SAR v3 Charge profile

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SAR v3 Charge profile

Postby boatguy on Wed Feb 16, 2011 12:09 pm

I am trying to drive two Electrodyne 150a @ 24v alternators mounted to a single engine, from a single SAR V3.

The Field and Alt Gnd wires from the SAR are both split and connected to the respective terminals on the Electodyne rectifiers (which are external and approximately 6" away).

When I started charging to test the system I see the Parallel LED is lit which I find odd.

I have previously seen the Parallel LED lit when the shore power charger was active, but it has been shut down for at least 12hrs.

Prior to starting the engine the Status LED was normal (3/3) and no other LEDs were lit.

1) Is splitting the Field and Alt Gnd wire the correct way to drive two alternators?

2) Why is the Parallel LED lit?


I just went through the first charge cycle on this installation. The wiring is fine, but the charge profile was not. The dip switches were set to all ON for the Ample Power Gel setting.

The battery bank consistes of 12x Mastervolt 1,000ahr 2v gel cells for a total of 1,000 ahrs @ 24v. There are two 150a alternators.

- The regulator went almost immediately into Absorption, with a voltage of 28.3. This wasn't a problem as the amperage was still very high and the voltage was probably close to correct after temperature adjustments.

- After just 1.5 hrs of charging, with the battery still absorbing 123a @ 28.2v it moved to Float! The voltage dropped to 26.5v, well below the temperature adjusted target of 26.9, so amperage dropped to just 26a, not worth running the engine.

- Ten minutes later I turned on the shore power charger (Mastervolt 100a charger) and it ran in Bulk for over an hour before moving to Absorption. After an hour and a half of charging the Mastervolt charger was still at 28.2 at the battery was accepting 40a. This is a Mastervolt charger and Mastervolt batteries.

3) Why did the regulator move to Float so early? How can I keep it in Absorption longer?

Thank you.
Last edited by boatguy on Wed Feb 16, 2011 1:57 pm, edited 2 times in total.
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Re: SAR v3 Charge profile

Postby Coulomb on Thu Feb 17, 2011 3:26 pm

The ALT_GND wire from the V3 needs to get back to alternator negative.

The FLD wire from the V3 goes to the field of both alternators, not on rectifiers.

Please read this post. It also has a link to the Primer which is useful.

Finally, you can lock the V3 into Absorption if you want. That's not generally needed if the batteries are absorbing current as expected.

Did you break the batteries in?
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Re: SAR v3 Charge profile

Postby boatguy on Thu Feb 17, 2011 4:41 pm

Sorry for the confusion, the connections (Field and Gnd) for the Electrodyne alternators are on the external rectifiers. Those connections have been made and the alternators are working as they should.

The batteries are 3 years old, they are broken in. They have a capacity of 1,000 ahrs and they were still absorbing 123a when the SAR v3 moved to Float.

I do not wish to lock the regualtor into Absorption, I want it to switch over to Float at the appropriate time, usually when the absorption current falls to below 2-5% of the capacity as suggested in the primer. 123a is obviously way too early to move to Float.

Please advise what should be done so that the regulator will move to Float at the appropriate time.
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Re: SAR v3 Charge profile

Postby Coulomb on Thu Feb 17, 2011 11:32 pm

The Ample Power Gel setting has the least absorption time because it has been designed for batteries that have a high absorption rate during the bulk cycle. If you want a longer absorption time, select thick plate setting.

Generally charging to less that 2-5% is a waste of fuel, so it should be done periodically, not every time.

The V3 is the smartest, and most reliable regulator that can be purchased anywhere in the world. The only device with smarter battery management is the EnerMatic Controller,(, with a price tag that reflects its sophistication.

The V3, with occasional help from the owner, who learns how to use it, is a very functional and effective regulator.
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Re: SAR v3 Charge profile

Postby boatguy on Fri Feb 18, 2011 5:52 am

I agree that getting to 2% is a waste of fuel, over the last 3 years I've found that charging to 5% takes 2.5 - 3.0 hrs and provides about 90% of a full charge. However, I have been using a Balmar regulator and it can't handle the field current so I've burned out 4 units in 500hrs. Ample Power was recommended as product that could handle the field current and provide accurate, temperature controlled regulation.

I am happy to learn how to use the v3, but as far as I can tell the only adjustment I can make (the limit settings are not applicable here) are the DIP switches. I cannot find any information about the charge profiles so I'm left with trial and error to see what each charge profile will do. It takes a couple of days to discharge the batteries, then a few hours to run a test charge cycle. I would like to resolve this quickly so I can transit the canal and prepare for crossing the Pacific. Trying each charge profile setting to find the correct one could take several weeks.

I'm sure you know that gel cells are very sensitive to charge voltage and I am concerned that using the thick plate setting will charge them at too high a voltage. The Ample Power Gel settings were charging at voltages which were quite close to the Mastervolt recommendation so that is working fine. During my first test cycle the voltage rose from 24.5 to 28.0 in the first few minutes and the regulator went immediately to Absorption, even though the Masetrvolt bulk target is about 28.5 (temp compensated). This was not a big problem because the alternators were still at full output for the first half hour (300a less active consumers).

The problem was that they transitioned to Float after about 1.5 hrs and they needed to stay in Absorption about another 1-1.5hrs. And then the Float voltage was about .5v below the Mastervolt spec (temp compensated). We're trying to restore about 500ahrs with 300a of charging source, it's going to take more than 1.5hrs. However, this assumes a particular state of discharge, is the transition to Float based solely on time? If I start up with a more fully charged battery they will need less time in Absorption.

At 25C, Maservolt recommends a Bulk target of 28.8, an Absorption voltage of 28.56 and a Float of 27.6.

Before I purchased the V3 I gave a full description of the batteries and charging system to Ruth and she came back and told me that the V3 and Ample Power Gel setting was the solution. Based on her reply, I purchased two V3's and expected a working solution. Paying an additional $250 to get them to work does not seem reasonable. However, if that is what is required to get this resolved quickly I would consider it.
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Re: SAR v3 Charge profile

Postby Coulomb on Sat Feb 19, 2011 1:48 pm

The primary difference between the Ample Power Gel setting and the Thick plate setting is absorption time.

However, you have now identified the real problem: The batteries.

Please read this from the Primer: You may recognize yourself at the bottom of the article.

If a battery reaches the absorption level in a few minutes, either the battery is full, or it's not accepting current as it should.

Here's the plot of a good battery under charge. Notice how slow the voltage rises during the bulk charge portion of the curve. Notice how steeply the current declines after reaching the absorption voltage.

This plot courtesy of the book "Living on 12 Volts with Ample Power".

How did the batteries go bad in only three years? Batteries that are chronically over discharged and then not charged appropriately can fail in a few months or less.

chrg8_all_rot.jpg (42.87 KiB) Viewed 3999 times
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Re: SAR v3 Charge profile

Postby boatguy on Sat Feb 19, 2011 4:06 pm

Why do you say my batteries are bad? They are accepting a charge and holding the charge.

I charged them on Friday, and when the V3 switched to Float they were still accepting 123a so I shut down the engine and ran the shore power charger to give them a full charge. Here is the charge profile in table form. The columns are time, voltage, amperage, ahrs, ahrs added and elapsed time. The ahrs counting is never accurate so you can ignore it. You can see where the V3 dropped to Float at 11:20 while the batteries were still accepting 123a. The shore power charger is only 100a so it took another 1.25hrs to charge them enough to get down to 5% of capacity (1,000 ahrs).

9:45 24.54 298 -504 0m
10:00 28.37 288 -440 64 15m
10:15 28.32 224 -381 123 30m
10:30 28.34 191 -334 170 45m
10:45 28.24 160 -294 210 1h
11:00 28.20 140 -262 242 1h 15m
11:15 28.20 123 -231 273 1h 30m
11:20 27.50 80 -222 282 1h 35m
11:25 26.53 26 -219 285 1h 40m

11:45 27.89 95
12:00 28.10 90
13:00 28.20 47 -124

I then ran the 110v air conditioner from the inverter (35a @ 24v) all day yesterday and half the night so I could run another test today (Saturday). I charged them again today with the ABS hold on. Here is the charge profile from today with the ABS hold, without the ahrs columns.

12:03 24.47 307 0m ABS Hold is ON. Regulator indicates Absorption.
12:15 27.97 290 12m
12:30 28.25 280 27m
12:37 28.15 244 34m Alternator down shifted to 28.15, presumably the temp increased. I could hear the load coming on/off as it was switching back and forth from 28.25 to 28.15, then settled on 28.15. I dropped the RPMs to 1700 with no change in amps.

13:00 28.18 195 57m Dropped to 1600 after these measurements.
13:30 28.18 145 1h 27m Dropped to 1500 after these measurements
13:47 28.20 1h 44m Batt temp measured at 100F, voltage is too high! Shut down engine.

I was concernd the voltage was too high with a battery temp of 100F. I shut it down, then started up the Mastervolt charger to see what it would do. It's Absorption voltage was about the same as the V3. Both have temp sensors and while they are both high compared to what the specs say, they are at least at pretty much the same voltage.

** Shore power charger
13:50 27.60 91 Bulk
13:55 27.78 90 Bulk
14:00 27.88 92 Bulk
14:12 28.07 88 Bulk
14:22 28.08 73 Absorption - batt temp is 103F. Voltage should be more like 27.7!
15:15 28.15 15 Absorption
15:35 28.15 8 Absorption - batt temp is still 102F.
15:41 Charger OFF

I then wanted to test the V3 to see how it would move to Float. I started the engine up again and here is the profile. As you can see, and I'm sure as you expected, it moved to Float.

** Engine
16:00 25.75 Start engine with ABS Hold ON.
16:05 28.37 10 Remove ABS wire, Hold OFF. Regulator indicates Step to Float (1/6)
16:10 26.90 4
16:15 26.65 3 Regulator indicates Float (2/2) - Engine OFF

So now it's clear that if I install a switch on the ABS Hold wire, I can have two step regulator that is manually controlled. Not exactly what I want, but it will work.
Today I tried the Thick Plate profile. It moved to Absorption almost immediately, even though the voltage was only 28.1 and the temp adjusted target was 28.6 Then it stayed in Absorption longer than the Ample Gel profile, but the voltage is consistently .3 - .4v higher than it should be. The table below is time, voltage, current, comments.

11:30 24.74 303 Program set to Thick Plate (off/off/off)
11:35 28.10 299 Regulator is in Absorption - 11:42 batt temp = 86F
12:00 28.50 217 Batt temp = 87F: 12:13 move to 1600rpm
12:30 28.33 140 Batt temp = 95F - absorption should be at 28.0
13:00 28.35 71 Batt temp = 98F - absorptoin should be 27.8
13:15 28.38 28 Batt temp = 100F - absorption should be 27.8
13:20 28.38 22 Shut down

Is there a profile that will hit the right voltages, but stay in absorption long enough to charge a 1,000ahr battery bank?
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Re: SAR v3 Charge profile

Postby Coulomb on Tue Feb 22, 2011 7:05 pm

The regulator is working as it is designed to work. That is, charge batteries full without excessive overcharge. It will not work for batteries that have be abused. Your batteries do not charge like good batteries. If you compare their charge profile to the graph that was posted you will see the differences.

A profile to try has been suggested. It wll spend about the same time in absorption as the Mastervolt charger, which is way too long for gel batteries. BTW, the batteries may have a Mastervolt label on them, but most certainly were not made by them.

Gel batteries are not sensitive to over voltage any more so than other batteries. It's the time spent at over voltage that is the killer, on liquid, AGM, or gel batteries. If you boil the water out of liquid batteries, it can be replaced, but the damage is still there.

You would be well served by reading the book, "Living on 12 Volts with Ample Power" so that you gain some real battery knowledge. This forum is for support issues, not here to spoon feed information to those who won't take the time to learn it otherwise.
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Re: SAR v3 Charge profile

Postby boatguy on Wed Feb 23, 2011 5:30 am

It doen't matter who makes the batteries, anymore than it matters who makes the chips in the V3. They sell them, they offer the warranty, and they stand behind the product. It seems to be a very successful company, even with "dumb" products - I wonder what they're doing right?

The Mastervolt charger will not move out of Absorption until it's output is less than 5% of it's capacity (i.e, 5a). If the current consumption on the boat is more than that, it gets stuck in Absorption because it doesn't know where the current is going and isn't smart enough to talk to use the information from their own monitor and shunts. I have to shut down the air conditioner when on shorepower to get the consumption down, and thus the current from the charger, to get it to move to Float.

The point of the data is that the battery is accepting current, bad batteries don't accept a charge and they certainly don't provide 500ahrs of power before they need to be charged again.

It takes me 2-3 days to try a suggested profile, to discharge the batteries, and then run my engine with no load for 3 hrs. If you'd publish a little bit of information about your product you wouldn't have to spend so much time offering customer support and I wouldn't have to run my engine for as many hours just to try to figure out which of your profiles might work.

It must be very frustrating for you to be the smartest guy in the universe surrounded by all these stupid customers on whom you depend to make a living.

I'll make you a deal, I'll read your Primer, if you read this book: Customer For Life by Carl Sewell

If you agree, Ruth has my shipping and billing information and I will pay for "Customer for Life" and have it shipped to you.

I don't doubt that the regulator is working correctly, but it's still holding the voltage .4v higher than is recommendedIf which as you point out "is the killer". Is there a profile that won't kill my batteries?
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Re: SAR v3 Charge profile

Postby Coulomb on Wed Feb 23, 2011 1:01 pm

The U.S. Government spent a few hundred thousand dollars to discover that gel batteries should be charged at a higher voltage than recommended by the manufacturers - the guys at Sandia labs could have just read the book, "Living on 12 Volts with Ample Power" and saved the money. How many millions of dollars are wasted on batteries because people don't take the time to learn how to deal with them.

As I said, it's not the high voltage that is the killer, it's the time spent at the higher voltage that kills them. You want to spend more time there.

It takes about 5 minutes to get a charge profile after the regulator reaches absorption or there abouts. Activate the ABS input, wait a few seconds and record the battery voltage. Remove the ABS input and let the battery voltage step down to float over a few minutes.

Why is it you'll put up with a dumb charger that will most certainly cook your batteries if you don't turn of some loads, but you don't want to deal with a regulator that purposely avoids overcharge by occasionally putting it in ABS?

The book you need to read is "Living on 12 Volts with Ample Power".
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