Thx all - very helpful. I had a battery issue on the 1st. This thread is timely. R Tom Therapy C&C 29 MkII Solomons, MD
Sent from my iPhone > On Jul 5, 2019, at 7:26 PM, Josh Muckley via CnC-List <cnc-list@cnc-list.com> > wrote: > > 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 >> <cnc-list@cnc-list.com> wrote: >> Arrgh! My brain hurts. š >> Gary >> ~~~~~~~_/)~~~~~~ >> >> >> >>> On Fri, Jul 5, 2019 at 6:54 PM Josh Muckley via CnC-List >>> <cnc-list@cnc-list.com> 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 >>>> <cnc-list@cnc-list.com> 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 >> > _______________________________________________ > > 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
