AGM batteries

[thoer]

I thought that AGM batteries required a slightly different charging procedure than the WFCO provides?

[Santiago]

Originally Posted by Fox hunt

OK so i don't need to worry about over charging AGM batteries?

Yes you do need to worry about overcharging. Doing so will soon kill the battery.

My 2005 Scamp had one and when I sold it a year ago it was still good as new.
The new owner recently reported taking the old Scamp to Alaska for 3 months and is still using that battery. AGM batteries are drop and forget as they require no maintenance and can be mounted in any position except upside down. Always had them in the cabin with no fear of corroding near by metals, the terminals, cables nor gassing. I confirmed this indoor install with Lifeline last year.

My 2016 classic 21 ft came with the WFC 9855. It's specs reads:
Automatic three-stage battery charging maintains your battery’s life with three nominal voltage output modes: 13.2 VDC range “float” mode, 13.6 VDC range “absorption” mode, and a 14.4 VDC range “bulk” charge mode.

I have 2 sets of Lifeline dual 6vdc AGM and their requirements are :
LifeLine 6CT Bulk/Adsorb 14.2 - 14.4 v
Float 13.2 - 13.4 v

It seems that the WFCO 8955 we have in our trailers will properly charge AGM batteries without overcharging. Having said that, I disconnected the charging part of my WFCO as I have a 17 year old Xantrax Truecharge 40 amp charger with temperature sensor that takes battery temperature and adjusts the charging rate accordingly on all stages.

My AGMs are inside the cabin and over the axles on both street and curb sides for proper weight distribution. I expect they will be in service for at least ten to fifteen years hopefully more if not abused.

[Losangeles]

Originally Posted by thoer

I thought that AGM batteries required a slightly different charging procedure than the WFCO provides?

It is my understanding that AGM batteries need a 4 stage charge...

I seem to recall a lower float / trickle charge?

the stock (basic, cheap) battery controller in the Casita needed to be upgraded by myself to use an AGM.

I'll let someone much smarter than me chime in here... in 3....2....1....



John

[Santiago]

Originally Posted by Losangeles

We got it locally.... it was very very heavy.

I found the weight comparable to wet cell for the same amp-hour output.
Perhaps a little heavier, maybe ?

Nevertheless batteries are heavy suckers.
I purposely used 6 volt ones to cut the "haul in" weight in half.
Then I used two banks. This way I limit the weight I need to install and increase mounting options in a confined space. It helps that you can mount on its side.

I fully expect to never touch these again as they will outlive my use of the trailer. Like my previous trailer, the new owner will inherit them. They are Lifeline and I got a good price at a local but small, marine supply house.

[Santiago]

Originally Posted by Losangeles

It is my understanding that AGM batteries need a 4 stage charge...

I seem to recall a lower float / trickle charge?

The fourth stage is equalizing mode.

This is useful to do on wet cell batteries that that de-sulphonates their plates ( not terribly sure on how this works ) It seems that after some time, you should equalize to "refresh" the plates. Even more critical when you charge over and over but don't wait for a full charge to take place. Always do a full and complete charge if possible.

By and large AGM do not need this, some manufacturers forbid you to do so. I last heard that Lifeline is allowing users to do so but in a limited way. I will look into this with regards to Lifeline and act accordingly. My 17 year old marine Xantrax 40 will equalize on a schedule I choose.

[Brian B-P]

I've never heard of this brand, and I can't tell whether they are made by this company, or by someone else and just branded for them. They might be great... I assume that they work.

The weight will be comparable to flooded (conventional) lead-acid batteries of the same capacity and performance. For similar service (deep cycle), it's mostly just a matter of how much lead there is (more lead, more energy).

There is more detailed information available from the VMAX web site. The specific model in the Amazon listing is intended for golf car use; they have other models intended for RV use, which is largely a matter of dimensions and terminal styles.

Terminals which have a threaded hole generally work with the same cable ends as terminals which are threaded studs, as long as the bolt/stud diameter is the same.

[Fox hunt]

Jim -did you end up getting the Lifeline batteries GPL-4CT?

[alanmalk]

A little late to reply, I am. Been camping...

One advantage I didn't see mentioned is the very low self-discharge of AGMs.
Less than a quarter than that of a flooded equivalent battery. This means
that using batteries in parallel is reasonable, which is why I am using a pair
of 12v AGMs. At the time this saved me a bundle over a pair of 6v AGMs in
series - for the same net amp hours. (No other advantage to parallel that I
know of, just the $$ savings.) And the low self-discharge means no winter
charge is needed so I just leave the batteries in the trailer and they stay at
99%+ full all winter.

[Santiago]

Originally Posted by alanmalk

One advantage I didn't see mentioned is the very low self-discharge of AGMs.
Less than a quarter than that of a flooded equivalent battery. And the low self-discharge means no winter charge is needed so I just leave the batteries in the trailer and they stay at 99%+ full all winter.

Right Alan, the very low rate of discharge is wonderful.

I went with two 6 volt pairs simply because at my old age, dealing with the twice as heavy 12 volt was difficult especially when fitting in very tight quarters. Both 6 volts weigh about the same as one 12 volt but you divide the effort in half.

Because they last so long, I will not be removing to replace with new batteries. This was also part of my calculus. Their longevity actually makes them less expensive. The zero maintenance, drop and forget part clinched my decision.

[citabria90]

Originally Posted by Rossue

Hydrogen gas smells like rotten eggs.

Health Concerns with Batteries - Battery University

Hydrogen gas is odorless.
Hydrogen sulfide (H2S), which batteries give off when charging, smells like rotten eggs.

[Mike Lewis]

Originally Posted by Santiago

My AGMs are inside the cabin and over the axles on both street and curb sides for proper weight distribution. I expect they will be in service for at least ten to fifteen years hopefully more if not abused.

Santiago-

Could you give some details on your mounting location for your batteries? Also, what type/gauge wire do you use to connect one bank to the other, or is this even necessary? A solar controller and the WFCO would have to connect to both banks, I presume.

Thanks.

[Santiago]

Originally Posted by Mike Lewis

Santiago-

Could you give some details on your mounting location for your batteries? Also, what type/gauge wire do you use to connect one bank to the other, or is this even necessary? A solar controller and the WFCO would have to connect to both banks, I presume.

Thanks.

Mike,

When you say banks do you mean two 12v batteries in parallel ? or do you mean 2 6v in series making one 12v battery.

Assuming you meant the latter ... the goal is to operate the trailer as a 12v system, so you connect the 2 6v batteries in series to make one 12v battery. It's equivalent to purchasing one 12v battery. To me a bank is more than one 12v whether its from a single 12v or from 2 6v ones.

I connected my two 6v Lifeline AGMs together in series with AWG 4 welding cable. I use AWG 6 to connect positive and negative to my 3/8" lug terminals where "users" come in to feed on amps and chargers go to re-fill the battery. The 6v positive has a Blue Seas 60amp MRBF Terminal Fuse Block attached to terminal.

One highly desirable trait of twin 6v batteries is that you can more easily find a place to put them as each is half of a regular 12v battery. I have one 6v under counter on street side, the other half under refrigerator cabinet. The AWG 4 cable tying them runs inside the U dinette within the trough covered with paneling, out of sight and well protected. Nothing goes outside nor under the trailer.

Each 6v battery is mounted to a custom 3/4" plywood base (glued and screwed) that supports the holding straps. Just as a self contained passenger van seat supports the passenger by it's 3 point seat belt system attached only to the sturdy seat frame. What is left is to fully support the base to the trailer's plywood floor with 8 screws of correct length so as to not touch the fiberglass under belly. Trust me the custom base is hefty and will support the battery even is the trailer cartwheels on the highway. In addition to that, I made sure that steel angle iron on both sides would sandwich the battery. I would be negligent if this base could not easily come out as a whole unit. It does and I did several times to make sure. Access to battery terminal fuses, replacing cables, etc is doable. I hate when designers don't take repairing or replacing of components into account. A little overkill but that is how I do things and have never regretted it.

Due to the Classic's narrower floor line, I had to find space beyond the paneling back wall that actually has an inch or so more width before you touch the insulated wheel well. This was not an issue with the 6v under the refrigerator cabinet, in fact is was easier as that one had more room to work with when adding the inner lateral support member.

This is not an easy mod. I took it on because dense items like batteries should be over the axle, it's the purist in me. I later added two smaller 6v batteries under the curb side bench as far forward as the separation wall allowed meaning I wanted to distribute it's weight as close to the axle as I could. Compare this to the stock ETI wet cell battery in a box that was as far back as it would go. My reasoning for not separating these smaller ones was that with the refrigerator, furnace, water heater, etc already on the street side, I wanted to offset that on the curb side and they are smaller and lighter. Altogether I now have 530 amp-hour capacity.

[Mike Lewis]

Santiago-

Thanks for the detailed description of what you did. I appreciate the info.

[Santiago]

Originally Posted by Mike Lewis

Santiago-

Thanks for the detailed description of what you did. I appreciate the info.

Mike, as you can see it's not an easy mod nor necessary. The AGMs can just as easily drop into the curb side dinette bench next to the kitchen divider wall. I thought about doing that but because I knew I would need a second set of 6v needed to spread them around.

Did not post a photo or two because was just answering your question. If you need more info with whatever photos I can find, I would be happy to forward them to you.

BTW, your bellows is interesting, you obviously have good taste.

[fudge_brownie]

"Altogether I now have 530 amp-hour capacity."

I am curious as to why you have chosen to have four batteries? Running refrigerator on 12 volt while driving perhaps?

[Jim Bennett]

Originally Posted by fudge_brownie

"Altogether I now have 530 amp-hour capacity."

I am curious as to why you have chosen to have four batteries? Running refrigerator on 12 volt while driving perhaps?

His fridge runs on 12V only, all the time.

[cpaharley2008]

Santiago,
Are you saying that the 2nd set of 6v AGM batteries are not the same size, wattage, capacity as the original set of 6v you installed? You mention 2 smaller 6v batteries. You put 3 on the curb side and one on the street side, correct?

[Santiago]

Yes 12vdc Nova Kool 6.8 c.f. fridge always runs on 12vdc. Uses on average 2.5 amps. While driving, my DC to dc step up charger using truck alternator charges batteries at the maximum rate of 40 amps while driving. This is a smart three stage charger.

Why 530 amp-hr ? can easily do 4 days of boondocking before hitting the 50% discharge mark (12.1v).

[Santiago]

Originally Posted by cpaharley2008

Santiago,
Are you saying that the 2nd set of 6v AGM batteries are not the same size, wattage, capacity as the original set of 6v you installed? You mention 2 smaller 6v batteries. You put 3 on the curb side and one on the street side, correct?

Original 6v pair are identical creating one 12v battery. Second smaller pair of 6v are identical to each other, not the larger first pair and creates another 12v battery.

Both "12v" batteries are parallel to each other still only delivering 12v to house . My marine charger can individually handle three separate banks but I chose to see both "12v" batteries as one bank so that the trimetric can monitor total amp flow. I use this monitoring to see when I have used up 265 amp hours , the 50% mark indicating charging will soon be needed.

[cpaharley2008]

So your first dual sixers have a different capacity than the second sixers, correct. I always thought mixing different capacity batteries was not prudent, when charging the charger may only recognize the lesser battery, thereby you may not achieve 100% charging of all the batteries involved?