charging norms

[joe_db]

Yes you would!

[QUOTE=Borrowed Time;90921]Thanks all for the helpful feed back. I ran the boat around the harbor for an hour or so last evening and found the output voltage at wide open throttle to start out at around 14.3 to 14.4 for the first 15 minutes or so, then it settled at around 13.8 and stayed there at all RPM above 1200.

BTW, I typically am running a GPS/Sounder, Auto Pilot, Radio and at night the tricolor and bow lights.

Does that range of output voltage seem normal/acceptable?

Would I "cook" my batteries if I just run the Transpo at maximum output of 14.8 to 15V?[/QUOTE]

[ndutton]

Would I "cook" my batteries if I just run the Transpo at maximum output of 14.8 to 15V?

Why the interest in this voltage range?

[Borrowed Time]

"Why the interest in this voltage range?" Simply because the regulator was set at maximum when I received it. The question I have is whether it is productive to run it at maximum for the initial bulk charging (after running the starter and sitting on a trickle) with the expectation that the batteries will draw less as it comes up to charge (which seems to be happening based on readings), or will it simply kill the batteries in short order? BTW, the boat lives in a slip plugged in to shore power with a Guest 10A 5/5 charger feeding each of the two group 27 house combo start/deep batteries. The batteries are about two years old and I suspect have been somewhat undercharged during those two years, voltage readings at the dock are typically 13.3v. I am also concerned about the well being of my Pertronix EI and the MMI coil at those higher voltages. I do not use a ballast resister which may or may not have killed both the new Pertronix Flamethrower coil and then my spare original decades old coil. I've had no coil issues since I installed one of Don's coils. Sorry if this bit of info strayed off the charging norm thread.

"Where are you measuring voltage?" Using an el cheapo cigarette lighter type plug in digital voltage meter, at either of two outlets, one in the cockpit and another near the main bulkhead in the cabin. I now realize that I should be measuring it at the batteries. Five or so years ago, I had a corrosion issue interrupt the connection at the alternator + out terminal and I ran down the batteries coming back from Catalina in the morning with no wind. Sailing back to my slip up the main channel of LA Harbor proved a challenge I would rather avoid going forward. That was when I added a dedicated start battery to my collection. I also ran a fat (#4?) jumper between alternator out to the lug on the starter bypassing the charging circuit and its itty bitty wires completely. That connection was supposed to be temporary, but I have decided to leave it as is, so I expect to have no issue with getting most, if not all, of the alternator output back to the common lug on the 1, 2 or all master switch. I now do an annual cleaning of all those connections on both the positive and negative sides of the circuits.

Thanks again to all for the response to my questions. I have cobbled together this system over the past few years and want to keep it going with as little aggravation or expense as possible. I mainly use the boat to day sail and occasionally overnight at Catalina.

[ndutton]

Without getting into the popular 3 stage charging profile, consider that when the alternator is producing it delivers the same voltage to all the connected devices. Tunnel vision on the batteries can cause other unintended consequences. I've been engaged in a conversation off-forum on this topic, particularly the detrimental effect of elevated charging voltage to electronic ignition (and its effect on amperage) and the Johnson CM30-P7-1 coolant pump (with a narrow voltage specification). You'll either need to tame down the charge voltage (my preference and the preference of a particular iconic marine alternator shop in Newport Beach) or add protections at the devices to deal with it. If doing the latter, what happens when you throttle down to idle, the alternator drops out due to low RPM and you still have protective resistors at the 12V devices? Now you're on battery only, 3 volts less and further reduced by those resistors. I guess what I'm trying to say is look beyond the batteries and consider operation with and without the alternator producing.

FYI, I use fixed voltage charging @ 14.2V, one of my 2 banks is 10 years old and still performing well. Because of this experience I cannot imagine being tempted to even try multi-stage charging.

[hanleyclifford]

"Why the interest in this voltage range?" Simply because the regulator was set at maximum when I received it. The question I have is whether it is productive to run it at maximum for the initial bulk charging (after running the starter and sitting on a trickle) with the expectation that the batteries will draw less as it comes up to charge (which seems to be happening based on readings), or will it simply kill the batteries in short order? BTW, the boat lives in a slip plugged in to shore power with a Guest 10A 5/5 charger feeding each of the two group 27 house combo start/deep batteries. The batteries are about two years old and I suspect have been somewhat undercharged during those two years, voltage readings at the dock are typically 13.3v. I am also concerned about the well being of my Pertronix EI and the MMI coil at those higher voltages. I do not use a ballast resister which may or may not have killed both the new Pertronix Flamethrower coil and then my spare original decades old coil. I've had no coil issues since I installed one of Don's coils. Sorry if this bit of info strayed off the charging norm thread.

"Where are you measuring voltage?" Using an el cheapo cigarette lighter type plug in digital voltage meter, at either of two outlets, one in the cockpit and another near the main bulkhead in the cabin. I now realize that I should be measuring it at the batteries. Five or so years ago, I had a corrosion issue interrupt the connection at the alternator + out terminal and I ran down the batteries coming back from Catalina in the morning with no wind. Sailing back to my slip up the main channel of LA Harbor proved a challenge I would rather avoid going forward. That was when I added a dedicated start battery to my collection. I also ran a fat (#4?) jumper between alternator out to the lug on the starter bypassing the charging circuit and its itty bitty wires completely. That connection was supposed to be temporary, but I have decided to leave it as is, so I expect to have no issue with getting most, if not all, of the alternator output back to the common lug on the 1, 2 or all master switch. I now do an annual cleaning of all those connections on both the positive and negative sides of the circuits.

Thanks again to all for the response to my questions. I have cobbled together this system over the past few years and want to keep it going with as little aggravation or expense as possible. I mainly use the boat to day sail and occasionally overnight at Catalina.

Sounds like you have a bunch of issues running around your electrical system. Your "#4 jumper" is actually what you ought to have coming off alt +, but going to starter + it bypasses your gauge. You probably have a resistance issue in the tiny wire that runs to the ammeter from the alternator, a common problem BTW. In any case if you are running 15 volts off alt + (because you have the regulator cranked to max) you are risking overcharging the batteries unless you have beaucoup resistance lowering voltage at batt + to something more sensible like 14.0 volts or even less for all day running. Invest in a decent digital multimeter and it will pay for itself in problems avoided. Test voltage at batt + hot and running. The risk to your coil by running too much voltage is a topic all by itself.

[hanleyclifford]

Without getting into the popular 3 stage charging profile, consider that when the alternator is producing it delivers the same voltage to all the connected devices. Tunnel vision on the batteries can cause other unintended consequences. I've been engaged in a conversation off-forum on this topic, particularly the detrimental effect of elevated charging voltage to electronic ignition (and its effect on amperage) and the Johnson CM30-P7-1 coolant pump (with a narrow voltage specification). You'll either need to tame down the charge voltage (my preference and the preference of a particular iconic marine alternator shop in Newport Beach) or add protections at the devices to deal with it. If doing the latter, what happens when you throttle down to idle, the alternator drops out due to low RPM and you still have protective resistors at the 12V devices? Now you're on battery only, 3 volts less and further reduced by those resistors. I guess what I'm trying to say is look beyond the batteries and consider operation with and without the alternator producing.

FYI, I use fixed voltage charging @ 14.2V, one of my 2 banks is 10 years old and still performing well. Because of this experience I cannot imagine being tempted to even try multi-stage charging.

I agree that multi stage charging is not all it's cracked up to be, but as to the voltage coming of alt + --- that is only valid to the next terminal. After that voltages vary all over the system and all users do not get the same voltage unless they happen to be off once terminal with equal wiring and length (same resistance).

[BunnyPlanet169]

I agree that multi stage charging is not all it's cracked up to be, but as to the voltage coming of alt + --- that is only valid to the next terminal. After that voltages vary all over the system and all users do not get the same voltage unless they happen to be off once terminal with equal wiring and length (same resistance).

Voltages will vary, no doubt, but that's largely dependent on the quality and length of your wiring.

I think Neil's point is well taken that 15V at the alternator is too much from a nominal design point of view, unless that 15V is going directly into a multi-stage regulator that subsequently drops voltages to a more reasonable level. I.E. poor wiring shouldn't be a design compensation for a high output voltage.

[hanleyclifford]

Voltages will vary, no doubt, but that's largely dependent on the quality and length of your wiring.

I think Neil's point is well taken that 15V at the alternator is too much from a nominal design point of view, unless that 15V is going directly into a multi-stage regulator that subsequently drops voltages to a more reasonable level. I.E. poor wiring shouldn't be a design compensation for a high output voltage.

You might be surprised at what can vary voltages apart from wiring quality. For example, consider what happens when you switch on a 2000w inverter and you are running a 3 stage regulator at float---boom, the regulator resets to bulk. The usage and position of accessories in the wiring system have as much to do with voltage variations as wire quality. That is why all sensitive users should feed as close to the source as practical, and extended cobble-on circuits should be avoided. For this reason I have an array of OPSS feeding users right from the main buss bar.

[Borrowed Time]

Thanks again Jeff, Neil and Hanley for the helpful advice. I am learning new skills every time I dive into one of these systems. I will leave the voltage where it is for now and do some further investigating with a digital multimeter.

One more thing that keeps tugging at the back of my brain that I hope you guys can help me with, when my alternator ceased to send out current due to corrosion on the output lug, and I ran flat both batteries on that Catalina trip two years ago, shouldn't that have destroyed the diodes on the alternator?

I would guess I ran the engine for 6 or more hours on that trip blissfully unaware of the fact that I was running the alternator with no battery load on it. Wouldn't that be like turning the master switch to the off position with the engine running?

Thanks again for all the help gent's.

[hanleyclifford]

Thanks again Jeff, Neil and Hanley for the helpful advice. I am learning new skills every time I dive into one of these systems. I will leave the voltage where it is for now and do some further investigating with a digital multimeter.

One more thing that keeps tugging at the back of my brain that I hope you guys can help me with, when my alternator ceased to send out current due to corrosion on the output lug, and I ran flat both batteries on that Catalina trip two years ago, shouldn't that have destroyed the diodes on the alternator?

I would guess I ran the engine for 6 or more hours on that trip blissfully unaware of the fact that I was running the alternator with no battery load on it. Wouldn't that be like turning the master switch to the off position with the engine running?

Thanks again for all the help gent's.

The alternator did have a load on it; it just wasn't getting to the batteries. Instead it was being consumed in resistance for the most part.

[ndutton]

One more thing that keeps tugging at the back of my brain that I hope you guys can help me with, when my alternator ceased to send out current due to corrosion on the output lug, and I ran flat both batteries on that Catalina trip two years ago, shouldn't that have destroyed the diodes on the alternator?

I would guess I ran the engine for 6 or more hours on that trip blissfully unaware of the fact that I was running the alternator with no battery load on it. Wouldn't that be like turning the master switch to the off position with the engine running?

There's not enough information to answer with certainty. The dynamic that causes the diode-poofing voltage spike is the alternator working normally, connected to a battery and putting out volt+amps, then the connection at the output is removed mid-operation. Further, it's not guaranteed the diodes will poof but if they're gonna, this will do it. Simply spinning an alternator with no battery connected doesn't cause it alone.

Further-further, if the problem was a corroded output connection with ZERO continuity, there was no load on the alternator. None. It's the same as no wire attached. But here is one of those unknowns in the description, was there zero continuity or a compromised high resistance connection? If this, then that but on the other hand maybe something else. Unless we know precisely we can only explore a variety of possibilities.