Today we are testing the Fusion 4S 1500mAh LiPo battery from DemonRC. It’s labelled 666C which is joke as it’s the devil’s number. This is funny but it doesn’t tell us what to expect though so it would be interesting to find out how it performs.
Further Reading: The basics of LiPo battery for beginners
Specifications
- Cell Count: 4S
- Capacity: 1500mAh
- C Rating: 66C – 133C
- Balance lead: 5cm
- Discharge wires: 12AWG, 9cm
- Size: 88x35x33mm
- Weight: 190g
Battery Comparison
We will be testing and comparing the performance of the following batteries:
| Shops | Weight | Price | |
| DemonRC Fusion 4S 1500mAh | DemonRC | 190g | $32 |
| Acehe Formula 4S 1500mAh | GetFPV | 189g | $36 |
| Tattu 4S 1550mAh | Amazon | 178g | $21 |
Testing & Results
Table of Contents
Internal Resistance
The IR values are measured by my iSDT charger after they are fully charged. All numbers are in mΩ, the higher, the worse.
| Cell #1 | Cell #2 | Cell #3 | Cell #4 | |
| Fusion | 5.5 | 5.7 | 5.5 | 5.7 |
| Formula* | 6.5 | 6.8 | 6.5 | 6.5 |
| Tattu | 6.5 | 7.2 | 7.0 | 7.1 |
* Interesting observation, the IR of both the Formula and Tattu have gone up slightly compared to last time I checked, although I haven’t used them since my last review. This confirms that IR does go up over time.
Actual Capacity
The Fusion is actually a 1580mAh pack, close to 1600mAh. Capacity is measured by discharging the battery from 4.2V to 3.5V per cell during flight.
Discharge Performance Testing Format
To test the performance of the batteries, I flew around this race course multiple times. The routine includes a 5-second WOT punch out (100% throttle), and low throttle cruising the rest of the lap.
Current and voltage are measured where the red dots are, the data will help determine the performance of the battery, for example, how much power the battery can provide, how bad the voltage sag is, and how fast the voltage recovers from a “punchout”, etc.
Voltage Comparison
Pay attention to the voltage sag at each punch out, the lowest voltages.
The Fusion has outstanding performance in terms of voltage sag, it held up the best in punchouts. The Formula has really close performance, but it seemed to take a couple of laps to catch up. It’s was only 8°C so it’s probably affected by temperature more than the Fusion?
Power Comparison
Power is the product of current and voltage.
The clear winner is the Fusion, it consistently provided the highest power through the whole flight in all 3 batteries we tested.
Conclusion
The DemonRC Fusion 4S 1500mAh seems to be an excellent battery from the test: low and consistent IR, provides outstanding power and handles voltage sag like a champ.
I am surprised that it actually out-performed the more expensive Acehe Formula, which is also one of the top batteries out there in terms of performance.
If you are in Europe, you can’t go wrong with the Fusion :) Highly recommended!
8 comments
Hey Oscar,
do you happen to know what happened to Demonrc? I cannot access their website anymore. Not sure if temporary or if they shut down. If the latter, that’s a shame since I really loved their batteries! :(
Which regular 6s lipo packs do you buy these days which have a similar performance than the Demonrc ones and ship in Europe?
They shut down permanently a few months ago.
Here’s a list of my go-to batteries in 2023: https://oscarliang.com/best-5-inch-fpv-drone-parts/#Batteries
I’ve just bought the 6s version of these batteries based on your extensive review. Looking forward to trying them and hoping DemonRC produce the goods!
You are gonna love it :)
make sure you add some protection especially on 6S, they will last a lot longer :) How to Protect LiPo Batteries from Crashes / Physical Damage
Will you recommend this DemonRC batteries for Freestyle flying?
If no then witch batteries do you recommend for freestyle FPV
Yes they are very good batteries and should be great for Freestyle. Here are some other great options too.
The link to the Tattu battery you provide is the 45C version, not sure if the link is to the wrong battery or if you are comparing a high end battery to Tattu’s lowest end. It would have been more of a fair comparison to use at least the Tattu 75C or even the R line 100C.
The prices are clearly stated, the Tattu in this test are cheap, so people understand why the other two batteries are more expensive.