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I recently purchased 2 new Trojan T-1275 12V [email protected] batteries. They replaced 2 Trojan 30XHS batteries only 2 1/2 years old. Batteries+ convinced me that I abused the batteries by sulfating them beyond repair. So, I am now bound and determined to follow Trojan recommendations, and purchased a brand new battery charger, a ProMariner ProNautic 1240P. The main feature I was looking for is to be able to equalize the batteries, only when needed, using Trojan recommended 15.5Volts. The 1240P has that key feature. However while installing the charger I became concerned about how the charger changes from an absorption phase voltage to the float voltage. Trojan recommends that this switch be made when the current at absorption voltage falls to 2% of the 20hr capacity of the battery. If I am reading the literature correctly this is critical to determining a full charge and thus critical to the life of the battery. When setting up the charger, charge voltages are set based on battery type, but I see no way for it to determine the battery capacity, therefore the critical switch point from absorption voltage to float voltage. ProMariner support, while patient with me at first only stated "absorption time is self-calculated due to battery type and condition and is not adjustable. When pressed for more detail, I was told "this is proprietary information"

So, my question to the community is can a charger accurately determine when a battery is at full charge, when it "knows" only the battery type/charge voltage, the current the battery is accepting, and time. I hope I have provided adequate information for discussion. If I need to provide more detail, let me know.
 

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Where are all the electrical guru's? As a current battery abuser I too would like to see this one answered. Who knows we may even need a support group...
 

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AC chargers do not have the ability to find the capacity of your battery bank. They work on set voltage of the battery.

The Pronautic is an excellent charger, one of the best available. I have installed them, along with many others and prefer the Pronautic. Also one of the only chargers that come with a temp sensor - a required item as far as I am concerned.

Where did you read the information concerning the Trojan charging? I'm curious.

Batteries will sulfate if left discharged or partially discharged for long periods of time. Charging them fully after use is the solution.

While equalizing is important, as Trojan states it should only be done when necessary.
 

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I recently purchased 2 new Trojan T-1275 12V [email protected] batteries. They replaced 2 Trojan 30XHS batteries only 2 1/2 years old. Batteries+ convinced me that I abused the batteries by sulfating them beyond repair. So, I am now bound and determined to follow Trojan recommendations, and purchased a brand new battery charger, a ProMariner ProNautic 1240P. The main feature I was looking for is to be able to equalize the batteries, only when needed, using Trojan recommended 15.5Volts. The 1240P has that key feature. However while installing the charger I became concerned about how the charger changes from an absorption phase voltage to the float voltage. Trojan recommends that this switch be made when the current at absorption voltage falls to 2% of the 20hr capacity of the battery. If I am reading the literature correctly this is critical to determining a full charge and thus critical to the life of the battery. When setting up the charger, charge voltages are set based on battery type, but I see no way for it to determine the battery capacity, therefore the critical switch point from absorption voltage to float voltage. ProMariner support, while patient with me at first only stated "absorption time is self-calculated due to battery type and condition and is not adjustable. When pressed for more detail, I was told "this is proprietary information"

So, my question to the community is can a charger accurately determine when a battery is at full charge, when it "knows" only the battery type/charge voltage, the current the battery is accepting, and time. I hope I have provided adequate information for discussion. If I need to provide more detail, let me know.
In a perfect world the batteries would get full before the charger switches to float. The reality is NO ONE is willing to pay for that technology in a charger so they do the best they can with algorithms to try and achieve that. The Sterling ProCharge Ultra and ProMariner Pronautic P are the identical chargers and used the same algorithms.

The reason ProMariner does not understand is is likely because Charlie Sterling created the smart algorithm. These chargers use what I refer to as "adaptive learning" algorithms. This means they look at % of power supply, time it took to attain XX.XX volts, time it took current to fall etc. etc.. They use all these parameters to try and get your battery as full as possible BEFORE switching to float and they do a darn good job at it.. These chargers also revert back to absorption voltage every few days to keep the batteries healthy. They are one of the smartest chargers made.

Compare an algorithm like that to a "dumb" smart charger like those that use egg-timer based algorithms. Some of the chargers out there start a 4 hour "egg timer" when the charger has been switched on. Whether or not you even attained absorption voltage, on this particular brand of charger is irrelevant. It will simply go into float at 4 hours regardless of battery SOC. Talk about poor charging..

In order to do this based on current MULTIPLE shunts would need to be used. The charger has no idea what is a load, and what is going to the battery, so they simply can not use a single external current shunt as a measurement. To do current based charging, as opposed to voltage based, we would ideally need a loads shunt, a net current battery shunt and a charge shunt for other external sources such as solar. This would allow full cross checking to be sure what the charger was seeing was accurate. This would lead to MASSIVE wiring nightmares, heck folks can't even wire a single battery monitor shunt correctly, imagine three shunts! This is why every charger on the market, for marine use, is voltage based not current based.

Balmar was recently working on this type of charging for alternator regulation but put it on a far back burner when they likely realized the install level, liability and overall COST of the product when compared to just how effective the current regulators already are..

Many folks assume the old Link 2000's did this, but it is incorrect. The settings in the old Link 2000 were for the battery monitor portion though nearly every owner I talk to thinks they control the charging and that it goes to float when it sees 2% current. Nothing could be further from the truth and all charging is controlled inside the inverter charger and it still has a 4 hour max absorption override. I can point to many examples of Link 2000 controlled systems on large banks where it dropped into float at 4 hours regardless of whether or not the bank was truly full. The reason they do this is most like LIABILITY & cost.... Too many variables in owner or pro-level installs to rely on an external shut to control charging.

You have one of the best and smartest chargers out there. Focus on the myriad of other variables you CAN control.....;)

*Battery location/orientation - On sailboats this matters.

*Battery Temperature - Engine room = DUMB

*Average DOD - Shallow cycles equal longer life.

*100% Frequency - How often you get back to "full"?

*Temp Compensated Charging - Does your charger drop voltage above 80F? Does it boost voltages when below 70F?

*Charging Voltages - Are you getting to 14.8V?

*Float voltages (Trojan's really like 13.6 -13.8V)

*Periodic Absorption - Absorption boosts are healthy if batts left to sit

*Off season storage - The cooler the better, 100% disconnected.

*Equalize Before Lay Up - Wake up in the spring with a short one. *If cells are already in balance only push the 15.5V until current stops dropping. *Temp corrected of course.

*Equalization - Regular equalization, when necessary. This is normally at least bi-yearly. Proper absorption voltages lead to less need for equalization. Charging at 14.4V you may need four times per year but charging at 14.7 - 14.8V you may need only one or two per year. Even short periodic 30 minute equalizations help quite a bit.

*Proper bank wiring - How they are wired matters. Wire gauge matters, clean connections matter, low resistance connections/terminations matter.

*Electrolyte - Keep up with it or add a watering system

*Opening Cells Too Often - Avoid this DO NOT DO SG CHECKS CONSTANTLY! This only leads to increased potential for contamination. My customers who are chronic SG testers often have the shortest bank life due to cell level contamination. Keep battery tops SPOTLESS so when you do open them no crap falls in there. Contamination causes premature gassing. If cells don't all begin to gas at same voltage your most likely cause is contamination.

*SG Tester Storage - How are you storing your hydrometer & keeping it 100% clean?

*Commissioning Charge - Wire in parallel and push voltages to 15.5V for 12V or 7.75V for 6V for 30 minutes to one hour. I call this a wake-up charge & cell balance. Cell balance not important for parallel wired bank but can be helpful in series banks.

*Matched Bank - Matched for date codes and impedance measurements. Most any good battery shop will have an impedance tester (Midtronics etc.) ask them to test the batteries until you find a near perfectly matched set. I bring my own tester.

*Accurate Voltage Sensing - Inaccurate voltage sensing can lead to under charging.
 

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There you have it: a perfect recipe for good treatment and long life of flooded lead-acid batteries.

I agree 100%, as usual, with MaineSail's prescription.

Moderator: this should probably be a Sticky!

Bill
 

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And I will add; don't take for a fact what your Battery Monitor says as to state of charge etc. You have to recheck the BM once in a while by checking the SG etc.
Ah or Coulomb counting battery monitors are only as smart as the owners.... They need proper programing, calibration and a known capacity (this is ever charging) in order to be accurate..

I have a lot about the why's and how's in this article:

Balmar Smart Gauge Battery Monitoring Unit
 

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Discussion Starter #8
smart chargers need to go back to school?

Main Sail
Thank you for your well thought out response. Your list of variables that I CAN control, will go to the boat. I just bought my first hydrometer, so I will be careful. Your explanation that the ProNauticP and the ProCharge Ultra are the same, explains a lot. I have been impressed with what I have seen so far with the ProNauticP, but I have been less than enthusiastic with information provided by ProMariner support. In all fairness to them I do not give up very easily, and I am still interested in knowing more. Your explanation that the algorithm probably takes into account time to attain a specific charger voltage, and time it takes for absorption current to fall, therefore describing a specific charging curve, intuitively sounds plausible. So, at this point I am taking it that my charger probably does more than a simple measurement of time, voltage, or output current to determine when to drop to float voltage. It seems to me that the charger manufacturers would want to provide more detail, perhaps a white paper on charger parameters that would provide more detail, without giving up trade secrets. I wonder if we could invite the manufacturers to this discussion? Any ideas?
 

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Re: smart chargers need to go back to school?

Main Sail
Thank you for your well thought out response. Your list of variables that I CAN control, will go to the boat. I just bought my first hydrometer, so I will be careful. Your explanation that the ProNauticP and the ProCharge Ultra are the same, explains a lot. I have been impressed with what I have seen so far with the ProNauticP, but I have been less than enthusiastic with information provided by ProMariner support. In all fairness to them I do not give up very easily, and I am still interested in knowing more. Your explanation that the algorithm probably takes into account time to attain a specific charger voltage, and time it takes for absorption current to fall, therefore describing a specific charging curve, intuitively sounds plausible. So, at this point I am taking it that my charger probably does more than a simple measurement of time, voltage, or output current to determine when to drop to float voltage. It seems to me that the charger manufacturers would want to provide more detail, perhaps a white paper on charger parameters that would provide more detail, without giving up trade secrets. I wonder if we could invite the manufacturers to this discussion? Any ideas?
Yes your charger does far more than just use an egg-timer algorithm as many so called "smart chargers" do. It is also adaptive in that it learns your bank each time you discharge/recharge to give you the most accurate charge it can for that cycle..
 

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So where does one find a 100 mile long extension cord?
I believe there are a lot of there laying on the sea bottom here and there. The problem is plugging into them.
 

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I've only seen the option to program battery capacity (nominal rating) on an MPPT controller. FWIW.
 

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This is usually for the battery monitoring portion of the controller.

There are a few controllers that "allow" you to use return amps as an additional signal to flip to float but even companies like Outback suggest setting return amps to zero and letting it work on voltage and your pre-programed time setting. All of these chargers, inverter/chargers and MPPT's are CV chargers not current based. When the offer a "current" option it is nothing more than a "trigger" in addition to time/voltage/built in algorithm...
 

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Discussion Starter #14
Just what is an algorithm

OK Maine Sail, you have made me feel good about my purchase. But, I have questions.
I don't know how to do the quote thing so:
"These chargers use what I refer to as "adaptive learning" algorithms. This means they look at % of power supply, time it took to attain XX.XX volts, time it took current to fall etc. etc.. They use all these parameters to try and get your battery as full as possible BEFORE switching"

and you also say:

"It is also adaptive in that it learns your bank each time you discharge/recharge to give you the most accurate charge it can for that cycle."

With all due respect to your position on this forum how can you know these things? I don't see how you could determine this in a small laboratory or through experience. On top of that I don't know what all of this means. I am beginning to think algorithm is a pretty fancy word, that maybe I need to stay away from. I do know that I = E/R, and that battery resistance increases as the battery charges. I think it is predictable and at least for the Trojan line the charging profile seems to be the same for all size of batteries, ie the slope is the same, but the time and current change with battery size. So, maybe that information could be used to determine capacity, and therefore switch to float.
My original question was intended to be somewhat general, not really specific to the ProNautic, that could a charger manufacturer determine the full state of a battery without "knowing" the expected capacity of the battery? Right now I believe the answer is yes, maybe, sort of, but you better monitor the current going into you battery and on occasion, check the SG. And, if you have a history of battery abuse by sulfation, you will likely need to equalize using 15.5 volts on occasion. When this set of Trojans dies, I will let you know.
 

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Re: Just what is an algorithm

OK Maine Sail, you have made me feel good about my purchase. But, I have questions.
I don't know how to do the quote thing so:
"These chargers use what I refer to as "adaptive learning" algorithms. This means they look at % of power supply, time it took to attain XX.XX volts, time it took current to fall etc. etc.. They use all these parameters to try and get your battery as full as possible BEFORE switching"

and you also say:

"It is also adaptive in that it learns your bank each time you discharge/recharge to give you the most accurate charge it can for that cycle."

With all due respect to your position on this forum how can you know these things? I don't see how you could determine this in a small laboratory or through experience. On top of that I don't know what all of this means. I am beginning to think algorithm is a pretty fancy word, that maybe I need to stay away from. I do know that I = E/R, and that battery resistance increases as the battery charges. I think it is predictable and at least for the Trojan line the charging profile seems to be the same for all size of batteries, ie the slope is the same, but the time and current change with battery size. So, maybe that information could be used to determine capacity, and therefore switch to float.
My original question was intended to be somewhat general, not really specific to the ProNautic, that could a charger manufacturer determine the full state of a battery without "knowing" the expected capacity of the battery? Right now I believe the answer is yes, maybe, sort of, but you better monitor the current going into you battery and on occasion, check the SG. And, if you have a history of battery abuse by sulfation, you will likely need to equalize using 15.5 volts on occasion. When this set of Trojans dies, I will let you know.
I know this because I have have always been after smarter chargers than the simple egg-timers many charger makers stuff into a box and put a huge price tag on then have the nerve to call it "smart".

I know this because I have had numerous long phone conversations with Charles Sterling Sr., the designer, and specifically asked. I know this because I did lots of testing & research before writing my article on installing a marine battery charger, that featured a Sterling ProCharge Ultra. I know this because I am also a Sterling dealer, as well as many other brands. I know this because it is my job to know this sort of thing so that I can design and offer my customers a myriad of known quality products that do what they need to do when installed and incorporated into their on board system. These chargers work darn well for a charger with no user adjustable parameters other than voltage and a custom program option. There are also other good brands but sadly there are still many, many horrible chargers out there. If you really want a great charger I know where you can get a top quality telecom grade 20A model that will set you back a mere $1900.00... Sterling & PM are not the only ones using an adaptive algorithm and usually all of the better brands do. They all do it slightly differently but most do a pretty good job..

Heck we have finally gotten to the point with voltage algorithms that we now have shunt-less battery monitors capable of SOC accuracies to within 1%, all this without a clue about the banks Ah capacity.

If you really want to charge your batteries manually buy a lab grade bench-top switch-mode power supply. Set your absorption voltage and watch the current. When it drops below 2% manually adjust the CV down to float level.... These are all I use for charging, reconditioning and equalizing in my shop. I have a bank of Lifeline's on one right now. I also utilize them for balancing LiFePO4 cells.. Very, vey handy tools for a guy like me but perhaps overkill for the average boater. One could easily be installed on a boat but they are bulky and require user attention. The charger you have is much easier...

If you don't want that level of complexity, be happy you chose one of the better & smarter chargers out there.. BTW the multi-thousand dollar LiFePO4 bank on my own boat uses a Sterling PCU as the AC charger... There are only a small handful of chargers I would use on this bank and the PCU and a Pronautic P are two of them..
 

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Discussion Starter #17
It has been over a year and a half since I started this experiment with new batteries and a new battery charger. I have taken some of mainsails advice and not stressed over my batteries. Until this weekend I have not measured SG or equalized. SG measures between 1.275 and 1.290. Even though Trojan recommends equalizing when needed I did anyway. 15.5 volts for 4 hours. Very little difference in SG measurements. I am going to make 1 small change from 14.8 volt conditioning to 14.7. I am thinking I could be wearing the plates. We will have to see if I get 4 to 6 years life or more but so far so good. I am convinced my old "smart" charger was not up to the task.
 

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It has been over a year and a half since I started this experiment with new batteries and a new battery charger. I have taken some of mainsails advice and not stressed over my batteries. Until this weekend I have not measured SG or equalized. SG measures between 1.275 and 1.290. Even though Trojan recommends equalizing when needed I did anyway. 15.5 volts for 4 hours. Very little difference in SG measurements. I am going to make 1 small change from 14.8 volt conditioning to 14.7. I am thinking I could be wearing the plates. We will have to see if I get 4 to 6 years life or more but so far so good. I am convinced my old "smart" charger was not up to the task.
Forget the SG measurements. I know, this is heresy. But you're more likely to put holes in your clothes than to learn anything useful. For example, SG tells you almost nothing about battery capacity. It's perfectly possible to have a battery showing "normal" resting voltage after charging, have a "normal" SG reading and yet have a much reduced overall capacity. In fact, this is the "normal" condition of LA batteries.

Do not lower the absorption voltage. Trojan recommends 14.8 to 15.0 volts for their T-105's. Batteries more often suffer from undercharging voltage (14.2, 14.4, etc.) than too high an absorption voltage. Just check the fluid levels frequently and, better, get some Hydrocaps or WaterMiser caps to reduce loss.

It's more important to kick up the charging voltage frequently after being at a "resting" voltage (13.2-13.6VDC) for awhile. My Victron is programmed to revert to an absorption voltage of 14.8VDC every other day for about 30 minutes before dropping back to resting levels.

Bill
 
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