Does my class A converter need to be upgraded to swap in AGM batteries?

[Blaise]

Hi,

I'm getting my 2016 Winnebago Vista LX 30T ready for sale. It has the original flooded deep cycle batteries that not surprisingly won't hold a charge anymore. Yes, I certainly got my money's worth out of them!

I'm planning on getting a pair of deep cycle AGM batteries. My question is, can the 2016 converter properly charge AGM batteries, or do I have to upgrade the converter?

I've poked around among a number of threads here on the forum, and there seems to be some folks that think YES you must upgrade the converter, and some say NO, you can just swap in the AGM batteries.

Add to that, things may have changed since some of the older posts. Is there any definitive information about this?

Thanks

 

[Isaac-1]

It depends on the converter, if it is a multi-stage converter with automatic equalization mode that operates at over 14.4VDC then yes you need a different converter, if not you can probably get away with what you have, though without knowing what you have and its operating voltages it is hard to say for sure.

 

[Gary RV_Wizard]

I think you can be confident that any converter/charger installed in a 2016 Winnebago is compatible with AGM batteries. AGMs are still lead-acid batteries so the base chemistry is the same. Optimal voltages at each charge stage may vary slightly (I'm talking 1/10 of a volt difference) but that's not enough to justify a converter upgrade. Different battery makers recommend slightly different charge profiles anyway.

Basically, 14.4v peak for bulk/absorption charge and 13.6v for float will do the job nicely.

 

[Mark_K5LXP]

Maybe offer a "credit" to the buyer for the batteries of his choice. That way they end up with whatever chemistry/size/type they want instead of AGM's specifically.

Mark B.
Albuquerque, NM

 

[Gary RV_Wizard]

Why spend extra $ on AGM if you are selling it? Install the lower cost Marine/RV hybrid battery and you can still say " the batteries are new". With even modest care, the new owner should get 3 years of use.

 

[Kirk]

Unless the AGM is a condition of sale, I'd just make sure that it has a working battery. You could also give the buyer a choice of what they want installed?

 

[Blaise]

Thanks for the comments everyone. As a condition of the sale I agreed to install new batteries. The buyer agreed to purchase our coach without negotiation - that is, at the asking price. They then requested that the new batteries be AGM. Given that the selling price is considerably more than we expected, I feel that it is reasonable for me to spend a bit more on the battery type he requested. At least he didn't request Lithium batteries!

In the mean time, I discovered that the converter in the coach is a Progressive Dynamic model PD-9245C. According to the manufacturer, that converter supports flooded, AGM and Gel batteries. Though there is no temperature sensor, which as I understand it, is needed for an optimal AGM charger.

Thanks for all the responses and advice; it has given me some much needed peace of mind!

 

[Arch Hoagland]

Take pictures BEFORE you do anything!!

I switched to AGM a couple years ago and everything worked out good with no changes to my converter.

 

[Ray-IN]

Garys post #3 is accurate and brings up an important point. A converter cannot supply enough voltage to charge a battery. Charging voltage is usually around 14VDC-14.5VDC.

Just for accuracy's sake; a converter is not a battery charger. it converts 120VAC to 12VDC. It has a separate section that is a battery charger.
An inverter changes 12VDC to 120VAC, and also has a separate section that is a battery charger.

The 12volt Side of Life (Part 1) By Mark S. Nemeth

manmrk.net

 

[Mark_K5LXP]

It has a separate section that is a battery charger.

What contemporary converter is set up this way?

Mark B.
Albuquerque, NM

 

[Gary RV_Wizard]

Garys post #3 is accurate and brings up an important point. A converter cannot supply enough voltage to charge a battery. Charging voltage is usually around 14VDC-14.5VDC.

Just for accuracy's sake; a converter is not a battery charger. it converts 120VAC to 12VDC. It has a separate section that is a battery charger.
An inverter changes 12VDC to 120VAC, and also has a separate section that is a battery charger.

The 12volt Side of Life (Part 1) By Mark S. Nemeth

manmrk.net

I don't think I've ever seen a converter intended for RV use that was not a combo converter/charger, even those dating from the 1970's. Some are better quality converters & chargers than others, though. Whether any of the internal components are separate or not is surely academic as far as the RV owner is concerned.

Inverters, of course, are functionally much different than converters or chargers, so an inverter/charger is definitely two sets of internal components in one package. But again, that's all transparent to the RV owner.

 

[Ray-IN]

Mark; If a converter does not have a battery charge circuit, the output is limited to around 13VDC, which will not re-charge a battery sufficiently. It must have a separate circuit for battery charging with an output of around 14 -14.6VDC to reasonably re-charge a 12V battery bank.
I said section, which was not correct terminology, I should have said circuit.
Gary, you are right of course but I didn't specify an RV-specific converter. The RV-specific models do have a separate circuit for battery charging
I guess my reply #9 is poorly worded.

 

[Gary RV_Wizard]

Well, "converter" is pretty much an RV term, especially in the context of this forum. If not an RV component, that power converter would most likely be called a 12v power supply. In any case, I think the terminology has been clarified for those who are electrically tech oriented and completely muddied for those who are not.