LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

[OceanSeaSpray]

Fantastic claims and exceedingly high charge voltages in the datasheets could be good reasons in themselves for ruling out a manufacturer as not serious or competent.
A lot of names have appeared and then vanished in the LiFePO4 prismatic arena in recent years.

I got a call from a sales manager at Sinopoly the other day and the message was "we are conservative and this is where we want to be".

One interesting thing they were saying was that they recommend paralleling smaller cells, rather than using large units for making larger capacity banks in mobile applications. The small cells are much stronger mechanically. Their preference was for using 100Ah cells, 200Ah absolute maximum and they were adamant about this.
Large capacity cells don't handle shocks and vibrations as well and they also rate their larger cells for a lower number of cycles.

[bill good]

About to replace lead house batt with 3 rows of CALB CA100S. Just after all the bits & bobs are made up. I can say that there will be a bit to comment on when it is all sorted!!

Regards Bill

[ColdEH]

Originally Posted by typhoon

My version of the the "Flux Gate Capacitor" .

With separate charge and load bus bars in place , house BMS in the center and the Tyco EV 200 above .

Regards

Just got my system up and running this weekend. 8 Sinopoly 300 AH cells in a single 12v bank of 600 ah . Im using a Link 10 monitor with a Housepower BMS by Clean power Auto.

Going to run them steady and see how many Ahs I get out of them before I need to recharge .

What a difference! When anything switches on , nothing flashes from dropping voltage , I can't tell when my Furnace comes on anymore (Webasto 2010).

Getting the lead out

Regards

[HueyHuey]

Hi, hoping for some advice and hoping I have posted to the right area even though I am not one who is currently using Lithium yet, but I hope to be by next week or so!
I am planning to install 8 x 3.2 volt 200ah cells, with the idea of linking them to create two banks of four cells in series, making 12.8 volts, in parallel, making 400ah as my house bank.
This will replace my current lead acid bank. I have moved back aboard my catamaran after an 8 month forced absence to find the batteries even worse than before. I will be living aboard with my wife and daughter and will increase this capacity further down the track.
I'll be ordering these batteries ASAP and will also be ordering a Victron battery monitor.
My primary method of charge will be solar, approx 150 amp hr per day running through a solar regulator. Secondary charging will be Xantrex 60 amp charger set to AGM. I also will get charge from my alternators. Lastly my wind generator ( when there enough wind where I'm anchored) which is an Air Breeze with internal adjustable regulation.
I realize from what I have read so far that although this set up may not be ideal for the time being, are there any major flaws that will see me damaging these new batteries until I get up to speed with knowledge and updating my set up?
Can I start with this set up, and gradually change my charging systems to more suitable ones as money becomes available and as I gain more experience or will I be doing damage and throwing away my money, batteries and time.
I understand that I cannot over charge these batteries and believe that none of my charging methods will result in voltages over 16 volts, and will also install a low voltage cutoff. I may not get full capacity yet but is this a real problem?
I need some batteries ASAP, and was planning to be better prepared but circumstances changed. Rather than buying conventional batteries and continuing the daily frustration of under charged batteries I am hoping to jump in both feet with Lifepo4 technology.
If there is anything anyone can contribute to assist in this transition to make it smoother it would be greatly appreciated.

[darylat8750]

Originally Posted by HueyHuey

Hi, hoping for some advice and hoping I have posted to the right area even though I am not one who is currently using Lithium yet, but I hope to be by next week or so!
I am planning to install 8 x 3.2 volt 200ah cells, with the idea of linking them to create two banks of four cells in series, making 12.8 volts, in parallel, making 400ah as my house bank.
This will replace my current lead acid bank. I have moved back aboard my catamaran after an 8 month forced absence to find the batteries even worse than before. I will be living aboard with my wife and daughter and will increase this capacity further down the track.
I'll be ordering these batteries ASAP and will also be ordering a Victron battery monitor.
My primary method of charge will be solar, approx 150 amp hr per day running through a solar regulator. Secondary charging will be Xantrex 60 amp charger set to AGM. I also will get charge from my alternators. Lastly my wind generator ( when there enough wind where I'm anchored) which is an Air Breeze with internal adjustable regulation.
I realize from what I have read so far that although this set up may not be ideal for the time being, are there any major flaws that will see me damaging these new batteries until I get up to speed with knowledge and updating my set up?
Can I start with this set up, and gradually change my charging systems to more suitable ones as money becomes available and as I gain more experience or will I be doing damage and throwing away my money, batteries and time.
I understand that I cannot over charge these batteries and believe that none of my charging methods will result in voltages over 16 volts, and will also install a low voltage cutoff. I may not get full capacity yet but is this a real problem?
I need some batteries ASAP, and was planning to be better prepared but circumstances changed. Rather than buying conventional batteries and continuing the daily frustration of under charged batteries I am hoping to jump in both feet with Lifepo4 technology.
If there is anything anyone can contribute to assist in this transition to make it smoother it would be greatly appreciated.

You need to read a lot more. Preferred bank is parallel first and then series. 16 volts will destroy your LiFe battery in short order. AGM setting is not satisfactory. Do not float LiFe ....

[mcarling]

Originally Posted by HueyHuey

My primary method of charge will be solar, approx 150 amp hr per day running through a solar regulator. Secondary charging will be Xantrex 60 amp charger set to AGM. I also will get charge from my alternators. Lastly my wind generator ( when there enough wind where I'm anchored) which is an Air Breeze with internal adjustable regulation.
I realize from what I have read so far that although this set up may not be ideal for the time being, are there any major flaws that will see me damaging these new batteries until I get up to speed with knowledge and updating my set up?
Can I start with this set up, and gradually change my charging systems to more suitable ones as money becomes available and as I gain more experience or will I be doing damage and throwing away my money, batteries and time.
I understand that I cannot over charge these batteries and believe that none of my charging methods will result in voltages over 16 volts, and will also install a low voltage cutoff. I may not get full capacity yet but is this a real problem?

Yes, this is a real problem. 16V is way too high. A few seconds at 16V will not do any harm (if the temperature is within specs), but sustaining 16V for a few minutes is very risky and longer than several minutes at a time will eventually destroy your batteries. I suggest setting all your charging sources to 13.8V with a high power cutoff at 14.0V.

[HueyHuey]

Thanks for the response. I looked at the site again and extracted this:
Voltage: 3.2V nominal, 2.5V min, 4.2V max.
I understood this to mean the max voltage would be 4 x 4.2 volts = 16.8v
I thought if none of my charging methods exceeded 16 volts I would be safe.
If this is not the case, can I still use my gear but have it modified to reduce the max voltage being output, perhaps by the use of in-line resistors or such?
My Xantrex charger does have a custom setting that can be programmed by Xantrex or an OEM supplier, has anybody done this?
Thanks again

[bcn]

I would strongly recommend that you take you the time to read the following article thoroughly:
LiFePO4 Batteries - Thoughts & Musings Photo Gallery by Compass Marine How To at pbase.com

4.2V will trash the cells

[mcarling]

Originally Posted by HueyHuey

Thanks for the response. I looked at the site again and extracted this:
Voltage: 3.2V nominal, 2.5V min, 4.2V max.

Those specs are chosen to sell batteries, not to ensure they survive.

Originally Posted by HueyHuey

can I still use my gear but have it modified to reduce the max voltage being output, perhaps by the use of in-line resistors or such?
My Xantrex charger does have a custom setting that can be programmed by Xantrex or an OEM supplier, has anybody done this?
Thanks again

Adding resistance is not an optimal way to regulate your voltage. You'll need to check each charging source to see whether or not you can set the maximum voltage to 13.8V or 13.9V or worst case 14.0V. If not, you'll want to replace any component that would overcharge your batteries.

[bill good]

HueyHuey, Going thru the same process but as yet not on boat. Putting 3 cells in parallel with light pigtail fuses (4A)across the cells to keep the voltages balanced and to give a simple 4 port logger to provide tracking. Using 250 A ANL fuses to link directly the mid section of the 4 cells. (Same spacing on my cells as a fuse holder). Used two kits from Jaycar KC5377 voltage switch set to cut off at 13.65 by my choice & commences recharge @ 12.00V & KC1732 flexi timer set to give 7.5 mins before disconnecting the charge source. BMS is CM090 to give absolute cut off at 4V & 2.5V (daisy chained to cut off circuit) )with some bypass for top balancing if I find any real drift. Every sense & control wire is 24 G aircraft wire & every wire can be shorted any where as all feed connections are a min 47K. Will put on boat in New year & will provide cold beer at the rear end of my car in the mean time!! Keep the range well away from the max & mins like all are advising & you will be OK. Will do a proper report with logged results when finished & debugged!!

Regards Bill

[darylat8750]

Originally Posted by bcn

I would strongly recommend that you take you the time to read the following article thoroughly:
LiFePO4 Batteries - Thoughts & Musings Photo Gallery by Compass Marine How To at pbase.com

4.2V will trash the cells

+ 1 on This. Mainsail " knows whereof he speaks."

[deckofficer]

Originally Posted by darylat8750

+ 1 on This. Mainsail " knows whereof he speaks."

Maine Sail has over time mentioned on this thread everything in his article for Compass Marine, sure beats going through 4000 posts.

His section on alternator outputs is a must read for folks that already have a successful install. Our LiFePO4 cells can cook alternators the first time you do a charge at just fast idle with a bank at 80% DOD.

LiFePO4 Batteries - Thoughts & Musings Photo Gallery by Compass Marine How To at pbase.com

[Mobile Diver]

After reading this entire thread, I just want to add my thanks to all the posters who took their time to share their experience. I have learned a tremendous amount.

[T1 Terry]

Originally Posted by HueyHuey

Thanks for the response. I looked at the site again and extracted this:
Voltage: 3.2V nominal, 2.5V min, 4.2V max.
I understood this to mean the max voltage would be 4 x 4.2 volts = 16.8v
I thought if none of my charging methods exceeded 16 volts I would be safe.
If this is not the case, can I still use my gear but have it modified to reduce the max voltage being output, perhaps by the use of in-line resistors or such?
My Xantrex charger does have a custom setting that can be programmed by Xantrex or an OEM supplier, has anybody done this?
Thanks again

Haven't posted here for quite a while, been busy as a one arm wallpaper hanger.
The 4.2v is up in the death area but if you fast charge this is the very upper limit the voltage can reach, but the currant rate still needs to be 3CA, that's 300amps per 100Ah capacity, constant till the 4.2v is reached, then you stop charging. If you can't produce that 300 amps per 100Ah capacity for the full length of the charging cycle then the 4.2v is not relevant to the way you plan to charge the battery so that figure has no relevance to you. The low voltage figure does how ever and that voltage is under load, not rested voltage, drag the cells down to that rested voltage and you probably have already damaged them as the voltage under load would have been much lower than that.
This will get me crucified by the BMS sellers, but do not use cell top balance boards, I have 5 dead cells here, 2 with the cases burst as a result of cell top balance boards being used on house batteries, murdered over a 3 yr period by the death of a thousand cuts.
Why, every time the cell reaches 3.6v it is already 0.2v over full voltage charged so it is generating heat internally, then the balance board kicks in and starts to burn off some of current still entering the cell in an attempt to hold it's voltage at 3.6v till all the other cells reach 3.6v. To do this it creates a controlled short circuit and converts the current to heat, this heat has no where to go but into the cell terminal. The cell is already trying to dump heat via its terminal bolts, the last thing it needs is more heat added. The result is a small amount of the electrolyte is vaporized and creates pressure within the cell, the pressure relief valve will hold this pressure until it gets extreme, but not until that point is reached will it vent. Every time the cell gets hot the plastic case softens, add a constantly increasing pressure to a soft plastic case that is bundled to prevent bulging and weakness fractures will begin to form, particularly around where the cases are plastic welded together. Eventually either a cell internally shorts producing a rapid gassing or the case fails, either can eventually results in the case bursting a piece out and the death of that cell. No fire, no acid sprayed over battery compartment, with adequate ventilation there is not even a fire risk potential as nothing created a spark and the vapour is only flammable, not an explosive mix of hydrogen and oxygen like that from a lead acid battery, but a dead cell none the less.
Putting my tin hat on now and heading for the bunker.

T1 Terry

[T1 Terry]

Originally Posted by T1 Terry

Haven't posted here for quite a while, been busy as a one arm wallpaper hanger.
The 4.2v is up in the death area but if you fast charge this is the very upper limit the voltage can reach, but the currant rate still needs to be 3CA, that's 300amps per 100Ah capacity, constant till the 4.2v is reached, then you stop charging. If you can't produce that 300 amps per 100Ah capacity for the full length of the charging cycle then the 4.2v is not relevant to the way you plan to charge the battery so that figure has no relevance to you. The low voltage figure does how ever and that voltage is under load, not rested voltage, drag the cells down to that rested voltage and you probably have already damaged them as the voltage under load would have been much lower than that.
This will get me crucified by the BMS sellers, but do not use cell top balance boards, I have 5 dead cells here, 2 with the cases burst as a result of cell top balance boards being used on house batteries, murdered over a 3 yr period by the death of a thousand cuts.
Why, every time the cell reaches 3.6v it is already 2v over full voltage charged so it is generating heat internally, then the balance board kicks in and starts to burn off some of current still entering the cell in an attempt to hold it's voltage at 3.6v till all the other cells reach 3.6v. To do this it creates a controlled short circuit and converts the current to heat, this heat has no where to go but into the cell terminal. The cell is already trying to dump heat via its terminal bolts, the last thing it needs is more heat added. The result is a small amount of the electrolyte is vaporized and creates pressure within the cell, the pressure relief valve will hold this pressure until it gets extreme, but not until that point is reached will it vent. Every time the cell gets hot the plastic case softens, add a constantly increasing pressure to a soft plastic case that is bundled to prevent bulging and weakness fractures will begin to form, particularly around where the cases are plastic welded together. Eventually either a cell internally shorts producing a rapid gassing or the case fails, either can eventually results in the case bursting a piece out and the death of that cell. No fire, no acid sprayed over battery compartment, with adequate ventilation there is not even a fire risk potential as nothing created a spark and the vapour is only flammable, not an explosive mix of hydrogen and oxygen like that from a lead acid battery, but a dead cell none the less.
Putting my tin hat on now and heading for the bunker.

T1 Terry

That should read 0.2v, not 2v