Hi
Sorry if this topic has been posted before. I did a search but could find anything relevant.
I'm on a three month cruise and I've noticed that my relatively new (less than 3 years old) AGM batteries are not coming up to full charge.
I know the engine alternator is putting out 14.4 volts and after motoring for a few hours the batteries might move from 80% of charge to, say, 85% charge. It is almost impossible to get them higher.
Is is it because they've been on charge in a marina nearly all their lives and have lost some function?
Would it help if I dropped them down to, say, 30% before charging them?
Should I expect them to get up close to 100% on a full day's motoring?
I'm now shutting down the fridge at night to preserve battery life as in the mornings the charge is down to 70% and one morning the fridge wouldn't run due to low voltage.
Any suggestions most welcome.
Thanks
Robert and Louise
Breezly
Catalina 36 MkII
2000 Hull number 1864
http://www.sailblogs.com/member/breezly/
Robert,
How do you know the batteries are at 70 or 80 or 90% charge? Do you have a calibrated e-monitor, such as a Link or similar? If you are just going by voltage, even with an accurate digital volt meter, you are probably way off in your estimates. With most of the Link products (and others, I'm guessing), assuming you have calibrated them, they will reset to zero after the batteries are full, and you start using them. Also, what type of regulator is controlling your alternator? If it's the stock internal regulator, the current drops off very quickly, and it takes FOREVER to charge the batteries.
Tom Sokoloski
C36/375IA Past Commodore
Noank, CT
Thanks for the reply Tom. Much appreciated.
Even on the Xantrex charger plugged into the 240 volts (Australian system) they seem to be taking longer than, say, this time last year, to charge.
I have a "Xantrex CTEK Multi XS 25000" charger and a meter on the electrical panel that tells me, supposedly, the level of charge.
ARGGHH!!!! I've just got the torch out to read the fine print and see that I can manually reset the meter. Now they're showing 100%.
I learn something new about this boat every day. I feel such a dill now.
Again, thanks Tom.
Problem solved. :)
Robert and Louise
Breezly
Catalina 36 MkII
2000 Hull number 1864
http://www.sailblogs.com/member/breezly/
:-)
Tom Sokoloski
C36/375IA Past Commodore
Noank, CT
I little off topic. I just read up on my shore power charger and found that I was under charging my batteries by have the temperature set to "Hot". Should have been set to "Warm".
Using a hydrometer, I found that all cells were a little lower than "Full ". (true charge 20)
I couldn't have been getting full range usage out of my batteries. I did have my blue seas 422 meter calibrated for the full AH rating of the batteries. This number had to be too high. It seems that the batteries dropped off to quickly.
I'm sure under charging didn't help with sulfation. I did the equalizing of the batteries and that seemed to improve things.
I one good thing about flooded lead acid batteries, a good old hydrometer can tell you a lot about your batteries. condition and SOC.
Chuck Lennox
97 MKii Ventura Ca
Island Girl Hull #1611
Chuck,
I had the same charger in Julandra. I finally ended writing myself notes (via winterizing list and re-commissioning list) to remember to change the temp setting in the spring and fall. Can't remember ever using the hot setting. I simply switched between cold and warm.
Tom Sokoloski
C36/375IA Past Commodore
Noank, CT