T&T: Inverter Problems

[Peter Bennett]

Thursday, February 1, 2007, 7:40:51 AM, David wrote:

DH> A trawler friend has this problem and I told him this list would have the
DH> answer. After repowering his boat from twin 135 hp Perkins to Cummins 4 BT
DH> 3.9M, the technician says the alternators on the new engines do not put out
DH> enough amps to keep up the usage of the two 5 cu. ft. freezers and the 10 cu.
DH> ft. refrigerator/freezer. The alternators are supplying 2 - 12 volt batteries
DH> to the engines and 6 - 6 volt batteries for the house supply. He asked for a
DH> larger alternator on one engine. The technician said the alternator supplier
DH> said a larger alternator would not work because of the different batteries (12
DH> and 6 volt ) Technician said it would charge the weakest battery and then
DH> quit. He has a Xantrex Freedom 20 Inverter/Charger 2000 watts and a Xantrax
DH> Link 1000 Battery Monitor.
DH> David Harris
DH> 43 DeFever
DH> 'Moonstruck'

I expect that you have confused the tech by mentioning 6 volt
batteries - like most of us, you probably have the 6 volt batteries
connected in series pairs to make a 12 volt battery bank - any normal
12 volt alternator should have no problem charging that arrangement,
but would certainly cause problems if asked to charge a 6 volt battery
bank.

-- 
Peter Bennett, VE7CEI    Vancouver, B.C., Canada
Lien Hwa 28 (AKA Polaris 30) "Sea Spray"
GPS and NMEA info: http://vancouver-webpages.com/peter 
Vancouver Power Squadron: http://vancouver.powersquadron.ca