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Old 04-16-2009, 07:14 PM   #10 (permalink)
theunchosen
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Quote:
Originally Posted by Daox View Post

I think a much better ($) way to go is forget solar and stick with deep cycle batteries and a charger.
The problem with that is Metrompg.com( I assume this is the same metrompg here) already calculated the cost. Deep cycles eventually burn out and you have to replace them or supplement them(better because then you still get to keep some of the old storage instead of just throwing it away). His calculations were it cost .6 cents per mile to run the batteries(paying for replacing them after 1800 cycles(I think this was the number)) and only .36 to run the alternator(and alternators cost the exact same as a single deep cycle and they last alot longer).

The reason to go solar is it would pay for itself in fuel savings daylight driving for me in about 2.5 years while deep cycles really never pay for themselves because you have to replace them(given it takes a long time and increasing the number of batteries to increase battery life helps, but at the end of the day you will need new ones). Solar panels are usually warrantied against their own electronic failure for up to 20-25 years with some only giving a 15 year warranty.

Even if I only get a 15 year warranty I get 12.5 years of alternator replacement without having to pay for anything else.

Quote:
Originally Posted by RobertSmalls View Post
I've thought about trying to get an A/C style clutch mounted on the crankshaft, allowing me to stop the rotation of my alt + power steering belt. But I couldn't find one that would just bolt on.

No matter which way you go, you're going to need a deep cycle battery. You'll also have to bring the alternator with you, in case you need to take a longer trip than expected. Solar does not solve that problem, since solar doesn't work in the rain or at night.

Trivia: PV panels are 10-15% efficient at converting sunlight into electricty. There will be additional losses in converting their output to a regulated 13.5V.
Right, Deep cycles are going to be a neccessity and yes I would have to carry it in my trunk(but they aren't that heavy so no big loss). I figure about 100 additional #s of batteries for inclement weather and any long trips that I know are going to be non-solar friendly I just carry the alt and then hook it up if the drain is too much to make it to the destination. My point is if you add solar to the mix your deep cycles will last indefinitely, because they are trickle charging most days they aren't discharged as heavily if you do overrun your PV and most days they don't even get engaged just trickle charged.
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