Alternator burnt up with 100 engine hours?!?

[Sam Woodbridge]

Originally Posted by RaymondR

The alternator overheating problem is generally cause because we take an alternator which is designed to recharge a single cranking battery, say 100 amp hours, and connect it to 600 amp hours of house batteries.

Alternator output ratings have a time limit which is as low as about 10 minutes and when used with a single battery the battery voltage will have increased and wound the alternator output back within this time limit. When we connect the alternator to a large bank of house batteries the wind back does not occur and hence the over heating.

In addition to connecting to a large bank of house batteries we often charge large banks with the alternator running relatively slowly and consequently being inadequately cooled because the fan is running slowly and not pulling sufficient air through the alternator to properly cool it.

The most fool proof solution to the cooked alternator problem is the temperature sensing control of output wind back one although I have sometimes implemented a temporary solution by placing a high wattage resister in series with the batteries in the alternator.

Thank you RaymondR, I sincerely appreciated reading your thread.

[NYSail]

I bought my balmar 150 alt and 614 external regulator from Maine sail. He told me how to program the unit and it works like a charm. Many variables..... Are you plugged in to bring to 100% weekly or do you depend on alt to do all the work? Battery size?
If you bring your bank to 12.0 when you use your bow thruster or windlass..... you will see you electrical system flash.

[Sam Woodbridge]

Originally Posted by NYSail

I bought my balmar 150 alt and 614 external regulator from Maine sail. He told me how to program the unit and it works like a charm. Many variables..... Are you plugged in to bring to 100% weekly or do you depend on alt to do all the work? Battery size?
If you bring your bank to 12.0 when you use your bow thruster or windlass..... you will see you electrical system flash.

Thank you for your reply!

[Sam Woodbridge]

Originally Posted by NYSail

I bought my balmar 150 alt and 614 external regulator from Maine sail. He told me how to program the unit and it works like a charm. Many variables..... Are you plugged in to bring to 100% weekly or do you depend on alt to do all the work? Battery size?
If you bring your bank to 12.0 when you use your bow thruster or windlass..... you will see you electrical system flash.

Nysail, I attached a picture of the battery for refference. When I’m plugged in and leave the marina all is good! It’s only when I anchor out for a night or more and draw down the batteries. The next morning the no charging alarm and lights go off intermediately for a half hour. This boat is new to me. Only owned it for a week.

Thank you - Sam

[Sam Woodbridge]

I’m going to get the batteries tested tomorrow. There is three house batteries. One starter battery. Two bow thruster batteries. I’m feeling confident it’s the three house batteries that are causing grief. I know they have dropped below 12 volts on my anchorages over night and from what I understand that’s far to discharged.

[Mickeyrouse]

Originally Posted by Sam Woodbridge

Thanks Mickery for your thoughts. I agree batteries at 12 volts are low, but I expected that from two days of using them without anything charging them. Do you think after two days of using them they should have held a higher voltage?

Thanks again - Sam

Pretty hard to say without knowing the battery bank capacity and the demand placed on it. I would encourage you to work up an energy budget. Something like: anchor light- 1 amp x 12 hrs x 2 days = 24 amps. Water pressure pump- 6 amps- avg 1 hr per day = 12 amps. Cabin lights 2 amps x 6 hrs day times 2 days = 12 amps. (These are example numbers- the McGrath of your devices should be able to give more precise unit consumption figures.) Include everything you have: instruments, nav gear, running lights, stereo, fans, etc. and total it up. You’ll be surprised at the total. Compare that total to the total of your battery bank, which incidentally is for new, good condition batteries.
And about the condition of the batteries: I’ll bet they haven’t been equalized in some time. If you’re not familiar with the term it’s is a process that can extend the life of the batteries, though not indefinitely. Many boat chargers have a special equalization circuit. Check on yours. If it has one never hurts to do it. Follow the instructions in the manual.

[Sam Woodbridge]

Originally Posted by Mickeyrouse

Pretty hard to say without knowing the battery bank capacity and the demand placed on it. I would encourage you to work up an energy budget. Something like: anchor light- 1 amp x 12 hrs x 2 days = 24 amps. Water pressure pump- 6 amps- avg 1 hr per day = 12 amps. Cabin lights 2 amps x 6 hrs day times 2 days = 12 amps. (These are example numbers- the McGrath of your devices should be able to give more precise unit consumption figures.) Include everything you have: instruments, nav gear, running lights, stereo, fans, etc. and total it up. You’ll be surprised at the total. Compare that total to the total of your battery bank, which incidentally is for new, good condition batteries.
And about the condition of the batteries: I’ll bet they haven’t been equalized in some time. If you’re not familiar with the term it’s is a process that can extend the life of the batteries, though not indefinitely. Many boat chargers have a special equalization circuit. Check on yours. If it has one never hurts to do it. Follow the instructions in the manual.

Thank you Mickey, awesome post and I’ll look into it!

[dfelsent]

Buy a meter. With a clamp on DC Amps feature. Amazon has them for short money. The accuracy might not be great but all you really need is ballpark readings to help establish your current consumption for the different systems on your new boat.
And as well, to measure the charging current into the batteries.
This will go a long way towards understanding the energy consumption patterns on your boat.

It kind of seems to me that your regulator is set up to overload your alternator when the batteries are able to accept a lot of current. When the batteries are low they will take more current than when they are closed to full. So after a weekend, low batteries equals high charge current, equals overheated smelly alternator. (Or belts can reek too if overloaded)
Other posters have hinted at this as well.

[Mickeyrouse]

Originally Posted by Mickeyrouse

. “.... McGrath.....”

This damned spell checker got that out of” mfgr “

[Jamme]

Originally Posted by Mickeyrouse

And about the condition of the batteries: I’ll bet they haven’t been equalized in some time. If you’re not familiar with the term it’s is a process that can extend the life of the batteries, though not indefinitely. Many boat chargers have a special equalization circuit. Check on yours. If it has one never hurts to do it. Follow the instructions in the manual.

I thinks OP has AGM batteries. If so, I suggest he checks battery specs to see if equalization is or is not necessary. I definitely am not an battery expert, but, for instance, the manufacturer East Penn writes with respect to my batteries (2 x 8A24 AGM VRLA):
“Because the immobilized gel will not “float” or “sink” within itself when a non-uniform concentration exists, it cannot stratify. Therefore, no high-voltage equalizing charge is necessary. Simply recharge at the standard 13.8 to 14.1 voltage setting. This means longer life and consistent performance in stationary and standby applications. Electrolyte in an AGM battery is strongly held by the capillary forces between the glass mat fibers, but not completely immobilized. Stratification is possible in extremely tall cells, but cannot occur in batteries of the size covered in this document.”

[Sam Woodbridge]

Originally Posted by dfelsent

Buy a meter. With a clamp on DC Amps feature. Amazon has them for short money. The accuracy might not be great but all you really need is ballpark readings to help establish your current consumption for the different systems on your new boat.
And as well, to measure the charging current into the batteries.
This will go a long way towards understanding the energy consumption patterns on your boat.

It kind of seems to me that your regulator is set up to overload your alternator when the batteries are able to accept a lot of current. When the batteries are low they will take more current than when they are closed to full. So after a weekend, low batteries equals high charge current, equals overheated smelly alternator. (Or belts can reek too if overloaded)
Other posters have hinted at this as well.

Dfelsenf, thank you for your post. I’m thinking the same direction.

[CarlF]

You see what a little question about an alternator can stir up? While most of the posts have dealt with the alternator and regulator -- which is the place to start - I think it's likely your AGM house batteries are part of the problem.

For some fun bed-time reading google "PSOC AGM". PSOC stands for "Partial State of Charge". It occurs when a battery is not fully recharged as almost always happens when anchoring out. Boats that are always plugged into a marina don't suffer from PSOC. AGM batteries have a nasty habit of losing capacity quickly from PSOC. They can lose over 50% of their capacity in as little as one year.

You'll find lots on the internet about this. Many cruisers who anchor out a lot (myself included) have given up on AGM's. I switched to a type of battery that doesn't suffer from PSOC called "Firefly". There are other options too.

By the way - the instant battery testers at auto parts stores don't really work on AGM's. The only reliable test is a C/20 Capacity test where you discharge the batteries at their published 20 hour hour discharge amperage and see how close to 20 hours they last. The test is a pain in the neck to do but is the only really reliable method. You can google it too.

Good luck

[Sam Woodbridge]

Originally Posted by CarlF

You see what a little question about an alternator can stir up? While most of the posts have dealt with the alternator and regulator -- which is the place to start - I think it's likely your AGM house batteries are part of the problem.

For some fun bed-time reading google "PSOC AGM". PSOC stands for "Partial State of Charge". It occurs when a battery is not fully recharged as almost always happens when anchoring out. Boats that are always plugged into a marina don't suffer from PSOC. AGM batteries have a nasty habit of losing capacity quickly from PSOC. They can lose over 50% of their capacity in as little as one year.

You'll find lots on the internet about this. Many cruisers who anchor out a lot (myself included) have given up on AGM's. I switched to a type of battery that doesn't suffer from PSOC called "Firefly". There are other options too.

By the way - the instant battery testers at auto parts stores don't really work on AGM's. The only reliable test is a C/20 Capacity test where you discharge the batteries at their published 20 hour hour discharge amperage and see how close to 20 hours they last. The test is a pain in the neck to do but is the only really reliable method. You can google it too.

Good luck

Thank you CarlF - I’m on it!

[Mickeyrouse]

As noted in Jamm’s post, I overlooked his caution about equalizing Jamm’s post.
As a general resource, I alway’s recommend Nigel Calder’s book about boat mechanical and electrical systems. There has been a copy ( slightly smudged and dog-eared at this point) aboard our boat since the first edition in the nineties. I have found it amazing how many technical threads on this forum could use a good reading from his books.

[RaymondR]

Originally Posted by Sam Woodbridge

I was thinking about letting this thread go until I knew of a solution to my problem.But I have to mention.

** Alternator tested good **.

My problem is some where else. I’m better equipped with everyone’s help on the forums and with what I’ve learned from the local shop.

What I do know is. When my batteries are ran down (anchored out) for the first half in hour of running the motor. The no charging battery alarm comes on and off several times. If I where to leave the marina with fully charged batteries from being hooked up to shore power. There are no alarms everything works as intended. ** this is only happening when the batteries are low**

Anyways once I get it figured out I’ll be posting about it.

Thank you everyone for your input.

Sam

Sounds like your alternator may already have some kind of thermal protection which is kicking in and out as the alternator cycles into a high ampage mode to attempt to charge the very flat battery then backs off the amps to get cool again.