AGM vs Lithium

[Westley]

I don't know that there is anything wrong with a $60 NOCO with a lithium setting.

Speculating - it could be the amps of the charge. Lithium as I understand it, needs fast charge.

Anyway, looking at their site, they appear to be marine. Nothing wrong with that for RV. I prefer stuff made for marine to use on my RV when I have a choice.

But I see nothing in the $60 range. I haven't read the specs on the products, looking specifically for lithium compatibility.

https://no.co/products/charging/onboard

I did look at their 10 amp 1 bank charger, and it specifies lead acid. https://no.co/gen1

Here's the specs on etrailer: https://www.etrailer.com/Battery-Charge ... -GEN1.html

It says nothing that I see about being compatible with lithium for RV.

[John61CT]

Speculating - it could be the amps of the charge. Lithium as I understand it, needs fast charge

No, LFP is just **capable** of charging faster, accepting a much higher C-rate than lead. In fact LFP prefers a C-rate well under 0.4C, even slower when temps get cool

and it is AGM that requires a high current for longevity.


> I don't know that there is anything wrong with a $60 NOCO with a lithium setting.

Voltage is the key, vendor standards are way too high. For 4S, you want close to 13.8V, and no AHT is required for normal cycling, just CC only is better.

> I prefer stuff made for marine to use on my RV when I have a choice.

Absolutely, very little produced for/by the US RV sector is even barely acceptable.

Obviously good charge source at high amps will cost a high proportion of the bank's price.

That's why user-custom adjustability is important, will work with all your various chemistries at a given nominal voltage range.

Again, if you don't care about extended longevity, then not to worry, buy based on price.

In fact a cheap used server PSU will do the
job, combined with either you watching for the termination point, or set up an adjustable HVC to automate the stop charge.

With a BMS HVC protecting against that primary means failing. . .

[tony.latham]

But I see nothing in the $60 range. I haven't read the specs on the products, looking specifically for lithium compatibility.

The Noco charger I use on my AGM has a Lithium setting. I suspect all smart chargers have that capability.

It's my understanding that lithium batteries can --in theory-- be charged faster but they don't need to be. That $200 charger has a fan (and I don't know where it would fit in my teardrop since it is fairly large). I'll stick to my potted $60 Noco charger.

Tony

[Westley]

Quote: "Again, if you don't care about extended longevity, then not to worry, buy based on price."

I do care about longevity.

I also care a great deal about making good choices to avoid buying something then finding I went in the wrong direction. That's a waste and it's happened to me way too often.

And I'm just as guilty of overkill, or over thinking something. I wish I could find a happy balance. I'm working on it, but by now I figure I will always default to the side of over doing something, rather than minimalist.

And by-the-way, I appreciate your feedback but I'm new at these conversations online, and it takes a while to decipher your abbreviations, and in some cases I'm not sure I get it..

And Tony,

I wasn't recommending that charger. I was just showing it as an example where the specs talk about converter/chargers not all being suitable with lithium batteries. This fact is something to be aware of, in my opinion. And, etrailer.com seems to me to be a good source for products and info. They may not be the best price, so compare.

[John61CT]

If you can't grok something I write, feel free to ask for clarification after googling doesn't help.

Places like etrailer may sell good stuff but they won't have clue about how to optimally coddle LFP for extended longevity. Like most of the industry, they will assume the specifications as laid out by cell manufacturer in the cells' data sheets (e.g. 3.6V termination voltage, plus AHT / CV additional) are recommendations intended for normal functioning, operating conditions for day-to-day cycling.

In fact they specify absolute maximum / minimum limits of acceptable ranges only,

these are "stress ratings", to which the cells can only be subjected for short times, without causing irreparable damage.

Frequent exposure to such stressful conditions, or for extended periods, can adversely affect cell reliability and will greatly reduce lifespan.

Again, just ensure the setpoints of the charge sources you use are user-custom adjustable, avoid chargers touted as "lithium ready" but with only "canned" profiles to choose from.

[bdosborn]

I had an Iota charger for my LA batteries, they sell a charge wizard for LiFePo4 so it was easy for me to convert. Battleborn doesn't require a special charger. From their website FAQ:

Do I have to buy a special charger for LiFePO4 batteries?

You do not need a special charger to charge your LFP deep cycle battery. As I mentioned above the battery prefers to bulk charge at 14.4 volts and float at 13.6 volts. Most standard chargers can handle these settings. There are some made for lithium chargers available on our store page and they will charge faster than a regular charger in most cases.

Of course you would never know it reading RV forums. There are a lot of posts from people insisting that a special charge routine is required. So far, I haven't read any posts from people having issues with charging but its amazing to me how many people freak out over it. One year and counting for my LiFePo4 battery. I just did an 80% discharge test - still at 100% capacity.
Bruce

P.S. Here's the charge pendant I use for the Iota charger:Linky

[Westley]

From the same web site:

https://battlebornbatteries.com/charger ... ity-table/

They say the concerns are common.

If they bother to address compatibility, there must be something to it. Seems to me mixed signals.

If I was in a situation where I needed to know for sure right now, I would call their customer service # and ask.

Also, here:

https://battlebornbatteries.com/chargin ... batteries/

[John61CT]

As I have said many times just in this thread, every vendor source will give the same BS, that charging LFP over 14V ~3.6Vpc is "just fine".

And indeed it is, if you are willing to accept just getting the "standard" quoted cycle lifespan. Which of course will get you past the warranty period

But it is easily possible to go 10,000 plus cycles, IOW decades by treating the pack more gently and avoiding the voltage/SoC "shoulders".

Does not actually sacrifice much capacity utilization either.

[bdosborn]

I was set to buy a Battleborn till I emailed them about the Iota charger. The response I got back was disappointing, I got the impression they had a kid answering emails that didn't know much. I would definitely call rather than email...
Bruce

[bdosborn]

As I have said many times just in this thread, every vendor source will give the same BS, that charging LFP over 14V ~3.6Vpc is "just fine".

<snip>

So what cells, charger and BMS do you use for your setup?

Bruce

[John61CT]

Depends on the use case, haven't done a trailer yet.

Winston, CALB, GBS, Sinopoly and A123 for the cells.

Solar controller usually Victron, but have worked with dozens going back 40 years

Shore chargers mainly Sterling, Promariner, Magnum, some Victron, and very often ex-telecom PSUs (rectifiers) coupled with HVC.

DC-DC units mostly use Sterling, looking to test Victron and Kisae.

Have tried nearly every one out there, but only those three are adjustable.

Also balancing "hobby" chargers, can be excellent, but not cheap.

And Victron SCs can work well for DCDC also.

Lab style PSUs for balancing / maintenance / testing mostly Sorenson.

Alt VRs, Balmar MC-614, want to get into the new Wakespeed / APS units.

[bdosborn]

So what specific charger would you recommend for an LiFePo4 RV battery setup and what are the charge setpoints?

Bruce

[bdosborn]

Just to muddy the waters some more, here are 20 pages of discussion on charging Battleborn batteries:

https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/30043082.cfm

Bruce

[John61CT]

So what specific charger would you recommend for an LiFePo4 RV battery setup and what are the charge setpoints?

Bruce

One that has adjustable setpoints.

And one would need to either extract from BB or figure out how to reverse engineer the voltage where their BMS starts balancing

since that now dictates the minimum Absorb/CV voltage, rather than doing what's best for the cell chemistry.

Personally as I said that's one reason (out of many) I advise avoiding drop-ins

I would not use a BMS that didn't allow that setpoint to be adjusted to be compatible with my choice of charging regime

rather than letting a $20 generic component dictate the profile.

Also, requiring you to sit holding the Full charge point for however long to allow the criminally slow passive/resistance balancing to complete is very bad for the cells' longevity.

And afaik no way to even tell when the balancing is finished!

Just a stupid design IMO.

But hey great for noobs don't want to learn the details, wants to just use old lead-type chargers, and that's their target market.

And if their dropin lasts ten years, or they're still around and honor the warranty, then fine and good for many, worth the extra premium.

Just not for me.

[tony.latham]

But hey great for noobs don't want to learn the details..

John:

What lithium battery and charger are you running and how's it working in the real world?



Tony