AC Charger Help

All batteries are brand new. Bought them a week ago.

Maybe it's time for a new marina

Haha. Maybe. I do a lot myself. Always trying to learn.

hd2002hd said:

So, if the batteries charge with motors or the genny running, does that eliminate the isolated?

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Not necessarily. A shorted diode would still allow charging but would not serve its intended purpose. An open diode would prevent charging from the alternator. I guess it depends on the failure mode.

Whatever ends up being the issue. It's all for nought if the batteries are allowed to sit un-tended for extended periods of time. If you are not at a marina that can respect that, it's time to move on.

bobeast said:

Not necessarily. A shorted diode would still allow charging but would not serve its intended purpose. An open diode would prevent charging from the alternator. I guess it depends on the failure mode.

Whatever ends up being the issue. It's all for nought if the batteries are allowed to sit un-tended for extended periods of time. If you are not at a marina that can respect that, it's time to move on.

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Amen to that!!

I come down weekly. Winter time I only come down on occasion. Now it is virtually every weekend.

Not necessarily in this case the pro mariner 30 or 40 of that vintage is not a smart charger by any means it was a straight three bank charger if you leave it on there’s nothing to regulate charging and It will cook the batteries I have the same one and have been meaning to upgrade as well ,so if the mechanic or yard owner knows that particular battery charger then I would agree with him you’ll just wind up ruining your batteries

bobeast said:

Not necessarily. A shorted diode would still allow charging but would not serve its intended purpose. An open diode would prevent charging from the alternator. I guess it depends on the failure mode.

Whatever ends up being the issue. It's all for nought if the batteries are allowed to sit un-tended for extended periods of time. If you are not at a marina that can respect that, it's time to move on.

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joeyleggz said:

Not necessarily in this case the pro mariner 30 or 40 of that vintage is not a smart charger by any means it was a straight three bank charger if you leave it on there’s nothing to regulate charging and It will cook the batteries I have the same one and have been meaning to upgrade as well ,so if the mechanic or yard owner knows that particular battery charger then I would agree with him you’ll just wind up ruining your batteries

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Good point with respect to the older chargers. Now that the OP has a 1250P, hopefully the marina will knock that $hit off (or actually STOP knocking it off)

The charger is a 1240p and brand new. I replaced the original charger (weighed about 25#) with the new 1240p as was recommended.

You can loose a diode and the alternator will charge and act normal but when it's sitting the battery will back feed thru it and slowly discharge the battery over time. The diodes are in the voltage regulator and they are there to prevent the battery from back feeding to ground and discharging and to turn the ac current from alternator to dc. Diodes only allow current to travel in one direction which is how they turn ac to dc.

bobeast said:

Your battery isolator is wired between the alternator and the batteries on the load side of the battery switches. Conversely, the output of the charger is wired directly to the batteries. You should be able to isolate the isolator (no pun intended) by turning your battery switches to the OFF position. If it still doesn't charge, it probably isn't the isolator. If the problem goes away it may be your isolator.

You can test your isolator by;

1) Disconnect all wires.
2) measure resistance between the alternator terminal(s) and the battery output(s).
3) reverse the probes and measure again.

You should see relatively low resistance in one direction and not the other. (basic diode test)

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I turned the battery switches off and no change. I also pulled the 3 wires from the charger that go to the batteries and rearranged them to see if it would go to a different bank to charge but it did the same thing. When I powered it back up it showed the volts and the amps came up in conditioning mode and then slowly trailed off and it went into standby. Still just on the genny battery. I assumed it came programmed with everything except battery type. Is there additional programming steps?

hd2002hd said:

I turned the battery switches off and no change. I also pulled the 3 wires from the charger that go to the batteries and rearranged them to see if it would go to a different bank to charge but it did the same thing. When I powered it back up it showed the volts and the amps came up in conditioning mode and then slowly trailed off and it went into standby. Still just on the genny battery. I assumed it came programmed with everything except battery type. Is there additional programming steps?

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Not really. If it charges your genny battery it should charge the other banks as well. It sounds like you have a wiring problem between the charger and the battery banks. Note that on my 2002 310DA, the outputs of the charger go through "converter" breakers which on my boat are located under the cockpit sink. If those breakers are blown or defective, you would see a similar problem.

Hummmm.....I’m not sure about the converter breaker. If they are bad or tripped, your charger still comes on but it doesn’t allow charge to the batteries? As for the wiring I literally removed the old charger that had previously worked and installed this one. The only wiring difference in the chargers is that the 1240 has a battery temperature sensor that the manual says must be hooked up to any of the negative battery terminals. I attached it to one of the forward set of the 2 battery banks. I’m not sure if it is the port or starboard bank.

hd2002hd said:

Hummmm.....I’m not sure about the converter breaker. If they are bad or tripped, your charger still comes on but it doesn’t allow charge to the batteries? As for the wiring I literally removed the old charger that had previously worked and installed this one. The only wiring difference in the chargers is that the 1240 has a battery temperature sensor that the manual says must be hooked up to any of the negative battery terminals. I attached it to one of the forward set of the 2 battery banks. I’m not sure if it is the port or starboard bank.

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The breakers I'm referring to are DC breakers that are wired between the charger and the batteries. (that's how it is on my boat. not sure about yours). And yes If these breakers are tripped, it will prevent charging.

I have to ask, you mentioned the batteries are new, are you sure they are actually discharged? I wouldn't expect the charger to output much if your batteries already have a full charge.

Well, with the 12 volt systems on I check the voltage after a few hours to see if it drops. The Ginny battery shows over 13 volts. I have tested the other 2 banks at 11.6 volts and then a few hours later at just about 11 volts.

I don't know what to tell you. If the charger is functional and If it is connected to your battery banks, it will charge them. Just need to eliminate the Ifs.

bobeast said:

I don't know what to tell you. If the charger is functional and If it is connected to your battery banks, it will charge them. Just need to eliminate the Ifs.

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I appreciate all of your help. It is connected just like the old one was that had worked for years. It is starting to make me think there is something else wrong here between the charger and the batteries. If there is anything between the 2. I don't know that it charges the genny battery, it just appears that it is reading the voltage from that battery and when initially turned on it goes into conditioning mode and the amps jump up and then slowly go down to zero and it switches to standby mode since the genny battery is charged. I thought the wires from the charger went straight to the isolator and then to the batteries??

ttmott said:

Behind the 12V main disconnect panel are three 50amp breakers that are between the converter/charger and batteries. To access these breakers remove the panel screws and pull the top of that panel away and you will see those three breakers mounted by the hull. There is always the potential for current flowing from the starboard and port batteries regardless of the battery switch position such as for electronic memory, bilge pumps, alternators, etc. For this boat unless laid up you should always keep the converter/charger active as well as AC systems flowing air. BTW if the converter only went up to 5 amps on dead batteries you have a problem..... The best test is to turn on the converter and load the system down (turn on lights, refer, etc) and see if the converter approximates the draw you loaded it with. Oh, and by the way, if the batteries are really dead the charger may determine a no load condition and not go into charge mode.

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I reread this and I ma not sure what you are referring to. I assume the 12v main disconnect you are referring to is the rotating battery switches for port, starboard and generator? Mine are located in the cockpit on the port side behind a cabinet door. I've never had that panel off. It does have 2 rows of beakers there as well. Are you saying these breakers could be tripped or bad?

hd2002hd said:

I appreciate all of your help. It is connected just like the old one was that had worked for years. It is starting to make me think there is something else wrong here between the charger and the batteries. If there is anything between the 2. I don't know that it charges the genny battery, it just appears that it is reading the voltage from that battery and when initially turned on it goes into conditioning mode and the amps jump up and then slowly go down to zero and it switches to standby mode since the genny battery is charged. I thought the wires from the charger went straight to the isolator and then to the batteries??

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The only thing between your charger and the batteries would be wire, and the converter breakers that both I and @ttmott mentioned. If those breakers are tripped or bad, your batteries will not get charged.

hd2002hd said:

I reread this and I ma not sure what you are referring to. I assume the 12v main disconnect you are referring to is the rotating battery switches for port, starboard and generator? Mine are located in the cockpit on the port side behind a cabinet door. I've never had that panel off. It does have 2 rows of beakers there as well. Are you saying these breakers could be tripped or bad?

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400DA - Main Breaker Panel - Aft area of the cockpit on the port side - there are three main disconnects (one for starboard batteries, one for port batteries, and one for generator battery. There are two rows of circuit breakers and a single breaker for the anchor windlass. The left row is the fed from the port batteries and the right row is fed from the starboard batteries. The lower five circuit breakers for both the port and starboard rows are NOT switched; in other words the battery switches do not turn off these circuits. The upper three circuit breakers in both rows including the windlass are switched on and off by the battery switches. The battery switches do disconnect the main cables to the engines and their starters including the engine's alternators. Behind this Main Breaker Panel are some additional circuit breakers that are between the charger/converter and where the charger/converter output wires connect to the battery disconnect switches. The charger/converter connects to the main battery disconnect switches on the battery side of the three switches; in other words the charger/converter is not switched by the battery main disconnect switches.
There is a history of water intrusion into the 12V main disconnect panel and the consequential corrosion issues; so, you should open it up and inspect all of the wiring and connections.
Engine Alternators - the diodes in the rectifier circuits can short and cause a battery discharge through the engine's ground cabling however if the system is not maintaining both the port and starboard battery banks then doubt an alternator issue as both alternators would then have an issue.
Battery Isolators - Some 400DA has isolators and some did not; my 2000 model did not have isolators. The isolator simply allows current to flow from one battery bank to another provided certain differential voltages are apparent. The intent of the isolator is to allow battery charging should an engine alternator fail or one of the charging legs from the charger/converter fail. I don't see the practical need for an isolator if the system is routinely maintained and inspected.
Here are some pics of that main disconnect panel and the charger/converter circuit breakers behind it: