Inverter to lithium question

[freshalaska]

I have an old Xantrax inverter that will charge at 100 amps but is not compatible for chargeing lithium batteries. Can I have the inverter go thru a Victron 100 amp programmable solar controller so I can program the charging profile? Or what other way to do it? New charger is close to $900.
What do you think.

[sailorboy1]

Originally Posted by freshalaska

I have an old Xantrax inverter that will charge at 100 amps but is not compatible for chargeing lithium batteries. Can I have the inverter go thru a Victron 100 amp programmable solar controller so I can program the charging profile? Or what other way to do it? New charger is close to $900.
What do you think.

I don't know about the solar controller thingie idea.

But what is about the Xantrax that makes you feel it isn't compatible to your lithium?

[freshalaska]

The Xantrax inverter charger won’t let me set up a lithium charge profile.

[sailorboy1]

Originally Posted by freshalaska

The Xantrax inverter charger won’t let me set up a lithium charge profile.

What is a lithium profile to you and what can you setup?

[freshalaska]

I think it just has dip switches to say gel,agm and lead acid. Not at the boat now so don’t have manual in front of me although I might be able to view manual online. Just trying to get this straightened out in my head before I buy anything.

[GreenWave]

If you cannot alter the actual voltage levels on the charger I would NOT use it for lithium. Could it charge them- sure. Will it be good for them - NO.

[sailorboy1]

I don't have a "lithium" setting in my charger. But I have am AGM with 14.1 bulk and 13.4 float.

If I were the OP with a charger so old it only has dipswitches I would look at as this is the time to update.

[freshalaska]

I have the same settings as you do Sailerboy. Dip switches isn’t the problem.

[HeywoodJ]

Originally Posted by freshalaska

I have the same settings as you do Sailerboy. Dip switches isn’t the problem.

I think you may have missed the main point, Sailorboy runs LFP batteries on his AGM set charger. He has many threads on the subject, but the current one provides all the details you would need to make your own decsion.

There will be a fair amount of "you can't do that", and with some reason, but it has been demonstrated to work in a fair number of installations.

[GreenWave]

At risk of beating the horse here... If you buy cheap drop in Lithium then the financial risk of doom or shortened life is smaller. Therefore, a non-Lithium profile or a profile that cannot be adjusted is ok. If not, then buyer beware when your lithiums only last 4-5 years instead of 8-10.

[sailorboy1]

Originally Posted by GreenWave

At risk of beating the horse here... If you buy cheap drop in Lithium then the financial risk of doom or shortened life is smaller. Therefore, a non-Lithium profile or a profile that cannot be adjusted is ok. If not, then buyer beware when your lithiums only last 4-5 years instead of 8-10.

Just why in you world is charging the batteries in spec going to shorten the battery life?

[HeywoodJ]

Originally Posted by sailorboy1

Just why in you world is charging the batteries in spec going to shorten the battery life?

I'll bite. I know you regularly espouse the opinion that all this detailed charging consideration for LFP is hoodoo, but the "spec" was written by a marketing department that wants to sell you a "drop-in replacement" battery. For that to work the spec has to match what we do/did with the lead-acid batteries it is replacing. General industry consensus on LFP systems would say the spec is wrong. Just because somebody wrote it down doesn't mean it is right. Just because there is an industry consensus also doesn't mean it is right. So you get your opinions, you pay your money and you take your chances.

[sailorboy1]

Originally Posted by HeywoodJ

I'll bite. I know you regularly espouse the opinion that all this detailed charging consideration for LFP is hoodoo, but the "spec" was written by a marketing department that wants to sell you a "drop-in replacement" battery. For that to work the spec has to match what we do/did with the lead-acid batteries it is replacing. General industry consensus on LFP systems would say the spec is wrong. Just because somebody wrote it down doesn't mean it is right. Just because there is an industry consensus also doesn't mean it is right. So you get your opinions, you pay your money and you take your chances.

Sorry please explain what the answer is in there? My position is that charging in spec of the battery charging profile is correct. Why do you say that that only works if you use a charger that says "lithium" on it that the marketing department you are bad mouthing came up with?

As an engineer with an MBA who spent a good portion of his career in sales I don't believe you understand how engineered product sales work

[HeywoodJ]

Nope, not what I am saying. If the spec says to charge up to 14.1V, and the charger does that with something labeled "AGM" it really doesn't matter what the charger label says, what matters is what the charger does. If you're happy with the battery spec then go for it. But putting the term "engineered product" next to batteries you call "cheap" is stretching at least a little. The battery market is the wild west right now, everyone who wants to can sell as many as they can get their hands on, quality of product simply doesn't matter, and neither does reputation because it is 100% a seller's market. That will straighten itself out, but for now it is very, very much caveat emptor.

As an engineer who manages more than half-a-million LFP cells, and measures and records the voltage of every single one of those cells, I can tell you that the LFP industry as a whole has moved downward in total voltage at which you should finish charging every year. Right now, for greatest cycle life and least risk of damage, every single (A list) cell manufacturer from whom we purchase recommends running our batteries between 12V (3.0V/cell) and 13.6V (3.4V/cell), with an HV cutoff at 14.4V (3.6V/cell). They universally drop the allowable charge current starting at 3.4V, and at 3.5V are down to 0.05 to 0.1C as maximum allowed charge current.

14.1V is 3.525V/cell and is well into the knee with LFP, which means it is well into the area where a very small imbalance can lead to a large difference in voltage, and aggregate charge voltage settings become an issue.

It works for you, and on the basis of one sample you will never know if treating those batteries differently would increase or decrease their life, nor by how much. I don't think you should change a thing, really none of my business, and quite frankly, even though I am deeply into extending battery life as part of my job, if putting them on the boat I would probably opt for the ease of using "normal" charging settings and equipment, and accepting the imputed reduction in cycle life. The specs I cited above lead to a 12-year life at 365 cycles/year from 0-100% SOC and a guaranteed 80% capacity at EOL. I'll never treat my boat batteries like that, so even if the charge profile is not optimum I'd likely get more life out of them than I can use.

[sailorboy1]

and here I thought questions and replies about batteries on this site had to do with using them on boats