charging norms

[ndutton]

In the interim isolate an engine starting and running battery for the putt-putt back to the mooring. Draw your depth and GPS loads from a house bank.

[Skywalker]

Thanks for the help, I'll get by for now.

The shop just informed me there is nothing he can find from his suppliers to change the current performance. Great guy, he was very disappointed he couldn't do anything.

Called Ken, ordered at 55 amp unit. Luckily, from the warehouse to my house is usually a one day event, so tomorrow after work it should be at my door.

Ebay or craiglist for the old one, unless somebody here thinks they have a use for it.

Thanks again.

Chris

[joe_db]

Easy check:
Take the regulator off and connect the field to + 12 volts. THat should drive the alternator to full output. If it works, the regulator is bad. If not, it is something else. BTW, my alternator does not charge at idle either. I cruise at 2200-2400 RPM and can get decent output down to about 1800 RPM. I can hold my setpoint voltage with full batteries at around 1200 RPM.

[Skywalker]

The new alternator arrived today and I ran down to the harbor

At idle, 13.0V. Bump it up a little, and I mean 100 rpms or so, and 14V on the meter.

Threw all the switches (blower, lights, instruments), and it obviously kicked up the amps.

Done.

Oh, did I mention that it was raining, I mean pouring. I get to the boat, open the engine compartment, and ... lightening!!

Luckily, it was brief, but intense.

Thanks for the help and support, as always.

Skywalker

[Borrowed Time]

I have a newer (two or three years old) after market adjustable voltage regulator on my original 35A Motorola alternator that I found and installed after my original one died taking my coil with it. It is a Transpo M5-197A

Recently, the voltage output has been jumping all over the place, to the point where it drags the A4 down a 100 or 200 rpm with each spike in voltage output. So I took off the regulator, found its adjuster screw nearly wide open and turned the adjusting screw counter clockwise to zero and started cranking it back up in 1/8 turns to get it to put out 14 volts again. I wound up with the adjustment screw pointing to full volume and the voltage bouncing up and down again. So I backed it off 1/8th turn and it is a little more stable, but now is at approx 13.2 or so output with just some bouncing.

I am waiting for a replacement that I just found on Ebay (new old stock) to arrive, but wondered if anyone else on this board has any experience with this type problem? Is it a dead regulator or have I got another issue going on?

[hanleyclifford]

Sometimes other instruments can affect a regulator. I had to move my Transpo V-1500 away from an electric tachometer.

[Borrowed Time]

Thanks Hanley, something to consider. This thing is mounted directly on the alternator where all sorts of electrical activity is going on so I doubt that interference is the issue, but I am not an electrical engineer.

My guess is the adjusting mechanism is dirty or failing. If the thing wasn't fully potted in epoxy, I'd squirt a bunch of contact cleaner in there to see if that affects it.

[hanleyclifford]

Originally Posted by Borrowed Time

Thanks Hanley, something to consider. This thing is mounted directly on the alternator where all sorts of electrical activity is going on so I doubt that interference is the issue, but I am not an electrical engineer.

My guess is the adjusting mechanism is dirty or failing. If the thing wasn't fully potted in epoxy, I'd squirt a bunch of contact cleaner in there to see if that affects it.

Another thing to consider: have you checked the alternator itself for possible diode failure?

[Borrowed Time]

Hadn't thought of that. I assumed (and I know how dangerous that can be ) that when the diodes fail it does not put out any voltage rather than erratic voltage. My new/old regulator should arrive tomorrow. I'll let you know if its replacement solves the problem.

[Dave Neptune]

Borrowed Time, I did some checking on the Transpo M5 197A and it is set at 15V from the factory.

Dave Neptune

[Dave Neptune]

Borrowed Time, I dug out two part numbers for the same alt set to 14.2V : M 207-A " & M 250A and they are the same "housing". I am checking with my sources for either of those. I pulled the back off of mine as I have seen some "high charging" rates. Mine too is the M5-197A..

I'll post what I find out tomorrow.

Dave Neptune

[hanleyclifford]

Hmmm - http://www.moyermarine.com/forums/ar...hp/t-2617.html

[Borrowed Time]

Thanks Dave and Hanley. I did install the new/old regulator yesterday and took the boat out for a trial run. The voltage output was stable with this new regulator. At first I set it to wide open and it consistently put out 14.4 to 14.7 at wide open throttle, 2300 or so RPM. So I dialed it back a quarter turn and it dropped to 13.4 or so. Turned it up another 1/8th turn and got it to where it is putting out 13.9 and occasionally it will go to 14.1 at wide open throttle. Should I be setting it for wide open or cruise at 1800 or so RPM? Will it destroy the batteries if occasionally run at high output?

A related question is whether the alternator has the ability to "sense" when the batteries are fully charged and then drop the output voltage?

I normally run on the house bank, with a 3rd starting battery that is seldom used but is maintained on a trickle charger at the dock. On the house bank, I am running two group 27 12v combo deep cycle/start batteries wired in parallel.

Lastly, is this too much battery for my old 35A motorola alternator to charge?

[hanleyclifford]

Originally Posted by Borrowed Time

Thanks Dave and Hanley. I did install the new/old regulator yesterday and took the boat out for a trial run. The voltage output was stable with this new regulator. At first I set it to wide open and it consistently put out 14.4 to 14.7 at wide open throttle, 2300 or so RPM. So I dialed it back a quarter turn and it dropped to 13.4 or so. Turned it up another 1/8th turn and got it to where it is putting out 13.9 and occasionally it will go to 14.1 at wide open throttle. Should I be setting it for wide open or cruise at 1800 or so RPM? Will it destroy the batteries if occasionally run at high output?

A related question is whether the alternator has the ability to "sense" when the batteries are fully charged and then drop the output voltage?

I normally run on the house bank, with a 3rd starting battery that is seldom used but is maintained on a trickle charger at the dock. On the house bank, I am running two group 27 12v combo deep cycle/start batteries wired in parallel.

Lastly, is this too much battery for my old 35A motorola alternator to charge?

The alternator has no sense at all. It will put out what it can based on how much amperage is being supplied to the field; the regulator decides that based on where you set it. The regulator senses voltage wherever you connect it. Typically this means near alt + and what the batteries are actually receiving depends on the resistance (and losses) between alt + and batt +. This variable is one of the reasons I like external, adjustable regulators. If you want to maintain a specific voltage at batt + that is where you should sense. Alternatively you could just adjust the regulator until you get the desired voltage at batt+ (without regard to voltage at alt +). Whether your batteries are too much for the alternator actually depends more on what users you have. The Motorola could charge 6 batteries but might take all day to do it if you run a fridge and watch TV on the hook.

[ndutton]

Originally Posted by Borrowed Time

TThe voltage output was stable with this new regulator. At first I set it to wide open and it consistently put out 14.4 to 14.7 at wide open throttle, 2300 or so RPM. So I dialed it back a quarter turn and it dropped to 13.4 or so. Turned it up another 1/8th turn and got it to where it is putting out 13.9 and occasionally it will go to 14.1 at wide open throttle. Should I be setting it for wide open or cruise at 1800 or so RPM? Will it destroy the batteries if occasionally run at high output?

A related question is whether the alternator has the ability to "sense" when the batteries are fully charged and then drop the output voltage?

Please check out this link:
http://www.bcae1.com/charging.htm
Particularly the part about voltage regulation. It will answer your voltage questions and clear up some misunderstandings.

Lastly, is this too much battery for my old 35A motorola alternator to charge?

Maybe. It depends on how deeply you discharge your batteries before recharging. As mentioned previously, the stock 35A alternator will charge them up but it may take a while. Here's the problem with a small alternator though: it might be running at full capacity for much of that time and producing full capacity heat in the process. The little cooling fan under the pulley isn't all that great especially at our low RPMs and heat buildup in an alternator spells trouble in your future.

Let's say your battery bank is depleted to a point where it will accept 40A charging current initially. Your 35A alternator will be giving all it's got until the battery bank comes up to a point where less is required. Now, same situation but with a 100A alternator. It will be cruising along easily at 40% of it's output. In the example the bigger alternator can produce the same amperage without all the heat.

[hanleyclifford]

Neil - That is an outstanding link; should be in our "links of particular interest".

[hanleyclifford]

Those of us who cruise and run the engine all day must also consider the matter of voltage variation throughout the system, especially if you run a lot of accessories while under way. It is important over a period of days/weeks/months to ensure your batteries are getting the voltage you want them to have. Detailed and precise information helps you achieve that objective.

[BunnyPlanet169]

Originally Posted by ndutton

Please check out this link:
http://www.bcae1.com/charging.htm
Particularly the part about voltage regulation. It will answer your voltage questions and clear up some misunderstandings.

Let's say your battery bank is depleted to a point where it will accept 40A charging current initially. Your 35A alternator.....

That's a very readable link.

The OP mentioned 2 group 27 batteries. Using nominal data of about 105AH per battery and a nominal max charge acceptance of about C/8, each battery will accept about 13 Amps, or 26A for the system. They will probably only accept this rate of charge when > 30% discharged, and as they come up to voltage, the charge current will drop off.

Neil's point about reserve capacity is well taken, and having a larger alternator for the reason of reducing heat and load is worthwhile. The 35A OEM Motorola was fine for single battery boats as shipped from the factory, but how many of us have single battery boats anymore? The MMI 55A is a nice compromise, anything bigger and you probably need to look at the whole package, including remote smart-charging regulators.

[Borrowed Time]

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?

I should add that I installed a Pertronix EI with a Flamethrower coil, later replaced with one of Don's coils. The flamethrower died shortly after installed two years ago and the MMI coil has run ever fine since.

[BunnyPlanet169]

That sounds perfect to me. I would not turn it up. Where are you measuring voltage?

[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]

Originally Posted by Borrowed Time

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]

Originally Posted by 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.

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.