DF-140 Charging Issue

[TXFishin]

Any advice or trouble-shooting on this issue would be greatly appreciated!

I have a 2003 DF-140, while running the engine on the hose as normal maintenance and keep things in check, I received a regulator / rectifier over-voltage alarm, and was reflected on the voltage gauge, showing a charge rate near 17 volts, outside of the normal limit, so I turned the engine off and did some basic testing and came to the conclusion it was a bad rectifier / regulator.

I replaced the suspected rectifier / regulator with a brand new one, started the engine, and it did what it should, held tight at 14.2 volts no mater what the engine RPM's were at, everything working as it was suppose and shut the engine down.

As part of getting ready for the fishing season and as by-annual maintenance, I replaced the battery, which is just now 2 years old.

I put the new battery on charge and verified the battery was fully charged, installed the battery in the boat.

Now, it appears that the engine is not charging like it should, I went for shakedown cruise, around 120 miles, and the entire time the voltage stayed between 12.5 and 12.9, never displayed 14.2 like it should in the manual.

So now I am scratching my head trying to figure out what would cause this, it worked fine before replacing the battery, I cleaned all the connectors which were in good shape to start with, and even at that, if it was a bad cable going to the battery I am sure that it would lag or cause issues when trying to start the engine or something.

Everything seems to be working fine, no alarms, no issues, other than the voltage when the engine is running is between 12.5 and 12.9 volts

Any ideas?

Again any help or ideas would be greatly appreciated.

[boats.net]

Regulator will charge as much as needed depending on battery charge level, if draw battery down should see charge rate increase if charging system is working properly.

[TXFishin]

So everything may be working as it should since it is a new hot battery? Based off the manual I was under the impression the voltage should be around 14.2 volts continious, but that might lead to an over-charge situation.

I ran the boat around 120 miles round trip, and I would assume that if it was not charging at all I would have had issues running it for that length of time as well?

Thanks again for responding!

Regulator will charge as much as needed depending on battery charge level, if draw battery down should see charge rate increase if charging system is working properly.

[redlowrey]

Check for voltage drop between the voltage regulator output wire and battery positive. Connect a volt meter to the output wire and earth it should read around fourteen volts. When you crank the engine the starter would pull over 120 amps and when the engine is running around twenty for ignition and ECU. so you should see more than 12.9 volts after start up. Before you pull any thing apart put a different battery in it and try it.

[TXFishin]

Thanks for the information, I am planning to try a different battery next time I can get to my boat.

I notice in the service manual there is a fuse in the loop, could there be a blown fuse that would cause this and not cause an alarm by any chance?

So what you are saying is that once the battery is "full" the charge rate will throttle back and should see around 12.9?

Check for voltage drop between the voltage regulator output wire and battery positive. Connect a volt meter to the output wire and earth it should read around fourteen volts. When you crank the engine the starter would pull over 120 amps and when the engine is running around twenty for ignition and ECU. so you should see more than 12.9 volts after start up. Before you pull any thing apart put a different battery in it and try it.

[keakar]

yes a fully charged battery wont be asking for a charge so the regulator doesnt allow extra voltage to get to the battery.

to test if everything is working ok all you have to do is draw enough power from the battery so that voltage drops to or below 12 v and the regulator will kick in to allow the stator to charge the battery.

next time you go out turn on your running lights and plug in a high power spot light or something else that draws a lot of power

running lights may not do it alone but the spot light will draw enough power so that the battery should ask for a charge and you should see the voltage read 13.5 to 14 volts as the regulator begins to charge it.

after turning the light off it will soon drop back to 12 to 12.5 volts as the battery no longer needs charging. if the system doesnt work this way you would "cook" your battery by overcharging it untill it stopped working

[TXFishin]

Thanks again for the information, I feel a little better about what is going on now. I am thinking the battery being new is why the voltage is low. After replacing the rectifier/regulator everything worked fine, and on the old battery it was showing 14.2, which could be the case due to age and not being able to fully charge the battery, and when I put the new battery on it dropped to 12.8, and periodically would go to 13.2 simply because it is not requiring the effort to keep a full charge like the old battery did.

I have two 140's on the back, so it should be a quick test, I can reconnect the old batter or put a load on the new battery and verify everything is working properly

yes a fully charged battery wont be asking for a charge so the regulator doesnt allow extra voltage to get to the battery.

to test if everything is working ok all you have to do is draw enough power from the battery so that voltage drops to or below 12 v and the regulator will kick in to allow the stator to charge the battery.

next time you go out turn on your running lights and plug in a high power spot light or something else that draws a lot of power

running lights may not do it alone but the spot light will draw enough power so that the battery should ask for a charge and you should see the voltage read 13.5 to 14 volts as the regulator begins to charge it.

after turning the light off it will soon drop back to 12 to 12.5 volts as the battery no longer needs charging. if the system doesnt work this way you would "cook" your battery by overcharging it untill it stopped working

[TXFishin]

Still not charging

I performed several test, trying several batteries, etc.., and still not seeing much of a charge output.

I checked for A/C voltage on the output to rule out the possibility of the new rectifier / regulator being bad, and everything seems fine there.

I checked continuity between the W1-W2-W3 and all seems fine, but would not indicate if one of the phases are shorted though.

However, when I checked the A/C voltage coming from the charge coil, I received the following

White #1 = 6.5 - 7.1 volts A/C

White #2 = 1.6 - 1.8 volts A/C

White #3 = 6.8 - 7.0 volts A/C

Should I be seeing the same voltage across all 3? I have not had a chance to check this with the starboard engine, but it seems that all 3 should be approx. the same?

Now, what is the chance of the charge coil going bad after replacing the rectifier / regulator?