Charging AGM battery

[WDavidG]

Originally Posted by NEWYORKHILLBILLY

In my search i did find this response from Progressive Dynamics 9200

Equalization when applied in the conventional sense to LA battery chargers, means up to 15.5 volts for a period often exceeding an hour.
The equalization cycle that we use is mild, 14.4 volts for 15 minutes every 21 hours when in storage mode. This has been proven to be good at reducing sulfation in the Lead Acid Wet batteries. It also has no effect on AGM .
We have been reassured by AGM manufacturers that the profile we use is good for AGM batteries.

David Watson
Service Department Supervisor
Progressive Dynamics
269-781-4241 ext.143

Mike,
This is very helpful information. Thanks for sharing it.

[Raspy]

Originally Posted by NEWYORKHILLBILLY

Progressive Dynamics 9200


Equalization when applied in the conventional sense to LA battery chargers, means up to 15.5 volts for a period often exceeding an hour.
The equalization cycle that we use is mild, 14.4 volts for 15 minutes every 21 hours when in storage mode. This has been proven to be good at reducing sulfation in the Lead Acid Wet batteries. It also has no effect on AGM .
We have been reassured by AGM manufacturers that the profile we use is good for AGM batteries.

David Watson
Service Department Supervisor
Progressive Dynamics
269-781-4241 ext.143

Interesting that they say 14.4 volts for 15 minutes every 21 hours is good a "reducing" sulfation.

I get from that, that they are not correcting anything, just reducing the inevitable. And that is what I would expect from 14.4 volts. That is not an equalization voltage, and it is not dangerously high. It is about the same as what vehicle manufacturers run their normal voltage at. Car batteries tend to not sulfate if used regularly and the batteries can last for a long time. Every time we drive a car the batteries reach at least 14.1 or up to 14.4 volts. This is a normal voltage that is good for vehicle batteries that are not on a continuous charge, but it is not an equalization voltage. Cars run for a while and then sit for a while.

Car batteries don't normally get run down to 50% charge before charging back up, like RV deep cycle batteries, so the chance for sulfating is reduced. And taking an AGM sealed battery up to 16 volts every 21 hours seems dangerous and destructive. Lifeline Batteries seem to only allow equalization after some period of use and only after the battery has been normally charged. This makes a lot of sense in order to reduce gassing and temperature rise. Trojan does not allow equalization, but they seem to be confusing stratification with sulfation when they say their batteries don't need equalization.

It's always best to follow the manufacturers instructions, of course, but those instructions don't always make sense or equal what a charger manufacturer has designed their product to do.

Be nice to your AGM batteries. They are sealed and they can't stratify. Charge them at a reasonable rate and don't let them sit for long while discharged. Equalize them only after they are fully charged and the temperature is stable. I've traditionally held mine at 13.2 volts on float, as my marine charger was designed to do with AGM. Flooded can be at 13.8.

If you charge your trailer battery from the tow vehicle, it is trying to bring the battery up to at least 14.1. Sometime, after a long drive and before shutting of the TV, check the trailer battery to see what its voltage is. If it's 14.1, you are doing well and staring out with a fully charged battery at the campsite, as well as "reducing" sulfation.

[rbryan]

Good post John. I was puzzled too about the mention of stratification. The electrolyte in the AGMs won't separate and stratify like liquid electrolyte can, because the glass fibers absorb and hold it in place.

[WDavidG]

Good and informative analysis in your post John. One question/confusion I have from your last point. You specify leaving the TV running when checking the battery charge. Won't you be measuring the voltage coming from the TV alternator?

Originally Posted by Raspy

Sometime, after a long drive and before shutting of the TV, check the trailer battery to see what its voltage is. If it's 14.1, you are doing well and staring out with a fully charged battery at the campsite, as well as "reducing" sulfation.

[Raz]

Early Parkliners came with Optima blue AGMs and a Progressive Dynamics converter neatly stored under one of the benches. In at least one case the batteries off gassed. There is a rather long thread somewhere around here detailing the event. Parkliner has since moved the batteries to the tongue. While no cause was given, I came to the conclusion that the lack of ventilation and the destratification mode may have played a part. As my PD 4045 doesn't seem to have a way to stop that mode, I stopped using it to charge my battery. With AGMs being rather expensive, I'd rather not use a charger that wants to boil an electrolyte that can't be boiled.

[Raspy]

Originally Posted by WDavidG

Good and informative analysis in your post John. One question/confusion I have from your last point. You specify leaving the TV running when checking the battery charge. Won't you be measuring the voltage coming from the TV alternator?

Yes you will be measuring the voltage coming from the TV, which proves it is charging the trailer battery and, if the voltage is reading about 14 volts, it also proves the battery is fully charged after a long drive. If your house battery was at 50% and you started the TV, the house battery voltage will not just jump to 14, it would climb up to that value. How fast it gets there is a function of how many amps the TV is sending it and every TV seems to be different. Remember too, that if your house battery is sulfated, it will still charge up to a full charge. Problem is it's capacity is reduced. In severe cases, it has almost no capacity. So with a small or short term load the battery will become discharged. If your battery is older, or it has spent a lot of time at less than full charge, it is probably sulfated. If you seem to remember your system having more power or lasting longer, your battery cold be sulfated. You can have a load test done to determine this.

Also, in the Oliver trailers, we recently discovered that many of them were not wired to charge the house battery from the TV, even if the TV was sending current to the seven pin plug. I had to continue a ground wire to the neutral buss bar and from there to the frame grounding lug to make mine work. On another one, we had to take a ground from the seven pin plug and run it straight to the trailer frame to solve the problem.

Answering the charging question may then allow you to run the absorption fridge from 12 volts while driving, if you find out enough amps are getting to the house battery to support that load. If you are charging, you could turn on the fridge and see if your house battery stays charged while driving. In that case, an indicated house voltage of 13.2 or so, would be OK. Also, some people have been having problems in Fords with a "trailer connection" warning where the TV sees a poor connection to ground and thinks the seven pin is disconnected. This could lead to poor braking or no braking, even if the seven pin is plugged in. Again, in the Olivers, the problem was a discontinuous ground from the TV to the Trailer frame/battery where the brakes were being grounded through the trailer ball! That connection is not good enough to satisfy the Ford computer, so it sends out a warning message.

[NEWYORKHILLBILLY]

Originally Posted by Raz

Early Parkliners came with Optima blue AGMs and a Progressive Dynamics converter neatly stored under one of the benches. In at least one case the batteries off gassed. There is a rather long thread somewhere around here detailing the event. Parkliner has since moved the batteries to the tongue. While no cause was given, I came to the conclusion that the lack of ventilation and the destratification mode may have played a part. As my PD 4045 doesn't seem to have a way to stop that mode, I stopped using it to charge my battery. With AGMs being rather expensive, I'd rather not use a charger that wants to boil an electrolyte that can't be boiled.

I starting to think along this line also. Battery charger

It seems the problem is that the converters manufactures want to Sell a one size fits all converter

It would make more sense to have a converter that could be programed for you battery.

[Raz]

In fact the Morningstar charge controller I bought for my solar set up provides the option with a jumper.

[Alex Adams]

My Renogy Adventurer Solar charge controller lets me specify Sealed Lead Acid. I suspect most decent solar chargers allow you to specify.

[rbryan]

Originally Posted by Raz

With AGMs being rather expensive, I'd rather not use a charger that wants to boil an electrolyte that can't be boiled.

Exactly.

[NEWYORKHILLBILLY]

Originally Posted by Alex Adams

My Renogy Adventurer Solar charge controller lets me specify Sealed Lead Acid. I suspect most decent solar chargers allow you to specify.

Renogy Adventurer
but when set on the sealed battery it still does the Equalization overcharging every 28 days. At 14.6 volts
on wet cell it does the Equalization at 14.8volts
on Gel it does no do the Equalization

Originally Posted by Raz

In fact the Morningstar charge controller I bought for my solar set up provides the option with a jumper. Attachment 115688

Yes this controller will not do equalization with Jumber installed.
but the Absorption Voltage 14.1 is to low for my battery



I just saying it should be adjustable on the converter. I know some solar controllers it is

[Raspy]

Originally Posted by NEWYORKHILLBILLY

Yes this controller will not do equalization with Jumber installed.
but the Absorption Voltage 14.1 is to low for my battery

Why is 14.1 volts too low for absorption with your battery? That is a normal absorption voltage.

[gordon2]

Originally Posted by Raz

In fact the Morningstar charge controller I bought for my solar set up provides the option with a jumper. Attachment 115688

And the Bogart Engineering solar controller, when paired with their Trimetric battery monitor, is fully programmable. It has profiles for LA and AGM, and you can create your own profile based on the exact charging information from the battery manufacturer. See Section 4.5 on Page 7 of the manual.

That is why I explored the possibility of feeding the converter output (and/or TV charge line) to the solar controller input and then using the solar controller's charging profile. That turned out to likely be a bad idea BTW because of the interaction between the PWM controller and PWM converter which is too bad since the solar controller is a better and more versatile charger.

[NEWYORKHILLBILLY]

Originally Posted by Raz

In fact the Morningstar charge controller I bought for my solar set up provides the option with a jumper. Attachment 115688

Originally Posted by Raspy

Why is 14.1 volts too low for absorption with your battery? That is a normal absorption voltage.

my paper work says it should be 14.4-15 Volts . why i don't know , here the specs for the battery, maybe I am missing something.

https://www.renogy.com/template/file...-AGM12-200.pdf

But the renorgy adventurer controller is 14.4 and float is 13.8

[Raz]

I charge my battery with the tow vehicle on the road, a 60 watt panel when we camp and a two stage PWM charger I bought at a Napa store back in the '80s. None provide 14.5 volts. There are some that will say you need a set voltage to "fully charge" a battery but I have yet to get a technical explaination why. When this comes up I always hope there is a chemist in the house but so far no one has stepped forward. So my educated guess is that the lower voltages just take longer. My Napa charger is the lowest with an output about 13.8 volts dropping down to 13.2.

[John in Santa Cruz]

I installed a PD4645 in my Casita to replace a failed Parallax. When you put it in AGM mode, it does NOT do the 'equalizing' thing.

[Alex Adams]

Originally Posted by Raz

I charge my battery with the tow vehicle on the road, a 60 watt panel when we camp and a two stage PWM charger I bought at a Napa store back in the '80s. None provide 14.5 volts. There are some that will say you need a set voltage to "fully charge" a battery but I have yet to get a technical explaination why. When this comes up I always hope there is a chemist in the house but so far no one has stepped forward. So my educated guess is that the lower voltages just take longer. My Napa charger is the lowest with an output is about 13.8 volts dropping down to 13.2.

From HandyBob's blog:
https://handybobsolar.wordpress.com/...ging-puzzle-2/

VOLTAGE: For the sake of simplicity, I am only going to talk about the requirements of standard flooded wet cell lead acid batteries, which is what most of us use. The major points apply to all types of batteries, but the actual numbers will vary. It is very important for you to research the charging requirements of your batteries if you are using any other type and make sure that your charging system provides what they need, or you could end up damaging them by over charging or never getting them fully charged, which will also damage them. Battery manufacturer’s specifications say that a standard 12 volt wet cell battery needs to be charged to between 14.4 to 14.8V and then held there for some time before it will be fully charged. The Trojan Battery company says 14.8V daily charge (at 77 degrees F) and Interstate will tell you over 15V. Trojan’s 2010 Users Guide has a new chart that shows you should actually vary the voltage depending on the amps you supply for charging and even higher voltages are recommended. Of course they recommend temperature regulation. So all of those out there who are telling you 14.8V is too high do not know what they are talking about. How long it takes to get the charge in depends on how far it was discharged. Trojan says to keep charging until a hydrometer test shows that the battery is charged and not one charger available today can do this. The best chargers can do a reasonable guess at state of charge by providing constant voltage and watching the amps taper as the battery fills to tell them when the battery is full. However, they rely on whatever the designer or programmer gives them for guidelines and are only as good as that data. Many do no work worth a hoot. A fully charged battery can be maintained at a full state by applying a 13.2 – 13.6 volts “float” charge. All of the talk about how many amps a charger puts out means nothing. It is the volts (pressure) that you need to push the amps (volume) into a battery. VOLTS, VOLTS, VOLTS!! Also, the amps pushed into a battery at a higher voltage contain more power than those at a lower voltage. Remember, volts times amps equals watts, so amps pushed at 10% higher volts give you 10% more watts. Therefore, the power stored in the upper range of a battery’s charge is greater, so it is very important to get a full charge. Low voltage DC is not easy to get through wire without losing power due to voltage drop or resistance. It is huge problem in an RV. Use big wires and short wiring runs to get around this. It is good practice to use one or even two sizes bigger wire than recommended to limit voltage drop. This charge voltage has to actually reach the battery, not just the output terminals on a charger. If you cannot get your batteries up to 14.4 volts (14.8 is better & faster) with whatever charging system you have and then keep them there while pushing amps in for more than an hour or two, your batteries will never be full. Added in 2014: Please realize that the message here is for off grid living, not for being plugged in at an RV park. A converter that is set lower but left plugged in 24/7 may eventually fill a battery. It may not, too, but it doesn’t need to be set at 14.8V to work. Buy a hydrometer if you want to know.

[Raspy]

mike,

Yeah, they seem to want 14.5-15 volts just for normal charging and they will allow it to be pulled down to 9.6 volts during discharge. That charging voltage might be hard to find unless you have a specific charger designed for that battery.The Renogy Adventurer controller is a good match, but as is so often the case with solar, use has risen to meet and surpass available power and the batteries are unlikely to get to full charge very often. Maybe that voltage is designed to work better with solar output from an MPPT controller.

They seem to be hot rodding what appears to be a conventional AGM battery.

I don't see why 14.1 would be too low, but it would charge just a bit slower, while making less heat and gas. Those specs seem out of the ordinary. 9.6 volts is pretty much dead and useless for a lot of 12 volt equipment.

[Raz]

Being a retired Electrical Engineer I don't put much faith in Handy Bob. Lots of hand waving but no technical arguments.

[Raspy]

Originally Posted by Alex Adams

All of the talk about how many amps a charger puts out means nothing. It is the volts (pressure) that you need to push the amps (volume) into a battery. VOLTS, VOLTS, VOLTS!!

Means nothing?

A bit of an over simplification there, since voltage is relatively constant and amps are wildly varying both on the charge and discharge side, as well as with different battery capacities and expected loads.