AC DataSheet - E-Tec Li-Poly Cells


Lithium Polymer Charging, Handling, and Safety Information - SEE THIS!
	Pictured on the left is the new "Slim 10C" E-Tec HP 700mAh 11.1V pack of three cells connected in series. It is from the new range of High-Output Lithium Polymer cells by E-Tec, available at Air Craft, in 450mAh and 700mAh capacities. 450mAh and 700mAh packs come with JST connector pre-attached. The HP 1200 packs come with high quality silicone cable, without connector attached.
Pink Wire is POSITIVE ( + ) Blue is NEGATIVE ( - )

Capacity and Current:

The rated capacity for each cell type is the minimum guaranteed by the manufacturer at certain discharge rates. Capacity is a measure of how much energy can be drawn from the battery before it is completely discharged. A 1200mAh cell (1.2Ah) can deliver 1.2 amps or more for one hour, for example. The ability of a cell to deliver current, or amperage (A), is often expressed as a multiple of capacity, as shown below:

E-Tec HP Cell Type	Capacity (rates below = 1C)	4C	5C	6C	7C	8C	10C
450 10C continuous	0.45A/hr	1.8A	2.25A	2.7A	3.15A	3.6A	4.5A
700 10C continuous	0.70A/hr	2.8A	3.5A	4.2A	4.9A	5.6A	7.0A
1200 8.5C continuous	1.2A/hr	4.8A	6.0A	7.2A	8.4A	9.6A	12.0A
1200 "2P" (2400mAh)	2.4A/hr	9.6A	12.0A	14.4A	16.8A	19.2A	24.0A

E-Tec “HP” 450mAh and 700mAh cells can run at 10C continuous and deliver over 90% of capacity at that rate, with high voltage. Max peak discharge for sport models should be 12C for 15 seconds maximum, and using management to reduce average discharge to 10C or less. Gliders can run up to 16C for less than 10 seconds. Battery temperature must not exceed 60 degrees Celsius.
E-Tec “HP” 1200 cells can run at 8.5C continuous and deliver 100% of capacity at that rate, with very high voltage. Max peak discharge for sport models should be 10C for 20 seconds maximum, and using management to reduce average discharge to 8.5C or less. Gliders can run up to 12C for less than 10 seconds. Battery temperature must not exceed 60 degrees Celsius. Cells in packs should be separated by an air gap of 1mm minimum for cooling.

Throttle management can be used to bring the average rate down, thereby reducing the load on the battery and increasing flight times, but it is better to choose a larger capacity cell type when extra power is needed, and benefit from (1) increased voltage delivered (2) longer runtime (3) increased lifespan of the packs, as the load is now moderated.

If you are converting an existing model from NiMH batteries, you should plan on supplying nearly the same voltage with lithium cells, or more, and changing propeller, gearing, or motor type if required to achive your target current draw.

To get the most from your High-Output E-Tec batteries, you’ll need to match the battery size and arrangement to your model’s power system. If you haven’t got the tools or experience necessary to do that, then we STRONGLY urge you to seek assistance from experienced modelers.

Cell Type	Capacity	Cell Size (m/m)	Weight (g)	Volt (Nom)	Current	Applications
						Model Type	Power Units
ET HP 450	450mAh	5.00 21.0 60.0	10.5	3.7V	4.5A (10.0C)	Ultra-light Indoor Light Flyers *Mini E3D ~150g	LPS-B2C-A,B,C(2 cell)
							Mini IFO (2-3 cell)
							"Roadkill" Indoor Series (2 cell)
							Mini E3D Models <150g (2-3 cell)
ET HP 700	700mAh	5.50 25.0 60.0	15.0	3.7V	7.0A (10.0C)	Park Planes Sport Planes Small Helis Aerobatic 300 *E3D to 330g	LPS-RLC-A(1 cell)
							"Roadkill" Twins (2 cell)
							LPS-RXC-A,B,C(2 cell)
							IPS-DX-A,B,C,D,E,F(2 cell)
							EPS-100C (2cell)
ET HP 1200	1200mAh+ (at 8.5C)	6.00 34.0 60.0	25.1	3.7V	10.2A (8.5C)	Park Planes Sport Planes Small Helis Aerobatic 400	EPS-100C (2S)
							EPS-300C (2S )
							S400 (1P, 2S-2P - 3S2P)
							Larger models (xSxP)

Lithium batteries can be connected in series to increase voltage, and series packs can be connected in parallel to increase capacity (and therefore the maximum current available – remember “C”).

Lithium polymer packs may be arranged as series "S" connected, or a combination of series and parallel "P" connections.

A pack of 3 cells in series (3S1P, or simply "3S") has 3x1= 3 cells. This pack has NO parallel connections. If you take two 7.4V "2S" packs and wire them in parallel, it would be designated "2S2P", have 4 cells in the assembled pack, have 2400mAh total capacity, and be charged at the same "2-cell" setting as before.

Note that:
"S" affects charge VOLTAGE: A 2S pack is ALWAYS charged at 2-cell setting, "3S" at 3-Cell, etc...
"P" affects max charge CURRENT: A 1200-3S2P pack has 2400mAh capacity, so max charge current is 2.4A

An example: A larger model may use a pack of "5S4P" 1200mAh E-Tec - containing a total of 20 cells.

Multiply the "S" value of this pack by the nominal voltage for one cell (3.7V) to get the nominal voltage for the pack:
(when comparing with NiCd/NiMh, 3.6V nominal may be more convenient and accurate)
5S x 3.7V = 18.5V
Multiply the "P" value by the capacity for one cell to get total capacity of the pack:
4P x 1200mAh = 4800mAh
Multiply "C" ratings by the capacity of the new pack (4.8Ah) to get the max recommended rates:
6C x 4.8A = 28.8A (a reasonable max for continuous operation with highest capacity)
8C x 4.8A = 38.4A (a reasonable max for peak operation, with management for increased duration)

Performance Estimation:

MotoCalc is a superb software program which can help estimate all performance parameters of a power system, and even the flight characteristics of a model. It is a tool for estimation, and not a substitute for actual testing of the components and model in flight. Nonetheless, it gives very useful approximations of the amperage a motor/prop combination might draw with a particular battery.

http://www.motocalc.com

E-Tec RC Lithium Polymer Batteries are only approved for RC use, and may not be used in any other application. Battery discharging, charging, electric motors, spinning propellers, and flying models all have the potential for serious injury to persons and damage to property. In purchasing these products, the user agrees to accept responsibility for all such risks, and not to hold the E-Tec manufacturer, distributors, or retailers - (all including owners and employees) - responsible for any accident, injury to persons, or damage to property.

As used in radio-controlled model aircraft, discharge rates exceed the manufacturer’s specified maximum rates for these cells. Therefore, the use of E-Tec batteries in radio-controlled models is to be considered experimental, and there is no warranty, expressed or implied, by the manufacturer, distributors, or retailers with respect to the capacity, life in cycles, storage, or discharge characteristics of E-Tec cells in RC use, nor any other use nor aspect.