Had to send my FPE 2.4 into Kurt for minor repairs. He noted that the old CH ignition was no longer working (hmmm, had been just before I boxed it up, but OK....) Replaced with a new RCEXL ignition set. Model A-02. No instructions, and I can only find badly translated versions on the net. Nothing references the model number on the ignition itself.

On the ignition, it says "4.8 - 8.4 v" But the bad translations seem to say to use 4.8-5 volts, "unless engine rotation demands" (???).

So can I use a 2 cell LiFE direct, or should I put a voltage reg. in line?

you can use a LiFe pack with no regulator. dle engines use rcxel ignitions and I run LiFe packs on my DLE engines.

You can trust the 8.4v rating.

And later ignitions seem to prefer the higher voltage. You should be fine with the LiFe battery.