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

[hellosailor]

FC-
"I know Prius owners that are having to by battery packs...in less then 2 years. "
I only know one Prius owner, but he's gotten way more than two years, and as I recall the battery is under warranty for way longer than that. Making it most peculiar that any owners would really have to buy their own battery packs in less than two years.

Yes, other products have had learning curves, but at least with CFLs all I've had to do is call up and say "It didn't last" and I've always been mailed a coupon good for at least one free replacement. The service is a little better than what battery companies tend to offer.<G>

[deckofficer]

Lloyd,

When it comes to batteries, I don't mind being an early adopter. I have used lead acid 2 volt 1300 a-hr cells in a 48 volt string for off grid residential, AGM, Ni-Cad, nickel metal hydride in EVs, and the only claim that is important to me is cycle life vs cost. For the EVs, weight was a big factor, but when I was working on them, lithium was too pricey.

Current prices vs cycle life has the LiFePO4 winning hands down. The no voltage sag at heavy discharge, and minimal voltage drop during discharge is just the icing on the cake.

[diugo]

Bob/deckofficer, what kind of typical internal resistance are you seeing for your cells? To calculate, place an N-ampere load across a single cell and measure the voltage sag in millivolts. Resistance (in millohms) = millivolts divided by amperes.

[deckofficer]

I checked when I was using the jumper cables to short out a high cell, and if I remember around 2~3 milliohms.

[FlyingCloud1937]

Originally Posted by hellosailor

FC-
"I know Prius owners that are having to by battery packs...in less then 2 years. "
I only know one Prius owner, but he's gotten way more than two years, and as I recall the battery is under warranty for way longer than that. Making it most peculiar that any owners would really have to buy their own battery packs in less than two years.

Yes, other products have had learning curves, but at least with CFLs all I've had to do is call up and say "It didn't last" and I've always been mailed a coupon good for at least one free replacement. The service is a little better than what battery companies tend to offer.<G>

Jest you say...

I'm about ready to send 25 souls to the North Sea, with one of my designs.

lloyd

[downunder]

Originally Posted by FlyingCloud1937

I said it here http://www.cruisersforum.com/forums/...tml#post812652 date 07-11-2011, 11:02

Mainsail...you might be the one to answer some/most ?'s but how will your time translate into installed costs.

Just a note I support all of you here qualified to suss out the real solution....but I'm still not ready for prime-time...to a community of people looking/thinking they'll save a buck...

Especially the non-professionals that take a little idea and interpolate it into something really dangerous.

So Main.... and others the world waits.

don't try this at home

Lloyd

Flying Cloud,

You are very negative toward LiPo4 batteries. Whilst I can understand your hesitation to recomend them at present seems to me that that issue is exactly why this thead has value. Quite a few have gone and are currently going down this route, are very happy so far and the rate is accelerating which is all learning for us non electricians as well as the electrical experts.

Seems to me prime time is getting very much closer. In the high end racing fraternity its already prime time.

Main Sail's great documentation of his learning will be of great benefit to those of us contemplating this direction. I very much trust his recomendations on all matters marine.

Cheers

[FlyingCloud1937]

Originally Posted by downunder

Flying Cloud,

You are very negative toward LiPo4 batteries. Whilst I can understand your hesitation to recomend them at present seems to me that that issue is exactly why this thead has value. Quite a few have gone and are currently going down this route, are very happy so far and the rate is accelerating which is all learning for us non electricians as well as the electrical experts.

Seems to me prime time is getting very much closer. In the high end racing fraternity its already prime time.

Main Sail's great documentation of his learning will be of great benefit to those of us contemplating this direction. I very much trust his recomendations on all matters marine.

Cheers

REALLY

U mst ave msd me PT.....

l

[FlyingCloud1937]

Originally Posted by deckofficer

I checked when I was using the jumper cables to short out a high cell, and if I remember around 2~3 milliohms.

So Deck....

Are u really suggesting, that on the fly you can estimate the "milliohms" resistance of a LiPo4 battery bank..connected to a pair of jumper cables....are we talking typical car start jumpers.???

lloyd

[goboatingnow]

I still don't believe this technology is ready for prime time. It certainly is in BETA testing by the DIY community, with some success stories and failure stories.

LLoyd, I dont think anyone here is saying that everyone should rush out and buy LiFe tech and dump the LA. Yes right now its for technical people. Thats doesnt make it or not prime-time, its just the (we) technical people have to package it and dress it up so you will buy it in Wal-Mart. and this is not a condescending remark. All new technical things go through a learning curve, the technology rarely changes, its just the public get to understand it. ( Then it becomes prime time)

Just remember system cost, also include capable charging system, and safety systems. The real MTBF is only based on a computer algorithm. Remember when Gel and Agm's first hit the market? Many problems arose and I know that most if not all of the first to market batteries failed the manufactures claims.

I dont believe that anyone again is making exact comparisons. But the price of Li is now "closer" to high end AGMs ( or TPPL batteries). The fact is for GELS and AGMS there still are many problems as in general these batteries offer nothing for boaters. As to costs most people will have the charging systems anyway, and low cost cell monitoring BMS is available.

Li technology has now been mainstream in small capacities for several years, The chemistry is well understood, the circuits developed and the knowledge based disseminated. But of course old myths die hard, I recently was nattering on with my engineer peer group and I mentioned my latest design has LIFePo4 in it, lots of them them made exploding noises!!!!..

MTBF for LI is well understood, yes large prismatic LIFepO4 is new, ( or new-ish) but so far experience is bearing out the claims, in a general way.

How many of you have purchased CFL, CCFL, and LED lighting with manufacture claims of tens of thousands of hours lifetime, only to have to replace them in less then a thousand hrs? Those claims were based on a similar algorithm to guess the MTBF rate.

Yes the technology is capable of long life, of course the manufacturers dont want to make them so. ( see the same thing happened with incandescent ones )

If you think lead acid batteries are unforgiving of mistake and neglect, we haven't seen anything yet. I know Prius owners that are having to by battery packs that cost over 1/3 the price they paid for the car, in less then 2 years. I know dozens of owners that can't properly manage a well set-up lead acid bank, I sure wouldn't recommend these bats to those owners.

NiMh technology.

I haven't heard anyone speak to the Over Current Fault Protection required of these high discharge capable battery banks. A large 600 amp Gel bank requires a OCP of 10-20 times the amp hr size of the bank. I don't think the ABYC has even developed a standards for these bats installed to a yacht. How does this effect your Yacht Ins. policy? I'm only guessing but I wouldn't be surprised if OCP will require 30-40 times the amp hr size.

It will certainly require a voltage protection interface between NAV gear, and any other voltage sensitive electronics. This includes LED lighting, and Halogen lighting.

Suitable fuses are available, The problem is really no more acute then AGM high capacity banks. Your comments in realtion to LED and Halogen show you dont understand what you are talking about , HVC is a cell level battery protection issue, the system voltages are actually less in Li boats and far more stable. Please dont introduce red herrings. and dont play the insurance bogey man.

Don't even think about using welding cable for any of the high current cables!

To get max benefit of charge current acceptance rate of these batteries, is going to require a very expensive solution.

WHy the issue with welding cables, You do not design the cables to handle the maximum short circuit, you put in protection devices.

As to max charge acceptance, who cares, Thats not a defining interest for boaters, it is for EVs. We only have a certain range of charging ability one way or the other

I would not install these bat banks to a yacht unless they were in their own fire proof enclosure. With a dedicated automatic fire suppression system rated to the potential and chemistry.

This is serious mis-information and is based on your incorrect interpretation of Li Ferrous technology. Your comments could be applied to any high capacity bank. In fact LA is arguably more dangerous, yet we dont do what you suggest.

Please if you are not an early adopter or a technologist in this field , thats fine, but dont then "make up" stuff. Just sit back and listen.

I have seen two boat fires this year caused by lead acid bat banks. One was right across the dock from my boat. The bat bank was installed less than a month, by a well known battery manufacture's own in-house installers. In my lifetime I have seen dozens of melted/exploded lead acid battery banks.

Yes an the adoption of mainstream LIFerrous will lead to an improvement in that , LA is a nasty dated technology.

I look forward to the day these batteries are vetted and ready for prime-time...but that day isn't today, I doubt it will be this time next year

The same was said about smartphones!.

It's fun to look at the amorous projections of how efficient/cheap these bats are at a per KW value...but none of the projections I read include the total system costs.

Today, because we are not geared up for LI, means there is often hidden costs, especially for non EE types. I have an electronics lab at my disposal, hence for me its easy.[/QUOTE]

IN reality today if you designed a "proper", high quality high capacity LA AGM battery bank, it would have virtually the same components. About the only difference with Li is the need to monitor cell voltage ( something thats also useful on LA, but isn't even practical on 12v cells) , Then you add your various charging sources, Li can be charged on conventional equipment that has some adjustment.

As to whether you add HVC or LVC, thats an feature, I have an LVC on my LA system currently. ( Mastervolt)

The fact is we currently put the crappist electrical systems into 250K boats, we get away with it because we've grown acustomed to it and the knowledge is fairly widespread, Yet marinas everything are full of LA failures.

SIt down an spec out a high quality 600 AH capable ( not sticker value) LA battery bank, lets specify 2V tubular LA ( AGM if you like) high capacity long life cells, add in the other necessary bits, then compare with LIFe. Youll be surprised.

By all means be sceptical, dont be negative about something you dont know about.

dave

[FlyingCloud1937]

Originally Posted by FlyingCloud1937

IN reality today if you designed a "proper", high quality high capacity LA AGM battery bank, it would have virtually the same components. About the only difference with Li is the need to monitor cell voltage ( something thats also useful on LA, but isn't even practical on 12v cells) , Then you add your various charging sources, Li can be charged on conventional equipment that has some adjustment.

As to whether you add HVC or LVC, thats an feature, I have an LVC on my LA system currently. ( Mastervolt)

The fact is we currently put the crappist electrical systems into 250K boats, we get away with it because we've grown acustomed to it and the knowledge is fairly widespread, Yet marinas everything are full of LA failures.

SIt down an spec out a high quality 600 AH capable ( not sticker value) LA battery bank, lets specify 2V tubular LA ( AGM if you like) high capacity long life cells, add in the other necessary bits, then compare with LIFe. Youll be surprised.

By all means be sceptical, dont be negative about something you dont know about.

dave

dave,

you seem to think I am ill' informed ...

one, I'm not your average cheerleader...

two, I understand on-board power systems...

and last, I also understand early adoption...

WHAT, I don't understand is preaching to the masses...bc I'm an early adopter.

shehs

[FlyingCloud1937]

Originally Posted by goboatingnow

LLoyd, I dont think anyone here is saying that everyone should rush out and buy LiFe tech and dump the LA. Yes right now its for technical people. Thats doesnt make it or not prime-time, its just the (we) technical people have to package it and dress it up so you will buy it in Wal-Mart. and this is not a condescending remark. All new technical things go through a learning curve, the technology rarely changes, its just the public get to understand it. ( Then it becomes prime time)



I dont believe that anyone again is making exact comparisons. But the price of Li is now "closer" to high end AGMs ( or TPPL batteries). The fact is for GELS and AGMS there still are many problems as in general these batteries offer nothing for boaters. As to costs most people will have the charging systems anyway, and low cost cell monitoring BMS is available.

Li technology has now been mainstream in small capacities for several years, The chemistry is well understood, the circuits developed and the knowledge based disseminated. But of course old myths die hard, I recently was nattering on with my engineer peer group and I mentioned my latest design has LIFePo4 in it, lots of them them made exploding noises!!!!..

MTBF for LI is well understood, yes large prismatic LIFepO4 is new, ( or new-ish) but so far experience is bearing out the claims, in a general way.




Yes the technology is capable of long life, of course the manufacturers dont want to make them so. ( see the same thing happened with incandescent ones )



NiMh technology.



Suitable fuses are available, The problem is really no more acute then AGM high capacity banks. Your comments in realtion to LED and Halogen show you dont understand what you are talking about , HVC is a cell level battery protection issue, the system voltages are actually less in Li boats and far more stable. Please dont introduce red herrings. and dont play the insurance bogey man.



WHy the issue with welding cables, You do not design the cables to handle the maximum short circuit, you put in protection devices.

As to max charge acceptance, who cares, Thats not a defining interest for boaters, it is for EVs. We only have a certain range of charging ability one way or the other



This is serious mis-information and is based on your incorrect interpretation of Li Ferrous technology. Your comments could be applied to any high capacity bank. In fact LA is arguably more dangerous, yet we dont do what you suggest.

Please if you are not an early adopter or a technologist in this field , thats fine, but dont then "make up" stuff. Just sit back and listen.



Yes an the adoption of mainstream LIFerrous will lead to an improvement in that , LA is a nasty dated technology.



The same was said about smartphones!.



Today, because we are not geared up for LI, means there is often hidden costs, especially for non EE types. I have an electronics lab at my disposal, hence for me its easy.

IN reality today if you designed a "proper", high quality high capacity LA AGM battery bank, it would have virtually the same components. About the only difference with Li is the need to monitor cell voltage ( something thats also useful on LA, but isn't even practical on 12v cells) , Then you add your various charging sources, Li can be charged on conventional equipment that has some adjustment.

As to whether you add HVC or LVC, thats an feature, I have an LVC on my LA system currently. ( Mastervolt)

The fact is we currently put the crappist electrical systems into 250K boats, we get away with it because we've grown acustomed to it and the knowledge is fairly widespread, Yet marinas everything are full of LA failures.

SIt down an spec out a high quality 600 AH capable ( not sticker value) LA battery bank, lets specify 2V tubular LA ( AGM if you like) high capacity long life cells, add in the other necessary bits, then compare with LIFe. Youll be surprised.

By all means be sceptical, dont be negative about something you dont know about.

dave

i just re-read this....wow.


I must have misinterpreted you.
yea right

[goboatingnow]

i just re-read this....wow.


I must have misinterpreted you.
yea right

In what way?

[Maine Sail]

Originally Posted by FlyingCloud1937

I said it here http://www.cruisersforum.com/forums/...tml#post812652 date 07-11-2011, 11:02

Mainsail...you might be the one to answer some/most ?'s but how will your time translate into installed costs.

Just a note I support all of you here qualified to suss out the real solution....but I'm still not ready for prime-time...to a community of people looking/thinking they'll save a buck...

Especially the non-professionals that take a little idea and interpolate it into something really dangerous.

So Main.... and others the world waits.

don't try this at home

Lloyd

You are 100% correct that this is NOT ready for the average DIY prime time. Even over a year later. All one needs to do is venture into the EV forums to see the strong disagreements about the "how's" and "execution" even amongst the "industry experts"....

I do think however once I have the system built the second or third will be far less costly time wise. Half the time has been research and education.

For example the time needed to do a proper initial balance is not inconsequential so for a tech that does not have their shop at home this can get tedious and expensive, before you've even begun building the pack and wiring the BMS..

On top of that even the "experts" in the industry disagree on such elemental things as the best way to pre-balance a pack? Top or bottom, parallel or cell level, cell level, then parallel....????? Do not wire in parallel unless below 80% SOC, charge to 3.6V max, charge to 3.8 - 3.9V max etc. etc. etc.... Your head can spin reading all the contradictory info from the "experts"... I actually moved my power supply and test equipment from my barn/shop into the garage so it would be easier to keep tabs on the pre-balance.

There are also other costs such as battery compartment layout mods, OCP and wiring that need to be addressed. For example how to you charge a second bank adequately when the main bank is being charged at only 14.0V or so?

I will be into a 400Ah bank with BMS, alarms, LVE & HVE cuts etc. etc. for under 2k WITHOUT my time included. Small things like the aluminum stock I wanted to use for pack compression end plates are going to cost me about $50.00. I thought I had plenty of stock, read free, but when I measured it I was 1/4" to short... Doh'!!!! My metal cutting carbide blade is also toast from cutting too much SS with it. So I need a new metal cutting blade at about $80.00 but it gets used frequently anyway so not all of that cost can be attributed to the LiFePO4 pack...

So far:

4 - 400Ah Cells = $1032.00
Shipping Cells = $250.00
EV200 Contactor = $79.00
House BMS Board = $75.00
Cell Modules = $54.00
Aluminum for end plates = $50.00
Solar and Alt cut relays = $40.00
Switches, alarm buzzer etc. $40.00
Total Materials = $1620.00

Of course there will be more odds and ends before I am done like phenolic project boxes, terminal strips etc... For someone like me the wire is free. I have bins and bins of scrap wire end cuts I save but for a DIY the wiring, at minimum 25' spools per color, adds up..

DIY's also need to consider charging and a way to Coulomb count the bank. You can't track SOC on a LiFePO4 bank with voltage changes like you can on LA batts.. I would NEVER even consider trying to charge this pack on a single belt alt or even with a dual belt set up. Yet to see a dual belt set up, put to high load duty, that held up as well as a serpentine belt. Dual belts wear unevenly and stretch unevenly. They also never come sized exactly even "matched pairs"... I would invest in a serpentine kit. I would also never consider doing this with internal regulation. Temp compensation of the alternator with these banks is CRITICAL. If you don't have those systems already in-place, as I do, that is another 2k +/-. Now what about wind and solar controllers with voltage set points made at the factory that are not suitable for a LiFePO4 bank... That is going to be more expense..

Seeing as this is going on my own boat, and being done for my own education into LiFePO4, I can't really count my time and I simply become a DIY.. I consider it on the job "education"....

Yeah not ready for prime time... While working on this I came up with a but a hand full of customers who could grasp and understand a LiFePO4 system. course this does not include installing one, just getting the very basics...

[goboatingnow]

Yes Mainesail, but most of those costs and those systems would be needed in a say brand new high quality AGM system. About the only thing you would need is cell level monitoring. And in fact you could get away without this as I've certainly found that the cells do not get out of balance at sub-C activity levels. ( I would of course still recommend cell monitoring )

For example high capacity AGM needs all the issues you mention with alternators too. Equally it's also need amp counting as well. Lvc is useful to prevent battery damage only hvc is really necessary. ( though say that to people that regulary boil banks )

Then lets add in Li unique positives.

Top of the list

(A) no need to 100 charge ever. This is a killer issue. For AGMs and often very difficult for cruisers to achieve.

(b) discharge to 20% , more useable power even at equivalent weights

(C) extremely stable discharge voltage , ie an incredible low impedance. Way better for electronics and far better at absorbing spikes and load dumps. Your LEDs and electronics wil adore Li.

(d) usable in orientation , no worrying about spilled acid.

(E) no emissions when charging

(F) simple CC charging with Voltage cutoff. No need for complex three stage chargers needed to reliably charge LA. chargers for Li are actually simpler.

(G) lighter , a lot lighter

(H) large prismatics allow far more efficient series only construction., upto about 1000ah. This is very expensive with AGM for example.

In my vote the scales are way tipped over compared to a few lvc relays.

Note that initial balance is only a problem because some suppliers don't do it. MasterVolt for example do all that before you buy the battery.

In future cells will come pre packaged and balanced ( which is what I meant re Lloyd , ie the technology won't change , it's just the supply chain will simplify the purchase. )

There wouldn't be a lot of beef eaten if we all had to raise and butcher our own cattle. , don't mean beef isn't ready for the " prime " time.

Dave

[Maine Sail]

Originally Posted by goboatingnow

Yes Mainesail, but most of those costs and those systems would be needed in a say brand new high quality AGM system. About the only thing you would need is cell level monitoring. And in fact you could get away without this as I've certainly found that the cells do not get out of balance at sub-C activity levels. ( I would of course still recommend cell monitoring )

For example high capacity AGM needs all the issues you mention with alternators too. Equally it's also need amp counting as well. Lvc is useful to prevent battery damage only hvc is really necessary. ( though say that to people that regulary boil banks )

Then lets add in Li unique positives.

Top of the list

(A) no need to 100 charge ever. This is a killer issue. For AGMs and often very difficult for cruisers to achieve.

(b) discharge to 20% , more useable power even at equivalent weights

(C) extremely stable discharge voltage , ie an incredible low impedance. Way better for electronics and far better at absorbing spikes and load dumps. Your LEDs and electronics wil adore Li.

(d) usable in orientation , no worrying about spilled acid.

(E) no emissions when charging

(F) simple CC charging with Voltage cutoff. No need for complex three stage chargers needed to reliably charge LA. chargers for Li are actually simpler.

(G) lighter , a lot lighter

(H) large prismatics allow far more efficient series only construction., upto about 1000ah. This is very expensive with AGM for example.

In my vote the scales are way tipped over compared to a few lvc relays.

Note that initial balance is only a problem because some suppliers don't do it. MasterVolt for example do all that before you buy the battery.

In future cells will come pre packaged and balanced ( which is what I meant re Lloyd , ie the technology won't change , it's just the supply chain will simplify the purchase. )

There wouldn't be a lot of beef eaten if we all had to raise and butcher our own cattle. , don't mean beef isn't ready for the " prime " time.

Dave

Dave,

Not in disagreement at all. Most however don't have all those systems already in place which would be the "prime time" audience I am really talking about.. For an AGM convert the price is considerably more reasonable as they should already have those systems in-place though many don't....

As for pack balance over time I will need to see that for myself which is why I am doing this on my own boat..... I don't doubt it but am also choosing to go the BMS route for the extra $154.00 +/-.....