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rcoon3 · 05-16-2022, 05:46 AM

Greetings. I have a heart interface freedom 20D inverter/charger in my 1995 Beaver Marquis. Currently has 6ea 6V 235AH interstate deep cycle batteries that are well past their life expectancy being approximately 10 years old and starting to bulge on the ends. The manual for the current inverter indicates a setting for Gel batteries. Not sure, since the inverter is sooo old, if the terminology wasn't interchangeable 27 years ago between AGM and GEL. Just for clarification I am aware a new inverter is best practice, unfortunately I am also aware that would be an additional $1500 minimum expense. So, I am trying to do this on the cheap.

My question is can the current inverter charger (20D) effectively and safely charge AGM batteries? Has anyone done this with success? I fully intend to replace the inverter charger in the future but can only do one expensive project at a time. My biggest concern is the current batteries catching fire given their bulging condition. Thanks for the input

puttin · 05-16-2022, 09:40 AM

Howdy there,

Here's a link with alot there for your answer. You could use your current charger is the short answer but depending on it's output voltage and current it may not optimize your new battery's performance. I do know you could get a new charger for much less than you stated- just do a search and you'll find a few. Personally, I'd contact WFCO and see what they have.

https://www.google.com/search?client...harge+profiles

twinboat · 05-16-2022, 09:54 AM

Gel batteries had a different charging profile then AGM. Gels would fail if the charging voltage got to high.

I would stay with the Flooded setting and you should be fine.

Here is a screenshot of my solar controller showing the only slight difference in profiles of flooded and AGM batteries. # 5 and 6 are large L16 tracton batteries.

Click image for larger version

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Suburbazine · 05-16-2022, 02:11 PM

Your wet cell profile is likely alright for AGMs although it may cause some slight additional wear on the cells on extremely hot days. But that tiny little bit of voltage is likely within margin of error for cable resistance.

rffowler55 · 05-16-2022, 03:09 PM

Quote:

Originally Posted by rcoon3

Greetings. I have a heart interface freedom 20D inverter/charger in my 1995 Beaver Marquis. Currently has 6ea 6V 235AH interstate deep cycle batteries that are well past their life expectancy being approximately 10 years old and starting to bulge on the ends. The manual for the current inverter indicates a setting for Gel batteries. Not sure, since the inverter is sooo old, if the terminology wasn't interchangeable 27 years ago between AGM and GEL. Just for clarification I am aware a new inverter is best practice, unfortunately I am also aware that would be an additional $1500 minimum expense. So, I am trying to do this on the cheap.

My question is can the current inverter charger (20D) effectively and safely charge AGM batteries? Has anyone done this with success? I fully intend to replace the inverter charger in the future but can only do one expensive project at a time. My biggest concern is the current batteries catching fire given their bulging condition. Thanks for the input

Does the manual mention a 'Customs' option for the charger setting? If yes, then you can input the correct parameters recommended by the new battery manufacturer. If not, then the flooded setting, as referenced by others, is your best option.