• If you log in, the ads disappear in the forum and gallery. If you need help logging in, send request for help to: webmaster@southernairboat.com

Best battery for O540

Slidin Gator

Well-known member
Gary, I think the 9 bolts is while it is cranking, which is expected.

Duck, what’s the voltage once the engine is running?
 

DukHntr239

Well-known member
Slidin Gator said:
Gary, I think the 9 bolts is while it is cranking, which is expected.

Duck, what’s the voltage once the engine is running?

The voltage while running goes back up to 12
 

DukHntr239

Well-known member
Slidin Gator said:
Gary, I think the 9 bolts is while it is cranking, which is expected.

Duck, what’s the voltage once the engine is running?

The voltage while running goes back up to 12
 

DukHntr239

Well-known member
Slidin Gator said:
Your alternator is not working, you should see 13 to 14 volts while the engine is running.

Sorry, I looked at it too quick I guess. Just ran it and looked again. It says 13
 

Deano

Well-known member
While it is possible it's not applicable here, we don't know what kind of alternator is being used; or I missed it, if so stated.
Perhaps one of you good gentlemen could explain to the DuckHntr about what an excitation circuit is and how it works.
He seems to misinterpret and/or not understand what this "other guy" writes, so that is likely a better option. :wink:

I usually reinforce other good information in a thread such as Sliding Gator did, but spaced that out this time; sorry guys. As Gator implied,
Re-reading ALL their responses will only help you understand your options. Where the BEST battery question is concerned, believe what Gator said. Optima Blue Top is the answer to take to the bank. Given your space constraints, just be sure you get a Group 24 size.

On a different note:
From a diagnostics standpoint, having a Multi-Meter is one of the best purchases you could make and is an inexpensive means of saving yourself a bunch of grief. In this case, reading voltage across your battery terminals could tell a far more detailed story than relying on the volt meter built into your dash. You might well be surprised at the difference you find, thinking they would be the same. It could also enhance your ability to determine exactly what your alternator is doing and how productive it is or isn't.
 

Slidin Gator

Well-known member
Did starter click or not when it wouldn’t start?

If no, check, repair, replace the starter switch circuit all the way to the spade connector on top of the starter. The connection at the starter vibrates a lot.

If it did click but no cranking, check and clean all main power cables, hot and ground. If it happens again, give the starter several whacks with a hammer, big wrench, rock etc. When she cranks after that, repair/replace starter.
 

DukHntr239

Well-known member
Deano said:
While it is possible it's not applicable here, we don't know what kind of alternator is being used; or I missed it, if so stated.
Perhaps one of you good gentlemen could explain to the DuckHntr about what an excitation circuit is and how it works.
He seems to misinterpret and/or not understand what this "other guy" writes, so that is likely a better option. :wink:

I usually reinforce other good information in a thread such as Sliding Gator did, but spaced that out this time; sorry guys. As Gator implied,
Re-reading ALL their responses will only help you understand your options. Where the BEST battery question is concerned, believe what Gator said. Optima Blue Top is the answer to take to the bank. Given your space constraints, just be sure you get a Group 24 size.

On a different note:
From a diagnostics standpoint, having a Multi-Meter is one of the best purchases you could make and is an inexpensive means of saving yourself a bunch of grief. In this case, reading voltage across your battery terminals could tell a far more detailed story than relying on the volt meter built into your dash. You might well be surprised at the difference you find, thinking they would be the same. It could also enhance your ability to determine exactly what your alternator is doing and how productive it is or isn't.

Didn’t mean to call you “the other guy” I just couldn’t remember your name while I was writing that comment. Lol. 😄

Anyways. I appreciate the helpful information greatly.
 

DukHntr239

Well-known member
Slidin Gator said:
Did starter click or not when it wouldn’t start?

If no, check, repair, replace the starter switch circuit all the way to the spade connector on top of the starter. The connection at the starter vibrates a lot.

If it did click but no cranking, check and clean all main power cables, hot and ground. If it happens again, give the starter several whacks with a hammer, big wrench, rock etc. When she cranks after that, repair/replace starter.

No sir the starter didn’t click. It just turned the prop a couple times, then threw it backwards 1/8 of a turn and stopped. No noise other than a clank. And now for the last 5 days, it has been starting with no hesitation at all.

Anyways, thank you for your help. I’m learning.
 

kwanjangnihm

Moderator
DukHntr239 said:
Didn’t mean to call you “the other guy”

:toothy7:

7jp0.gif
 

Deano

Well-known member
inemh.png


Some alternators (the proverbial 'single wire' ones in particular) have internal circuitry that 'excites' them or 'kicks them off'' so to speak
AFTER they reach a given RPM. Ideally this would be <800 RPM (?), most I've been around are 1000-1200 RPM, while I've seen
some on their way out that needed over 1500 RPM and some bad ones that NEVER woke up.

The point being that, IF you successfully started it with no issues, you could possibly let it idle for a week and the alternator would never start charging for lack of RPM to 'excite' it. Another time, IF you had to fight with it to get it started, you might gain enough RPMs to 'excite' it without realizing that is what happened.

This could explain why you saw 12 volts and it looked like the alternator was puked, but then the next time it read 13 volts and implied that it was working. :idea: My Cadillac starts at idle as soon as the starter hits the flywheel; this is as it should be, but it NEVER excites the alternator until I either get on a plane, or manually tap the RPM up to around 1100.

Thus, if your battery is low (from whatever the cause) simply getting the engine started is only half of what you need to do. You additionally need to gain enough RPMs to excite the alternator to generate the charging you're after.

This is another instance where diagnostically using a multi-meter can, and will supply more detailed information than your dash volt meter.
 

Slidin Gator

Well-known member
DukHntr239 said:
No sir the starter didn’t click. It just turned the prop a couple times, then threw it backwards 1/8 of a turn and stopped. No noise other than a clank. And now for the last 5 days, it has been starting with no hesitation at all.

Follow the "Yes It clicked" instructions. There is a bad connection somewhere in the wiring, at the battery, or possibly the starter itself. It will show up again :banghead:
 

DukHntr239

Well-known member
Follow the "Yes It clicked" instructions. There is a bad connection somewhere in the wiring, at the battery, or possibly the starter itself. It will show up again :banghead:
[/quote]

Thank you for your help gator.
 

terrible ted

Well-known member
I hate those optima's If you every drain them you just cant fast charge and go. I have gone thru a few batteries over the last 20 years airboating. Now I just buy the 5 year batteries at AutoZone seams to be the most economical way to go.
 

Rick McC.

Well-known member
Gary S said:
If you have a volt meter look at it before you start the boat. Will be 12 to 13 volts. When you start the boat look for the voltage to increase.
You could add a second battery with a battery switch and run the stereo on it. While engine is off turn switch to battery for stereo and save your starting battery.

I always have dual batteries (1000 mca each) in all my boats, but I agree completely with the “turn the stereo off” comment above. I have a great stereo in one of my boats that rarely gets turned on, as we much prefer to hear the wind and the waves while out boating/swimming.

I’ve witnessed boaters packing up and leaving from one of our favorite island spots because some asshole thinks that everyone within a half mile should listen to their favorite audio crap.

Now, I do like good music, and have been a lead guitarist/singer in bands for over 55 years now; but there’s a time and a place for everything…
 

Rick McC.

Well-known member
DukHntr239 said:
Slidin Gator said:
Your alternator is not working, you should see 13 to 14 volts while the engine is running.

Sorry, I looked at it too quick I guess. Just ran it and looked again. It says 13

Both my airboat and my tri-toon show right at 14 volts when running, even at idle.
 

Rick McC.

Well-known member
Deano said:
inemh.png


Some alternators (the proverbial 'single wire' ones in particular) have internal circuitry that 'excites' them or 'kicks them off'' so to speak
AFTER they reach a given RPM. Ideally this would be <800 RPM (?), most I've been around are 1000-1200 RPM, while I've seen
some on their way out that needed over 1500 RPM and some bad ones that NEVER woke up.

The point being that, IF you successfully started it with no issues, you could possibly let it idle for a week and the alternator would never start charging for lack of RPM to 'excite' it. Another time, IF you had to fight with it to get it started, you might gain enough RPMs to 'excite' it without realizing that is what happened.

This could explain why you saw 12 volts and it looked like the alternator was puked, but then the next time it read 13 volts and implied that it was working. :idea: My Cadillac starts at idle as soon as the starter hits the flywheel; this is as it should be, but it NEVER excites the alternator until I either get on a plane, or manually tap the RPM up to around 1100.

Thus, if your battery is low (from whatever the cause) simply getting the engine started is only half of what you need to do. You additionally need to gain enough RPMs to excite the alternator to generate the charging you're after.

This is another instance where diagnostically using a multi-meter can, and will supply more detailed information than your dash volt meter.
I have to run my rpm’s up 1500-2000 to get the alternator to put out the first time I crank it after it’s been shut down for a couple of days or longer. After that, the alternator is putting out 14V as soon as the motor’s cranked.
 

GILLO

Member
Have you had the alternator checked and how's your cables?

My last battery was 650CCA on my AV540. It would spin the motor over ok. When I upgraded my cables to a heavier 1/0 gauge, ran the ground close to the starter, with the same battery, it spun the motor with authority!!
Ground number one problem most people try to ground the battery to the frame rigging needs to be run directly to the starter mounting bolt
 
Top