Interested in a LiFePO4 battery?

I’ve been flying an EarthX battery for five years now, highly recommend them.  

Seems like a lot of owners are using Earth-X batteries. I haven't heard of any specific issues.

Hi John,

LiFePo4 Batteries are well established. I used this kind of Batteries at my motorglider 15 years ago. My electrical system was simple because there was no generator. Charging the batteries before flight with a charger (the first charger was for Pb - it works than later a special charger for LiFePo4 on 230V. On a Rotax and its generator and regulator it is not so simple.

1. In my oppinion you don't need such a huge capacity like ROTAX recomended at its SI-P AC -027 R 1. 8 Ah works at a minimum. It depends on your electrical/electronical equipment.

2. Have a look at the size (measurement) of the battery. It must be fitted into your battery compartement.

3. And important the battery must included a Battery Mangaement System (BMS to synchronizise the cells at charging).

4, Have a look at the quality of the battery-cells and the BMS (not easy to find it out, inform you at a community (e.g. motorcycle)).

5. For the starter you need a battery witch perfom high Amperes aprox.200- 400A for a few moments at starting the engine. This is why this batteries are not the cheapest one. If You have to much money take the recommended EarthX battery.

6. For the voltage regulator ROTAX SI is in my oppinion not really helpful. There are some special voltage regulators on the market für LiFePo4 Batteries but i heard that the standard regulator (DUCATI) works too. Are there some at the community which have experiences about this?

7. Important for the regulator is the voltage at charging of 14,2V and a max. of 15V. (see the technical Informations about the battery ant the regulator). Some special voltage regulators (like my Schicke) need a wire out of the Battery for an over voltage control OVP which stopp charging if more than 15V are provided from the generator.

I am looking for a LiFePo4 too, I have my special regulator (Schicke) still in stock.

I appreciate every informations/corrections for this topic too.

Greetings

Quote: "In my oppinion you don't need such a huge capacity like ROTAX recomended at its SI-P AC -027 R 1. 8 Ah works at a minimum."

If you're operating an "iS" engine, be careful here.  The Rotax specification for a 16Ah battery is to ensure adequate battery-only engine endurance after loss of both charging systems, with allowance for capacity loss over the battery's life.

In the case of dual charging system failure, the battery has to restart the engine, run a fuel pump, power the ECU and ignition system, and carry any remaining airframe loads that the pilot hasn't turned off.  Once the battery is depleted and its BMS cuts off, the engine will stop.  Lithium batteries feature a sharp voltage drop off at end-of-discharge so this will happen with very little warning on your voltmeter (EarthX batteries will flash the fault indicator below 30% state-of-charge if an LED is connected).

The three common EarthX aviation starting batteries (ETX680 - 12.4Ah, ETX900 - 15.6 Ah and ETX1200 - 20Ah) are all the same physical dimensions so getting adequate capacity is just a matter of writing a bigger check.  Rotax appear to recommend the ETX900 for "iS" engines despite its capacity falling just short of their specification, as that's the largest model listed in SI-PAC-027.

I agree with Eric on this.  The regulations for power in any certified aircraft call for the design to be sufficient to supply power to fly for at least 30 minutes in DAY VFR or 45 for night flight.   In the case of an injected engine where we must maintain electrical power to run the fuel pumps and injection and ignition the battery is your only power source in the event of a full stator failure.  The battery power is very important.  

As long as you can fly for 45 min on battery alone to power it all you would be in compliance with regulation. 

Cheers