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

[Stumble]

Originally Posted by T1 Terry

Then you have to consider this advice is from someone who is quoting from "all he has read" They may be hobbyists but they do have the hands on knowledge and do not have an reason to push an add on product they just happen to make and sell. So the real question is, do you want a reliable battery system, and do you want fries with that? Or will you be happy to stay with the old stand-by that everyone knows everything about

T1 Terry

Terry,

I don't mind being a leader into new technology. I have done it with everything else, so why not battery technology. The trick is to make sure that you are looking at it from a dispassionate approach, and that the technology is really suitable for the level of work you want to put into it.

[T1 Terry]

Originally Posted by Stumble

I have tried to read thru this thread, and sadly it gets to technical for me quite quickly. I am trying to figure out what type of work I would be looking at to replace my current 300ah lead acid system with a LiFePO system? We had an on the dock electrical spike that fried the battery charger, and the batteries are 5 years old, so I don't mind replacing them. So at this point my installed system is pretty much toast and before I spend a lot to replace it with what I have I would like to understand my options.

Secondly would a system like this require significant monitoring or is it a replace it and forget it system. I don't mind periodic maintenance, but I don't want to have to manually try to balance different cells. I don't have the patience for that.

Finally the current boat profile is mostly daysailing, with a few weekends a year we will anchor out for 2-3 days. The installed 300ah of lead acid is fine for our current demands, so could I go to a smaller battery bank because of the deeper discharge allowed on LiFePO?

I would recommend 200Ah for this application, 8 x 100Ah cells, 2 in parallel and 4 sets of these in series. This will minimise balancing requirements as the 2 cells in parallel tend to balance each other out. Buy a cell logger, connect a smoke alarm to the alarm port and set the high cell voltage to 3.6v and the low cell voltage to 2.8v. set the charger to 14v and only charge when you are on board, stop charging if the smoke alarm goes off, stop using the battery when you are away from the mains when the smoke alarm goes off, simple as that.
For balancing, if the smoke alarm goes off when charging, look on the Junsi cell logger and see which is the lowest cell voltage, charge that cell up to 3.6v with any sort of DC charger by just connecting the wires across that pr of cells. When you have done that, forget about them till the alarm goes off again.
The only balancing required is to prevent a cell going over 3.6v before the battery reaches 14v, nothing flash or fancy required, you have the best intelligent battery monitoring system sitting on your shoulders, it can think in multi level management and act accordingly.
For house batteries, the only BMS should stand for Battery Monitoring System and a $28 Junsi cell logger will do that do just fine. If you want to know more about how the battery is travelling while you are using it, fit a Victron BMV 600s, set the low SOC alarm to 20% SOC and fit a warning light to it, just so you know that you are into the last 20% of the battery capacity so either you need to set up some sort of charging or if you still want to stay out for a while, look at reducing the loads a bit.
If you want it to start doing stuff automatically you do need to add on a few things, but forget about automatic cell balancing, that is asking for automatic problems to appear that wouldn't have appeared if it wasn't there.

T1 Terry

[deckofficer]

Originally Posted by roetter

At this moment I am going really simple. I have a small inflatable dinghy with soft bottom, that we used when travelling with our motor home. It can be rolled up quite small and has a bag. With that we used a small cheap 12V trolling motor from a fishing store. We will see how it works and the. Go from there. We a dinghy with a 20Hp Honda as our main car. The electric one will only be used by my wife when I can not take her and the dog to shore.

I can say firsthand LiFePO4 will really shine in this application. I replaced a 47 lb group 24 LA battery in my Ocean Torque kayak with (2) 30 lb 100 a-hr LiFePO4 banks. For a 13 lb increase using the Winston cells my range increased from 16~18 miles to 80 miles. One battery used as the outbound battery, the other used as the return battery.

47 lbs of lead = 18 miles
30 lbs of LiFePO4 = 40 miles

[T1 Terry]

Originally Posted by Stumble

Terry,

I don't mind being a leader into new technology. I have done it with everything else, so why not battery technology. The trick is to make sure that you are looking at it from a dispassionate approach, and that the technology is really suitable for the level of work you want to put into it.

My house batteries are into their 3rd yr of 24/7 operation now running the lights, computers and all 3 fridge/freezers. they are charged predominantly by solar, they get mains charger assistance if I've dragged them down to 0%SOC for a capacity test or if it's rained for 4 days straight, the capacity test is every 6mths, the rain issue has happened maybe 4 times since the system has been set up. My next capacity test will be in the new yr but each test so far has shown the batteries still have their advertised capacity so I'm happy with that. My charging system is all controlled by a single solar regulator that controls a number of relays and holds the max charging voltage to 14v and float at 13.8v, as my solar system is 2.5kW and they don't make solar regulator for 12v batteries that big this was the system I developed and it works well for me, it also controls the mains charger. I have a Junsi cell logger as the back up secondary system with a set up I designed to turn the charging off if a cell goes over 3.6v. After nearly 2 1/2 yrs the battery still doesn’t need balancing so this may give you some idea of the amount of time required to keep them in check. It may occur a few time when the system is first installed as it can take a while for the charge to saturate through all the cells. Still need to check the cell logger every so often, just for peace of mind really, still need to ensure the terminals are secure every 6 mths and that none need cleaning, but properly installed this isn't an issue really, again, just more peace of mind stuff. The biggest issue is generally people trying to fix balance problems that really don't exist, they end up putting the cells further out of balance where if they had just left the system alone it would have highlighted when and if something need to be done, then it's still a minimal balancing thing, no requirement to get them within a few millivolts of each other, that's just over servicing and creating a job that didn't need to be done.

T1 Terry

[Stumble]

Terry,

I appreciate the detail, but I don't think having my batteries not charging while I am away is realistic. The boat lives in the marine on shore power, and while I am aboard the engine almost never runs. This is a fine system if you are there and monitor the boat regularly, but my dock mates would kill me if I left a smoke alarm going off all the time.

[hellosailor]

Terry-
I don't use "hobbyists" as a derogatory term, but put it in perspective. There are folks with degrees and years of day after day experience who are still trying to figure out how to best use "new" kinds of batteries. And then there are folks who have just bought one set, or two sets, and spent just two or three years poking around with them. Which is all well and good--but won't be the same as full-time lab testing to figure out what really can or should be done for what purpose.
That doesn't mean hobbyists aren't important or accurate, just that there is no way they are going to generate the same amount of documented data in the same timeframe, so whatever a hobbyist reports has to be questioned in terms of just what it does or doesn't represent versus all the other situations that hobbyist hasn't tried.

To me it would look simple to use a Lithium-anything battery. Put on a low-voltage cutoff set to 11.5 volts, and rely on the regulator not running amok so there's a 14.4 maximum, well under the typical 16v "things get exciting now" limit. But, those pesky battery makers, probably concerned with litigation and sales (in that order) still say that's not good enough, they want a full-time BMS doing cell-by-cell management.

I have no dog in the fight. I consider myself to be an objective observer, observing a whole batch of part-timers contradict a whole batch of squabbling full-timers. I just can't understand how Fox hasn't put "The Housewives of Lithium Valley" on TV yet.

Of course, this is all nothing new. Stanley Steamers never, literally never, had boiler explosions, but the Detroit makers who were using infernal combustion engines (with those explosive fuels<G>) convinced the public that steam cars blew up, and Detroit buried the steamers fast and forever. Similar to what GE did with diesel locomotives after WW2.

Stumble-
The ISAF is probably thinking along the same lines as a number of auto industry and regulatory thinkers. Sealed batteries prevent acid burns, and spilled battery acid supposedly sends thousands of people to the ER every year in the US alone. Including first responders to accidents, who have no idea where the acid has sprayed.

I understand JCI has bought into lithium in some manner, but haven't heard if any other established battery maker has. I discount the Chinese exporters mainly because a warranty from China is worth a bowl of rice to me. Some of them literally have no idea what the US warranty laws are, even if you trust the quality of their product, or can get a straight answer on deep discharge cycle life.

As the punchline of the joke goes, the kid says "because I just know there's got to be a pony in this pile!"

[ebaugh]

Originally Posted by Stumble

I have tried to read thru this thread, and sadly it gets to technical for me quite quickly. I am trying to figure out what type of work I would be looking at to replace my current 300ah lead acid system with a LiFePO system? We had an on the dock electrical spike that fried the battery charger, and the batteries are 5 years old, so I don't mind replacing them. So at this point my installed system is pretty much toast and before I spend a lot to replace it with what I have I would like to understand my options. Secondly would a system like this require significant monitoring or is it a replace it and forget it system. I don't mind periodic maintenance, but I don't want to have to manually try to balance different cells. I don't have the patience for that. Finally the current boat profile is mostly daysailing, with a few weekends a year we will anchor out for 2-3 days. The installed 300ah of lead acid is fine for our current demands, so could I go to a smaller battery bank because of the deeper discharge allowed on LiFePO?

Unless you have weight or space issue that prohibit LA batteries, I would not switch. Yet. I still like LFP for large banks (I have a 1200 Ah one). But for someone with a 300Ah bank in occasional use, it's overkill.

[Stumble]

Originally Posted by ebaugh

Unless you have weight or space issue that prohibit LA batteries, I would not switch. Yet. I still like LFP for large banks (I have a 1200 Ah one). But for someone with a 300Ah bank in occasional use, it's overkill.

The problem is that ISAF doesn't allow flooded LA batteries anymore. So I can go sealed, agm, or gell. Alternatively I could switch to LiFePo. At this point it looks like the LIFE batteries may actually be the cheapest way to go, or at least within the same ballpark. And I would rather use lighter weight, smaller, batteries if I can. The trick for me is that I am trying to figure out what exacally I would need to install to get them working. Since I have a fried charger, and fried batteries, assuming it works, this is the optimal time to make the switch.

Think of it like this, on a clean install with no legacy equipment (except the engine alternator) what would you need to install? Obviously a battery charger (but which one), a regulator for the alternator (which one), a battery manager (suggestions), and a slab of batteries. If the cost for the LIFE rig is within spitting distance of a sealed LA then why go with the sealed?

I am just beginning this research, but for the price it seems the LIFE may actually be cheaper than lead.

[T1 Terry]

Originally Posted by Stumble

Terry,

I appreciate the detail, but I don't think having my batteries not charging while I am away is realistic. The boat lives in the marine on shore power, and while I am aboard the engine almost never runs. This is a fine system if you are there and monitor the boat regularly, but my dock mates would kill me if I left a smoke alarm going off all the time.

Lithium batteries don't need to stay on charge like lead acid batteries, they don't go flat if they are just sitting. If you wanted to just leave them sitting on a charger then drop the voltage to 13.6v or lower, highly unlikely to have a cell run away then. when you are back on board, set the charger up to 14v while you are getting ready to set off, this will just top the batteries up, hen head off for 3 days and live off the batteries, they won't be harmed by not recharging every day, then put them back on 13.6v charge when you get back and just leave them at that. What would happen on the boat if it wasn't plugged in while at the marina? I'm guessing automatic bilge pumps and maybe some lights, there couldn't be refrigeration as you don't have the lead acid battery capacity for refrigeration to operate for 3 days without access to recharging.

T1 Terry

[T1 Terry]

Originally Posted by hellosailor

Terry-
I don't use "hobbyists" as a derogatory term, but put it in perspective. There are folks with degrees and years of day after day experience who are still trying to figure out how to best use "new" kinds of batteries. And then there are folks who have just bought one set, or two sets, and spent just two or three years poking around with them. Which is all well and good--but won't be the same as full-time lab testing to figure out what really can or should be done for what purpose.
That doesn't mean hobbyists aren't important or accurate, just that there is no way they are going to generate the same amount of documented data in the same timeframe, so whatever a hobbyist reports has to be questioned in terms of just what it does or doesn't represent versus all the other situations that hobbyist hasn't tried.

To me it would look simple to use a Lithium-anything battery. Put on a low-voltage cutoff set to 11.5 volts, and rely on the regulator not running amok so there's a 14.4 maximum, well under the typical 16v "things get exciting now" limit. But, those pesky battery makers, probably concerned with litigation and sales (in that order) still say that's not good enough, they want a full-time BMS doing cell-by-cell management.

I have no dog in the fight. I consider myself to be an objective observer, observing a whole batch of part-timers contradict a whole batch of squabbling full-timers. I just can't understand how Fox hasn't put "The Housewives of Lithium Valley" on TV yet.

Of course, this is all nothing new. Stanley Steamers never, literally never, had boiler explosions, but the Detroit makers who were using infernal combustion engines (with those explosive fuels<G>) convinced the public that steam cars blew up, and Detroit buried the steamers fast and forever. Similar to what GE did with diesel locomotives after WW2.

Stumble-
The ISAF is probably thinking along the same lines as a number of auto industry and regulatory thinkers. Sealed batteries prevent acid burns, and spilled battery acid supposedly sends thousands of people to the ER every year in the US alone. Including first responders to accidents, who have no idea where the acid has sprayed.

I understand JCI has bought into lithium in some manner, but haven't heard if any other established battery maker has. I discount the Chinese exporters mainly because a warranty from China is worth a bowl of rice to me. Some of them literally have no idea what the US warranty laws are, even if you trust the quality of their product, or can get a straight answer on deep discharge cycle life.

As the punchline of the joke goes, the kid says "because I just know there's got to be a pony in this pile!"

Look at it from the other direction, these guys don't work cheap, all those hrs of research need to be paid and a profit needs to be made from this investment, so a finding that a proprietary (their unit) BMS is not required would not be in their best interest.
So the Stanley Steamer spray of B/S is spread across all forms of communication and they try to tie in things like the Boeing problems to back up their claims, knowing full well they are different chemistry batteries, but they are all in this together so they need to keep the myths going.
If the major electric car manufacturers with up to 300 cells in series don't use cell based BMS monitoring or balancing then it's a hard sell that a 4 cell in series battery is going to require one, but they keep trying.
If you attempted to fit multiple 12v lithium batteries up in strings like lead acid batteries are, then you would have a problem and every one of the 12v batteries would need a control system, but a properly set up 12v lithium battery doesn't have those problems, there is only 1 battery of 4 cells to maintain, all the cells in parallel are seen as one cell to any monitoring system as basic electrical laws still apply, they must all be the same voltage if the are all connected in parallel.

The package deal drop in battery suppliers have a problem with that, each set up needs an individual system built to match the requirements, so you can't put a battery on the shelf for a blow hard salesman to sell, how do you mass produce individual systems and how do you recoup the big $$ outlay the propeller heads demanded to tell you your wiz bang system wasn't required?

T1 Terry

[deckofficer]

Originally Posted by Stumble

The problem is that ISAF doesn't allow flooded LA batteries anymore. So I can go sealed, agm, or gell. Alternatively I could switch to LiFePo. At this point it looks like the LIFE batteries may actually be the cheapest way to go, or at least within the same ballpark. And I would rather use lighter weight, smaller, batteries if I can. The trick for me is that I am trying to figure out what exacally I would need to install to get them working. Since I have a fried charger, and fried batteries, assuming it works, this is the optimal time to make the switch.

Think of it like this, on a clean install with no legacy equipment (except the engine alternator) what would you need to install? Obviously a battery charger (but which one), a regulator for the alternator (which one), a battery manager (suggestions), and a slab of batteries. If the cost for the LIFE rig is within spitting distance of a sealed LA then why go with the sealed?

I am just beginning this research, but for the price it seems the LIFE may actually be cheaper than lead.

On a clean install I would just program the inverter's charger for 14 volts, set the mppt controllers and alternator's regulator for same.

[roetter]

Originally Posted by Stumble

Terry, I appreciate the detail, but I don't think having my batteries not charging while I am away is realistic. The boat lives in the marine on shore power, and while I am aboard the engine almost never runs. This is a fine system if you are there and monitor the boat regularly, but my dock mates would kill me if I left a smoke alarm going off all the time.

I have my boat set up for the winter as follows.
LiFePo batts are about half discharged and completely disconnected- i.e. Disconnected all cables
My shore charge is still on keeping the start battery happy, it also supplies the house 12V system ( mainly lights when someone comes aboard to check) with no battery attached. Works fine.

I made no changes to my alternator nor the alternator on my friends boat. mine is an internally regulated Mitsubishi, friend's is an internally regulated Hitachi. Both deliver about 14V to the LiFePo when they are full and stop drawing the alternator down. I have put in a manual battery switch to disconnect the alternator from the LiFePo, but NOT the LA starter battery, if I am motoring for a long time.

This is what I recommend for around the battery
Charger - pick one that can be set to 14V and then drop back to 13.6V. About 10-20% of the battery capacity in amps output.
Programmable voltmeter http://www.lightobject.com/Programma...stem-P408.aspx $39
Solenoid Blue Seas. http://www.amazon.com/Blue-Sea-Syste...noid+blue+seas $160 on Amazon
12V relays - http://www.amazon.com/SainSmart-4-CH...ords=12v+relay. $13

The voltmeter has two relays. Each can be programmed with a switch-on and a switch-off voltage. The low voltage relay is connected to the solenoid. So when the battery gets empty the relay triggers and disconnects the solenoid. Once the voltage has risen a bit it reconnects the solenoid.

Program the voltmeter:
- for low voltage 12.5-13V to switch the solenoid off, set the switch on point about 0.3 to 0.5 V higher
- for high voltage 14.1V and reset 13.3V. I just use one of the four relays to cut the 110V power to the shore charger. On my boat there is enough drain from the house bank that the charger will kick in every 1.5 to 3 days. If you charger can be set to go back to 13.6V after absorption is done, then you do not need the high voltage control.

[Stumble]

Roetter,

We use the boat 12 months a year, so I don't have to worry about taking it out of service. I appreciate the recomendations. It may take some thinking about, but it doesn't look terribly difficult, and for the same money it seems nuts to try and load on another set of heavy lead batteries.

[Opie91]

How do you guys feel about someone who uses their boat on the weekend mostly and a 3-4 week cruise every summer putting LifePO4 batteries in their boat?

I have been reading this thread for quite some time and it seems that at least the primary people here seem to put quite a bit of time into managing/testing their banks.

Do you guys feel its feasible to install a system that is "self sustaining" for the average Joe?

[Lagoon4us]

Originally Posted by Stumble

I have tried to read thru this thread, and sadly it gets to technical for me quite quickly. I am trying to figure out what type of work I would be looking at to replace my current 300ah lead acid system with a LiFePO system? We had an on the dock electrical spike that fried the battery charger, and the batteries are 5 years old, so I don't mind replacing them. So at this point my installed system is pretty much toast and before I spend a lot to replace it with what I have I would like to understand my options.

Secondly would a system like this require significant monitoring or is it a replace it and forget it system. I don't mind periodic maintenance, but I don't want to have to manually try to balance different cells. I don't have the patience for that.

Finally the current boat profile is mostly daysailing, with a few weekends a year we will anchor out for 2-3 days. The installed 300ah of lead acid is fine for our current demands, so could I go to a smaller battery bank because of the deeper discharge allowed on LiFePO?

Stumble, i've ran our 400amp system that i built my self all season without an ounce of trouble.

My cells were brand new consecutive numbered and around 5 weeks old perfectly in balance from the manufacturer WINSTON, They are LiFeYPo4 cells i.e. they handle colder temperatures better.

I'm the BMS.But i use a BEP Monitor and it's VERY good.

Charging is via three methods:-
1) per the standard Volvo alternator with the Lead Acid in that circuit NO PROBLEMS.
2) Dolphin 80Amp battery charger on a setting to suit, this charger was installed in the boat in 2007.
3) 750Watts of solar with a Lithium controller giving 35amps on moderate days.

Easy Peasy.

Cheers Frank