Please advise....AGM Battery Charge Information

[jimvette999]

FWIW: Here's Customer Service's Complete Reply
"It will go into storage after 30 hours of being connected to the battery.

Since you have connected and disconnected , Place it there manually. "


Oddly, the Converter doesn't even know that there's no battery connected. The so called "Wizard" may be misnamed IMO. Look at the RED portion in my customer service request below and see the behavior/response of the Power Converter.

"I just installed the PD4635 Converter and it seems to be staying in the "Normal Mode" even though my amp reading is 0.03 amps in "Normal Mode" @ 13.50 volts. Wizard button it to "Boost Mode" and the amps read 0.07 amps @ 14.4 volts. I disconnect the converter and the battery has a resting voltage of 12.9 so it should be in "Storage Mode". Using a battery disconnect switch, I can turn the converter back on and even though the battery is disconnected, the converter has a 1 second flashing light. Engage battery and the green light stays the same. Disconnect battery and power down the converter and turn both on at the same time, I get short Boost mode then Normal mode and it stays there. Disconnect the battery while converter is operating and the green light doesn't change. Please advise."

I don't understand why the converter would just charge a battery for 30 hours and then go into Storage Mode....let's say I have a power blip and the shore power to converter is disconnected for 5 min., would it then hit the battery for 30 hours at 13.5v even though it's fully charged???????????

[RV2traveler]

It would be nice if the PD converters were much smarter but then they'd be 5X the price.

I wouldn't worry too much about the 13.5V for 30 hours. The amps in (acceptance) at that voltage will likely be very low. Use the button to force storage mode if you are 100% certain the battery is fully charged.

Also note that the PD converter lacks any form of temperature compensation. If your RV spends most of its time in a mild to cooler climate then the 13.5V becomes even less of an issue.

I'm with you in wishing more chargers could accurately assess the battery's SOC after a power outage or when plugging in after driving and go straight to the appropriate charge mode. Most chargers seem to be timer based in some way. Some have complicated timer systems where the time at constant current then determines the time in bulk mode and therefore also determines the speed at which float mode is achieved and some are simple like the PD units. They're both still timer base systems though.

[Mr_D]

Originally Posted by jimvette999

Interesting....my coach is not fancy enough for auto start anything though...
Jim

The 12.3 volts comes from a seminar at a Country Coach rally put on by techs that built the rigs and are now in business for themselves.
Not having an AGS means you need to monitor your voltage rather than being automatic.

[jimvette999]

Originally Posted by RV2traveler

It would be nice if the PD converters were much smarter but then they'd be 5X the price.

I wouldn't worry too much about the 13.5V for 30 hours. The amps in (acceptance) at that voltage will likely be very low. Use the button to force storage mode if you are 100% certain the battery is fully charged.

Also note that the PD converter lacks any form of temperature compensation. If your RV spends most of its time in a mild to cooler climate then the 13.5V becomes even less of an issue.

I'm with you in wishing more chargers could accurately assess the battery's SOC after a power outage or when plugging in after driving and go straight to the appropriate charge mode. Most chargers seem to be timer based in some way. Some have complicated timer systems where the time at constant current then determines the time in bulk mode and therefore also determines the speed at which float mode is achieved and some are simple like the PD units. They're both still timer base systems though.

Yes, perhaps, BUT, a car/truck/van or even an RV chassis has a voltage regulator that pumps juice into the battery based on need, not time. A voltage regulator is not a very expensive component of the alternator itself. I'm sure you're right, I just can't see why you're right because of my limited understanding of AMPS, Volts, Converters, etc.

Originally Posted by Mr_D

The 12.3 volts comes from a seminar at a Country Coach rally put on by techs that built the rigs and are now in business for themselves.
Not having an AGS means you need to monitor your voltage rather than being automatic.

Yes Sir, I was just teasing, I knew what you were saying to do. I have no doubt opinions vary and one really never knows who to believe without due diligence. I do plan to monitor voltage, I have an LED display in plain sight that I keep an eye on. Thank you for the replies and at least I know if I sink to 12.3, a group in the know think it's OK to recharge from that set point.
Jim

[RV2traveler]

Originally Posted by jimvette999

................ BUT, a car/truck/van or even an RV chassis has a voltage regulator that pumps juice into the battery based on need, not time. ..............

That's not my understanding of how alternator charging works. Maybe very modern vehicles have smart voltage regulators - I don't know. In typical systems the alternator does its best to maintain system voltage as set/required by the voltage regulator. At some point heat build up in the alternator affects output and the output voltage is reduced. That gives the appearance of it being smart but the voltage would go back up if you could cool the alternator.

I really did just guess about what the cost of truly smart charging system would be. I'm only aware of one setup that monitors return amps to determine transition points and that's a Magnum with a couple of add-on options.

There must be others and it would be nice to know brand & model numbers.

[jimvette999]

Originally Posted by RV2traveler

That's not my understanding of how alternator charging works. Maybe very modern vehicles have smart voltage regulators - I don't know. In typical systems the alternator does its best to maintain system voltage as set/required by the voltage regulator. At some point heat build up in the alternator affects output and the output voltage is reduced. That gives the appearance of it being smart but the voltage would go back up if you could cool the alternator.

I really did just guess about what the cost of truly smart charging system would be. I'm only aware of one setup that monitors return amps to determine transition points and that's a Magnum with a couple of add-on options.

There must be others and it would be nice to know brand & model numbers.

Please read these and reconsider your position.

https://www.carparts.com/classroom/charging.htm
The Voltage Regulator
The voltage regulator can be mounted inside or outside of the alternator housing. If the regulator is mounted outside (common on some Ford products) there will be a wiring harness connecting it to the alternator.

The voltage regulator controls the field current applied to the spinning rotor inside the alternator. When there is no current applied to the field, there is no voltage produced from the alternator. When voltage drops below 13.5 volts, the regulator will apply current to the field and the alternator will start charging. When the voltage exceeds 14.5 volts, the regulator will stop supplying voltage to the field and the alternator will stop charging. This is how voltage output from the alternator is regulated. Amperage or current is regulated by the state of charge of the battery. When the battery is weak, the electromotive force (voltage) is not strong enough to hold back the current from the alternator trying to recharge the battery. As the battery reaches a state of full charge, the electromotive force becomes strong enough to oppose the current flow from the alternator, the amperage output from the alternator will drop to close to zero, while the voltage will remain at 13.5 to 14.5. When more electrical power is used, the electromotive force will reduce and alternator amperage will increase. It is extremely important that when alternator efficiency is checked, both voltage and amperage outputs are checked. Each alternator has a rated amperage output depending on the electrical requirements of the vehicle.

https://www.howacarworks.com/basics/...g-system-works
Regulating the current to the battery
The current from an alternator is rectified into direct current by a set of diodes that allow current to flow through them in one direction only.

To charge the battery the voltage supplied to it must not be too low or too high.

The alternator has a transistor-operated control device that regulates the voltage by supplying more or less current - as required - to the electromagnet.

The rectifier and regulator are usually inside the alternator housing, but on some alternators they are outside, mounted on the alternator body.

[twinboat]

They make smart, 3 stage, voltage regulators for marine alternators. There is no reason not to use them on an RV.

I've used one for years on my boat. They now offer Lifepo4, Lithium settings.

http://www.balmar.net/product/regula...ator-mc-614-h/

[RV2traveler]

jimvette999 - your links confirm my understanding of an alternators role in the system. Link #1 indicates that the alternator does it's best to maintain but never exceed a system voltage of 14.5V. Link #2 explains that the output is converted to DC and that a target voltage (typically 14.4V or so) is maintained.

I'd add that heat can quickly limit an alternators output.

The charger maintains the chosen system voltage by increasing or decreasing current. Bulbs and batteries etc. are parts of the system.

The PD Converter and battery interact in a similar way. You need the pressure of higher voltage to see an increase in current flow. It is easy to see this when using an ammeter. If you switch from Storage Mode at 13.2V to Boost mode at 14.4V you'll see an increase in current flow.

I know the Balmar 3 stage voltage regulators mentioned by twinboat are also used some current RV's that use a second high output alternator. I'm not aware of them being used in RV's with just the single stock alternator but I don't know why they couldn't be either. My guess is that they are not used on a single stock alternator because of the relatively short engine run-time. Typical automobile alternator usage can be measured in minutes or at most hours - hardly a need for multi-stage charging. Converter/charger or inverter/charger usage could be measured in weeks or months or years by comparison so multi stage charging is beneficial for battery life.

That's the about the limit of my knowledge of this stuff so I likely can't help more with the discussion.

[jimvette999]

Originally Posted by RV2traveler

jimvette999 - your links confirm my understanding of an alternators role in the system. Link #1 indicates that the alternator does it's best to maintain but never exceed a system voltage of 14.5V. Link #2 explains that the output is converted to DC and that a target voltage (typically 14.4V or so) is maintained.

I'd add that heat can quickly limit an alternators output.

The charger maintains the chosen system voltage by increasing or decreasing current. Bulbs and batteries etc. are parts of the system.

The PD Converter and battery interact in a similar way. You need the pressure of higher voltage to see an increase in current flow. It is easy to see this when using an ammeter. If you switch from Storage Mode at 13.2V to Boost mode at 14.4V you'll see an increase in current flow.

I know the Balmar 3 stage voltage regulators mentioned by twinboat are also used some current RV's that use a second high output alternator. I'm not aware of them being used in RV's with just the single stock alternator but I don't know why they couldn't be either. My guess is that they are not used on a single stock alternator because of the relatively short engine run-time. Typical automobile alternator usage can be measured in minutes or at most hours - hardly a need for multi-stage charging. Converter/charger or inverter/charger usage could be measured in weeks or months or years by comparison so multi stage charging is beneficial for battery life.

That's the about the limit of my knowledge of this stuff so I likely can't help more with the discussion.

You've been very helpful and I don't wish to offend/insult you so let's just say the links I provided did not support the theory that heat is a factor on how the voltage is regulated from the alternator to the battery. It's done in the manner described below and is not heat related/time based.

"The voltage regulator controls the field current applied to the spinning rotor inside the alternator. When there is no current applied to the field, there is no voltage produced from the alternator. When voltage drops below 13.5 volts, the regulator will apply current to the field and the alternator will start charging. When the voltage exceeds 14.5 volts, the regulator will stop supplying voltage to the field and the alternator will stop charging. This is how voltage output from the alternator is regulated."

My position/point is that the Converter should first sense the level of charge the battery has, either by applying a charge and measuring the amperage and then accessing the needs of the battery and charging accordingly while monitoring the charge every 30 seconds or some other safe interval. When the battery is no longer taking a charge at a rate that indicates less than 90% charged, it should modify strategy and charge at a modified voltage....etc. etc etc. But what do I know? Not a lot, only what I read.

[jimvette999]

Thanks to all for your help. This thread is done and I will no longer be monitoring it. Happy travels to everyone.
Best regards!
Jim

[JimPeoria]

One thing about AGM batteries is they can take a very high charge rate so 14.5 or even as much as 15 volts is not unheard of and should not hurt the battery. The best way I have found to charge an AGM battery is with an automatic charger that will go as high as 20 to 30 amps and as the battery charge comes up will reduce the charge down till it is maintaining around 2.5 to 5 amps. This may well take 24 to 36 hours and I have seen some fully discharged batteries go 48 hours before being fully recharged. By the way most alternators will charge in this fashion. I have had guys use AGM batteries for trolling motors and run them clear down to dead basically and still be able to recharge them but it takes a couple days with a 30 amp deep cycle charger. If you could get into the cells like a older style flooded cell type battery you can stick your meter leads in each adjoining cell and you should get a reading of 2.2 volts per cell fully charged. An AGM battery varies a bit from that but it will or should be close. This is why a fully charged battery should read 13.2 volts or very close, also why it doesn't hurt to charge at 14+ volts and as high as 30 amps to begin with tapering off to 2 to 5 amps to finish it off. I say all this from the experience of 17 years repairing and rebuilding starters and alternators as well as selling batteries and chargers.

[shootist]

Your charge voltage should be 2.4 volts per cell (14.4 v) the float v should be 2.25 per cell ( 13.5) if your charger doesn't put out these voltages you will ruin the battery fairly fast. And don't trickle charge it. Use a charger with the proper algorithm for an agm

[snevetsinc]

Originally Posted by jimvette999

Thank you. I do have a battery disconnect I use and the battery resting voltage seems to be at 12.7. I have a small built it digital display I use and everytime I check it it's at 12.7. I run a trickle charger on a timer that hits it for an hour twice a day to keep it topped. The post I made was what I was experiencing on my first trip out while actually using the battery on a trip. I just noticed that the charge dropped from 12.9 rather quickly in my opinion from 12.9 to 12.7 to 12.6 to 12.5 then hung there. I was under the impression that it should start out at 12.9 and "gradually" drop based on the very light load I had on it. I really do appreciate the replies, I plan to let the inverter stay on it for 8-10 hours today and see if Soppy's theory is right....may be I never really "filled it up".
Jim

There is a co/propane leak detector that is connected directly t o your battery by law, so even if you have your battery disconnect off, there will always be a drain. The only way to not have a drain when stored is to disconnect 1 battery cable. I used to disconnect the neg lead before I installed solar.

[rfmaude41]

Originally Posted by jimvette999

Thank you... I will investigate putting it on my charger and seeing if it's not actually fully charged.




Thank you, but as you can see, I'm already getting conflicting information. My top Thumbnail from Duracel, the battery brand and Member Soppy, both indicate that the AGM should have a resting charge level of 12.9 volts when at 100% charge level. You say it should be at 12.7 volts. Additionally, respectfully, you didn't address my question/concern about the weird voltage drop.

Any "standard" Lead / Acid battery should be "fully charged" at 12.6 volts (possibly 12.7).