Alternative to Lead Acid Batteries

northerner

Re: Alternative to Lead Acid Batteries

Blackcherry04 wrote: »

I didn't know there was a problem with lead Acid batteries, I must have missed that one for the last 50 years.

Absorptions are just one of the problems. There's a loss in efficiency to do an absorption or equalization and is a requirement to do them on a regular basis. Not to mention water loss as a result. But the main problem with lead acid batteries is there rather limited life span. I don't want to be spending thousands of $ every 5 to 15 years on replacement batteries. Other minor issues are hydrogen production and acid mist. Plus they're considered hazardous goods for shipping, so shipping costs can be high as well.

Blackcherry04

Re: Alternative to Lead Acid Batteries

northerner wrote: »

Absorptions are just one of the problems. There's a loss in efficiency to do an absorption or equalization and is a requirement to do them on a regular basis. Not to mention water loss as a result. But the main problem with lead acid batteries is there rather limited life span. I don't want to be spending thousands of $ every 5 to 15 years on replacement batteries. Other minor issues are hydrogen production and acid mist. Plus they're considered hazardous goods for shipping, so shipping costs can be high as well.

I don't see any of that being a problem, it's what you deal with to have energy storage. Good Luck to you in your quest for a better battery, I am listening.

Buoug

Re: Alternative to Lead Acid Batteries

northerner wrote: »

A company in Pittsburg is about to begin manufacturing a sodium ion based battery that they claim will offer better cycle life than comparable lead acid batteries, and through the use of non toxic materials. Axion Energy has come up with a battery that uses sodium sulphate as the electrolyte, and carbon and manganese dioxide as the plates. They claim a less than 10 % capacity fade after 5000 cycles to over 50% DOD. They also say that these batteries can be kept at a partial state of charge for long periods without damage. They are also fault tolerant, with no risk of fire or explosion, if short circuited, and are tolerant of higher temperatures without affecting lifetime or performance. Here is there site:

http://www.aquionenergy.com/technology/
http://triblive.com/business/headlines/3032248-74/aquion-energy-batteries#axzz2MK8wAAyy

Efficiency is as good or better than most lead acid batteries as well. Sounds very promising, and time will tell.

There are other approaches that also sound promising, but still no product. Lead acid has not been displaced yet!

I didn't see it already so if this is double listed, sorry. I sent an email out to see when the batteries would be sold for residence and they said late 2014. Business owners could expect early 2014. Can't wait to see how much a stack will be and how it performs!

SolInvictus

Re: Alternative to Lead Acid Batteries

Startup Thinks Its Battery Will Solve Renewable Energy’s Big Flaw, Technology Review News, January 23, 2014:

Aquion has started production of a low-cost sodium-ion battery aimed at making renewable energy viable.

Aquion, the startup that developed the battery, has finished installing its first commercial-scale production line at the factory, and is sending out batteries for customers to evaluate.

The Aquion site still lacks a data sheet. To evaluate its suitability for replacing lead-acid batteries in residential systems, very detailed technical specifications are essential. The S10 stores 1.5 kWh, weighs approximately 100 kg and measures 1000mm H x 310mm W x 330mm D.

For comparison one of my Crown CR-395 L-16 lead-acid batteries stores 2,370 kWh @ 20 hr rate of discharge, weighs 55 kg. and measures 419 mm H x 183 mm W x 310 L. The S10 stores 63% energy, has about twice the weight and occupies 4.3 times the volume of one L-16. To store a little more than 1 day of power output from my PV array (24% of my current battery array) would require 3 S10's , 68% of the weight and 1.6 times the volume of my present battery array. The energy density is nearly 7 times less than my L-16 battery. Even if I can buy fewer of them because they can be cycled harder, they may not fit in the space I have allocated for the battery array. The S10 is too heavy for me to carry. So far, the specifications do not look good for besting lead-acid batteries.

PNjunction

Re: Alternative to Lead Acid Batteries

northerner wrote: »

Originally, I had thought price of LiFePo4 were high due to the cost of lithium and relatively short supply, However, I'm hearing that the real reason is due to all the control electronics required to keep them safe. Even if price does come down, what will the potential cycle life be? And will they be cost competitive with lead acid?

LiFepo4 is where it is headed. It is available NOW. To the common man. If you amortize the extended cycle life, they cost more up front, but can be cost competetive with Pb. Depending on the application, a BMS is NOT mandatory, but quality monitoring is. For example, if one understands how to "bottom balance" a battery of cells, then complicated bms circuitry is not needed. An internal or external LVC or HVC may be desirable.

I can pick up a series of CALB gray-cell LiFepo4's from a variety of vendors in a few days and be in business. Note that I'm not talking about RC toy batteries, but ones that can do some real work.

LiFepo4 (Lithium-Iron) is extremely safe, although all batteries can be subject to abuse. They are half the density of the older LiCoo2 (lithium-cobalt) which have shown to be very unstable when the smallest deviation from specified charging voltages are exceeded. Not so with LiFepo4 which is more forgiving. Most consumers don't know the difference and lump all lithium chemistries together. Kind of like not knowing the difference between a flooded Pb lead acid, and an AGM.

A red flag is raised when a site touts their product and does not make this differentiation, thus furthering the consumers non-awareness leaving them to only think of recent tragedies involving lithium-cobalt, or things not directly involved with the battery like unsafe wiring harness engineering and other faulty exterior infrastructure.

They are about 1/5th the weight of Pb, which helps in the overall life-cycle carbon energy cost of shipping and distributing other heavy batteries. They are also non-toxic and easy to recycle - far easier than lead that's for sure. I mean lithium and iron are pretty non-toxic and easy to find worldwide.

They typically can be cycled down to 80% DOD without harm, (remember how AGM *used* to promise this and we all know it is really 50%?) and due to their extremely low internal resistance, maintain a very high voltage until the very end. Likewise, there is hardly any absorb. Essentially the useful life is between 80% and 10% DOD is basically flat across the board. Those who use gensets to charge, will find that due to the extremely low internal resistance, that the generator runs more efficiently, and all the way up to about 95% SOC or so. Thus, less fuel is wasted charging them. In fact, in cyclic use, there is no point to charging up to 100% as there is very little power there anyway, and LiFepo4's don't actually like sitting at a full charge for a long time. Just bring them down off the peg a bit to greatly extend life.

Just look around - LiFepo4 is everywhere even if the consumer doesn't know it. The sodium battery may be too little-too-late in comparison. But not to worry - those who would actually make a difference with large bulk purchases aren't hanging out in forum threads anyway. Wrong marketing demographic.

Buoug

Re: Alternative to Lead Acid Batteries

SolInvictus wrote: »

Startup Thinks Its Battery Will Solve Renewable Energy’s Big Flaw, Technology Review News, January 23, 2014:


The Aquion site still lacks a data sheet. To evaluate its suitability for replacing lead-acid batteries in residential systems, very detailed technical specifications are essential. The S10 stores 1.5 kWh, weighs approximately 100 kg and measures 1000mm H x 310mm W x 330mm D.

For comparison one of my Crown CR-395 L-16 lead-acid batteries stores 2,370 kWh @ 20 hr rate of discharge, weighs 55 kg. and measures 419 mm H x 183 mm W x 310 L. The S10 stores 63% energy, has about twice the weight and occupies 4.3 times the volume of one L-16. To store a little more than 1 day of power output from my PV array (24% of my current battery array) would require 3 S10's , 68% of the weight and 1.6 times the volume of my present battery array. The energy density is nearly 7 times less than my L-16 battery. Even if I can buy fewer of them because they can be cycled harder, they may not fit in the space I have allocated for the battery array. The S10 is too heavy for me to carry. So far, the specifications do not look good for besting lead-acid batteries.

I won't be doing solar for 5 yrs minimum so for me the size doesn't matter. I will be most likely building my house and when I do I will be doing so with solar in mind. If in 5 yrs the only bad thing about these are that they are just alot of space, then i will build a portion onto the house just for them. Again i wont be doing it for 5 yrs so I'm just keeping this alive so later on we can see where they are at. I'm also looking at the LiFepo4. I just hope that when i start solar they have soemething better than the lead-acid battery.

mtdoc

Re: Alternative to Lead Acid Batteries

PNjunction wrote: »

LiFepo4 (Lithium-Iron) is extremely safe, although all batteries can be subject to abuse. They are half the density of the older LiCoo2 (lithium-cobalt) which have shown to be very unstable when the smallest deviation from specified charging voltages are exceeded. Not so with LiFepo4 which is more forgiving. Most consumers don't know the difference and lump all lithium chemistries together. Kind of like not knowing the difference between a flooded Pb lead acid, and an AGM.

Very well put! I've been saying this for some time now but the "exlpoding lithium battery" alarmists just seem to go on lumping all lithium chemistries together. I agree that LiFePO4 batteries are at this point the most likely successor to Lead Acid. Keep up the great work ! - I will likely be getting some prismatic LiFePO4 cells for my next system.

PNjunction

Re: Alternative to Lead Acid Batteries

Thanks - but know up front that I'm testing with high-rate powersports batteries, which are the *least* cost effective when doing low-current draw tests. Lifepo4's come in different C ratings, so that's another spec to match to your application. However I am getting valuable hands-on from them.

Cold weather performance may also seem to be an issue, until enough current is drawn to warm them up internally. Bikers that are not used to that in the tundra freak out when it may not fire up the very first time. That is not a factor I've looked into from a non-starting bike applicaton say for a house bank.

PNjunction

Re: Alternative to Lead Acid Batteries

Buoug wrote: »

I'm also looking at the LiFepo4. I just hope that when i start solar they have soemething better than the lead-acid battery.

Perhaps your best bet is to jump in now with quality, TRUE deep-cycle agm's. We're not talking dual-purpose hybrids you get at the automotive parts center. If taken care of properly, there should be no harmful mist, overly long absorbs and the like. In 5 years when they are ready to be recycled, you'll have much more valuable experience in planning your real power-budget so that the next chemistry you choose will be a much better match and there won't be any wasted resources.

This is also insurance against waiting forever for patent-trolling and proprietary lock-down to play their part which sometimes results in a product never making it to market in the first place.

mtdoc

Re: Alternative to Lead Acid Batteries

PNjunction wrote: »

Thanks - but know up front that I'm testing with high-rate powersports batteries, which are the *least* cost effective when doing low-current draw tests. Lifepo4's come in different C ratings, so that's another spec to match to your application. However I am getting valuable hands-on from them.

Cold weather performance may also seem to be an issue, until enough current is drawn to warm them up internally. Bikers that are not used to that in the tundra freak out when it may not fire up the very first time. That is not a factor I've looked into from a non-starting bike applicaton say for a house bank.

I have experience using 48V nominal (16s) LiFePO4 packs with my ebike. Good point about temperature issues. My utility room were my current battery bank is never gets below 50 F but I am soon going to add a new system for my detached garage/shop. The space there is currently unheated (though that may change).

PNjunction

Re: Alternative to Lead Acid Batteries

If you are drawing current, that alone may be enough to keep them warm internally. I suppose the only issue would be firing up a house from a dead-cold start.

northerner

Re: Alternative to Lead Acid Batteries

Batteries are an expendable component of an off grid system and the most important factor with any battery is cost. Of course other factors such as space or weight may be an issue for some. That will ultimately determine which battery will eventually replace the traditional lead acid battery. Of course the battery must be efficient, safe and reliable. Two major factors affect the cost of an off grid battery, upfront purchase price and lifespan. It will be interesting to see what the life span of a sodium ion battery actually is. Aquion reports no degradation in storage capacity after 4000 cycles! And sodium ion batteries are expected to be less expensive to purchase than lithium phosphate batteries, although, that remains to be seen.

karrak

Re: Alternative to Lead Acid Batteries

PNjunction wrote: »

Lifepo4's come in different C ratings, so that's another spec to match to your application. However I am getting valuable hands-on from them.

For the majority of off-grid systems I would think the current draw and charge requirements are well below the C ratings of most LiFePO4 batteries. In my case my charge current is < 0.1C and discharge current is <0.5C, well below the specs of 3C for my Winston Prismatic LiFeYPO4 cells.

Cold weather performance may also seem to be an issue, until enough current is drawn to warm them up internally. Bikers that are not used to that in the tundra freak out when it may not fire up the very first time. That is not a factor I've looked into from a non-starting bike applicaton say for a house bank.

The low temp spec on the Winston batteries i use is -45C (-49F) for both charge and discharge http://en.winston-battery.com/index.php/products/power-battery/item/wb-lyp90aha?category_id=176 I find that hard to believe but Winston have been around for a while and their cells have Yttrium added to them which enhances low temperature performance. There is lots of information on the web on cold weather experience with LiFePO4 batteries, just google "cold forum LiFePO4"

PNjunction

Re: Alternative to Lead Acid Batteries

northerner wrote: »

Batteries are an expendable component of an off grid system and the most important factor with any battery is cost. Of course other factors such as space or weight may be an issue for some. That will ultimately determine which battery will eventually replace the traditional lead acid battery.

The lighter weight of LiFepo4 compared to traditional lead acid (about 1/5th) means that they take less of a toll on the environment to ship and distribute. Transportation costs go down since freighters, trains, trucks, and so forth aren't expending as much fuel to get them to you. That's a win-win financially and environmentally since the overall life-cycle costs from manufacturing to recycling must be taken into account.

Larger systems are easier to install as it lessens the need for reinforced flooring, or for the DIY'er, not having to use forklifts and small cranes to populate a battery vault that may be in less accessible locations. Shlepping T105's around at my age up and down into the basement is not a pleasure.

In Aquion's case, i really don't see the need to discuss something that has not made it to market and is certainly not something I'm going to invest time and energy on. All the would-be, could-be, single-vendor estimates, lack of *published* specifications, NDA's and so forth make Aquion discussions mere financial investment speculation.

PNjunction

Re: Alternative to Lead Acid Batteries

karrak wrote: »

There is lots of information on the web on cold weather experience with LiFePO4 batteries, just google "cold forum LiFePO4"

Sure is. One of the best things I learned during my tests is to be sure to differentiate between starting applications, and constant-current draw applications. The results / characteristics do tend to differ, especially when one isn't taking things to extremes. Most LiFepo4 discussions revolve around motive power starting issues. Our house-banks are treated quite well - or should be.

Our environments are also better controlled and monitored. Needless to say, extremes like shooting nails through the cases, intentional massive shorts, reverse currents, high voltages, etc make for dramatic videos or discussions, but I can also do that with my standard batteries too, not that I want to.

PNjunction

Re: Alternative to Lead Acid Batteries

karrak wrote: »

For the majority of off-grid systems I would think the current draw and charge requirements are well below the C ratings of most LiFePO4 batteries. In my case my charge current is < 0.1C and discharge current is <0.5C, well below the specs of 3C for my Winston Prismatic LiFeYPO4 cells.

I'd be interested at what capacity you are charging up to - 100% or a bit less?

I found the following pretty interesting as I won't be able to charge at high rates with solar either when I build a larger pack. Basically, at low rates, just pull the charge when you reach the target voltage. At high rates (I'm thinking 0.5C+), keep the voltage present, but monitor the current until it is about 10% of the initial starting rate and then shut off.

The article presents BOTH LiFepo4 AND Licoo2 voltages, so for our LiFepo4, be sure to substitute 3.65v anywhere you see a reference to 4.2v, which will cook our lifepo4's. The procedure is the same, but it might be easy to miss that one sentence about the proper voltage for Lifepo4:
http://www.powerstream.com/li.htm

I did note the safety warnings at the end, but when that article was written it seemed intended primarily for Li-Cobalt as seen by the voltages listed (substitute 3.65v high and 3.1v low per cell for Lifepo4). In addition, most Lifepo4's can accept higher than 0.7C - but of course refer to the manufacturer's spec for the final say.

Personally, I don't think I'll be taking cells to 100% / 3.65v every time. For daily use, I think maybe 90-95% SOC from 3.55 to 3.6v per cell would be more than adequate. These are charging voltages, not the "at rest" voltages which will drop down after a few hours.

karrak

Re: Alternative to Lead Acid Batteries

PNjunction wrote: »

I'd be interested at what capacity you are charging up to - 100% or a bit less?

I currently have my MPPT controller programmed to charge to 3.45 volts/cell once a week which i use to reset my SOC counter, and to 3.375 volts/cell (which equates to around 80%SOC +/-15%) for the rest of the week. We live in a Mediterranean climate and in summer do not need the batteries to be full. When i get around to improving the accuracy of the current sensing circuitry on my controller I will use an SOC of around 80% rather than the voltage. One of the great things about these batteries is that the coulomb/current efficiency is greater than 98% and so even after one week (seven charge/discharge cycles) my JLD404 AH counter is only ever out by a few %

I found the following pretty interesting as I won't be able to charge at high rates with solar either when I build a larger pack. Basically, at low rates, just pull the charge when you reach the target voltage. At high rates (I'm thinking 0.5C+), keep the voltage present, but monitor the current until it is about 10% of the initial starting rate and then shut off.

Personally, I don't think I'll be taking cells to 100% / 3.65v every time. For daily use, I think maybe 90-95% SOC from 3.55 to 3.6v per cell would be more than adequate. These are charging voltages, not the "at rest" voltages which will drop down after a few hours.

From the research I have done and my experience, i can't see any point in taking the voltage higher than 3.45 volts/cell if you have a low charging current, i might even try 3.35 V/cell. Going to 3.65 volts only gives you at most a few extra %. In my case i charge to the voltage and then current limit until the current gets to C/20 at which point I go to a float voltage until the next day.

There is some good information here,
http://batteryuniversity.com/learn/a...ased_batteries ,not specifically for LiFePO4 batteries but i would think relevant
http://www.cruisersforum.com/forums/...nks-65069.html ,excuse the size of this thread, lots of information here but needs some filtering.

PNjunction

Re: Alternative to Lead Acid Batteries

karrak wrote: »

One of the great things about these batteries is that the coulomb/current efficiency is greater than 98% and so even after one week (seven charge/discharge cycles) my JLD404 AH counter is only ever out by a few %

Right on - instead of measuring SOC voltage, watt-hour/amp hour measurements are my preferred option.

I think I have cracked the marketing codes and trends from off the shelf testing...... roll Monty Python skit ...

User-A routinely uses his bank from 0 - >80% DOD. Taken below 80% DOD on a regular basis by either design or accident aggravates the balance issue, especially if the cells are not matched at the factory for both capacity AND internal resistance. Complicating matters is hammering the bank with full charge current below the 80% DOD mark. While he may get all the capacity he paid for up front, unless he uses a balance circuit all the time, cycle life will be reduced further than normal.

User-B routinely only uses his bank from 80 - 10% DOD. While he is not getting the capacity he paid for up front, balance issues are lessened by not operating in the sharply sloped charge-discharge knees, but is made up for by extended cycle life. Quality of the battery of cells is important here too - needing to be matched for both capacity and internal resistance before assembling the pack. This is a KISS operation not necessarily needing a balance circuit all the time. When calculating battery needs, figure on only getting 70% of rated capacity.

Is this an issue for User-B ? If you look at it from a glass half full standpoint, compared to Pb which we often buy twice the capacity to regularly operate at no more than 50% DOD, this is a net gain of about 20-30% operationally. Still, to do it perfectly, one has to buy more capacity than stated if they operate in the 80-10% DOD window.

Note that I'm not saying one shouldn't ever balance a pack. Common sense mandates checking balance regularly, much like the maintenance one does on 2V cells with Pb with either a hydrometer for flooded or a standing resting SOC with agm.

So what is approx 80% DOD for LiFepo4? Unless you do amphour / watthour measuring, a resting voltage of *just below* 3.2v per cell (or about 12.8v for a nominal 12v battery) if taken with an accurate meter (Fluke 87V spec or higher) will suffice. To be sure you are out of the flat part of the curve, and actually into the start of the steep discharge slope, then perhaps modify this to 3.175v / cell, or 12.75v for the typical 4S nominal 12v batt. This is what I'm going to do DIY. Staying within perfect manufacturer warantee voltages is another.

I'm going to operate as User-B and see how it goes keeping an eye on balance. This might take me awhile, but will be fun.

AzSun

Re: Alternative to Lead Acid Batteries

To put thing into perspective, after thorough testing, my little set of Edison Nickel-Iron batteries manufactured in 1928 have a higher reserve capacity than the
brand new Walmart "Everstart MAXX" deep cycle group 29 marine battery I just returned. Lead is heavy and sulfuric acid is messy.

Cariboocoot

Re: Alternative to Lead Acid Batteries

AzSun wrote: »

To put thing into perspective, after thorough testing, my little set of Edison Nickel-Iron batteries manufactured in 1928 have a higher reserve capacity than the
brand new Walmart "Everstart MAXX" deep cycle group 29 marine battery I just returned. Lead is heavy and sulfuric acid is messy.

Not that a Marine/RV battery is really suitable for RE work nor that reserve capacity is what deep cycles are concerned with.

karrak

Re: Alternative to Lead Acid Batteries

PNjunction wrote: »

I think I have cracked the marketing codes and trends from off the shelf testing...... roll Monty Python skit ...

Which Python skit did you have in mind?

User-B routinely only uses his bank from 80 - 10% DOD. While he is not getting the capacity he paid for up front, balance issues are lessened by not operating in the sharply sloped charge-discharge knees, but is made up for by extended cycle life. Quality of the battery of cells is important here too - needing to be matched for both capacity and internal resistance before assembling the pack. This is a KISS operation not necessarily needing a balance circuit all the time. When calculating battery needs, figure on only getting 70% of rated capacity.

Winston's battery specs give >5000 cycles for 70% DOD and >3000 cycles for 80% DOD. I emailed them to find out their testing methodology, and although didn't get an answer on that, did manage to get them to agree that the best way to maximise the lifespan was to cycle between 85% to 15% SOC. This agrees with other information i have seen which suggests to try and keep the SOC of the cells centred on 50%. This is easier to achieve with an electric vehicle where you have some idea how far you have to travel, than being off-grid at the mercy of the weather.

With some care and planning in off-grid installations i think you can get an effective 90% of capacity from the LiFePO4 cells by charging them to 3.45 volts when bad weather is forecast and being prepared to take them down to 10% SOC occasionally without impacting on the overall lifespan too much.