Contray to Jimbo's post I believe they do!
My A'PEXi RSM shows the voltage drop to about 12.1v when warmed up and not running any accessories, turn the lights or fans on or exceed ~3000rpm and the voltage shoots up to 14.1-14.3v which fits with the characteristics of the ELD's behavior, that combined with the brown box (the ELD) in the engine bay fuse box I'd say they do!