Battery capacity???

[MonacoMike]

I read about "don't discharge more than xx%", what is 100%? What is the unit of measure for it? How do you measure it on the boat? MM

 

[skolbe]

On my 260 - I had an inverter with 4 golf cart batteries - the inverter had a remote panel - where I could program it to shut off at a certain percentage. I set it at 50%. I have no idea what it measured in regards to discharge.

 

[Nature Boy]

On a wet cell battery, one you add water to and have removable caps to do so, its 12.67 volts for a 12 volt battery. If its a sealed AGM(absorbed glass mat) its 12.9. When a battery is first disconnected from charging it will have a voltage reading often higher that listed above.

You have to momentarily cut on and off a fairly high load like flood light or blowers or blip the starter to burn this off. Then let sit 2 -3 minutes and take reading at battery terminals to get true voltage. Use a high quality Fluke digital Multimeter if you can.

 

[ChuckW]

This will answer all your questions and many more.... http://www.windsun.com/Batteries/Battery_FAQ.htm

 

[tbirdvet]

I have a cut off on my gen. battery that is factory set at 11.8V. This is a standard used that ensures most starter motors will still be able to supply sufficient voltage to crank most engines.

 

[BonBini]

This will answer all your questions and many more.... http://www.windsun.com/Batteries/Battery_FAQ.htm

Yes allot of good information. Typical of an outfit selling battery's

However I’m gona disagree with there "State Of Charge Chart" as %‘s go. Also the yellow zone needs to be moved up one notch to 40% as far as things relate to boats. We all know heat from charging/discharging kills battery's. Perhaps in a slow "Solar" charge application there scale may be more applicable.

On the back of my “Battery Voltmeter Tool” is a scale.
12.7 … 100%
12.4 ….. 75%
12.2 ……50%
12.0 ……25%

 

[MonacoMike]

Thanks for the input. 2 questions have been answered: volts are the unit of measure, and 12.7v is 100% for a 12v battery. What is the best way to monitor the volts available? MM

 

[Summer Fun II]

What is the best way to monitor the volts available? MM

With a Link's 1000. :smt001

 

[MonacoMike]

Anything cheaper? Can't use most of theos features and need readable output information. How about this? MM

http://www.rc-electronics-usa.com/ammeters/rv-battery-monitor.html

 

[ChuckW]

MM, both my SmartCraft and ChartPlotter (Garmin) are able to display the voltage on the wire. You might want to check your plotter for that value in it's setup. I can also set an alarm on my plotter if the voltable drops below a defined value.

 

[MonacoMike]

Thanks Chuck, I will double check thr manual for display. I know about the alarm but do want to monitor it. I also have a small inverter that will display the voltage digitally but I worry it also consumes a lot even when not being used as an inverter. MM

 

[MonacoMike]

The manual makes no mention of voltage display, only alarm. If anyone knows of this let us know. I have a Garmin 441s.

MM

 

[ChuckW]

Check the Information>Dashboard>Numbers screen and for the number to display look under the category "Other" to see if you have voltage available. It also appears to be available under your "Data Bars" configuration.

 

[MonacoMike]

Thanks, will check. Also asked in a separate post. MM