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Old 26-01-2017, 19:35   #5506
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

So when extended cruising do your batteries get to 100%SOC then remain there until getting to an anchorage/destination or are you continually cycle them?
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Old 26-01-2017, 20:08   #5507
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Current LFP setup in boat. which has served me well for 4 years and 30,000+ miles.



Relearning how to add attachments and pictures. Been off forum for awhile. The other attachments I posted in the pior post I can open. Don't know if viewers can.
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Old 26-01-2017, 20:27   #5508
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

I think the idea is when the bank gets charged, disconnect the charging sources and let your house loads draw on them wherever you are. When cruising you need to monitor them, and when not cruising run them down to half full and disconnecting them.
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Old 26-01-2017, 20:50   #5509
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Thanks to all who responded, especially Maine Sail.
No floating, so will check with victron to see if there is a setting(assistant) that stops charging at 100%SOC then restarts charging when bank down to a 30% SOC(perhaps use the relay in the BMV 602s fed to a multi input.
So when underway running the engines cruising with alternator(s) charging you need to turn them off, or risk damaging them unless there is another battery in line? Hum, I am going to need to some run separate voltage sense to the start batteries as the alternator's voltage sense wiring is run straight to the LFP bank. If no voltage sensing is connected to the target battery the alternator can run away. This is getting more and more complex for this novice. At this point I will just cruise as is but be sure to isolate the LFP when stopped with shore power available.
Best Regards to all
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Old 26-01-2017, 21:31   #5510
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Originally Posted by Joe Parklane View Post
Thanks to all who responded, especially Maine Sail.
No floating, so will check with victron to see if there is a setting(assistant) that stops charging at 100%SOC then restarts charging when bank down to a 30% SOC(perhaps use the relay in the BMV 602s fed to a multi input.
So when underway running the engines cruising with alternator(s) charging you need to turn them off, or risk damaging them unless there is another battery in line? Hum, I am going to need to some run separate voltage sense to the start batteries as the alternator's voltage sense wiring is run straight to the LFP bank. If no voltage sensing is connected to the target battery the alternator can run away. This is getting more and more complex for this novice. At this point I will just cruise as is but be sure to isolate the LFP when stopped with shore power available.
Best Regards to all
Once the alternator takes LFP house to 100 per cent (determined based on X minutes at Y voltage or Y voltage until current drops to Z, Mainesail has provided data for that) you can have a relay that disconnects house from alternator but keeps the engine's FLA battery connected to the alternator (to protect it) which at this time can go up to normal LFP 14.x V voltage.

Then you wait until SOC drop to 50 or 70 percent, then connect all charging sources again.

You can use BMV monitor to control solid state relays to connect or disconnect charging sources.
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Old 27-01-2017, 09:46   #5511
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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This is getting more and more complex for this novice. At this point I will just cruise as is but be sure to isolate the LFP when stopped with shore power available.
Best Regards to all
Joe,

The thing you need to focus on most is losing the lead acid mind set.

IDEAL LFP USE= Charge>Shut off All Charge Sources>Use Stored Energy>Charge>Shut off All Charge Sources>Use Stored Energy>Charge>Shut off All Charge Sources>Use Stored Energy>Repeat>Repeat

Getting over the lead acid mind set is the absolute hardest thing for most LFP converts. Floating or keeping LFP at high states of charge will lead to loss of capacity.

These batteries like to be used, they do not like to be floated or kept at high SOC's. Unlike lead, keeping these batteries full actually causes harm and capacity loss.

If you are on-board the easiest solutions, beyond your BMS protections, which won't protect the bank from you keeping the bank at high SOC's continually, is to wire manual shut offs for:

Alternator = Switch at helm to shut down regulator or cut field
Solar = Switch wired per controller manufacturers instructions to isolate PV
Battery Charger = Already has a switch
etc..

When at the dock isolate the LFP, discharge it to 50% SOC, and let it sit there. Use a lead acid reserve bank for dock side buffering.
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Old 27-01-2017, 10:03   #5512
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Originally Posted by Maine Sail View Post
Joe,

The thing you need to focus on most is losing the lead acid mind set.

IDEAL LFP USE= Charge>Shut off All Charge Sources>Use Stored Energy>Charge>Shut off All Charge Sources>Use Stored Energy>Charge>Shut off All Charge Sources>Use Stored Energy>Repeat>Repeat

Getting over the lead acid mind set is the absolute hardest thing for most LFP converts. Floating or keeping LFP at high states of charge will lead to loss of capacity.

These batteries like to be used, they do not like to be floated or kept at high SOC's. Unlike lead, keeping these batteries full actually causes harm and capacity loss.

If you are on-board the easiest solutions, beyond your BMS protections, which won't protect the bank from you keeping the bank at high SOC's continually, is to wire manual shut offs for:

Alternator = Switch at helm to shut down regulator or cut field
Solar = Switch wired per controller manufacturers instructions to isolate PV
Battery Charger = Already has a switch
etc..

When at the dock isolate the LFP, discharge it to 50% SOC, and let it sit there. Use a lead acid reserve bank for dock side buffering.

Wow, what an elegantly succinct set of go bys. These will be posted at the helm included in operational instructions so retention is better. Thanks to all for your responses and especially Maine Sail. After four years and doing some damage to my bank this lesson finally borrowed through my titanium skull and into my thinker parts.

Best to all,

Joe in New Bern,
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Old 30-01-2017, 17:59   #5513
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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I recently ended a very expensive experiment regarding storage SOC & LFP. The cells were 100Ah CALB SE's. I conducted this test because there was scant data on prismatic cells and storage SOC in terms of real world scenarios.

...

After 12 1/2 months of doing nothing but sitting there, at 100% SOC, the cells had lost -11.6% of their previous rigorously confirmed Ah capacity.
Great experiment, with a result very similar to what Bob Ebaugh had reported after leaving his house bank fully charged for a year or so, but the data is a lot more solid here as it was deliberate and started with a very precise baseline.

Very recent lab work
with LFP cells shows a similar picture, see below.

By using a lot more cells at different SOC values, they were able to show the contributions of temperature and SOC, but also keep in mind that the cells were cylindrical A123, not CALB prismatic cells and electrolyte chemistry has a lot to do with how the cells react to storage.

Those clearly didn't like being stored above 70% SOC and LFP cells always absolutely hate being warm.

Cells ship from the factory at about 50% SOC to give them a long shelf life, but if they are not going to be used, the lower the better basically.
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Old 01-02-2017, 09:10   #5514
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

I'm so sorry for your loss roetter. That was certainly a fine source of energy storage. It is tough when you boat is a great distance away. I've been away from my boat now for nine months and was not the last person off. The other owner departed a month later in May. I wanted those same 700ah batteries but you beat me to them.

Our cells are 16 400Ah with HVC/LVC Kilovac disconnect and small parasitic drain House BMS. We run 2160 Watts solar through a 440HVA Missouri Wind controller that handles the solar charging, Alphagen DCX3000 x2 Charging at 60amps each until 52.5v and when on shore the 2 Lestronic II feroresonant auto chargers that kick out at 53.3 volts (want more juice reset power bar for chargers they will turn on again.).

The following images pretty much sums up our storage solution for the batteries over nine months. Much to my dismay I was a little concerned with the first image. Turns out when the main disconnect was turned on to spot check the voltages the 2 Lestronic II chargers were still plugged in and registered as such. Either way it did not produce any charging current only skewed the actual check as such. I had the wharfinger shut the breaker off for the chargers and recheck in the second photograph. The 27.4 is typical of the amps we used all winter continuously running the heaters to beat the rain away on the hard.

We lived with batteries for six months over last winter while outfitting the catamaran. They supplied all our needs from day one. The hardest thing was getting them up and into the boat on the first day but we managed the two 265lb cubes without disassembly and had power and heat that very night.

20kwh of storage was quite enough. It runs our two Quick BX16 boilers, fridge, two induction cooktops, washing machine, heaters, laptops, dehumidifiers, electric incinolet toilet and all electronics on board. We do this from a pair of Cotek 3000w 48v inverters. If anything one more inverter would be a welcome addition but having two there is seldom a cause for over taxing the amp draw domestically. We can produce 20+amps from solar power on a good sun day so the generators really are just for backup but if voltages were ever below 52.5 volts and we were drawing 60 amps continuous underway during the night I wouldn't hesitate to start the Alphagens.

https://www.youtube.com/channel/UC6B...view=0&sort=dd

Some not so great videos there of the shakedown cruise up and down river against with 4-5 knot current.

This upcoming years projects include purchase of lestronic 36v 42amp charger to power 36v motor guide gps anchor to complete the electronics and autopilot package. Work on the interior, complete the atmospheric water maker and finish securing everything properly. A new fridge/freezer would be nice something horizontal. Would like to replumb the boilers as I'm not happy with how they turned out. Proper radar arch, better outboard mounts. Full doghouse if I can swing it and sloped back canopy over cockpit.

Proper benchmarking and testing of the bank - priceless but then the expert lives in Maine. I can only hope I did not loose capacity. My baseline based on Compass Marine was roughly 480ah.
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Old 03-02-2017, 12:54   #5515
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

After much appreciated input, I am setting the bank up to continually cycle from full to a discharge point 20% SOC to prevent my CALB LFP04 bank from further loss of capacity from being floated or stored or kept at an apparent 100% SOC. I intend to change the charging program of my Multiplus Inverter/Chargers to "stop charging" instead of "force to float" via the Lynx BMS assistant. This will require a setting to restart Attachment 140634charging at a certain voltage as using SOC is not available.
My question is:
What voltage should I use as the "start charging" ? I realize that voltage is a poor indicator for SOC. However hoping for an rom (rough order of magnitude) setting that would just permit somewhat of an automated action setting. I have performed some very simple low amperage draw down bank capacity tests so have some data as to the relative voltages at certain SOC although not a linear scale. Also the shown SOC is not valid as the banks capacity was not correct as bank had lost capacity. My assumption from this test is that the bank now has only a 400 amp capacity before reaching the LVC action set point.
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Old 03-02-2017, 14:41   #5516
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

The order of ROM is based on your individual cell voltages and the answer lies therein considering the well defined maxim of avoiding thus the upper and lower knee of the cycle. 3.0v per cell as plainly you can see of course the alarm will trigger below that and the cells fall quickly out of proportion after that.

Consider first though how you normally used your pack. An applied constant float charge without discharge as you surmise has degraded capacity and of course your data suggest plainly 400 is the capacity from what you surmise to be your rated capacity of 3.325 volts per cell.

Now question how long the cells sat at 3.325 volts before the test commenced? Question also how and when the cells came to be at your opinion 100% state of charge at 3.325 volts per cell? Question also how long after reaching the theoretical state of 100% charge was the test conducted? Straight up did you only charge your batteries to 3.325 volts and then immediately start the test or were the batteries found in this condition after sitting for some time and then you decided to do the test?

Perhaps as you surmise voltage is not a good indicator of state of charge and I would concur but on the lower knee only. To be more succinct you have I believe conducted a test on a 2/3 full bank and only realize the amount of amps you have placed in the bank. Question what it is about your charging that only allows you to store this amount of energy?

Ask yourself what is 100% state of charge anyhow? In an automobile charging cycle for lithium batteries top balanced the end charge voltage per cell for 100% state of charge should very well be 3.5 volts per cell safely and proceeding any further is unwise because of the acceptance factor and certainly the ability of your chargers to actually push the constant charge constant current higher. It is simply only worth going to the upper extremes only during initial calibration of top balance of all new cells.

To charge or not to charge to 3.5 volts per cell before using the stored energy that is the question? In a living environment utilizing the stored energy in a matter of fact. Will you always have the luxury to charge to 3.5 volts per cell before you disconnect a charge source? I contend no you will not depending on your system that is unique to you the owner.

Oft missed in this thread and briefly ever so touched on is constant draw constant charge buffering. Recently one would say use a lead acid buffer and or advocate the separation of lithium from propulsive and house loads. Considering the only various advantages and disadvantages of the school of thought as it pertains to the inherent individualized solutions mariners have implemented is the difference between splitting the 2-ply or simply buying the best Charmin.

Real use dictates otherwise. From personal experience there is zero possibility of any lead acid bank buffering for long an extended, prolonged constant 30 +/- 20 amp draw of four months 24/7 with any reasonable amount of fail safe operation given the fluctuation of daily living. Simply put the ability to buffer amps in versus amps out is what lithium was made for. Eventually due to usage the bank will be full when the cooking is done and there is only one heater running and you have retired for the evening. The charger will then stop happily to where you have set it hopefully at roughly 3.325 volts per cell which is not full and not empty but the resting voltage of the cells.

But then what is the state of charge? Why contemplate it then in a static dockside situation? If for some reason during the night you get a low voltage cutoff and are awakened by alarms you realize your bank is now more empty then full. Start the chargers, turn the heater back on and go to bed. But now how does your charging solution come into play? How long does it take you to put back in 700 Ah back into that bank and should you today is the decision.

Without knowing how much charging potential you have I can't begin to say how long it will take you to actually charge your bank back to full 3.5v 700 Ah as I interpret your bank. How many amps can you throw at it continuous and does it keep up with your daily usage?

In my case recharging fully a 480ah 48v pack is a needless and lengthy affair usually aside from a voyage of any distance. With only two chargers each at 15amps it is 16 hours at 30amps continuous. In reality this translates into 10 amp charge considering the heater is usually going and there is some variations in the amp usage I'm simply rounding as the heater may be 16 amps and the chargers may only produce 27 amps but you get the idea.

Consider also the extra charging that must occur at times to fully or quickly augment your bank state of charge when needed to 100%. Do you have enough solar, wind or generator to make your bank full? In some situations dockside if I wanted to I could put 150 amps back into my batteries continuous for some duration based on voltage for my specific generator and the solar charge potential of any given day with 2160 watts of solar. But that is never reality only a theoretical maximum.

In real life away from a dock the system must function without the luxury of a 30 amp electrical outlet. Are you able to buffer accordingly with enough solar, wind or generating capacity to keep your batteries fat and happy 3.28v to 3.3v and to never let them reach the lower knee? That is the successful implementation of a lithium battery boat from a safety perspective.

To surmise would an active Captain take the chance whilst watching voltage drop beneath 3.1 volts per cell without starting a generator during a night voyage or in fog or otherwise? I submit to you that no you would not and foolish if you did.

Dockside as others have concluded certainly use what is stored and understand what potential is stored in terms of your vessel and system. Understand the deficits produced by turning on the 50amp water heaters and then cranking the induction cooktop up as well. Most induction cooking can be maintained around 1 or 2 setting for a small but efficient still cooking amp draw. Perhaps wait until the water is hot before cooking and or wait until the water heaters are cycled off or simply control them yourself by breaker. If you don't know how much energy is in your bank off by heart can you sleep comfortably at night in freezing temperatures or hot temperatures knowing that the heater or air conditioner is using 20 amps per hour and how many hours can you sustain.

Most nights I would buffer energy usage with one charger and run a small deficit on the bank. This is the proper way for lithium utilization. Easily sustainable and recoverable without major ah loss from the bank towards the bottom knee with anticipated usage and acceptable full capacity realized during the daylight hours when your up and about and the heaters are turned off or the energy is used for other things sporadically whilst your charging is supplemented from other sources perhaps another charger, solar or wind.

Use the energy storage you have purchased without abandon. Enjoy it. 3000 cycles of daily use at a minimum is eight years. With that figure alone they are counting full cycles not partial or static use. Perhaps the next test of the calb 100ah now degraded from being held in full state compass marine batteries should be how long they can have a charge applied and simultaneously discharged and still maintain a modicum of capacity.

When I go back to read the specifics of your batteries and your choice of lead acid charger I realize Joe from looking at the specifications on your calb 180's they list a recommended charging current of 54A .3C. When I open the PDF of your Battery Test Phase I see that and according to the Victron literature you are utilizing the 170 amp charge rate. Could this be where the capacity loss is coming from?
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Old 03-02-2017, 15:32   #5517
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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Current LFP setup in boat. which has served me well for 4 years and 30,000+ miles.



Relearning how to add attachments and pictures. Been off forum for awhile. The other attachments I posted in the pior post I can open. Don't know if viewers can.
Now additionally I might suggest having only limited experience with smaller calb 72 cells that you inspect each cell for other possible reasons for loss of capacity other than the interpretation I provided as to the charge rate used during your 30000 miles. I would seriously pull each cell and inspect for defects on the entire cell, busbars, washers and everything. Tear it down completely.
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Old 03-02-2017, 15:50   #5518
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

Also Joe from the literature on your batteries and if indeed I am right or wrong about the charge rate on them you did get 4 years and 30000 miles out of them the specifications list 2000 cycle lifetime or roughly 5.4 years.

You are quickly approaching that time congratulations and I believe you have successfully implemented and lived fat and happy with your lithium cells as only the lithium crowd can and in your case having to make up a deficit of 700 ah I believe at 12 volts at 170 ah charge rate made for some nice living.

Personally if you ever do it again I would avoid the 12v and go to a minimum and maximum of 48volts and go with the largest prismatic you can find and make work.
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Old 03-02-2017, 16:04   #5519
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

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What voltage should I use as the "start charging" ? I realize that voltage is a poor indicator for SOC. However hoping for an rom (rough order of magnitude) setting that would just permit somewhat of an automated action setting.
Personally I would set a low/start setpoint of no lower than 3.2V, probably would feel better with 3.3. When in regular cycling use, there is no harm in keeping the low-point SoC above 30-40%, but a catastrophic risk letting it get too low - or too high, as you've learned.

You should charge at 3.45vpc, 3.50 is max.

Apparently the ideal rate is ideally between .3 and .5 of C.

When current drops to C/50, stop, don't float at all. If "must" then 3.3V, but IMO better to get a charger that can just stop.

After no loads, resting for a couple hours, are they around 3.40vpc?

That is "100% full" SoC if you want longevity. And within .001 of the SoC you'd get pushing in a higher, more harmful voltage.

If you actually try to get to higher than 3.5v resting, you will only get a fraction of the lifetime cycles treating them gently will get you.
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Old 03-02-2017, 17:02   #5520
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Re: LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

https://www.i4wifi.cz/img.asp/?attid=255114

I presume these are the specifications for Joe's batteries. It lists 2000 life cycles at a 54A charge rate. On this ageing pack I would start to charge now at 3.0 volts and see if it recovers from there as you fall wildly off the knee thereafter with much larger voltage deviations and I would charge to 3.5 volts but find a charger that can do it with say 10-54 charging amps only and see if there is any difference which I doubt because these batteries over 4 years have been used well.

I believe I'm interpreting the .3C of 180ah correctly for charge rate at 54Amps and that the cells should not have current applied beyond a 54Amp charge rate. But the Victron 3000 multiplus is charging these small calb cells at 170Amp rate and how many cycles did it do this for that is now the question.

Now the question of actual number of cycles over 4 years with the estimated lifetime of perfect lab usage 80% DoD equates to 5.4 years. I don't think he is far off.

I think that if he at a minimum would have purchased 16 winston 200ah cells he would have been in much better shape today as they at least can take the massive 170amp 12v charge he is throwing at them simply by cell specifications alone.
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