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NeilV · 10-13-2006, 12:02 AM

I asked the lead tech about this the last time I had my coach serviced because my batteries had to be replaced under warrenty and I was willing to pay the difference to upgrade to AGM's, his answer was:

If they did not install a converter/charger certified for deep cycle AGM batteries and set it to AGM mode then of course the batteries would fail. They deal with this all the time and simply put a good quality set of lead acid batteries back in place of the AGM's to resolve this in most cases. You may get by with some of the older converter/chargers but since there is not compatibility list that he is aware of you are just taking a chance on loosing your investment if you don't replace it with one certified as AGM compatible.

For most people it is just not worth it inless they need a new converter/charger anyway.

He may have just been giving me a line to get out of having to swap out the batteries that he had just installed but he did seem sincere.

RV Wizard · 10-13-2006, 12:17 AM

Do some homework on the AGM batteries and you will find that they are more durable than the lead acid and can be charged with the same chargers as lead acid; www.dcbattery.com/faq.html

Half Dimes · 10-13-2006, 09:57 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by NeilV:
I asked the lead tech about this the last time I had my coach serviced because my batteries had to be replaced under warrenty and I was willing to pay the difference to upgrade to AGM's, his answer was:

If they did not install a converter/charger certified for deep cycle AGM batteries and set it to AGM mode then of course the batteries would fail. They deal with this all the time and simply put a good quality set of lead acid batteries back in place of the AGM's to resolve this in most cases. You may get by with some of the older converter/chargers but since there is not compatibility list that he is aware of you are just taking a chance on loosing your investment if you don't replace it with one certified as AGM compatible.

For most people it is just not worth it inless they need a new converter/charger anyway.

He may have just been giving me a line to get out of having to swap out the batteries that he had just installed but he did seem sincere. </div></BLOCKQUOTE>

I think the tech was right. According to the book Managing 12 Volts by Harold Barre where multi-stage battery chargers are discussed:

'One feature is a switch that allows the charger to produce a changing profile designed for a sealed gel cell battery or a conventional wet cell battery. Wet cell batteries need a voltage of 14.4 volts during the bulk stage to remove the lead sulfate from the plates, however, this voltage is too high for a gel cell battery.'

I ran across this issue when I was upgrading my converter/charger to a PDI and getting new batteries. At the time, there were two versions of the 'charge wizard' available, one for conventional wet cell, and another for gel cell batteries.

RV Wizard · 10-14-2006, 01:16 AM

AGM and Gel Cell batteries are two very different animals. You can damage a gel cell very easily with too high of charging voltage. Don't mistake an AGM for a gell cell. I have about 60 pages of print on the different battery types, maintenance of them and the good and bad of each for any one that is intrested I can provide a list of links and you can compile this too. Stay safe.

NeilV · 10-14-2006, 01:56 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RV Wizard:
AGM and Gel Cell batteries are two very different animals. You can damage a gel cell very easily with too high of charging voltage. Don't mistake an AGM for a gell cell. I have about 60 pages of print on the different battery types, maintenance of them and the good and bad of each for any one that is intrested I can provide a list of links and you can compile this too. Stay safe. </div></BLOCKQUOTE>

Mike,

I was looking into this some more during my noon break at work yesterday and found one manufacturer of marine AGM batteries who had the charge rates posted for their batteries. When ambient temperatures are hovering around 100 degrees they listed a charge rate of 2.1 volts per cell as the max acceptable voltage. That would be 12.6 volts not the 13.8 to 14.4 that you get from a standard wet cell charger.

However this is from the internet and could be suspect as could the information provided by the lead tech at LazyDays.

My portable charger does support that the needs of these three different battery types are unique as it has three different charge programs, Wet, Gel and AGM and cautions not to use the Wet program on the Gel or AGM batteries.

It would be conforting to have a few links to some credible sources of information on this topic.

I do not have a very high confidence level in the service advisors at LazyDays and if their lead techs are also blowing smoke my way I would like to have then dead to rights on this.

I look forward to reviewing any links to information counter to what LazyDays is giving me that you can provide.

Thanks,

Road Pilot · 10-14-2006, 10:30 AM

Neil,

These statements don't seem to be consistent with Concorde batteries pages on AGM batteries.

Here's a reference to a curve they publish for charging voltages versus temperature. http://www.lifelinebatteries.com/rvgraphs.php

Their graph is speced for ambient temperatures up to 50 degrees. I wouldn't want to think about a battery charging at temps above that.

If you read all their info on AGM versus gel versus std lead acid, AGM's have a much lower internal impedance so they can be charged with currents twice that of std batteries (as they said don'[t try this at home or your cables might melt) and with float voltages and bulk charging voltages the same as std lead acid.

They should know what they're talking about since they sell a lot of AGM's to the military.

RV Wizard · 10-15-2006, 04:26 AM

Here are some other links for anyone wanting to do research on this topic:
http://www.dcbattery.com/faq.html#1
http://www.usbattery.com/care.htm
http://www.windsun.com/Batteries/Bat...ery%20Charging

NeilV · 10-16-2006, 07:39 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RV Wizard:
Here are some other links for anyone wanting to do research on this topic:
http://www.dcbattery.com/faq.html#1
http://www.usbattery.com/care.htm
http://www.windsun.com/Batteries/Bat...ery%20Charging </div></BLOCKQUOTE>

Mike,

That and the info at:

http://www.batterystuff.com/batterie...PS-121000.html

Gave me all I needed to know. Some manufacturers may void the warrenty if you are using an older charger that does not have controlled charge stages and temperature compensation. Most RV charges don't fall into that catagory is the claim from Power Sonic. They back up that claim with the following:

"Power Sonic Batteries requires no special battery charger as do GEL CELL batteries. If uncertain if the battery charger you currently using will properly charge an AGM battery please consult us before using the charger. Typically RV and Marine charging systems require no modification when using Power Sonic AGM Batteries."

As for LazyDays, well there are some shadows being cast in their direction and they are not sitting in a good light in my book.

Thanks for the info it got me started in the right direction. The misinformation that I got from the LazyDays tech has delayed the transformation to AGM but I live in South Florida and wet batteries just don't last too long over here.

Regards,