T&T: High Output Alternator

[Peter Bennett]

Friday, July 18, 2008, 4:25:53 AM, Craig wrote:

CM> Looking to get information on some alternators and what else is
CM> out there.  My golf batteries can last two days without charging
CM> which is great for a weekend.  But should I stay on the hook
CM> longer than that I start to to show lower voltage (10.5 - 11.0)
CM> and the led indicators on the 2000 inverter board start to flash
CM> red.  The only thing I am using significantly is a 110v undercounter refrig/freezer

CM> I have a 100 amp alternator from Delco that I just put in last
CM> year, but after two hours at 1000 rpm (engine) appeared to do
CM> nothing on the board (Xantrex).  It kept showing 11.0 and the LED
CM> lights were still flashing red.  I even tried it at 1500 rpm for a
CM> 1/2 hour and nothing appeared to be indicating a re-charge.  I am
CM> not even sure how long it needs to run in order to charge the bank properly.

If the battery voltage didn't rise from 11 volts, the alternator was
not trying to charge the batteries.  You may have to run the engine at
a higher RPM to start the alternator, then reduce the RPM to something
acceptable - but you will only get full output from the alternator at
a fairly high RPM.

You can't really tell what's happening without an ammeter to indicate
battery charge/discharge rate - even better would be something like a
Link 10 Battery Monitor.

If the battery voltage was 11 volts before starting the eingine, I'd
expect it to rise to 12 volts or so if the alternator is charging at a
significant current.  As the battery nears full charge, the voltage
should get up to 14.5 volts or so. (but you really need an ammeter to
see how much current is actually going into the battery.)



-- 
Peter Bennett, VE7CEI    Vancouver, B.C., Canada
Ennos 31 "Honeycomb"
GPS and NMEA info: http://vancouver-webpages.com/peter 
Vancouver Power Squadron: http://vancouver.powersquadron.ca