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Home Forums Search Trailer Sailor Roster Chandlery Events Classifieds Resources About TSBB SBO Sites	Instructions/FAQ | Rules & Etiquette | Edit Profile | Forum Login View Thread | Post Response | Return to Index | Read Prev Msg | Read Next Msg | Need more information Posted By: Chris J, P19 "Rocky" SLO CA Date: 12/11/08 8:08a.m. Report: outside forum guidelines In Response To: Watts and Amps and Volts -- Oh my! (link) (John Turpin, P-15 "Tetra", Edmond, OK) The most important spec for a battery in this application is its total amp-hour rating, which you have not provided. The run time for the autopilot in hours will be about one-half of the amp-hour rating of the battery divided by the average current draw of the autopilot. (Starting amps and peak amps have no direct relation to the amp-hour rating.) For example, the battery on my P19 is rated at something like 80 amp-hours. If I installed an autopilot that drew 1 amp average, I'd get about 40 hours run time per charge. (The 1/2 factor is just rule-of-thumb, the idea being that no battery will deliver usable power all the way down to full discharge.) As for the solar panel, its wattage rating tells you how many hours of full sunshine exposure it will take to recharge the battery. If it is (for example) a 12 watt panel rated at 12 volt output, it delivers one amp in full sunlight. If you are recharging an 80 amp-hour battery, it will take 80 hours of full sunlight for that panel to fully recharge the dead battery. Another way to look at it is to consider the output of the panel versus the average load on the system, but that approach is probably not as useful for Potters, since they spend more time sitting than cruising.

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Messages In This Thread

Watts and Amps and Volts -- Oh my! -- John Turpin, P-15 "Tetra", Edmond, OK -- 12/11/08 6:34a.m.

 Need more information   -- Chris J, P19 "Rocky" SLO CA -- 12/11/08 8:08a.m.

Found a little more info -- John Turpin, P-15 "Tetra", Edmond, OK -- 12/11/08 8:27a.m.

OK, 22 aH then... -- Chris J, P19 "Rocky" SLO CA -- 12/11/08 7:08p.m.

An alternative... crew! -- Eric, P-19, #1221 Austin, TX -- 12/11/08 8:56a.m.

Maybe a little help from the Sun -- John Turpin, P-15 "Tetra", Edmond, OK -- 12/11/08 10:19a.m.

John, I plan to do the same with my P-15, -- Ken Lockhart, P-15 #1121 Indianapolis -- 12/11/08 2:14p.m.

Maybe we should experiment on your boat, then perfect it on mine! -- John Turpin, P-15 "Tetra", Okie Land -- 12/11/08 5:50p.m.

I'll watch, too! -- Katie Lea P-15 "Follow Me" Santa Clara -- 12/11/08 6:12p.m.

I did install the one on my P-19, it was not too difficult, -- Ken Lockhart, P-15 #1121 Indianapolis -- 12/11/08 6:29p.m.

WE ARE MISSING SOME CRITICAL ISSUES!! -- Dave Chase P15 #1074, Lk MI -- 12/12/08 5:59a.m.

"ISSUES!" -- Dan Phy P15 #1051 Ol' Geezer , Ft. Bragg, Ca. -- 12/12/08 7:23a.m.

LOL! Dan and Dave, here's to simplicity. -- Steve Haines, catboats, Goose Bayou, FL -- 12/12/08 8:22a.m.

How do you heave-to in a catboat Steve? -- John Madill WWP15 Mackinac Dreamer -- 12/13/08 6:09a.m.

Lash the tiller -- Steve Haines, catboats, Goose Bayou, FL -- 12/13/08 7:48a.m.

yarning with Stanley Smith -- Dave Chase P15 #1074, Lk MI -- 12/12/08 4:20p.m.

These are critical issues, all right, but... -- Chris J, P19 "Rocky" SLO CA -- 12/12/08 7:39a.m.

Good thoughts, but... -- Dave Chase P15 #1074, Lk MI -- 12/12/08 9:14a.m.

It will be interesting to see how it can be used -- John Turpin, P-15 "Tetra", Okie Land -- 12/12/08 12:27p.m.

Tetra -- Dan Phy P15 #1051 Ol' Geezer , Ft. Bragg, Ca. -- 12/12/08 2:12p.m.

John, are you thinking T200 in '09? -- Westcoaster - O'day 19 -- 12/12/08 2:38p.m.

Are YOU thinking about going? -- Tim..."Morning Dove" P19 #457 Potter Valley CA -- 12/12/08 3:09p.m.

Just not sure. -- Westcoaster - O'day 19 -- 12/12/08 7:17p.m.

Three events in a short amount of time -- John Turpin, P-15 "Tetra", Where the wind comes sweepin' -- 12/12/08 6:42p.m.

Tetra's Events -- Dan Phy P15 #1051 Ol' Geezer , Ft. Bragg, Ca. -- 12/12/08 7:13p.m.

It'd be a helluva season, wouldn't it?! -- Westcoaster - O'day 19 -- 12/12/08 7:17p.m.

Dates and Info -- John Turpin, P-15 "Tetra", Where the wind comes sweepin' -- 12/13/08 3:57a.m.

Events -- Ron -- 12/13/08 4:38a.m.

Ron tell me more about the festival at Cortez, please. -- Steve Haines, catboats, Goose Bayou, FL -- 12/13/08 7:49a.m.

Events/Tetra -- Dan Phy P15 #1051 Ol' Geezer , Ft. Bragg, Ca. -- 12/13/08 7:55a.m.

If anyone could Dan....... -- Tim..."Morning Dove" P19 #457 Potter Valley CA -- 12/13/08 9:53a.m.

Northern Calif. PYC -- Dan Phy P15 #1051 Ol' Geezer , Ft. Bragg, Ca. -- 12/13/08 12:20p.m.

Road trip -- Kurt-P15 "Sea Gypsy" -- 12/13/08 2:59p.m.