Battery trouble

[pablosgirl]

Hi all,

Found this artical on deep cycle batteries that came from the solar charging / renewables industry While I was searching for 6volt battery replacements.  Explains the differences (pros and cons) in very easy to understand language that complements Mainsail's comments.
http://www.windsun.com/Batteries/Battery_FAQ.htm
Hope this will aid you in your decission on which battery to purchase.

Fair winds,
Pablo

[Lance Jones]

Informative article Paul Thanks!

[Stu Jackson]

In addition to my pm to you, there's also this:  http://www.c34.org/wiki/index.php?title=C34_Battery_Selection

Not much has changed, other than Maine Sail's excellent discussions about the serious downside of AGM batteries for general recreational use.  Those issues are covered in the "Electrical 101" topic.

[Ron Hill]

Paul : The article site you posted is EXCELLANT !!  It's SO great because it covers the entire field of battery aspects!

It should be required reading for all boat owners.

I surely hope that this site in in our C34 WiKi.  


Added to the wiki, electrical then batteries.  Ken Juul

[Ralph Masters]

Paul,
The read on the battery is excellent.  Answered several questions I had.  Covered very well all aspects of battery life and life with a battery.

Thanks for the post,

Ralph

[Lance Jones]

Thanks all! Swapped batteries around yesterday and all are cool today. Woo-hoo!

[Ralph Masters]

The one question I still have is how do they figure percent of discharge.  If I take 10 percent of 12.7, 1.27 that does not add up to what they show on the chart as 10 percent discharge.  Answers please.  

Ralph

Ken, I'm just a poor black shoe sailor, give me a break.

[Ron Hill]

Ralph : The way I figure discharge is:
If I have a 400 amp hr house bank and I discharge it 10% I now have 360 amp hours remaining.

To me the only important % discharge number is to never go below 50%, so you get the best number of charge/discharge cycles out of your battery bank (and get the biggest bang for your $$). If you can go less than 50% discharge - all the better.

If you are referring to the chart in the WindSun site - each .05 volts represents approximately 5% of charge.   

The electrical Gurus may not agree, but that's the way I figure it!!   A few thoughts

[mainesail]

The one question I still have is how do they figure percent of discharge.  If I take 10 percent of 12.7, 1.27 that does not add up to what they show on the chart as 10 percent discharge.  Answers please.  

Ralph

Ken, I'm just a poor black shoe sailor, give me a break.

A number like 5% is measured in hundredths of a volt and a 10% drop is in the tenths of a volt range hence why using voltage to tell state of charge, even after the batteries have rested for 12-24 hours, is often a futile effort. Also the drops in voltage are not linear for each 10% drop..

These are Trojan's numbers for open circuit voltage readings for approximate state of charge.

100% = 12.73
90% = 12.62
80% = 12.50
70% = 12.37
60% = 12.24
50% = 12.10
40% = 11.96
30% = 11.81
20% = 11.66
10% = 11.51

[Ralph Masters]

Ron, Mainesail,
Thank you for the information.

Ralph