LiFePO4 - The future for off-grid battery banks?

[Sunny Solar]

As INETDOG has pointed out you can buy a 12,24,48,96,and 144v Life PO4 battery with the BMS built in.This then allows you to use them with any inverter no problems. And many solar chargers can have the settings adjusted to suit adequately the batteries charging needs.

[Sunny Solar]

Russ dont know where you got your info but Mikes batteries are Ni Fe. He has many posts talking about them .

[Sunking]

Before anyone gets too excited about the LifEPO4 batteries they might want to read Mike's (another moderator) posts about his set.

He does not have LiFePo4 (Lithium Iron Phosphate). He has NiFe I believe.

[russ]

Before anyone gets too excited about the LifEPO4 batteries they might want to read Mike's (another moderator) posts about his set.

[Fatawan]

Hi,

Has anyone run across an inverter/charger designed to charge lifepo4 batteries?

Thanks,
Zak

Yes--no need to custom build one

http://www.victronenergy.com/upload/documents/Datasheet%20-%20Quattro%203kVA%20-%2010kVA%20-%20rev%2012%20-%20EN.pdf

http://www.victronenergy.com/upload/documents/Datasheet_Lithium_ion_rev03_EN_web.pdf

[inetdog]

Nope no demand for them. Only ones I know about are ones made for RC toys. You would have to custom build one.

Or find an LiFePO4 battery system with internal BMS which has been designed to work with a conventional inverter/charger. More than one way to skin a cat, although not what the OP asked for.

[Sunking]

Hi,

Has anyone run across an inverter/charger designed to charge lifepo4 batteries?

Nope no demand for them. Only ones I know about are ones made for RC toys. You would have to custom build one.

[zak650]

lifepo4 compatable inverter/charger

Hi,

Has anyone run across an inverter/charger designed to charge lifepo4 batteries?

Thanks,
Zak

[Fatawan]

I am working on a 6. 5 kw system and are considering lithium nmc or iron phosphate batteries. I am currently doing research and have found Corvus energy that offers these for actual solar systems. I am waiting for more info and pricing from the manufacturer. Will get back when I hear more.

Northernflyer

Did you ever get any more info on these batteries? I have a call into the company but no response yet

[russ]

http://www.evtradinpost.com/item/556

The discription says that they are "ideal for solar installations, wind and other energy storage applications". Also reads that they include the BMS.

Sorry but that site sounds one or more steps lower than fleabay

[billvon]

Sounds like you have had some bad experiences with lithium ferrous and talked to some people who weren't particularly cluey about lithium ferrous cells, certainly not manufacturers.

We worked with two manufacturers, actually, to get a better spread of experience.

Pulse charging is actually the preffered method of ultra fast charging but there are very few charging systems capable of doing it, these cell are tested at 20C pulse charge rates so pulse charging certainly isn't a problem for lithium ferrous cells.

After the pulse charging disasters of the 1990's no one is willing to try that charge regime any more.

Like I said, glad it's working for you. We find that there is a big difference between "it looks like it will work" and "we can guarantee its operation over X cycles when charged to Y volts at Z temperatures."

[deadbeat]

Any Thoughts About These 12V 1000AH LifePO4 Batteries?

http://www.evtradinpost.com/item/556

The discription says that they are "ideal for solar installations, wind and other energy storage applications". Also reads that they include the BMS.

[T1 Terry]

Sounds like you have had some bad experiences with lithium ferrous and talked to some people who weren't particularly cluey about lithium ferrous cells, certainly not manufacturers. Pulse charging is actually the preffered method of ultra fast charging but there are very few charging systems capable of doing it, these cell are tested at 20C pulse charge rates so pulse charging certainly isn't a problem for lithium ferrous cells.
There are no secrets or mysteries wit the chart, the cut offs are 3.6v, I'll do a reprint
Brian's battery test day one.jpg

T1 Terry

[billvon]

Lithium ferrous are far more rugged than lead acid could ever hope to be

That hasn't been our experience, but good luck with your experiments.

Here is graph of one in action on a 24v battery pack

That sort of charge profile was rejected by at least two LiFePO4 cell manufacturers that we talked to. They were worried about pulse charging, especially the peak voltages it entailed. It would be interesting to see the entire graph without the high voltages cut off.

[T1 Terry]

actually there are very close similarities between lithium ferrous chemistry and super capacitor chemistry, same electrolytes, very similar coatings but a much thinner plate coating on a super capacitor which enables it to to charge and discharge at such high currents, the down side is bugger all storage capacity.
Lithium ferrous are far more rugged than lead acid could ever hope to be, what lead acid battery would recover from a 100% discharge repeatedly without loss of capacity or sit for 3 yrs at 50% state o charge and still have the same 50% when the come out of the box? 4.5V is the true danger no return point for lithium ferrous cells, a simple HVC circuit using the Junsi cell logger stops the over charge of any cell, switch the solar output to a water heater element while the battery voltage settles, then back to charging or simply switch the element on if the current draw is greater than the solar input potential. Here is graph of one in action on a 24v battery pack
Brian's heater in action.jpg

The load is greater than the solar input so the cell voltage drops, the fact that there is no capacity over 3.4v is shown here by the near vertical drop of cell 7 & 8 voltage from the high 3's to below 3.4v.

T1 Terry