As FPV drone fans, we’re all the time on the lookout for methods to boost flight efficiency. One game-changer 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 turn into well-liked, 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 conventional LiPo (Lithium Polymer) batteries however with a key distinction in chemistry and voltage. Whereas commonplace 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 larger voltage interprets into a number of efficiency advantages, making LiHV batteries a pretty 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 the next voltage, resulting in elevated thrust and sooner speeds. For racing drones or high-performance acrobatic drones, this generally is a vital benefit, providing faster response instances and extra highly effective maneuvers.
Weight and Capability
LiHV batteries are inclined to have a barely larger vitality density, which implies they provide extra energy with no vital enhance in weight or measurement in comparison with equal LiPo batteries, probably translating to longer flight instances. Moreover, because of the larger voltage, the C score of LiHV tends to be barely larger than LiPo for a similar measurement battery.
Compatibility
Regardless of the distinction in most voltage, LiHV batteries are typically suitable with most FPV drones that use LiPo batteries. This makes it easy for drone pilots to change to LiHV without 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 received’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 related specs to deal with 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 evaluate to LiPo by way of discharge efficiency?
In my testing, LiHV confirmed superior efficiency relating to discharge price, with decrease voltage sag beneath load, notably within the first half of the pack. Nevertheless, this benefit was much less noticeable in the direction of the second half of the pack. One other attention-grabbing reality is that for a similar weight, the LiHV battery affords larger 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 vitality 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 sooner 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! For those who discover it helpful, please contemplate subscribing to my Patreon so I can proceed offering this kind of content material: https://www.patreon.com/oscarliang
In the case of discharge efficiency, the distinction is way smaller, as proven within the discharge graphs beneath. The primary degradation appears to be in how a lot cost these batteries can maintain—the capability decreases with utilization.
LiPo:
LiHV:
One factor we now have but to confirm is how these batteries’ efficiency is impacted over time when not in use. I consider LiHV and LiPo batteries naturally lose their efficiency over time, however utilization positively accelerates this course of. Nevertheless, utilization doesn’t appear to affect their discharge efficiency as a lot as I anticipated. Voltage sag is analogous after 100 cost cycles, however the discount within the cost they will 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 need to use them as a lot as you possibly can to get probably the most out of them. Get on the market, fly, and have enjoyable!
Can You Cost LiPo to 4.35V?
Completely NOT. You need 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 overheating, swelling, and even catching hearth. Overcharging additionally reduces the lifespan of the battery and might trigger everlasting harm.
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 possibly can cost it to is 4.35V per cell. Nevertheless, you might be solely utilizing 90% of its capability.
LiHV Is Not for Everybody
There’s a priority in regards to the longevity of LiHV – its efficiency degrades sooner than a typical LiPo. Additionally, as you go up in cell rely, the advantage of the upper voltage turns into smaller. Due to this fact, LiHV is generally well-liked for micro drones that makes use of low cell rely batteries, similar to Tiny Whoops and 2S Toothpicks, the place the upper voltage could make a noticeable distinction.
Last Ideas
LiHV batteries have turn into a well-liked alternative within the FPV drone group for his or her potential 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 essential 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 positively value contemplating.
For LiHV battery suggestions for micro drones, try this publish: https://oscarliang.com/whoop-toothpick-lipo-battery/
As all the time, when working with high-performance batteries, security needs to be a high 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 retaining your tools and your self secure.
