German distributor and manufacturer Pichler Modellbau lately introduced it’s newest battery packs targeting at the mini quad market. As demand for power is steadily increasing in this segment buyers are looking for high C-rated batteries. We ran the new LemonRC 4S 1800 mAh 70C on our test stand.
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THIS REVIEW NEEDS UPDATING. WAITING FOR RE-TEST!
The new LemonRC* packs come carefully packed. The outer appereance is nice, the pack seems very well made in terms of build quality. The pack is transparently shrink wrapped with a carbon-style layer on the inside that holds all the printed logos and information. Data and warning messages are printed in German as well as in English.
The LemonRC 70 C* packs are based on Fullymax LiPo cells. The pack is a standard 4S1P config flight pack for high power use. A foam layer on the front and pack provides extra impact protection on the cell edges.
Build Quality: Very good. Pack feels very well made on the outside. Connection terminal looks solid.
Plugs: The LemonRC pack comes without any connectors*. Installation of own connectors required. XT60 minimum recommended.
Cables: LemonRC / Pichler uses 12 AWG wires on this packs. The high flexible silicon layer is rated up to 200°C. Cable length is about 10 centimeters.
Balacing plugs: Standard XT-system*. Balance wires are rather short (3,5 cm) which is a benefit in terms of getting them out of the prop-range on the aircraft. Main power line and balancing wires are coming out of the same side of the pack (top).
(Click to enlarge.)
|Type||LemonRC 70 C|
|Cell chemistry||Lithium Polymere (LiPo)|
|Cell type||Fullymax LiPo|
|Max. Charge Current||1,8 A|
|Max. Discharge Current
99 x 30 x 38 mm
|Note||This battery has been directly donated by the manufacturer / distributor for review purposes.|
The battery followed the standard break-in-process: The pack is charged at a rate of 1C until CV-phase ends with current of 1/10C. The break-in phase consists of four charging cycles at 1C and four corresponding discharges at 1 C / 4C / 10C and 20 C.
Anomalies: No anomalies during break-in.
Internal resistance measurements during break-in phase using iCharger 406Duo
|Cycle||Cell 1||Cell 2||Cell 3||Cell 4||Total|
|After first charge||8||8||10||13||39|
|After second charge||7||7||12||12||38|
|After third charge||7||7||9||11||34|
|After fourth charge||8||8||10||11||37|
CV-Phase is short on this cell type. Balancing in normal mode only took 2:50 mins. Cell drift during charge was unobtrusive. This is for 1C charge (1,8 A).
The main part of this battery test will consists of different load test settings showing the battery performance. Constant load testing is used to judge the advertised C-ratings as well as look at cell drift under high loads. We also check on internal resistance once more. Next up is the dynamic current test, which simulates a „real“ flight with changing (=dynamic) loads. For test methodology please check the dedicated methodology page!
Constant Load Testing
Constant load testing follows a certain load pattern of different constant currents. Base load is 10 C. Current pulses at 50 C, 35 C, 20 C and 30 C are maintained for time intervals between 10 and 20 seconds. For more details please refer to the test methodology page.
During this test the pack delivered 1705 mAh. This is 94,7 % of nominal capacity. A very solid value.
Average cell voltages
The following table lists the average voltages per cell, of the total pack, as well as the averaged value per cell as fraction of total voltage during phase of active load.
|Cell 1||Cell 2||Cell 3||Cell 4||Total||Average per cell|
|Avg. Voltages||3,735 V||3,733 V||3,739 V||3,725 V||14,933 V||3,733 V|
Just looking at average values the Tattu pack performs good. All cells stayed well above 3,7 V on average.
Exceptionally interesting when testing a battery under a constant load for a longer period of time: the lowest voltage per cell just before load impulse is disabled. On top, you should have look at voltage recovery rate, that is: how fast do cell voltages rise again once load impulse is cut.
|Phase||Cell 1||Cell 2||Cell 3||Cell 4||Total|
|End of 50 C||3,527 V||3,517 V||3,533 V||3,515 V||14,092 V|
|End of 35 C||3,546 V||3,541 V||3,562 V||3,553 V||14,203 V|
|End of 20 C||3,595 V||3,595 V||3,591 V||3,596 V||14,377 V|
|End of 30 C||3,348 V||3,303 V||3,287 V||3,261 V||13,199|
The LemonRC pack* showed solid performance during all three current pulses. Whether during 50 C or during 35 or 20 C pulse: No cell dropped below 3,5 V.
Average voltage recovery per second
Those values are specific to the test setting and not valid for the pack in general!
|Cell 1||Cell 2||Cell 3||Cell 4||Total|
|Avg. Recovery||0,0336 V / s||0,034 V / s||0,0319 V / s||0,0326 V / s||0,1321 V /s|
IR measurement is conducted using the four current pulses. Resistance for each cell is calculated in all four discharge phases. Shown values are averaged to cancel out different temperature points due to different discharge states during measurements.
Interpretation: The internal resistance of 2.67 mΩ average per cell indicates a „true“ C-rating of around 35 C (63.6 A). This is on the conservative side and represents a current draw that will make the pack last for a long time. The pack had no problems delivering during high C discharge pulses. Voltage stayed well above 3,5 V on this test for 50 C, 35 C and 20 C loads.
Cell drift under load
|Discharge Phase||50 C||35 C||20 C||30 C|
|Max Cell drift (V)||0,034 V||0,034 V||0,029 V||0,087 V|
Key Temperature Facts
All temperature probes reported values below cut-off point at 58°C. Max. temp during discharge was around 52,3 °C on side of pack. Note that heating of stressed LiPo packs will continue for some more time even when load is cut.
The following chart shows all reviewed LiPos in the same product segment for direct comparison of performance. Higher values under load are better.
Constant 25 C Discharge
Pretty much a standard benchmark in the LiPo industry.
Cut-Off /warning value for this battery should be chosen 3,45 V minimum. After this point voltage drops quick. The battery provided 1543 mAh (85,7 %) during the 25 C discharge.
Comparison of different reviewed 1800 mAh batteries under 25 C load.
Dynamic Load Testing
The dynamic load testing setting consists of two separate discharge scenarios that have been developed of two different real-life FPV flights. Pattern one represents a high speed low proximity flight around the open field with some hovering to the end. Average load is around 22 A. Second pattern is a free-style flight around trees in the park with some current spikes near 70 A. Average load on this flight is around 13 A due to longer floating periods.
During the test of pattern 1 the pack delivered 1525 mAh. This is 84,7 % of nominal capacity. A solid result. In pattern 2 the LemonRC pack yielded 1542 mAh. That’s 85,6 % of nominal capacity.
The following charts give an overview of all tested packs in the 1800 mAh class so far.
The LemonRC 4S 1800 mAh 70 C battery* is a rather large pack with an ordinarily capacity to weight ratio of 8.57 mAh/g. The measurements are standard for this capacity class. The build quality of this battery is very good, not even to say exceptional. The option to put on you own connectors is nice, but in the price region this battery is offered at least one XT60 at the side would be a nice gesture. The 70 C rating is a little over the top, which is pretty normal for those high rated packs. Regarding to IR measurements and general performance I think it is fair to classify this pack at around 45 C maximum. If you are planning on drawing constantly high currents a 35 to 40 C rating might be the better classification. This is all under the assumption that you don’t want to damage your pack prematurely and are looking at maximum performance within the specs of a battery. With this knowledge in mind, you really can say that the LemonRC 4S 1800 mAh 70 C performed well in every category. Capacity usage is high under constant load settings. Same is true for both dynamic current test patterns. The LemonRC 4S 1800 mAh 70 C* therefore is a good companion on any mini quad in the 6 inch category, assuming that you are willing to carry around some extra grams due to high quality materials. Pricing on the other hand is rather high. With around 50 € you are getting a very well made battery with warranty and support of a well known German distributor. This fact is going to cost you around an extra 10 Euros, compared to other competitors.
Other packs of this line up tested:
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