I have an "auto Mac alternator control" on 1989 cat 30 I recently bought. I read the instruction manual but haven't used for fear of blowing out the alternator. Has any one used one of these things? If so is it OK? MIke Conway
auto mac alternator control
- Thread starter cpconway4@msn.com
- Start date
- Status
Yes, here is what I wrote about operations. You should also read about the care and feeding of batteries and understand clearly how they work with charging sources. Try the Ample Power Primer, tech tab here: www.amplepower.com
June 3, 2000 Updated: November 7, 2009
Here is the Automac manual and Aquavite’s wiring diagram link is found in Reply #23 at http://c34.org/bbs/index.php/topic,4623.15.html!
The trick with the Automac is to use it manually just like the three stage chargers do automatically. Start with the rheostat turned down and the switch off. When your engine starts, the alternator is going to want to put out as much as it can because it sees the batteries need to be charged (unless you’ve just disconnected your shorepower and the batteries are fully topped off.) Don’t turn the Automac on just yet; you don’t want to immediately load your alternator. In fact, the amperage output may be pretty high to begin with, all by itself. Wait until the amperage goes down a bit after you start the engine.
After the initial startup, say about five minutes, and only after you’re running the boat at cruising speed, start the Automac. The reason you want to wait until you’re motoring at cruising speed is simply to avoid having to constantly change the Automac settings, which change at different engine, and therefore, alternator RPMs.) Turn the switch on with the rheostat still turned all the way down. What you (personally – so much for “Auto…”) need to do is balance the voltage and the amperage. The volts should be on your electrical panel, or have a voltmeter connected to the batteries. Slowly turn the rheostat up until you get to 14.0 to 14.2 volts on the voltmeter. As you are doing this, both the voltage and amperage will be rising. Watch the amperage rise. Do the voltage adjustment first and watch the amps rise in this order for this reason: the Automac will automatically shut off if you exceed the preset (but adjustable) voltage setting. The adjustment on the Automac is most likely set for 14.2 or 14.4 volts. [The manual includes instructions as to how to adjust it. Don’t bother with this yet, and you may likely never have to.] So, the trick is to set the Automac based on voltage, with the resultant rise in amperage. Don’t set the amperage first, because the voltage rise may cut it out automatically.
So let’s say your batteries need to be charged. Run the Automac to maximize the charge amperage starting with the 14 point something voltage. You will see that the Automac raises the amperage once you reach that voltage. To see the effects, turn the AutoMac on and set it, then turn the switch off. You’ll see the amps drop and the voltage, too. Then switch it back on! What it is doing is “fooling” the alternator’s output signal and increasing the amperage. The trick to charging batteries is balance BOTH the voltage and amperage.
As the batteries get charged while you are motoring, the voltage will continue to rise because of the “inflated” amperage you are giving them thru the Automac. You’ll need to keep checking and slowly turn down the rheostat to keep the voltage near 14. This will reduce the amperage, too. Do it or else the Automac will turn itself off as the voltage rises above the preset 14.something volts. That’s why the three stage chargers are better because you don’t have to continually manage the charge.
Once you’re fully charged, don’t forget to turn the Automac switch off. It draws 2 amps whether the engine is on or off. Doesn’t matter what position the rheostat is in, but I got in the habit of turning it counterclockwise and off as a matter of habit. Have fun, any questions, let me know.
You can email me from this message board and I'll send you a PDF of original AutoMac manual.
June 3, 2000 Updated: November 7, 2009
Here is the Automac manual and Aquavite’s wiring diagram link is found in Reply #23 at http://c34.org/bbs/index.php/topic,4623.15.html!
The trick with the Automac is to use it manually just like the three stage chargers do automatically. Start with the rheostat turned down and the switch off. When your engine starts, the alternator is going to want to put out as much as it can because it sees the batteries need to be charged (unless you’ve just disconnected your shorepower and the batteries are fully topped off.) Don’t turn the Automac on just yet; you don’t want to immediately load your alternator. In fact, the amperage output may be pretty high to begin with, all by itself. Wait until the amperage goes down a bit after you start the engine.
After the initial startup, say about five minutes, and only after you’re running the boat at cruising speed, start the Automac. The reason you want to wait until you’re motoring at cruising speed is simply to avoid having to constantly change the Automac settings, which change at different engine, and therefore, alternator RPMs.) Turn the switch on with the rheostat still turned all the way down. What you (personally – so much for “Auto…”) need to do is balance the voltage and the amperage. The volts should be on your electrical panel, or have a voltmeter connected to the batteries. Slowly turn the rheostat up until you get to 14.0 to 14.2 volts on the voltmeter. As you are doing this, both the voltage and amperage will be rising. Watch the amperage rise. Do the voltage adjustment first and watch the amps rise in this order for this reason: the Automac will automatically shut off if you exceed the preset (but adjustable) voltage setting. The adjustment on the Automac is most likely set for 14.2 or 14.4 volts. [The manual includes instructions as to how to adjust it. Don’t bother with this yet, and you may likely never have to.] So, the trick is to set the Automac based on voltage, with the resultant rise in amperage. Don’t set the amperage first, because the voltage rise may cut it out automatically.
So let’s say your batteries need to be charged. Run the Automac to maximize the charge amperage starting with the 14 point something voltage. You will see that the Automac raises the amperage once you reach that voltage. To see the effects, turn the AutoMac on and set it, then turn the switch off. You’ll see the amps drop and the voltage, too. Then switch it back on! What it is doing is “fooling” the alternator’s output signal and increasing the amperage. The trick to charging batteries is balance BOTH the voltage and amperage.
As the batteries get charged while you are motoring, the voltage will continue to rise because of the “inflated” amperage you are giving them thru the Automac. You’ll need to keep checking and slowly turn down the rheostat to keep the voltage near 14. This will reduce the amperage, too. Do it or else the Automac will turn itself off as the voltage rises above the preset 14.something volts. That’s why the three stage chargers are better because you don’t have to continually manage the charge.
Once you’re fully charged, don’t forget to turn the Automac switch off. It draws 2 amps whether the engine is on or off. Doesn’t matter what position the rheostat is in, but I got in the habit of turning it counterclockwise and off as a matter of habit. Have fun, any questions, let me know.
You can email me from this message board and I'll send you a PDF of original AutoMac manual.
thanks--auto nac
stu...Thanks for the clear & concise response. Following the step you mention does it take how many hours to recharge the batteries, at let say, only 50% charge....Mike
stu...Thanks for the clear & concise response. Following the step you mention does it take how many hours to recharge the batteries, at let say, only 50% charge....Mike
Well, cap, that depends on a LOT of things. How big is your house bank? How discharged is it? And, how big is your alternator? also, what do you have running while you are charging with the alternator (i.e., nothing during daylight or a fridge, all running lights at night, etc. All of those will factor into how long it will take. It's like speed, time & distance: level of discharge, load, input and time.
As you most probably already know, you shouldn't discharge your banks more than 50%, so recharging your banks "only 50% means from 50% to 75%. As you may also know, the last 10 to 15% of charge is the hardest to get into a bank because of battery acceptance, so going from 50% to 75% to 80% is the most efficient use of your alternator for charging. The last 15% should be done with shorepower or solar.
Here's a discussion of battery acceptance:
We've had some discussions about battery acceptance (search on "acceptance") in the past. I thought it might be helpful to describe just what happens, step-by-step when charging after, say, a simple day sail.
The battery acceptance drops off the ability to recharge, to an incredibly low rate of charge as the bank gets fuller and nearest to full. Many times, now based on my Link 2000 experiences, it takes almost overnight to fully recharge a bank.
What goes OUT of your house bank becomes easy to learn from the Energy Budget previously discussed and posted. It's what goes back IN that most people are missing, and relates to the state of charge of your house bank in a very direct manner.
What I've seen, for example is this, from our Link 2000:
--- Return from a day sail, bank is down 15 amp hours, plug into shore power with our 75 amp charger, batteries will only ACCEPT 15 amps (360 AH house bank, they're pretty fully charged if only 15 ah down)
--- Most people will then assume that it will take an hour to replace the 15 amp hours at 15 amps of charge
--- NOT!
--- As the batteries absorb that 15 amp charge, they get fuller
--- The charge RATE goes down to 10 amps after 15 or 20 minutes and the bank is now down to 10 amp hours down
--- Now, it should only take another hour to charge those minus 10 amp hours at 10 amps -- wrong assumption again; we're now up to an hour and twenty minutes to fully charge, right?
--- NOT again, because this keeps recurring
That's why a full charge takes a LOT longer that most people expect.
What goes OUT is easy, what goes BACK takes MUCH, MUCH longer. That last 15% to 20% takes a long time because of the REALITY of battery acceptance.
Please believe me, folks, because I see this all the time now that I have the Link 200 installed and working.
Please note that this true with alternators as well as shorepower chargers. Battery acceptance usually "rules" the charging regimen, so even with 100A alternators or shorepower chargers in excess of 40 A, the battery acceptance will determine the amount of charge that can go back into a house bank, usually around a max of 50A for a 400 ah bank. And it "tapers off" as the bank gets fuller as noted above.
This is why people say the BEST investment for un-knowledgeable and knowledgeable skippers alike is to buy a battery monitor FIRST. Wish I did, because I'd been chronically UNDERCHARGING my house bank, even after all the spouting I do here and on other forums!
Please, believe it!
For a parallel discussion of how much comes OUT, please see the Energy Budget topic, here: http://c34.org/bbs/index.php/topic,3976.0.html
As you most probably already know, you shouldn't discharge your banks more than 50%, so recharging your banks "only 50% means from 50% to 75%. As you may also know, the last 10 to 15% of charge is the hardest to get into a bank because of battery acceptance, so going from 50% to 75% to 80% is the most efficient use of your alternator for charging. The last 15% should be done with shorepower or solar.
Here's a discussion of battery acceptance:
We've had some discussions about battery acceptance (search on "acceptance") in the past. I thought it might be helpful to describe just what happens, step-by-step when charging after, say, a simple day sail.
The battery acceptance drops off the ability to recharge, to an incredibly low rate of charge as the bank gets fuller and nearest to full. Many times, now based on my Link 2000 experiences, it takes almost overnight to fully recharge a bank.
What goes OUT of your house bank becomes easy to learn from the Energy Budget previously discussed and posted. It's what goes back IN that most people are missing, and relates to the state of charge of your house bank in a very direct manner.
What I've seen, for example is this, from our Link 2000:
--- Return from a day sail, bank is down 15 amp hours, plug into shore power with our 75 amp charger, batteries will only ACCEPT 15 amps (360 AH house bank, they're pretty fully charged if only 15 ah down)
--- Most people will then assume that it will take an hour to replace the 15 amp hours at 15 amps of charge
--- NOT!
--- As the batteries absorb that 15 amp charge, they get fuller
--- The charge RATE goes down to 10 amps after 15 or 20 minutes and the bank is now down to 10 amp hours down
--- Now, it should only take another hour to charge those minus 10 amp hours at 10 amps -- wrong assumption again; we're now up to an hour and twenty minutes to fully charge, right?
--- NOT again, because this keeps recurring
That's why a full charge takes a LOT longer that most people expect.
What goes OUT is easy, what goes BACK takes MUCH, MUCH longer. That last 15% to 20% takes a long time because of the REALITY of battery acceptance.
Please believe me, folks, because I see this all the time now that I have the Link 200 installed and working.
Please note that this true with alternators as well as shorepower chargers. Battery acceptance usually "rules" the charging regimen, so even with 100A alternators or shorepower chargers in excess of 40 A, the battery acceptance will determine the amount of charge that can go back into a house bank, usually around a max of 50A for a 400 ah bank. And it "tapers off" as the bank gets fuller as noted above.
This is why people say the BEST investment for un-knowledgeable and knowledgeable skippers alike is to buy a battery monitor FIRST. Wish I did, because I'd been chronically UNDERCHARGING my house bank, even after all the spouting I do here and on other forums!
Please, believe it!
For a parallel discussion of how much comes OUT, please see the Energy Budget topic, here: http://c34.org/bbs/index.php/topic,3976.0.html
- Status