying to push the boundaries of their flying expertise, LiHV batteries are undoubtedly price contemplating.
As at all times, when working with high-performance batteries, security ought to be a high precedence. Make sure you use appropriate chargers and observe finest practices for battery care and upkeep to take pleasure in the advantages of LiHV batteries whereas conserving your gear and your self protected.
