Sport Pilot Talk

I fly a Remos GX with S/N less than 377. The original battery (2009) was getting weak so it was replaced with a lithium LFP-7 from Autozone. On increasing RPMs first time there was a High voltage warning (the amp number went up to 14, the voltage number stayed in the green). The warning went away for the rest of the flight. Second time out the high voltage warning was accompanied by an electrical smell in the cockpit. The lithium battery was swapped for a different one- same electrical problem. I replaced the lithium battery with a Yuasa YTX20HL-BS (the original YTX20-BS, was not available- The H is for High capacity, 330 CCA rather than 270, and the L puts the + and - in opposite position for easier connection. I found it at a motorcycle store.) The problem went away immediately. I saw somewhere on the web that the charging system in S/N 377 and above is different than what is in S/N 376 and below and that Lithium batteries use a different charging system than lead acid batteries.
In summary, I do not know exactly what the problem was, but I tried 2 different lithium batteries, and both caused electrical problems. I put a compatible lead/acid back in and everything worked perfectly.

First off, be aware that if your Remos is an SLSA, you can't legally change battery types without a Letter of Authorization from the manufacturer. Secondly, there have been known safety issues with lithium batteries, and FAA has issued airworthiness directives prohibiting them in certified aircraft. This is a major fire hazard not to be taken lightly.

Along with known safety issues mentioned above, the electrical/charging system requires modification to accommodate a lithium battery. Suggestion is change back to the factory authorized battery before the next flight. VR.. Don - Remos #357

I put an Aerovoltz lithium iron battery in my Sky Arrow. Seems to work just fine with the stock ROTAX charging system. Saves me about 13lbs on my EW, valuable on my porker.

That's different from a lithium ion battery, right? Aren't those the ones with fire/explosion issues?

In any case, does anyone know of verified fires caused by these batteries in Light Sports? From our trip to Lakeland for the Sport Aviation Expo, they seem to be getting fairly common.

i own a 2012 Remos GX s/n 406. in sept 2012 i replaced the factory lithium-iron-phosphate with a japanese made Li-Fe-PO4 battery. Remos told me i do not need an LOA for this exchange. I believe that Since then Remos has shipped new a/c with the same battery that i installed. i have experienced no electrical problems.

my battery charges to full charge much more quickly than a lead acid battery. it stays cools when charging; for roughly the same energy as lead acid; its roughly 11 lbs lighter; much smaller; much less dangerous in a crash because it is so light and there's no acid to worry about. i've left it for three months with no measurable voltage drop. the only two negatives are the relatively small additional cost; and if it does get totally discharged it will not recover.

Sounds like you would want to keep a battery tender on it if your plane is hangared for long periods of inactivity.

Actually, the leakage is very small in LeFePo batteries and they can keep charge for years without a tender attached. Of course if your avionics drain it with standby current, then it will drain.

The ferrous chemistry is much less likely to experience a thermal runaway, but it's not an absolute guarantee. Also, the cell balance is very important to reduce the likelyhood of that further. For that reason, I went with a EarthX ETX24D. As much as I understand, Aerovoltz product line, while being quality batteries, does not include an onboard levelling controller.

The Type Certificate Datasheets for the Remos GX and the Remos G3/600 approve the installation of LiFePO4 batteries.