How to test battery charger

Sneds

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My Sealine F36 has it's original 1999 Phase Three battery charger
Anyone know how I can check it is charging the batteries when plugged in to shore power?
 
The ammeter on the dash board shows the batteries are charging when the engines are running, the needle is well into the green
But when I get back to my berth and plug in the ammeter show only a slight defection into the green
I have just replaced all four batteries and suspect they are not charging unless the engines are running
 
Engines / charger off, boat rested for at least 24 hrs - measure battery voltage. Expect in the region of 12.6 -12.8v

Turn charger on, measure battery voltage at the terminals with the charger on - expect a higher voltage than the rested off charge batteries. Give it a few hours, measure the voltage at the battery terminals again, expect 13-14.5v if the charger is working. Don’t know exact output of charger - old ones can be as low as 13.8v, but more likely to be around 14.4/14.6v.
 
When on shore power is you turn on your batteries they should show about 12.5 - 12.6 volts. If you then turn one you Battery Charger and watch the voltmeter if it kicks after a second or 2 to between 13 - 14.6 volts the charger will be working


If it is the original charger and it has gone smile because there is a lovely Victron one you can replace it with. I had to this year and it actually turned out to be a good thing..... Thread on here


Hope this helps

Dennis
 
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