Flooded vs, AGM vs Li comparison - interesting but not objective I think

[Christian P.]

Let's say your use case is to drive to Tuktoyaktuk in the winter, where temperature would be regularly between -20C (-4F) and -40C (-40F).
Let's say also that you may not be able to keep the batteries warm all the time. There is a good chance that the vehicle would be parked for days or even week without moving.

What would be the best choice then?

 

[Joe917]

We lived in our camper through Jan to March in Ottawa. We hit -25C for a few days and nights.
If you are living in the vehicle in those conditions the heating is on and the camper will be kept at 20C. If you have Li batts install them inside the heated envelope just like your water. Lead acid, do what you want, you will lose capacity with them outside but they will be fine. Our FLA bank is outside the heated envelope and power supply was not an issue.

 

[01tundra]

There's also things like depth of discharge, charge rate, maintenance, mounting options and physical weight that play into why I will never own another LA battery in any of our trailers.

 

[Christian P.]

We lived in our camper through Jan to March in Ottawa. We hit -25C for a few days and nights.
If you are living in the vehicle in those conditions the heating is on and the camper will be kept at 20C. If you have Li batts install them inside the heated envelope just like your water. Lead acid, do what you want, you will lose capacity with them outside but they will be fine. Our FLA bank is outside the heated envelope and power supply was not an issue.

I was talking about not living full time in the camper. A camper that will stay parked unheated and not running for a few days or weeks at -20C. It is fairly typical in Quebec. Park the camper at the camp, take the snowmobiles out for a few days and come back later.

 

[pnichols]

LOL fast charging an LFP bank when well below freezing temps can render a 20,000 investment instant scrap dead as a doornail.

How anyone "feels" about that fact is irrelevant, and it's very easy to test if you really doubt it.

Now milder temps and slower rates, you might only be losing a few hundred cycles per incident iff the back end, might not notice for 15 years, so yes hard to get data, lots of variables involved.

LFP as a generic chemistry is only "getting better" in two senses

1. manufacturers have been improving energy density (not power density)

2. we now know better how to treat them in order to get 8-10,000 cycles before SoH hits 75-80%

The problem compared to 15years ago, is that the list of proven top notch quality cell makers has hardly expanded, but there are hundreds of "cheap Chinese" vendors selling via eBay and Ali, and then all the so-called "drop ins" and powerpacks where no one know what the cells are like, often not user replaceable, so have to assume 2-3000 cycles is best case scenario.

Bang for the buck in lead, so long as you are buying true deep cycle units

by far is FLA.

Unless you really need the higher C-rates, or mounting on their side or something.

The best lead battery value by far is Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries, 2x6V, around $200 per 200+AH @12V pair from BatteriesPlus or Sam's Club. NAPA relabels it here: https://www.napaonline.com/en/p/NBP8144 Deka self-labeled also sold at Lowes.

The only good AGM for true deep cycling usage is Odyssey, Northstar and Lifeline

with some special use cases justifying Firefly Oasis.

But the cost per Ah per year is at least 2-3x the Deka's.

Well John ... what do think of these true deep cycle AGM batteries at over $300 each and over 72 lbs. each:
https://www.fullriverbattery.com/product/dc115-12/

 

[john61ct]

Relative to the NA market, Full River are not great, but certainly better than AGM you find in automotive / big box retail.

On par perhaps with Deka / Trojan AGM

but much poorer from a **value** POV than the top notch FLA GCs those two sell, as well as Superior / US Battery / Crown.

Being Chinese, far too much of their value is eaten up by shipping around the world,

likely not available at a dealer near you for pickup

and afaik do not have top notch tech support teams standing by to answer question and discuss the finer points of your specific use case, as all these other vendors do.

Do they even have detailed datasheets and manuals readily available?

Also technically far inferior from a longevity POV, compared to top AGM makers Northstar, Odyssey and Lifeline.

Apparently however in international markets where duty / tax factors apparently are a big issue

Full River is pretty much the top quality available at pricing considered relatively reasonable there, maybe even cheaper than say Trojans

but then everything decent in those markets seems outrageously expensive by USA standards. Which is why the LFP business is much more mature there, often same price per usable Ah as top AGM, compared to 5-8x the price in the US.

As a side note, among those NA companies that sell "meh" quality deep cycling AGMs but do not actually have factories that produce same

apparently FR is the OEM / outsourcer for many of them.

If that is true for the likes of Rolls / Surrete at the very top of the FLA industry (15 year lifespan routine)

I would reckon their QA specs as FR's customer would result in a much higher quality product than what FR sells under their own label.

 

[john61ct]

In filing the above screed, I came across a notation

"Maine Sail sez they aren't half bad"

So **if** they are much cheaper per Ah than those top 3 AGM makers, and

you really can't make use of FLA

then go for it!

 

[pnichols]

I quit using FLA batteries years ago in my offroad 4X4 PU, our motorhome, our home backup generator, and our garden sprayer ... got tired of corroded terminals, constantly checking their water, and having to stock distilled water in my shop.

I rejected use of Lifeline AGMs in our motorhome because of their specified float voltage value - after phoning Lifeline to confirm. The most competitive battery right next to Lifeline AGMs, and almost as expensive at the time, was a true deep cycle Fullriver AGM battery model. Some Trojan distributors even stock Fullriver as a choice instead of their house brand Trojan batteries.

I'll consider lithiums in our RV once they're offered in Group 31 size (instead of Group 27/29) and are made up of six large cells instead of a bunch of little cells soldered together. BTW, I wonder how many lithium RV batteries are made up of a bunch of lithium cells manufactured from somewhere outside of the U.S.?

 

[john61ct]

The US has not had any significant role in LI batteries for decades.

A123 was a pioneer, out of MIT, the production factories all in China of course

now owned by a Dutch conglomerate.

That toothpaste is not getting back into the tube.

And LFP 12V is 4 cells not 6.

Other LI chemistries you have to 24V.

 

[pnichols]

Well ... at least this lithium "Group XX size" battery sure isn't only 4 or 6 cells ... and probably a lot of their lithium competition, as used in RVs, is built the same way (i.e. IMHO way too many little cells soldered together to be mechanically reliable in the long run):
https://www.lithiumion-batteries.com/uploads/files/15019/12V 100AH Internal Design PDF.pdf