I know Gary! You only had to read it! Imagine my difficulty, I had to write it!
Josh On Fri, Jul 5, 2019, 7:23 PM Gary Russell via CnC-List < [email protected]> wrote: > Arrgh! My brain hurts. š > Gary > ~~~~~~~_/)~~~~~~ > > > > On Fri, Jul 5, 2019 at 6:54 PM Josh Muckley via CnC-List < > [email protected]> wrote: > >> Edd, >> >> As I recall you are still on a mooring right? You're using the motor and >> solar to keep the batteries "charged"? If so then it is unlikely that you >> are ever really getting all the way 100% charged. >> >> As others have mentioned the only good way to use voltage as a measure of >> the state of charge is by reading the NO LOAD (and No CHARGE) voltage. >> Seems simple enough.... But it's not. There is also a effect known as >> surface charge. This is the residual voltage that is greater than 12.7v >> read after applying a charge. Immediately after charge you'll see 14.7v >> and slowly dropping over 24 hours until it stabilizes at 12.7v. The >> surface charge can represent ~1% of battery capacity. To remove the >> surface charge you need to apply a relatively small load. In your case >> 4.5A-hrs....so 4.5 amps for 1 hour...or just let the battery sit >> disconnected for ~24 hours. With the surface charge removed the volts >> should read 12.7v and every 0.1v below 12.7v is roughly equal to 10% >> capacity. >> >> So during charge there are 3 different stages of charge (bulk, >> acceptance, float). You'll see volts climb steadily through the first >> stage finally stopping at ~14.7v. At the end of the first stage a lay >> person might casually look at the battery voltage, see 14.7v, and think >> that the battery is fully charged. The reality is that it is only about >> 80% charged. Most battery monitors like your blue sea are kinda dumb. At >> best they measure A-Hr in VS A-Hr out. Some reset to 100% charged when >> 14.7v is reached. Some keep accumulating A-Hrs from a pseudo-float while >> actually still in the acceptance (2nd stage). Some can be reset to 100% >> manually. Some need to be reset. I say pseudo-float since charge sources >> like solar can be sized insufficiently to actually change the chemical >> state of charge to get the batteries out of the 2nd stage and sometimes not >> even out of the 1st stage. So while a charge current IS being applied (and >> measured/accumulated by the battery monitor) the state of ACTUAL state of >> charge is not actually changing. I believe this is probably what is >> happening in your case. >> >> Summary of stages of charge: >> 1st = BULK = constant current and charger max current with steadily >> climbing voltage up to ~14.7v >> 2nd = ACCEPTANCE = constant voltage at ~14.7v with current steadily >> lowering from max to ~2 amps. >> 3rd = voltage maintained at ~13.6v. If the current required to maintain >> 13.6v goes above ~2amps then the charger will switch back to stage 2 mode a >> d you'll see volts jump up to ~14.7. >> >> I know you asked for simple... Sorry. >> >> Josh Muckley >> S/V Sea Hawk >> 1989 C&C 37+ >> Solomons, MD >> >> On Fri, Jul 5, 2019, 12:23 PM Edd Schillay via CnC-List < >> [email protected]> wrote: >> >>> Listers, >>> >>> Last year, I installed a Blue Sea battery monitor and Iām a little >>> perplexed about the readings I am seeing. >>> >>> Last night, before an amazing fireworks display at Hempstead Harbor >>> (thanks to fellow Lister Neal Gallagher for the guest mooring), I looked at >>> the display. Out of the 450 amp hours in the House bank, we had used around >>> 6 amps between using the electric head, cell phone charging, etc. for >>> several hours ā with the display showing 99% capacity. But the voltage was >>> showing 12.38, which I understand to mean closer to 75%. >>> >>> Someone on a YouTube video said that the Voltage reading is not really >>> the one to go by, as the voltage will increase when you start switching >>> things off. >>> >>> Is that all true? Is what Iām seeing normal? Can one of you Amperage >>> Aces or Voltage Vixens explain this to me? (Please keep it simple - way too >>> much Romulan Ale and Klingon Blood Wine flowing last night.) >>> >>> - Confused on City Island >>> >>> All the best, >>> >>> Edd >>> >>> -------------------------------ā- >>> Edd M. Schillay >>> Captain of the āStarship Enterpriseā >>> C&C 37+ | Sail No: NCC-1701-B >>> Venice Yacht Club | Venice, FL >>> www.StarshipSailing.com >>> ----------------------------------- >>> 914.774.9767 | Mobile >>> ----------------------------------- >>> >>> >>> Sent via iPhone X >>> iPhone. iTypos. iApologize >>> >>> _______________________________________________ >>> >>> Thanks everyone for supporting this list with your contributions. Each >>> and every one is greatly appreciated. If you want to support the list - >>> use PayPal to send contribution -- https://www.paypal.me/stumurray >>> >>> _______________________________________________ >> >> Thanks everyone for supporting this list with your contributions. Each >> and every one is greatly appreciated. If you want to support the list - >> use PayPal to send contribution -- https://www.paypal.me/stumurray >> >> _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > >
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