As FPV drone fans, we’re at all times in search of methods to reinforce flight efficiency. One game-changer 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 turn into in style, how they examine 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 conventional LiPo (Lithium Polymer) batteries however with a key distinction in chemistry and voltage. Whereas customary LiPo cells are charged to a most of 4.2V per cell, LiHV cells might be charged as much as 4.35V per cell. This greater voltage interprets into a number of efficiency advantages, making LiHV batteries a beautiful choice for sure kinds of FPV drones.
LiHV and LiPo Variations
Voltage
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. In FPV drone motors, the utmost RPM is proportional to the voltage utilized. LiHV batteries present a better voltage, resulting 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.
Weight and Capability
LiHV batteries are likely to have a barely greater power density, which suggests they provide extra energy and not using a important enhance in weight or measurement in comparison with equal LiPo batteries, doubtlessly translating to longer flight occasions. Moreover, as a result of greater voltage, the C ranking of LiHV tends to be barely greater than LiPo for a similar measurement battery.
Compatibility
Regardless of the distinction in most voltage, LiHV batteries are usually appropriate with most FPV drones that use LiPo batteries. This makes it easy for drone pilots to change to LiHV while not having to improve {hardware}.
Charging Necessities
Charging LiHV batteries requires a charger that helps the upper finish voltage. Whereas many trendy chargers do, it’s important to confirm this earlier than trying to cost LiHV batteries. You possibly can safely cost a LiHV with LiPo settings, however you gained’t be utilizing the LiHV battery to its full potential.
These chargers that I like to recommend can all cost LiHV batteries: https://oscarliang.com/choose-lipo-battery-charger-power-supply/#Prime-LiPo-Charger-Suggestions
LiHV Batteries Testing
For this check, I chosen LiHV and LiPo batteries with very comparable specs to give attention to the variations between these battery varieties:
- GNB 2S 550mAh 90C LiPo
- GNB 2S 550mAh 100C LiHV
You possibly can test their specs right here: https://oscarliang.com/whoop-toothpick-lipo-battery/#2S-LiPoLiHV
Discharge Efficiency
So, how does LiHV examine to LiPo by way of discharge efficiency?
In my testing, LiHV confirmed superior efficiency relating to discharge charge, with decrease voltage sag below load, significantly within the first half of the pack. Nonetheless, this benefit was much less noticeable in direction of the second half of the pack. One other fascinating reality is that for a similar weight, the LiHV battery presents greater capability, making it a extra energy-dense battery than a typical LiPo.
- LiPo (GNB 2S 550mAh 90C LiPo):
- Weight: 30.2g
- Measured Capability: 525mAh
- LiHV (GNB 2S 550mAh 100C LiHV):
- Weight: 29.3g
- Measured Capability: 558mAh
These outcomes point out that LiHV batteries not solely present higher preliminary efficiency but in addition pack extra power for a similar weight.
Lifespan Comparability
Does LiHV have a shorter lifespan than LiPo?
In one other check, I absolutely charged each LiHV and LiPo batteries to their most voltage at 2C, then discharged them at 20C till 3.3V per cell, repeating this for 100 cycles. My testing means that LiHV loses its potential to carry cost quicker than LiPo with utilization. After 100 cost cycles, LiHV loses about 5.4% of its authentic capability whereas LiPo solely loses 3.8%.
| LiPo | LiHV | |
| Cycle #0 | 525mAh | 558mAh |
| Cycle #50 | 515mAh | 545mAh |
| Cycle #100 | 505mAh | 528mAh |
* Capability was measured by discharging the battery slowly at 2C from absolutely charged till 3.3V per cell.
This check took me almost 100 hours to finish! In the event you discover it helpful, please contemplate subscribing to my Patreon so I can proceed offering any such content material: https://www.patreon.com/oscarliang
In relation to discharge efficiency, the distinction is way smaller, as proven within the discharge graphs under. The primary degradation appears to be in how a lot cost these batteries can maintain—the capability decreases with utilization.
LiPo:
LiHV:
One factor now we have but to confirm is how these batteries’ efficiency is impacted over time when not in use. I imagine LiHV and LiPo batteries naturally lose their efficiency over time, however utilization undoubtedly accelerates this course of. Nonetheless, utilization doesn’t appear to affect their discharge efficiency as a lot as I anticipated. Voltage sag is comparable after 100 cost cycles, however the discount within the cost they’ll maintain is noticeable.
The conclusion right here is, don’t fear an excessive amount of about charging and discharging your batteries! Whereas they’re sitting in your drawer doing nothing, their efficiency slowly degrades anyway. You must use them as a lot as you may to get essentially the most out of them. Get on the market, fly, and have enjoyable!
Can You Cost LiPo to 4.35V?
Completely NOT. You must 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 overheating, swelling, and even catching fireplace. Overcharging additionally reduces the lifespan of the battery and might trigger everlasting injury.
Can You Cost LiHV to 4.20V?
Sure, it’s secure to cost a LiHV battery to 4.20V per cell, as the utmost voltage you may cost it to is 4.35V per cell. Nonetheless, you’re solely utilizing 90% of its capability.
LiHV Is Not for Everybody
There’s a priority concerning the longevity of LiHV – its efficiency degrades quicker than a typical LiPo. Additionally, as you go up in cell rely, the advantage of the upper voltage turns into smaller. Subsequently, LiHV is generally in style for micro drones that makes use of low cell rely batteries, resembling Tiny Whoops and 2S Toothpicks, the place the upper voltage could make a noticeable distinction.
Remaining Ideas
LiHV batteries have turn into a well-liked selection within the FPV drone neighborhood for his or her potential 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 price contemplating.
For LiHV battery suggestions for micro drones, take a look at this put up: https://oscarliang.com/whoop-toothpick-lipo-battery/
As at all times, when working with high-performance batteries, security needs to be a prime precedence. Make sure you use appropriate chargers and comply with greatest practices for battery care and upkeep to take pleasure in the advantages of LiHV batteries whereas preserving your tools and your self secure.