Mark, Just keep in mind that the voltage method is not very accurate...though neither are the A-hr meters if they are not periodically recalibrated. That being said, I believe that my method errors on the conservative side.
Just in case I do forget (or lose my shore power) I installed a Priority Start device which will monitor battery voltage and then disconnect prior to dropping below the requisite voltage to start the engine. A low battery and difficulty starting can also be assisted by decompressing the engine. http://www.prioritystart.com/ Josh On Feb 2, 2015 1:57 PM, "Dr. Mark Bodnar via CnC-List" < cnc-list@cnc-list.com> wrote: > Josh, > Thanks for the info on using voltage to gauge battery level. > With my tiny bank and very limited loads it does not make sense to be > wiring in a monitor or Balmar Smart Gauge (to the tune of $360 cdn). But I > was thinking about adding a voltmeter so I could maintain some track on > drain. > Say something like > > http://www.amazon.com/DROK-Voltmeter-3-50-30-0V-Anti-reverse-Protection/dp/B00DUTJXWO/ref=sr_1_8?s=automotive&ie=UTF8&qid=1422902563&sr=1-8&keywords=voltage+meter&pebp=1422902722997&peasin=B00DUTJXWO > > I have to hook up and figure out how to mount my solar panel this spring, > and I will re-wire my 1-2-off switch as per MaineSail's instructions. > Rather than going to a "starting bank" and a "house bank" - I'll likely > stick with A bank and B bank - use them interchangeably for starting and > house. > > Mark > > > > > > There is no cure for birth and death save to enjoy the interval. > - George Santayana > > On 2015-02-02 1:20 PM, Josh Muckley via CnC-List wrote: > > What you are looking for is an amp-hour meter. Discharging a flooded deep > cycle battery rated at 100 Ahrs below 50% should be avoided. This roughly > equates to 50 Ahrs of use. 5amp for 10hours or 50 amps for 1 hour....you > get the jist. Discharging a flooded deep cycle below 50% will decrease its > effective useful service life. Many batteries publish a the number of > cycles and depth of discharge. One loose rating convention is that a deep > cycle will survive 200 charge/discharge cycles of 50%. The cycle number > increases when the depth of discharge is reduced. > > When using a voltage meter, it is important to take a "no load" voltage > after the battery has had time to "recover". The easy way to remember a > capacity to voltage conversion is 0.1v per 10%. A fully charged battery > will read 12.7v and a fully discharged one will read ~11.7v. By this > convention one should avoid voltage readings below 12.2v. I have a total > of 500Ahrs between 2 banks so when one gets to a "loaded" voltage of 12.2v > I start considering a switch to the other battery. I can go about 2 days > in the middle of summer with no charging source before I start to worry. > The engine charges at 100amps so motoring on and of the hook keeps me > pretty well topped up. > > I put one of these in my first sailboat. It is similar to the Link 2000 > that Edd suggested. I have a Link 2000 installed on my current boat but it > has never worked right. I believe the current shunt is bad or somehow > bypassed on the charge or discharge circuit.....I'll get to it... > > > http://www.altestore.com/store/Meters-Communications-Site-Analysis/Meters-Battery-Monitors/Ammeters-Voltmeters-Battery-Monitors/Bogart-Engineering-TM-2025-A-F-TriMetric-Meter-Includes-fuse-and-fuse-holder/p10112/ > > Josh Muckley > S/V Sea Hawk > 1989 C&C 37+ > Solomons, MD > On Feb 2, 2015 8:27 AM, "David Knecht via CnC-List" < > cnc-list@cnc-list.com> wrote: > >> Looking at the wiring diagrams reminded me of a question I am sure this >> list can answer. I have not done much cruising yet, but plan to do more in >> the future. One of the things I am unsure of is how people monitor the >> state of their batteries when you know shore power is not going to be >> available. I have a digital voltmeter on the panel that I can check the >> batteries and a chart that translates voltage into percent charge and I >> have used that as a rough guide, but that seems crude for such an important >> function. My understanding is that you have let the batteries sit for a >> while if they have been charging to get an accurate reading. I am not sure >> if current draws also have to be off. For instance, how would I know if >> it is safe to run the refrigeration while sailing to the next destination? >> Can you get a meter that gives you "hours of battery life remaining"? What >> strategies to listers use to solve this problem? Thanks- Dave >> >> Aries >> 1990 C&C 34+ >> New London, CT >> >> >> >> _______________________________________________ >> >> Email address: >> CnC-List@cnc-list.com >> To change your list preferences, including unsubscribing -- go to the >> bottom of page at: >> http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com >> >> >> > > _______________________________________________ > > Email address:CnC-List@cnc-list.com > To change your list preferences, including unsubscribing -- go to the bottom > of page at:http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com > > > > _______________________________________________ > > Email address: > CnC-List@cnc-list.com > To change your list preferences, including unsubscribing -- go to the > bottom of page at: > http://cnc-list.com/mailman/listinfo/cnc-list_cnc-list.com > > >
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