hi all. my first post. i'm pretty impressed with the signal/noise on this site. good work.
here's an idea to mull over. pardon me while i think out loud...
i read recently about a guy who
removed the alternator from his vw bus, installed pv solar panels on the roof and a couple of deep cycle (marine/RV) batteries on-board. The output of the panels and the extra storage capacity of the deep cycle cells kept the sytem working fine, even at night - he drove round trip from texas to seattle on this set up.
how much fuel would it save if an engine didn't have to turn the alternator? depends on how much power the alternator is supplying and the parasitic losses needed to supply it.
if i had to guess, i'd predict savings between 1 to 5% - but that guess is based on a series of assumptions so unfounded, i'm not even going to bother sharing them here. maybe someone else is more informed on this topic and can accurately predict (if so, please share).
other options...
<ul><li>leave the alternator on, but add a switch in the rotor field control wire, effectively giving YOU control over when the alternator is active (from an efficiency standpoint, it's best "ON" when you're decelerating or descending a grade - the same times regeneration is active in hybrids)<\li>
<li>same setup as above, but only use the alterator switch as a back-up for long range trips. for short-range use, re-charge the battery with a charger in the evening. (you can tell your neighbours you've got one of the first plug-in hybrids.) or recharge with solar when you're parked.</li>
<li>even more efficient: take the alternator belt completely off (there are still parasitic losses (bearing/pulley fan) in options 1 & 2). again, recharge when only when necessary via solar/dc charger. downside: less convenient when you need the alternator for long-range trips or "emergency" charging</li>
<li>buy 2 batteries and charge one (trickle/solar) at home during the day, then swap batteries each evening or as required</li></ul>
just a note: deep-cycle type batteries (RV/marine) would be a necessary part of this approach. a regular automotive battery will be damaged/degraded from a significant discharge.
anyone with a scangauge want to do a quick'n'dirty run to give an idea of potential savings? "normal" vs. belt on/alternator disconnected vs. belt completely off?
i've got a scangauge, and would do it, but don't have a heated garage. winter has truly arrived here in ontario, with the result that further efficiency mods are on hold until the spring!
darin
www.MetroMPG.com
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