another battery charger problem

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ches2443

ches2443

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deal island, maryland
I'm wiring a boat. It has a 12 volt 30amp constant/volt battery charger ,with is fed by a 120 volt circuit on the shore power. It's connected to to a 8D marine battery. Battery supplies power to two dc panels one in engine room and one in the pilot house. The battery is also used to start the diesel engine. My problem is that after starting the engine for the first time; the battery charger stop working. Could this have been caused by a voltage surge from the alternator which back fed into the charger during start-up. In turn shorted out the charger. :rolleyes:
 
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ches2443 said:
I'm wiring a boat. It has a 12 volt 30amp constant/volt battery charger ,with is fed by a 120 volt circuit on the shore power. It's connected to to a 8D marine battery. Battery supplies power to two dc panels one in engine room and one in the pilot house. The battery is also used to start the diesel engine. My problem is that after starting the engine for the first time; the battery charger stop working. Could this have been caused by a voltage surge from the alternator which back fed into the charger during start-up. In turn shorted out the charger. :rolleyes:
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Is it designed to drop out the 120V charger when the engine is started?Maybe an alternator on the engine charges the battery.
Put a meter on the battery while the engine is running and see if the battery is charging.
 
The thought is. Even if the battery had a full charge. During start-up the voltage on the battery would drop from 13.5 volts to 11 volts. When this happens the charger would see the voltage drop as a drain on the battery and go into a bulk charge. (Putting out 14 volt) Now almost at the same time, the engine would start and the alternator would kick in giving out another 14-16 volt. So the question is? Can the charger react quick enough and shut back down before shorting out?
 
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the battery charger stop working

I think the answer will be in how exactly the charger stopped working. Was it damaged? Breaker tripped or fuse blown?

-Hal
 
ches2443 said:
It blowout a large 80 amp post fuse, located inside the charger .:confused:
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It may be blowing during starting, not after. Either way, it would probably be a good idea to disconnect the charger before starting.
 
i have cranked countless deisel motors in the manner that you are describing - and never had that happen - some with the exact battery you mention
 
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Sounds to me like the starter is drawing current from the charger and the battery. That could easily exceed 80 amps.

It has a 12 volt 30amp constant/volt battery charger

You want something that is current limited just to charge the battery. If it has an 80 amp fuse on its output it's really a power supply to be used instead of the battery while on shore power. You need to cut power before cranking the engine.

-Hal
 
hbiss said:
Sounds to me like the starter is drawing current from the charger and the battery. That could easily exceed 80 amps.

It has a 12 volt 30amp constant/volt battery charger

You want something that is current limited just to charge the battery. If it has an 80 amp fuse on its output it's really a power supply to be used instead of the battery while on shore power. You need to cut power before cranking the engine.

-Hal
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I think the 80 amp fuse is a main fuse. Because the charger is rated as a 30 amp charger. But is capable of charging three battery banks at the same time. (This boat only has one.)
 
This may sound like a dumb question, but how old is the battery ?

If it is not up to par, then it is more than likely is that the battery voltage dropped so far under the load of cranking the engine, that the charger attempted to make up the loss by going full-bore on output.

Which blew the fuse.

And as others have pointed out, it sounds more like a 'power supply' than a 'battery charger' (nothing wrong with using it to keep the battery charged, just making an observation).
 
Gary Glaenzer said:
This may sound like a dumb question, but how old is the battery ?

If it is not up to par, then it is more than likely is that the battery voltage dropped so far under the load of cranking the engine, that the charger attempted to make up the loss by going full-bore on output.

Which blew the fuse.

And as others have pointed out, it sounds more like a 'power supply' than a 'battery charger' (nothing wrong with using it to keep the battery charged, just making an observation).
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Sorry for the late reply. The battery is band new.
 
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I couldn't get a clear understanding why the charger blow it's main fuse during start-up. So I went ahead and put in a separate service switch, so the charger could be shut down when the engine starts.:wink:
 
I believe that the charger is simply being overloaded by the engine starter.

Even if you have a good battery, the power (amps) required to crank a diesel engine is really high...it takes a lot of juice.

During cranking, it's possible that the starter is drawing up to 200 amps or more.
A good battery will provide that kind of current, but likely the battery voltage will drop to 10 or 11 volts while doing it.

The charger will sense the voltage drop, and ramp up it's output...kinda like what ches2443 mentioned.
It will try to supply the required amperage at full battery voltage, so it will wind up being seriously overloaded.

You can buy battery chargers that have a "crank" mode.
This type of charger is designed to prevent damage to the charger by overload caused by cranking.

If you're commited to the type of charger that you're using, you may have to install a relay to disconnect the charger from the battery circuit when cranking the engine.

Just a idea
steve
 
nolabama said:
i want to bet a nickel its starter related and not charger related - i mean what else is gonna produce the amps enough to blow the fuse ?
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The 8D battery has 230 amp/hour charge. I maybe wrong; but I think with that large of a battery (with a full charge), The charger shouldn't see the kind of amp draw to blow it's main fuse.
 
hillbilly said:
I believe that the charger is simply being overloaded by the engine starter.

Even if you have a good battery, the power (amps) required to crank a diesel engine is really high...it takes a lot of juice.

During cranking, it's possible that the starter is drawing up to 200 amps or more.
A good battery will provide that kind of current, but likely the battery voltage will drop to 10 or 11 volts while doing it.

The charger will sense the voltage drop, and ramp up it's output...kinda like what ches2443 mentioned.
It will try to supply the required amperage at full battery voltage, so it will wind up being seriously overloaded.

You can buy battery chargers that have a "crank" mode.
This type of charger is designed to prevent damage to the charger by overload caused by cranking.

If you're commited to the type of charger that you're using, you may have to install a relay to disconnect the charger from the battery circuit when cranking the engine.

Just a idea
steve
Click to expand...



Could the alltinator play a part in this?
 
hillbilly said:
I believe that the charger is simply being overloaded by the engine starter.

Even if you have a good battery, the power (amps) required to crank a diesel engine is really high...it takes a lot of juice.

During cranking, it's possible that the starter is drawing up to 200 amps or more.
A good battery will provide that kind of current, but likely the battery voltage will drop to 10 or 11 volts while doing it.

The charger will sense the voltage drop, and ramp up it's output...kinda like what ches2443 mentioned.
It will try to supply the required amperage at full battery voltage, so it will wind up being seriously overloaded.
Click to expand...
All valid points. Voltage during cranking would certainly drop and the charger would increase its output. That said, I would have expected the charger to go into current limit. If it has such a feature. Failing that, it ought to have an electronic overload trip.
If it has neither, it is a cheap and nasty design and should be sent to the round filing cabinet.

That said, I admit that my experience of chargers available to the consumer market is nil, zero, zip. But it would still surprise me to find a unit with no internal protection.

We, as a company, design, manufacture, and supply battery chargers primarily for the marine, industrial, and commercial sectors.
Maybe my expectation for consumer products is a tad optimistic.
 
Besoeker said:
All valid points. Voltage during cranking would certainly drop and the charger would increase its output. That said, I would have expected the charger to go into current limit. If it has such a feature. Failing that, it ought to have an electronic overload trip.
If it has neither, it is a cheap and nasty design and should be sent to the round filing cabinet.

That said, I admit that my experience of chargers available to the consumer market is nil, zero, zip. But it would still surprise me to find a unit with no internal protection.

We, as a company, design, manufacture, and supply battery chargers primarily for the marine, industrial, and commercial sectors.
Maybe my expectation for consumer products is a tad optimistic.
Click to expand...


The chargers that we buy are two brands and are both used in marine applications. Charles & Newmar and both are constant/volt three stage battery chargers that can handle three bank at the same time. The Charles chargers are being instilled in 96' tugs And the Newmars are mainly for the 260' cruise liner. The charger in question was a Newmar installed on a small 6 car ferry
 
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