Question about power converter....

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stepbill

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I would like to upgrade my single battery to two agm batteries mounted in parallel to give me more amp hours. I currently have a WFCO 65 amp power converter, model WF-9865 and was wondering if I need to upgrade the amp power? The batteries that I am looking at are Weize 12V 100ah agm sla vrla batteries. Bought the TT used and found out that I also have a Progressive Industries electrical management system, model EMS-HW50C.
 

Kirk

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AGM batteries do NOT require a special charger. However, LIKE ANY OTHER BATTERY, it will benefit from the ministrations of a quality "smart" charger. According to the WFCO owners manual for your model on page 5, it states that it is a 3 stage charger. It is available on the WFCO website if you don't have one.
I also have a Progressive Industries electrical management system, model EMS-HW50C.
If you would visit the website of the products in the RV you can download a copy of the service manual for almost any item. The Progressive website has this copy of the manual you need.
 

Mark_K5LXP

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AGM's can accept a higher bulk charge rate than flooded but at 20% rated Ah even a nominal 55A converter hits that mark for 275Ah worth of battery. So knowing what those 2 batteries in parallel actually are size wise will tell you if there's any room for increased converter capacity.

Mark B.
Albuquerque, NM
 

John From Detroit

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First on the PI HW-50C Excellent. best of class.

Now on the converter.. There is one company that recommends what I call fast charging of their AGM'd (Lifeline) but most recommend standard.. Standard is LESS than 30% C/20

What doesd thast mean? It means if your batteries are Group 27 the WFCO is actually a touch big for a pair of 'em. Group 29's about right for a pair of 'em

Frankly I'd go with a pair of GC-2 Flooded wed over AGM.
 

stepbill

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I just checked and the battery that is currently in the camper is an Interstate group 24M-XHD. What size dual batteries should I go with? Thanks for the replies!
 

Gary RV_Wizard

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The WFCO 9865 is fine for 200 AH of battery. The amp value isn't critical anyway - a low amp rate just takes a little longer to reach full charge and a high rate is just unused capacity.

The 65 amp max rate is combined battery charging and 12v source for the trailer electrical to use. The electrical system has priority and charging gets what is left over. Very little of the charging cycle can use the max rate anyway - the battery essentially throttles down the charge rate as the percent of charge builds up. The max rate would occur only briefly while the battery was at a very low state-of-charge.
 

Gary RV_Wizard

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the battery that is currently in the camper is an Interstate group 24M-XHD. What size dual batteries should I go with?
It depends on how much amp-hour capacity you think you need (and are willing to pay for!).

The 24M-XHD is a marine battery (hybrid of cranking & deep cycle) with an 81 AH capacity. Doubling the number of a similar size/type of battery would double the AH and thus double the time between the need to recharge. Or enable you to run more powered devices for a lesser amount of time. If the budget permits, the group 27 size increases the AH by about 20% over the 24 size.

AGMs typically have a slightly lower AH capacity vs flooded cells like the 24M-XHD, but they have far less maintenance needs.
 

Rob&Deryl

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Long story.
I have 2 AGM CG2 6v batteries. 220ah.
I have been doing solar experiments for the last week, leaving converter off and seeing how long I could go on solar alone. Details…. I was on city water so no pump, fridge on electric (though controls I believe are 12v), hot water on propane heat & lighting. My solar fully recharged the battery every day until 2 days of overcast where at the end of 3 nights and 2 cloudy days the batteries were at 50%. Oh, it was cold nights, mid 30s, so heat ran a bit.
I turned on the converter. It is a WFCO. 55a. For the first hour or so it provided about 25a of charge. This reduced as the batteries charged. Al in all, I got an average of 5% per half hour.
My goal was figuring generator runtimes.

Your data may vary!
 

Mark_K5LXP

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I turned on the converter. It is a WFCO. 55a. For the first hour or so it provided about 25a of charge.
A data point that would be useful to measure is voltage right at the converter and voltage on the battery terminals during bulk charge. I would expect that any battery at 50% or less would initially draw the full capacity of the converter and if it doesn't, it implies there's some voltage drop in the wiring between the two. "Less" current is OK if you have time for the charge to soak but on genset you typically don't want to run any longer than you have to.

Mark B.
Albuquerque, NM
 

Gary RV_Wizard

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Just out of curiosity, would this converter charge a lithium battery?
Yes, but the battery would probably NOT reach full (100%) charge. The absorption and float charge voltages are a little low for optimal charging of a lithium battery. WFCO now offers improved versions of it's charger that include battery charge profiles (modes) optimized for lithum instead of lead. They even have a switchable model that can do both, so you can upgrade your converter now and change battery type later.
 
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