AGMs and Dumb Regulator . . .

[Maine Sail]

Tried to upload the video to YouTube but the video is 1.9GB and they only allow 1GB max file size. IF anyone knows a way to shrink a video before uploading please let me know? I shot it uninterrupted for the length my camera allows and now the file is too big.

[goboatingnow]

Originally Posted by stevensuf

Oe advantage of agms many people apear to miss is the fact that they have a lower internal resistance compaired to normal lead acids, so you can save about 10-15% in charging time.

Not really. They have theoretical higher acceptance charge currents but in a typical battery bank you can't generate that high a charge feature. It's another example of a AGM feature that's not applicable

[btrayfors]

Originally Posted by goboatingnow

Not really. They have theoretical higher acceptance charge currents but in a typical battery bank you can't generate that high a charge feature. It's another example of a AGM feature that's not applicable

I believe stevensuf was referring to the charge efficiency of AGMs rather than their charge acceptance capability.

It is true that AGMs have a much higher charge efficiency (approaching 96-98%) than do either flooded or gelled lead-acid batteries. This means that less of the available charging current is lost (by converting to heat) and, therefore, more of it goes into charging the battery.

This is from von Wentzel:

Quote
The higher charge efficiency of AGMs allows you to recharge with less energy: Flooded cells convert 15-20% of the electrical energy into heat instead of potential power. Gel-cells lose 10-16% but AGMs as little as 4%. The higher charge efficiency of AGMs can contribute to significant savings when it comes to the use of expensive renewable energy sources (wind generators, solar panels, etc.) as your charging system can be 15% smaller (or just charge faster). Unquote

This is from the Northern Arizona Wind and Sun website:

Quote
Battery Internal Resistance Losses

Losses from internal resistance shows up as heat, which is why batteries tend to get warm when heavily charged or discharged for a while.
Internal resistance losses in standard flooded Lead-Acid batteries is usually around 10% to 15% for a new battery, and can be as high as 25%+ for older batteries. This can vary considerably, depending mainly on the age and quality of the battery. In general you get what you pay for - cheaper batteries with thinner plates and internal connections tend to be less efficient.
Gel batteries are better at approximately 12% to 16% internal resistance so would require around 115 amp-hours of charge for every 100 amp-hours used.
Concorde AGM has the lowest internal resistance of any commercial battery that we know of - only 2 percent in a new battery. In solar electric systems, this is the same as getting an extra 10 to 15% out of your panels. This also allows Concorde AGM batteries to be charged much faster if needed and also to deliver higher currents when required. Owners using high output alternators, operating inverter banks, or relying on solar panels can benefit significantly when using Concorde Advanced AGM batteries with their equipment. Concorde AGM's are more efficient.
Heat: Better efficiency means much less heat is developed in the batteries - any current that does not actually go to charging a battery turns into heat. That is why some batteries, especially older flooded batteries (and even some non-deep cycle AGM), can get very warm or even hot. In extreme cases you can get " thermal runaway", which can be dangerous. If you have ever felt the side of a battery under heavy charge, you have probably seen that they can get very warm.
Concorde batteries far exceed the US Coast Guard test for thermal runaway: These MW-SPEC (Military Specification) tests involve fully charging a battery, heating it to over 130 degrees (Potential Thermal Runaway Conditions) and then overcharging the battery to simulate a shorted cell. (16V for a 12V battery).
Unquote
Bill

[Target9000]

Originally Posted by Maine Sail

Tried to upload the video to YouTube but the video is 1.9GB and they only allow 1GB max file size. IF anyone knows a way to shrink a video before uploading please let me know? I shot it uninterrupted for the length my camera allows and now the file is too big.

If your camera records the file in .AVI format it may be very big. If that is the case the easiest way to "compress" it would be to convert it to MPEG. There are many free utilities in the wild that allow you to do this.

[FlyingCloud1937]

For the record,

Automotive alternators/regulators were never designed to be battery chargers, especially in the sense of large house battery banks. Their design purpose is was to replace the small amount of amps removed while starting, then produce assessor power for on-board needs, on-board an auto that is, AKA...SLA starting, lights & accessory.

Their duty cycle design never intended to be 100% out-put, 100% of the time. With every new alternator comes an instruction sheet, that alerts you to recharge the battery before install of the alternator.

The early alternators used external mounted buzz coil regulators, which maintained set voltage, these were adjustable to some extent. Then came discrete component regulators, still externally mounted, their voltage was factory set, and not adjustable. These regulators were typical of 14.5-15 volts, I've even seen some of these go above 16 v. The batteries were open vent flooded SLA batteries. Because of the high voltage setting the batteries used a lot of water. Every time you filled up at the gas station the attendant, checked the radiator, oil, wiper fluid, battery water, and washed your windshield.

As on-board power requirements became greater, larger alternators, with internal regulators were installed by the auto manufactures. This resulted in shorter life of the batteries, because of boiling. In the 80's the auto manufactures started switching to maintenance free batteries, that's also when gas stations stared with, you pump your own gas.

A maintenance free battery was and is just smoke and mirrors. It's just the same flooded SLA, open vented battery, just without removable caps. So you can't and don't need to add water. How did they not boil the battery? They lowered the voltage out-put of the alternator and regulator to 14.1 to 14.4, flooded batteries don't gas below 14.3 V. With the associated voltage drop of the charge wire from the alternator and the bat cables the voltage at the battery ranged between 13.8 & 14.2 V. This also accomplished another goal of protecting on-board halogens lights, and the computers that started showing up. These regulators are either on or they're off, their goal is to maintain the set voltage. They are not battery chargers. A very select few of these newer regulators have a voltage set pot.

Next,

Most large house battery banks die an early death due to sulfation, as a result of chronic under-charge. FLA's really want to charge at 14.8, and AGM's want be charged at 14.4, GEL's at 14.1 V. If you maintain these voltages past absorption you will kill the bats early from chronic over-charge, or positive grid plate corrosion. FLA's will use a lot water, AGM's will vent, and you can't replace that water, GEL's will also vent, and dry out.

In reality large battery FLA's and AGM's will not be able to produce their C/20 rated amp hr until about 20 discharge/charge cycles. A good installer will initiate a commission cycle, as well as make sure you have proper charging capabilities to meet the battery needs.

What is a commission cycle? After the bank is installed the bank is discharged at the C/20 rated amps to 11 Volts, then a full charge through absorption into float, this is done times 2 cycles. This does 2 things. 1. it allows the installer to determine the length of time to hold the bank in absorption. 2. It conditions the plates so the whole surface area is capable of producing current by chemical reaction. The last step of this condition cycle is a equalization cycle, which balances all the cells in the bank. A good installer will hand over the a chart log of each bat in the bank with each cell listed.

This chart will have documented all bats voltage, and each cells SPG. The chart will document the same before install as received from the manufacture. Then the volatge, and SPG at the end of each discharge cycle before re-charge, and at the end of each charge cycle. The end of charge cycle voltage and SPG is measured after a 24 hr rest. It will also include the time and hourly readings of voltages, and each cells SPG during the equalize session. This session is determined by the bank readings, not some preconceived time. The bank is ready for service when the 24 hr rest voltage meets the manufacture stated voltage and all cell SPG readings are in balance.

This commission chart will be your road map to maintaining the battery bank. A 24 hr resting voltage, and each cell's SPG should be taken and entered into the chart once a month for the first 2 months of the new bank. It will alert you to the need of adjusting the absorption time, as well as cell balance issues that result from cabling issues. Depending on the number of discharge cycles I recommend this be done once or twice annually there after.

Most battery banks don't die of old age, they are murdered in the prime of their life. Some a slow death, and others a quick one.

A battery bank installed with out the above process, and proper charge regime will usually start sulfating before the the first 20 discharge cycles, and will never reach the manufacture amp hr rating. How do I know this? Dozens of on-board inspections of 1-2 year old battery banks. That the owner complains I got a bad batch of batteries.

A dumb regulator isn't really dumb, it's just doing the job it was intended to do. That job is to maintain voltage, and provide for the on-board accessory current needs. It doesn't know the difference between bulk, absorption or float. The battery acceptance rate has little to do with how a dumb regulator works, and does it's job. Sure it can be pressed into service to do a job it was never designed to do. But it will be at the costs of the battery bank.

Again most battery banks are murdered, either from improper charge regime, or neglect. Whether FLA, AGM, GEL, or Li all banks need the proper care to reach their potential. If your bank under performs, and or dies a short life, don't blame the battery...look at the charge/maintenance regime.

Lloyd

[Target9000]

Sounds expensive.

[hellosailor]

MaineSail-
"Can you or someone please explain in detail, electrically, how this happens? "
No, I can't. Although I can tell you that the older Delcotrons were all pulse width modulated output (PWM) 14.3-14.4 VDC, never varying the voltage but using the feedback from the SENSE LEAD (often disconnected or tied back on boats) and reading battery voltage with that.
The process is that the alternator puts out a string of 14.4VDC pulses, and in between the pulses it reads battery voltage. If battery voltage is low, it puts out pulses something like 1000x per second (1000Hz output) and if voltage if high that may drop to 100Hz, with each pulse being of the same power. So a DC meter will read "14.4" all the time, but the battery may be seeing 10x more power when the Delcotron sees low battery voltage.
The newer alternators from the (two now) Delco companies may no longer use this logic, I present it simply to show you that the charing power may vary while the voltage APPEARS to be the same. And if the sense lead has been tied back to the output in typical "built to a price" fashion, all bets are off.

Since you've seen different results with newer products (and I'm assuming you ran them with the sense lead connected? and you've run them for at least ten minutes, so they could heat up and engage whatever thermal sensors they had, etc. in a realistic scenario?) it could well be they've done something different in recent years. FlyingCloud's post seems to indicate they've changed targets to suit those sealed wet lead batteries, if that's so that would make them doubly unsuitable for other uses.

The constant and consistant explanation of "automobile" alternators with integral regulators that I've seen from so many sources and authors always says the same thing, that the alternator "throttles back" as battery voltage rises, putting out less amperage to the battery. I suppose the way to get to the bottom of this would be to contact a couple of alternator makers directly and refer to specific products. And of course to see what happens when the product is intentionally misused by failing to run the voltage sense lead to the battery, and bank switch it as needed.


On videos, I'd suggest resizing the image (smaller) or the resolution (UTube doesn't need much, even 1/4 VGA is enough sometimes for the small viewing size at limited bandwidth) or splitting it into two.


On AGMs and charging...IIRC because there is no liquid electrolyte in AGMs, there is no problem of bubbling as the charging occurs, and there is no problem of uneven electrolyte distribution (from the heat and bubbling and electrolyte trying to move around and circulate evenly) so the charging characteristics remain closer to "steady state" compared to a liquid filled battery.

Are they overpriced? Probably. Are they different? Certainly. Meanwhile we wait to TPPL to sneak up and take over the market. Or something.<G>

[stevensuf]

yeah sorry btrayfors, i did mean 10-15% more efficient in charging,

My reasons for agms are,
1 in my battery space for the house batteries i can only manage 360AH of LA ,but 440AH of AGM.

2 No topping up, finding distilled water.

3 10-15% less wastage in charging

4 No freezing issues (it gets cold here in scotland)

5 less self discharge

By using MPPT regulation and AGMS i should see a good 20-30% AH or more, going into my house bank each day , reducing the space required for the solar, lowering
weight below and more so aloft.

Well a trip to the electronics store today saw me come back with a 80amp current sensor (6 uk pounds) a 70 amp auto relay (8 uk pounds) a a 5v regulator (0.5 uk pounds) (the current sensor is 5v power) a 2 amp transistor (0.8 uk pounds) a potentiometer (variable resistor) (1 uk pounds) 2 small fixed resistors (1 uk pounds)

This will make a very simple circuit wherby the output of the current sensor controls the on/off of the transistor , which enables the relay, In simple terms, i can adjust the variable resistor to switch on the relay at any current level i wish.

The charging cable from the alternator goes via the current sensor , the output of the current sensor goes via the potentionmeter controlling the on/off of the relay via the transistor.

Ok In laymans terms i can automatically cut off the charging from the alternator to the batteries at any current level i wish ,therefore avoiding proglonged over charging of the batteries by the dumb regulator.

[Maine Sail]

Originally Posted by hellosailor

MaineSail-

The constant and consistant explanation of "automobile" alternators with integral regulators that I've seen from so many sources and authors always says the same thing, that the alternator "throttles back" as battery voltage rises, putting out less amperage to the battery.

I suspect this comes from what people "see" or saw happening. That is, you start the car and the battery is still at near 100% SOC so the voltage quickly rises to the regulators set point and the in-rush current begins to "taper" quickly due to battery acceptance, not the regulator cutting back. I suspect this "tapering" caused by trying to charge an already full battery is where this "understanding" comes from. I can repeat this same scenario with a smart regulator too. Heck we still have people who won't leave batteries on a concrete floor.. The regulator regulates the voltage the battery is regulating how much current will flow. Even fancy Balmar regulators don't know "current" this is why the absorption phases are timed and not based on what the actual current flowing to the battery is..

Originally Posted by hellosailor

I suppose the way to get to the bottom of this would be to contact a couple of alternator makers directly and refer to specific products. And of course to see what happens when the product is intentionally misused by failing to run the voltage sense lead to the battery, and bank switch it as needed.

I have talked with a few manufacturers to get to the bottom of this, Leece-Neville being one. Per these conversations it seems the only time these regs cut back the field, or shut it off, is when they sense an over temp situation. The reality is that very few even have this feature or have any temp sensing abilities at all.

Some external reg manufacturers claim their field voltage is higher so they could drive two alts but when every dumb reg I have tested has the ability to drive the alts to their rating what sense is a higher field voltage in bulk?

Originally Posted by hellosailor

On videos, I'd suggest resizing the image (smaller) or the resolution (UTube doesn't need much, even 1/4 VGA is enough sometimes for the small viewing size at limited bandwidth) or splitting it into two.

I am going to try and figure that out. My camera shoots in .mov...

Originally Posted by hellosailor

On AGMs and charging...IIRC because there is no liquid electrolyte in AGMs, there is no problem of bubbling as the charging occurs, and there is no problem of uneven electrolyte distribution (from the heat and bubbling and electrolyte trying to move around and circulate evenly) so the charging characteristics remain closer to "steady state" compared to a liquid filled battery.

Are they overpriced? Probably. Are they different? Certainly. Meanwhile we wait to TPPL to sneak up and take over the market. Or something.<G>

Yeah, I was an early adopter of AGM technology and got a lot of arrows in my back and a lot of unhappy customers who got less than 4 years out of a set of Lifeline's, before they said you could equalize/condition them.. I have a few customers with TPPL but the oldest bank is only on year three. I am waiting cautiously to see how they do out towards 5,6 & 7 years. Their cranking amp capacity is simply amazing....

[Maine Sail]

Originally Posted by stevensuf

Ok In laymans terms i can automatically cut off the charging from the alternator to the batteries at any current level i wish ,therefore avoiding proglonged over charging of the batteries by the dumb regulator.

Just be sure you are cutting the field before cutting the B+/alt output or you could have some toasted diodes...

[FlyingCloud1937]

Dumb regs, can't temp compensate a battery charge voltage.

10 degrees can effect the state of charge, 20 degrees is really bad.

Voltage doesn't charge batteries current does.

I don't know of any dumb regs that temp protect the alternator.

It is normal for human to error, the biggest human error is to chose the wrong tool/ machine for the job.

A well built smart reg has MTBF of over 20 years, that's about 4 battery banks. A $275.00 smart regulator works out to be $68.00 dollars per bank over 20 yrs time. That in turn works out 5.1% of one average bat bank costs. Over the life of the regulator or 4 battery banks that less then 1% for smart regulation.

A well designed charge system will pay for it's self in battery savings.

Lloyd

[hellosailor]

Maine-
" Heck we still have people who won't leave batteries on a concrete floor.."
Well there you go, justification for AGMs. You know, battery acid can mess up that concrete, the heck with the battery. Floors make batteries look cheap!

I've only used up one deep cycle AGM. that was in light deep cycle use, not on a boat, but it took eight years to use it up. Eight years with no acid burns on anything, which is my main disagreement with wet cells. I think of wet cells like the Blessing for the Czar, from Fiddler on the Roof: "May God bless and keep the Czar! Far away from us!"

And I'm still looking for Reddy Kilowatt, who promised us all home nuclear piles by the 70's or 80's. Like Ricky Ricardo said to Lucy, he got some 'splainin' to do!

[Marqus]

Good discussion - appreciate reading the interesting stuff from Stevensuff, MaineSail, Hellosailor, Btrayfors, Flyingcloud and others.

I know the question below is not strictly the topic, but since we have moved into discussing the details of Alternator Regulators I will ask it here:

*** What will happen if you charge your lead-acid battery bank via an alternator, and the ONLY control you apply is Battery Temperature?

Thus, as the battery's temperature rises, a simple electronics circuit cuts back the alternator Field Current, gradually bringing down the charging voltage to ensure the battery temperature stays within limit.

What will happen? Will the battery be fully protected from damage?

Obviously, we can analogously monitor the alternator housing temperature, and reduce the same field current to protect it. But, if we may just focus on the Battery Temperature in this hypothetical scenario (assume a super-cooled alternator), do you really need to do anything more than the Temperature-to-Field Current mediation to protect the battery?

One possible problem could be ambient temperature when you're in the tropics, but then, high temperature may be a contra-indication for batteries irrespective of whether it arises from charging or external heating sources. So if the battery is hot, cut down on charging without asking how it got hot.

[FlyingCloud1937]

Originally Posted by Marqus

Good discussion - appreciate reading the interesting stuff from Stevensuff, MaineSail, Hellosailor, Btrayfors, Flyingcloud and others.

I know the question below is not strictly the topic, but since we have moved into discussing the details of Alternator Regulators I will ask it here:

*** What will happen if you charge your lead-acid battery bank via an alternator, and the ONLY control you apply is Battery Temperature?

Thus, as the battery's temperature rises, a simple electronics circuit cuts back the alternator Field Current, gradually bringing down the charging voltage to ensure the battery temperature stays within limit.

What will happen? Will the battery be fully protected from damage?

Obviously, we can analogously monitor the alternator housing temperature, and reduce the same field current to protect it. But, if we may just focus on the Battery Temperature in this hypothetical scenario (assume a super-cooled alternator), do you really need to do anything more than the Temperature-to-Field Current mediation to protect the battery?

One possible problem could be ambient temperature when you're in the tropics, but then, high temperature may be a contra-indication for batteries irrespective of whether it arises from charging or external heating sources. So if the battery is hot, cut down on charging without asking how it got hot.

While temp is critical both from an under/overcharge.

Voltage is king, for regulation.

During bulk, depending on source, a healthy a battery can take almost all the current you throw at it, as long as it doesn't exceed voltage, and temp. During absorption Voltage control is mandatory, any over voltage is wasted as heat. So environmental temp would cause effy losses.

I don't think you could ever develop a controller based on temp, that could compete with temp controlled voltage..

To many variables, and the spread between a warm bat and a hot bat is just to big.

The temp/voltage diff would not be linear, for environmental temp, SOC, or health of battery.

Lloyd

[Marqus]

Originally Posted by FlyingCloud1937

During bulk, depending on source, a healthy a battery can take almost all the current you throw at it, as long as it doesn't exceed voltage, and temp. During absorption Voltage control is mandatory, any over voltage is wasted as heat.

Lloyd

During the equivalent of Bulk charging, the dumb regulator would not exceed 14.4volt.
Later on (equiv of Absorption), as you say "any over voltage is wasted as heat". So the temperature feedback loop would reduce the voltage in order to contain the heat.

I get the feeling I'm not getting your point - what am I missing?