New Agm Fullriver Dc85 Battery On The Way

Continental Battery up in Fishers IN apparently gets them in. Which I assume is close enough for you to drive to and not have it shipped.

Again, just a word of caution that the plywood battery "door" needs to be modified slightly on the inside, if you do get the 85.

 

Sweeney: Sorry. I just digested your other concurrent battery thread and realized that you have already gone the Continental Battery route in Fishers… with less than satisfactory results. Though maybe your query to them didn’t include the Fullriver specifically at the time. Or maybe it did.

I think that any automotive source is going to get you the same quizzical response. They may be a designated “dealer, but may sell only 1 or 2 a year. Which is why I went with a solar supplier, who may be more amenable to a low-cost shipping solution, and can provide better technical specifics on their AGM products. Even though they may not be within driving distance.

 

The Continental Battery in Fishers is about 5 minutes from my office. I visited the store...and was told they don't have them, and if I wanted one, they would have to transfer it from their warehouse in Jacksonville, and they would want me to pay the shipping fees. I'll never hear from them.

So now, I'm on the hunt for a plan B --- I'm not sure what CampInn uses, nor do I know what my other options are.

I like the idea of a dedicated, actual deep cycle. But if I can't get an answer I'll be getting a $90 lead acid before my next trip, feeling justified in being grumpy about the finickyness of LIFEPO4.


What modification to the door was needed? I assume it needs to be shaved somewhere?

 

Yah… the inside “L’ bracket that holds down the battery needs to be shaved back 1/2”. And the big brass terminals unscrewed. Minor renos. Still lots of room for hands to get it in and out.

 

I'm not sure what L bracket this is, mine just sits on a wooden tray....Sounds like the brass knobs just screw off? I'd be better with this, but right now all of my tools are stored in such a way as to be completely useless.

I'm not a fan of modifications of any camper -- things never look the same afterward, even if noting is visible...something about knowing the change is there...waiting Its my ADD that kicks in....

I've seen some videos from these guys; these batteries look REALLY substantial!

 

The L is on the door and holds the battery down when the “door’ is replaced. Door won’t go back on without some very minor surgery. Easily replaced/duplicated/modified again if another battery of slightly different dimensions comes along. Which I’m sure is what CI intended in the beginning.

I thought that yours is 2019 and had it as well. Without it, the battery would have a tendency to “jump” if given the requisite inertia.

I lost my aversion to extra holes about 3 major modifications ago. Besides… only a CI owner or factory employee would know what I’ve done. And the older you get, you eventually forget what you’ve done. Win-win.

 

Mine is a 21. I don't remember seeing anything 'L' bracket there.

<EDIT>OH! THAT L bracket. I had metal in my mind when yo said that, the bracket you are talking about is perfectly clear now. Yah, no problem modifying that, although the plywood they use even for that is BEAUTIFUL, I almost hate to cut it </EDIT>

But I haven't been that focused on that part of the camper, I'll look at it today. Right now, it's still all disassembled while I am waiting on the final selection of a battery. Its strange continental has the reatil store but seems put off when you try to buy from them. Very odd.


HAHAHA --- I've made a couple of mods to mine already, too, I'm not totally averse to it. There are things I'd never to, such as drilling holes in the skin --- those are too "undoable"

 

This is interesting. I was looking at the Walmart website, and their battery, the DC24, shows a 101Ah Capacity... which is only 85.

It looks walmart uses a non-standard discharge rate --- they use a 1 amp discharge to get to 101 Ah, the industry standard is a 5 amp load --- anyone know about this? I could only find mentions in forums nothing in documentation.

I'm curious what the capacity is at 5amp load...how does it compare to the 85amp of the Full River...

 

I'm not sure how that amp load above translates.... but the standard "oranges-to-oranges" spec is the "20 Hour Rate" for comparing deep cycle batteries. Any reputable battery (and battery manufacturer) will have that listed as at least one of their AH specs. For a decent Group 24 AGM, with some legs, that works out to between 75 and 85 AH. Much more than that (i.e. in the 100's) and they are fudging the numbers or using a different calculus to make it appear you are getting more AH, when you aren't. The physical size of the box creates the absolute upper limit of 85 (or at the most 90), no matter how they try try slice it up inside. Group 27s legitimately get into the 100's. But they are significantly bigger in volume than ours.

When comparing batteries, my thoughts were that once you're above 75, the desire to try to cram in and squeeze out those couple extra amp hours begins to take a back seat in importance to the overall build quality of the battery, and other purchase considerations.

 

Man, I love it when I can learn something Thank you Sir! I want you on my team when TEOTWAKI happens!

This question has taken me down a few rabbit holes, and with the input above has made a light bulb come on, and I think I got it!

I think where I went wrong was not knowing the 20 amp rate was standard. And that Wallymart fudges its numbers. I did find a deka sheet (who used to make walmart batteries) and they claim 75ah capacity at standard rate. Neither Deka nor Clarios are really good at details, especially when compared to Fullriver. Looking exclusively at Fullriver from here on out.

The DC85 gets the ~8ah capacity due to the AGM. 85AH is the optimal number, but since I'm planning around a relatively high 4 amp load, I need to use the C10 value. Giving a usable capacity of somewhere around 75 Ah. From here, the calculations are pretty simple

Standard power laws apply here -- if I am pulling at the C10 (10 hour) rate, that will give 77AH available in the DC85. 77ah/4amp=19 hours of actual use, leaving the battery dead flat. If I want to keep at 50% depth of discharge, I would need to charge at 9 1/2 hours. I could discharger further, but reduce the number of charge/discharge cycles the battery will have.

Of course, that's worst case (why do I want sausage and cheese?) In the real world of shedding loads and duty cycles of things like the fridge, I would use considerably less energy. The fridge might run 40% of the time, the lights 10% (2 hours) Laptop Charge 2 hours etc.

Looking at cycle counts, if I discharge down to 60% routinely, I can still expect 700-1000 cycles out of the battery. If I stay above 60% remaining, that number goes up. If it is discharged only 10-20%, the battery will last thousands of cycles. Assuming I have a daily charge with solar or charging off the tow vehicle, I should rarely go below 80%.

Other than rainy days and extended stays, this really does put a good-quality AGM battery in a strong contender place. The lithium really gains on extended stays in cloudy or tree-covered places since it charges much faster so you could theoretically charge in just a couple hours. However, with reasonable sun or tow vehicle power, the argument isn't quite as strong, especially at 2.5-3 times in cost. IF you can even get one.

I think I just sold myself on Fullriver.

https://fullriverbattery.b-cdn.net/wp-content/uploads/DC85-12.pdf

 

You crunched far more numbers than I ever did before I pulled the pin.

The AHs available at the 20 hr rate, I believe, reasonably approximate real world, average RV usage and drawdowns. Which is why manufacturers (generally) use it as the default measuring stick. If you have lower retail integrity and wish to sell to an uninformed consumer, you quote them the 100 hr rate and watch their eyes light up.

The slightly fewer AHs available at the 10 hr rate is probably more accurate, or what one could expect, if you are continually operating a number of devices or a power-hungry fridge. The 100 hour rate is only truly useful information if all you ever power are a few LED lights and the occasional water pump. Either way, the AH difference between the quickest (5hr) and slowest (100hr) full drain on the battery is only 25%. Not enough to really get worked up about.

Besides, only drawing down to 50% DOD (which is a reasonable strategy, and probably very good advice, even with a true Deep Cycle, and especially if you want to extend your battery replacement intervals) automatically cuts in half whatever nominal AH increase you may have realized by getting a slightly higher capacity battery. You're always leaving AHs on the table.

Probably, the only way to really know what you're able to suck out of the battery on an ongoing basis, and throughout its working life, is to stick a meter on it.

I would trust Fullriver's posted specs and testing processes. Their batteries are used more often in stationary solar situations by informed consumers who have a far greater interest, far more batteries in their collection, and far better ongoing diagnostic equipment, than the average RV'er; Fullriver would be foolish to fudge or misquote their numbers like a WalMart.

The other upside to the AGM, is that it will be far more tolerant of unplanned full drains. Especially if you haven't fully figured out the "how" and "where" and "why" of your run of short-lived batteries.

I still think the best and most convenient and functional place for a lithium is outside of the trailer, where it is portable for a myriad of other camping and domestic purposes, where (above-freezing) charging temperatures can be much more easily controlled, and without the need for extra electronic gadgetry to make it play well with the trailer and the tow vehicle.

 

I'm often accused of over analysis. In this case, I'm in an unusual situation where today I can afford it, tomorrow I may not -- so I'm trying to find the best overall solution.

When I was in flight school, my instructor asked me to make a flight plan from my home airport to one that was about 40 minutes away, then to a 3rd airport and home --- to make a triangle. He never really told me what HE meant by that. I calculated departure, wind, rate of climb, point where we would reach cruise altitude using air density charts, and calculated time in climb. We would reach cruise altitude at this point on the chart. Cruise would continue to X minutes, where we would begin descent at this point on the map, all with math far more advanced than my ability.

He laughed out loud when I shared it. Saying "You're going to LOVE instrument training..." Then pointed out it took longer for me to plan the flight than the flight would actually take. He was right. Flight time was a little over an hour, it took me two to plan it. But I knew down to the quart how much fuel I was going to burn darn it!!!!

For what its worth, I ordered the battery and am making an "L" bracket on my 3d printer. I want to be able to leave the factory untouched...Look for the drawing on Thingiverse when I'm done. No one will need it but me, but I'll know its there.

Whats wrong with me

I suppose the thing is that now I have a much better understanding of battery rating, and I agree totally with your assessment of quality and "stationary solar use" principles. I also have my own numbers to prove it --- so when my friends at work (bit lithium fans) tell me that Lithium batteries are HOT right now...I can say they are right, knowing I made the right decision for me.

 

There are days I just shake my head. After wanting to charge me to ship it, and being unclear if they even could, I specifically said "Call me if you can get one..."

Apparently in some ones mind that is "order one for me"

They just called and were put out when I told them I found another solution. I mean come on folks!!!! It flat out amazes me sometimes that companies make any money. The waste and poor communication astounds me some times. So, if you're in the midwest...I know where there's a battery.

 

I now am pretty sure that battery replacement can be one of the more vexing aspects of trailer ownership, and best prolonged, if at all possible.

Who was your other source?

 

yah, this is the first replacement. I’ve been through this 3 times now. Joy of repeat ownership.

my first upgrade to AGM. But in this case to an obviously superior battery. I likely will be doing a little more boondockig, actually planning on trip out west in March and April.

we will see how it actually goes!

 

I went with the Victron Super Cycle AGM that claims it can withstand 100% depth of discharge. It fit into my battery compartment without modification.

Victron 412110081 Data Sheet | Unofficial Camp-Inn Forum

 

Very nice option! I wish I had seen this one.

 

I think that most true, well-made deep cycles can withstand the occasional 100% discharge. Doing so will reduce the overall number of lifetime cycles. But the the total number of amp hours that it will provide over its lifetime stays roughly the same.

For example, the Fullriver (and I assume the Victron, or any other quality deep cycle, like a Trojan) can provide, according to its spec sheet:
500 cycles of 90% DOD (which amounts to 45,000 "units" of energy) or
5,000 cycles of 10% DOD (50,000 "units").

Not a big difference in total lifetime output considering the quite different discharge profiles.

What could possibly have a greater (or a negative) impact on the total number of "units" recovered from the battery over its lifetime, is not necessarily which DOD profile to which you ascribe, but the practice of not fully recharging the battery before you start to draw from it again. I seem to recall in my distant, previous research that there is some irreversible degradation of the plates that can take place with the practice of beginning to discharge before full recharging has completed. But please don't quote me on that.

In other words, it would seem to be far more important to bring the battery back up to 100% of charge after each discharge, rather than trying to pay close attention to the DOD you regularly or occasionally take it down to. This is where a DC-DC charger will shine, and extend the life of the battery and maximize the lifetime number units of energy you can pull out of it.

And before you have to start the agonizing search all over again.

 

All done finally! The battery is charging now, so it should be ready in a few hours for its first trip. I don't know when that will be, but it will be soon. Basiclaly the first decent weekend...

Just as Steve and Karen said --- its pretty much a direct drop in replacement. I chose to remove the brass posts

The only modification necessary is the removal of material from the battery tiedown. It would have taken me 3 hours to unpack the woodworking tools. I'm lazy. It took 10 minutes to draw it and $1 in filament. So I just used a 3d printed it instead. plus, I have the factory original mount. If, for any reason, I want to reinstall it. The plywood they use is a thing of beauty...

I published the change in thingiverse if anyone wants it...

 

Nice “thingi”.