The pitfalls of bying Lithium batteries (article)

[Almot]

In my quest for REALLY lightweight battery I found this article (haven't found lightweight battery though, nothing under 28lbs for Gr31).

http://www.electriccarpartscompany.com/The-Pitfalls-of-Buying-Lithium-Batteries

Not technical, but interesting insights on raw material sources (please let's not make it political). Buyers beware for those considering sources like Aliexpress. I particularly like this: "Lying is a perfected art and a way of survival in China" :)...

But read the article.

They have BMS-less kits too, for those interested in tinkering.

[GordonThree]

Glad I'm not manufacturing lithium batteries.

[Almot]

pianotuna wrote:
15 is 200% less than 45.

It is not half-empty, it is half-full 🙂

When you reduce 45 by 100%, this 45 minus 45 =zero. Can't reduce a material item any further without resorting to devices kept under guard in Area 51.

But you can increase 15 by 200%, yes.

[pianotuna]

15 is 200% less than 45.

[Almot]

road-runner wrote:
A statement from the linked article:

"Raw Low grade lithium can be as much as 220% lower in cost than high grade refined lithium."

Is it possible for something to be more than 100% less? Isn't "100% less" equal to zero?

The article is not technical. He probably meant 2.2 times lower cost than high grade refined lithium. The point was - with many sources you don't know what you're buying. Low-grade Lithium will affect performance tremendously. 2 or 3 times difference in cycle life between good ones and bad ones is not unheard of.

Mex: There are "some" data on cycle life vs DOD, not much. Relion is one of bigger players - or more aggressively marketed, and by the appearance of their Manual I don't feel like trusting it. Last graph on the last page.
3,000 cycles at 90% DOD and 4,000 at 80% DOD before capacity drops to 80%, if I understand it correct.
In total AH per $ over battery life it looks like Li is already ahead of flooded. Or so the advertisers say.

Top charging voltage affects life even more than DOD, there isn't much about this in marketing materials and I don't see programmable 115V chargers that would stop at desired adjustable 14x voltage (or switch to 13.6, same thing with Li) when it's 85-90% full. Average solar controller will do a better job.
Annual capacity loss (3-4%, more when hotter?) is usually missing from marketing materials too.

Itinerant: light weight is important to me because this is a trolling motor in a light boat. My RV is happy with 70 lbs AGM, they are not moved.

[2oldman]

road-runner wrote:
Is it possible for something to be more than 100% less? Isn't "100% less" equal to zero?

lol.. yeah.

Almot wrote:
, but interesting insights on raw material sources (please let's not make it political).

The article doesn't mention Australia, Chile or Argentina as sources of lithium. and those are numbers 1,2 and 3 on the list of biggest sources.

I'm very happy with my 48v battery. I've mistakenly discharged it to 10% a couple times, where it shut itself down and recovered just fine. It's Lifepo4 with all the BMS built in. If you're going Li I don't recommend shortcuts or going diy cheap.

[theoldwizard1]

For RV applications, I would ONLY consider lithium-iron (LiFe). Less power, different charging, but MUCH SAFER]/b] !

[pianotuna]

For your never off the grid an LI battery would be wonderful, if you have deep pockets.

Assuming lead acid:

What is the longest time the RV will not have shore power? Double that time, and measure the consumption. Use a Kill-a-watt meter. From that data it would be possible to calculate the number of amp-hours needed for the bank.

[MEXICOWANDERER]

Planning-

Depends on the number of amp hours of the battery. How far down does it discharge? And the percentage remaining whereupon you connect to A.C. power? Let's say you have 2 100 amp hours dual-purpose batteries. That would be fine. A single battery may discharge into the + - 50% range...a dual purpose battery would not be optimum.

[MEXICOWANDERER]

INDEED!

"It is more equal"

[road-runner]

A statement from the linked article:

"Raw Low grade lithium can be as much as 220% lower in cost than high grade refined lithium."

Is it possible for something to be more than 100% less? Isn't "100% less" equal to zero?

[Planning]

Mexico,

What battery type do you recommend for this type of use:

Never off Grid.

On 50 amp service to converter/charger (Charge Wizard) to RV every evening from check-in until check-out each travel day.

5th wheel plugged into truck while traveling with usual travel day of 8 - 10 hours.

2000W Magnum pure sine inverter powering Fisher/Paykel residential inverter style reefer while traveling.

On 50 amp service while at destination.

[MEXICOWANDERER]

It might be helpful to refer to a trusted depth-of-discharge-versus-cycle-life-chart.

For an off-grid situation cycle life is crucial. But take a number like "500" cycles then see how great a DOD that would allow. Five hundred cycles is nothing to sneeze at. How about 700 cycles?

How many vacations equal 500 cycles? Weekends. Boondocking...?

Take care of an AGM and it will last an eyebrow raising number of cycles even at 80% depth of discharge.

But abuse will kill these numbers. These batteries must be recharged correctly.

What a lot of folks misunderstand is that battery plates get eaten whether they use the battery or not. Telecomm battery float life is something like 12-15 years. But thin plate AGMs like Full River and Odyssey only float well for 6-8 years.

During that period of time Go For It. If I hauled batteries to the wilderness every weekend they'd better be prepared for an 80% depth of discharge (20% remaining). But right after they got near a power line they would be meticulously recharged. There is NOTHING wrong with impressing 14.4 volts regulated charge across the battery, then have a timer shut the charger off. A 105 amp hour battery and a 20 amp charger can be timed for say eight hours. The extra hour or two spent at 14.4 WILL NOT HURT THE BATTERY. The voltage of course must be changed in cold weather.

Would lithium make sense for a weekend warrior or even for a 2-week camping spell, in comparison to AGM? I would like to have some numbers ran past me if you think lithium is justified under these conditions. The entire and I mean TOTAL factor of justifying lithium is TIME. Many weeks spent partially recharging the battery. Repetitive cycles.

Too often, customers read of a battery "trait" then extrapolate it to the boundaries of sanity. Chemistry does not work that way. An AGM battery will not be killed by occasional periods of 80% recharged. It's when the batteries see weeks and months of partial recharging that will occlude negative plate material.

So sifted down, flooded batteries "have their place". So do AGM batteries. And lithium construction has their optimum setting. Pluses and minuses. Strong points and weak. Compromises. Everything has it's compromising nature.

[GordonThree]

I'm waiting for the LiFePo4 craze to pass. That particular chemistry doesn't excite me.

[Isaac-1]

It is battery replacement time for me too, and I am looking at a compromise possibly going with Firefly Oasis Carbon Foam AGM, they get nearly the deep discharge capacity of Lithium in a lead acid AGM for about half the price of LiFePO4. So while they still have the weight of Lead Acid, they have nearly double the effective power with safe deep discharging.