A 3w PV won't charge a dead battery or serrious depleted battery in a acceptable amount of time. For solar charging I found that 15v is a realistic number on 12v systems for calculating PV wattage requirements. A 12v PV will produce more than 15v, more like 21v open voltage but that's just not a useable number to use as it will cause you to under size the actual PV wattage requirement.
So that would be 7.5v on a 6v system. At 3w/7.5v=0.4ahr(amps per hour) that the PV will charge at. That's enough to maintain the state of charge in a fully charged battery without a CC(charge controller) and without overcharging the battery. A CC is nothing more than a voltage regulator. You'll need a CC on any PV greater than 5w or the battery will over charge if given enough recharging time.
At 0.4ahr then with a PV tracking the sun (move the PV once at 1pm to face west and once at dusk to face east) then we can plan on 8 solar collecting hours in full sun, cloudy then about 1/2 of the rated amp/hr, or about 3.2amps/day output on a 3w rated PV.
If you have a typical 6v starting battery at a 100ahr capiticy, then 100ahr/(3.2a/day)=31days/2= 16days to recharge a battery that's 50% discharged with a 3w rated PV.
And yes, you would need to put a 5a diode in one leg of the PV wire to keep the battery from discharging at night.
If you run a battery much past a 50% discharge rate then it will severely shorten the battery life.
We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]
Today's Featured Article - The Day Mom Drove the 8N - by Brian Browning. My Dad was wanting to put in a garden but couldn't operate the 8N and handle the old horse drawn plow he had found and rigged up to use with the tractor. Well, he decided to go get Mom out of the house and have her drive the tractor while he walked behind the plow. You got to understand that while my Mom is a hard worker who will always help whenever she can... she had never operated farm machinery before that day. Dad got her out there, explained how the clutch was the same as in our o
... [Read Article]
Latest Ad:
Oliver 550 Diesel runs like a watch three point hitch pto engine gone threw about two hundred hours ago nice clean tractor
[More Ads]
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy
TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.
