T&T: Battery question

[JSpence47 at aol.com]

Artie, I think your current 20 amp charger is way to small to charge 4 8D  
batteries. It may work OK while at the dock on shore power keeping the batteries 
 topped off. Under charging batteries one way to kill them. Your inverter is  
approx 10 amp. That would be ok for the refer. Surge when the compressor 
comes  on may hit 12 to 15 amps with 2 to 4 amp running. Even a small microwave 
(1500  watt) will exceed the inverter. The same is true for the toaster oven. 
Correctly  charging and equalizing the batteries may give you more life out of 
them but you  aren't going to get that with a 20 amp charger. 
 
It sounds to me like your boat is configured to run only the refer while  
underway. (gen not running). Battery charging is taking place from the mains.  
When at anchor Generator is run to provide charging from the alternator on the  
generator.  
 
Jim aboard  m/v Sea Eagle

"Semper Fi"  

 
In a message dated 6/3/2008 10:29:16 P.M. Eastern Daylight Time,  
lortmann at optonline.net writes:

Our  current power set up is as follows (40 foot down east lobster boat,  3208
Cat single engine).



We have two sets of two 8D  batteries  two dedicated to starting engine, two
for house  batteries.  The average age is approx 5years old, and they  are
probably getting tired. We have a xantrex true charge 20 amp  multistage
charger, and an offbrand Vector 1200 watt (2400 watt peak)  inverter.



As a test, we ran all our usual appliances (galley  microwave, toaster oven,
lights, small refrig etc) for over 1 =  hours.  The inverter began a high
pitched screaming noise, and  eventually the power surged on and off then
stayed off. We used a tester to  determine that one house battery was down to
12.16 volts, 5.97 miliamps and  542 cold cranking amps(42% capacity), the
other house battery was 3.69  milliamps impedance, 888 cold cranking amps
(76%  capacity).







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