LiFeP04 Batteries for Solar & BMS

[nativewolf]

You just don't get it and keep on slyly hawking used batteries, regardless of whether or not you get them to "work".

That is entirely irresponsible here. Sure, in some of the experts hands over at DIYELECTRICCAR that can be done safely and properly. Take your wares over there, where that crowd can deal with them responsibly. Or take it to Endless-Sphere, where some are responsible, there is a whole crowd who think nothing of using duct-tape and junk cells. I frequent both, but I always keep in mind the engineering needs here are different. And oh yeah, it is also different from hacking laptop cells to power your flashlights over at Candlepowerforums.

The engineering for a solar housebank is DIFFERENT from that of an EV, regardless of whether you can hack those cells to work.

I can see the keyboard fingers flying. Hmmmm how can I make a buck on the Musk market - I know! Tell amateur hacks they can duplicate it with crash-victim Nissan cells of their own.

No matter your self-justification, replete with salesman-like figures, it is just WRONG and can be in many cases illegal. Some might actually want to know who your source is, so we can start to examine the hazmat shipping records for compliance all along the chain, where these cells, regardless of whether they work or not, are intended for TRUE recycling, and not slipped out the back door for resellers. I think Nissan might want to keep track too.

Did your wrecking-yard provide you with a warantee? - I think not. You are a GAMBLER, and here we don't like to gamble with safety.

A123 pouch cells suffered the same fate from amateur hacks like yourself promoting used and unsafe batteries under the umbrella-term of "recycled". So it is no surprise to see that done here.

What you are promoting is admittedly finely crafted prose in order to not set off any immediate red-flags, but I read right through it.

Note that I'm not new to this game either - when years ago reject / recalled Optima agm's were slipped out the back door by non-authorized dealers instead of being sent back, recycled or destroyed - looking to make a quick buck on the cheapskates and unknowing.

Instead of promoting responsible use of lithium, you are helping to destroy the industry - if you can look that far.

Huh from a newbie perspective with no, and I mean no clue on building a solar system (other than a few weeks reading of forums- this being like my 3-4th post) you seem to be awfully keen on attacking this idea. I just thought it was clever. but then I'm a forester and farmer and consultant, so I like clever solutions to expensive troubles. So, educate me. Why are the EV lithium cells different? Why would the Tesla power pack work?

[PNjunction]

You just don't get it and keep on slyly hawking used batteries, regardless of whether or not you get them to "work".

That is entirely irresponsible here. Sure, in some of the experts hands over at DIYELECTRICCAR that can be done safely and properly. Take your wares over there, where that crowd can deal with them responsibly. Or take it to Endless-Sphere, where some are responsible, there is a whole crowd who think nothing of using duct-tape and junk cells. I frequent both, but I always keep in mind the engineering needs here are different. And oh yeah, it is also different from hacking laptop cells to power your flashlights over at Candlepowerforums.

The engineering for a solar housebank is DIFFERENT from that of an EV, regardless of whether you can hack those cells to work.

I can see the keyboard fingers flying. Hmmmm how can I make a buck on the Musk market - I know! Tell amateur hacks they can duplicate it with crash-victim Nissan cells of their own.

No matter your self-justification, replete with salesman-like figures, it is just WRONG and can be in many cases illegal. Some might actually want to know who your source is, so we can start to examine the hazmat shipping records for compliance all along the chain, where these cells, regardless of whether they work or not, are intended for TRUE recycling, and not slipped out the back door for resellers. I think Nissan might want to keep track too.

Did your wrecking-yard provide you with a warantee? - I think not. You are a GAMBLER, and here we don't like to gamble with safety.

A123 pouch cells suffered the same fate from amateur hacks like yourself promoting used and unsafe batteries under the umbrella-term of "recycled". So it is no surprise to see that done here.

What you are promoting is admittedly finely crafted prose in order to not set off any immediate red-flags, but I read right through it and cannot willingly help to create any sort of black-market buzz.

Note that I'm not new to this game either - when years ago reject / recalled Optima agm's were slipped out the back door by non-authorized dealers instead of being sent back, recycled or destroyed - looking to make a quick buck on the cheapskates and unknowing.

Instead of promoting responsible use of lithium, you are helping to destroy the industry - if you can look that far.

[nativewolf]

ev battery

We're not talking about cars that are junked because of age or flooding here, or cars that have been in major accidents where the battery too has suffered structural damange. We are talking about new to 3-4 year old cars that have been in accidents serious enough to not make it economical to repair, but which have also left most of the cars parts in good shape. Typically except fenders, hood, trunk lid and so forth. Car repairs have been getting more expensive the last years, EVs even more so, so it doesn't take all that serious a collision to send an EV to the wrecking yards. The battery modules from those are generally of exceptional quality, closely matched together and needing minimal balancing.

Heck, you could even buy a used 2012 Leaf just out of lease, dismantle the battery and end up with a cheaper 24kWh battery bank than you can get from new large prismatic LiFePO4. For example, to get ~24kWh from these: http://www.ev-power.eu/Winston-40Ah-...-2V-400Ah.html you'll need 19 of them for a total cost of over $10k + shipping. You can get a nice Leaf for $10k with minimal battery degradation, and you'll still have a whole car to sell parts from after dismantling the battery. A nice pack would be 6P8S from the modules (which are 2P2S internally) for a 12P16S battery (60V nominal).

And the EV batteries keep falling in price fast, while large prismatics really haven't moved much lately. Nissan already sells a new 24kWh pack for $5000, though you need to return the old one. Tesla sells the 10kWh PowerWall for $3500 which is $8400 for 24kWh. Still 16% cheaper than LiFePO4 cells. The LiFePO4 manufacturers really need to get the prices down or be left in the dust. Their problem is that the volume is so small compared to EV battery volume.

Sort of what I was thinking. There have to be lots of Volt and Leafs that have been scrapped and have good battery packs. I'd just not thought about it. Musk could crush this whole market I'd think. Give the factory 2 years to get going.

[jkirkebo]

Using equipment from wrecks or junked car is ok for a lot of mechanical components but when it comes to electrical and batteries IMO it is like playing Russian roulette with 3 chambers loaded. Even worse then putting on a set of old retread tires.

We're not talking about cars that are junked because of age or flooding here, or cars that have been in major accidents where the battery too has suffered structural damange. We are talking about new to 3-4 year old cars that have been in accidents serious enough to not make it economical to repair, but which have also left most of the cars parts in good shape. Typically except fenders, hood, trunk lid and so forth. Car repairs have been getting more expensive the last years, EVs even more so, so it doesn't take all that serious a collision to send an EV to the wrecking yards. The battery modules from those are generally of exceptional quality, closely matched together and needing minimal balancing.

Heck, you could even buy a used 2012 Leaf just out of lease, dismantle the battery and end up with a cheaper 24kWh battery bank than you can get from new large prismatic LiFePO4. For example, to get ~24kWh from these: http://www.ev-power.eu/Winston-40Ah-...-2V-400Ah.html you'll need 19 of them for a total cost of over $10k + shipping. You can get a nice Leaf for $10k with minimal battery degradation, and you'll still have a whole car to sell parts from after dismantling the battery. A nice pack would be 6P8S from the modules (which are 2P2S internally) for a 12P16S battery (60V nominal).

And the EV batteries keep falling in price fast, while large prismatics really haven't moved much lately. Nissan already sells a new 24kWh pack for $5000, though you need to return the old one. Tesla sells the 10kWh PowerWall for $3500 which is $8400 for 24kWh. Still 16% cheaper than LiFePO4 cells. The LiFePO4 manufacturers really need to get the prices down or be left in the dust. Their problem is that the volume is so small compared to EV battery volume.

[SunEagle]

I'd not thought about finding wrecked volts or leafs for batterys. Guess that makes me a newbie

Using equipment from wrecks or junked car is ok for a lot of mechanical components but when it comes to electrical and batteries IMO it is like playing Russian roulette with 3 chambers loaded. Even worse then putting on a set of old retread tires.

[nativewolf]

wrecked leafs- cool battery source

Interesting thread. I'll put in my 5 cents since I actually have an off-grid lithium system.

My battery is 35kW big and consists of 70 modules from the batteries of wrecked Leafs. Each Leaf battery holds 48 modules which each has 4 cells connected 2S2P. I have connected those 7S10P, for a 14S battery with 662Ah capacity. Total cost for the modules was approx. $3750 which I consider a good deal.

Picture of the battery bank: [ATTACH]7218[/ATTACH]

I use a Orion Jr. BMS which is set to start balancing at 3.900V if the difference is more than 10mV. This seems to work very well. I charge to 4.07V per cell and discharge to 3.40V per cell max. This means I use approx. 25kWh of the 35kWh the battery can deliver, this should vastly prolong the life of the modules.

Inverters are twin Outback VFX3048E's, a single Outback FM80 charge controller connected to 8 Sunpower 327W panels and an Outback FN-DC to monitor the energy of the pack (triple shunts, works better than the CAN-BUS output from the BMS). A Mate2 displays the info and there's a Victron Orion 360W DC-DC to supply the 12V devices from the 53V battery bank without going through the inverters (which are turned off when we're not at the cabin the system is installed in).

[ATTACH]7219[/ATTACH]

Wrecked EVs should be plentiful in the future, I think the best deals for off-grid systems will be cells/modules from these and not brand new ones.

I'd not thought about finding wrecked volts or leafs for batterys. Guess that makes me a newbie

[PNjunction]

Lock up your Nissan Leafs from THEFT

Wrecked EVs should be plentiful in the future, I think the best deals for off-grid systems will be cells/modules from these and not brand new ones.

Interesting concept but no thanks. What nearly every serious forum that deals with batteries stresses is the importance of getting them from *reputable* dealers or authorized sources, be they AA rechargeables, FLA's, AGM's, to the latest lithiums. Wrecks or not, they are NOT SAFE when gotten from irreputable unauthorized sources. Nissan doesn't sell them to the public.

Aside from the ability to diy it for a one-off project for the true battery geek (and I am one!), all this really promotes is aside from salvage-yard non-authorized resellers, is the large temptation for outright THEFT. Why wait for a wreck? Leaf owners - better lock up your cars. Seriously advanced diy'ers will move beyond wrecks and eye your pristine cells...

There is a reason that we don't use hundreds of laptop-like cells - even if new- and simplify with large capacity lifepo4 prismatic cells instead again from authorized dealers who are reputable. There are many. Those that cheap out and go gray market pay the price both figuratively, and literally.

I know WB9K over at endless-sphere would probably agree about getting cells from *authorized* sources. Those that don't again pay the price for gray market, counterfeit, and unsafe cells. Your system is pretty much like a large e-bike. If you can manage that, then great, but I would never recommend this as a normal practice.

I know I will NEVER be PM'ing you to find out how and where to get wrecked cells. I recommend nobody else do either.

[inetdog]

Wrecked EVs might be plentiful in the future in a progressive country like Norway but here in Australia I think not...

Carcasses of EVs burned by Luddites then?

[karrak]

Interesting thread. I'll put in my 5 cents since I actually have an off-grid lithium system.

My battery is 35kW big and consists of 70 modules from the batteries of wrecked Leafs. Each Leaf battery holds 48 modules which each has 4 cells connected 2S2P. I have connected those 7S10P, for a 14S battery with 662Ah capacity. Total cost for the modules was approx. $3750 which I consider a good deal.

Wrecked EVs should be plentiful in the future, I think the best deals for off-grid systems will be cells/modules from these and not brand new ones.

Interesting is one word for it...

Sounds like a great system, I am envious, it cost me around $4,000 for 10kW of new LFP batteries.

Wrecked EVs might be plentiful in the future in a progressive country like Norway but here in Australia I think not...

I think you are right, that for those people with enough technical knowledge to understand how to put together a safe system using these batteries that this is a good way to go.

I look forward to seeing future posts on how your system is going and how long the battery lasts for.

Simon

[jkirkebo]

Interesting thread. I'll put in my 5 cents since I actually have an off-grid lithium system.

My battery is 35kW big and consists of 70 modules from the batteries of wrecked Leafs. Each Leaf battery holds 48 modules which each has 4 cells connected 2S2P. I have connected those 7S10P, for a 14S battery with 662Ah capacity. Total cost for the modules was approx. $3750 which I consider a good deal.

Picture of the battery bank: 2015-04-25 23.39.41.jpg

I use a Orion Jr. BMS which is set to start balancing at 3.900V if the difference is more than 10mV. This seems to work very well. I charge to 4.07V per cell and discharge to 3.40V per cell max. This means I use approx. 25kWh of the 35kWh the battery can deliver, this should vastly prolong the life of the modules.

Inverters are twin Outback VFX3048E's, a single Outback FM80 charge controller connected to 8 Sunpower 327W panels and an Outback FN-DC to monitor the energy of the pack (triple shunts, works better than the CAN-BUS output from the BMS). A Mate2 displays the info and there's a Victron Orion 360W DC-DC to supply the 12V devices from the 53V battery bank without going through the inverters (which are turned off when we're not at the cabin the system is installed in).

2015-06-18 16.04.22.jpg

Wrecked EVs should be plentiful in the future, I think the best deals for off-grid systems will be cells/modules from these and not brand new ones.

[tom rickard]

I'm not a manufacturer, i'm a DIY off-grid customer who is trying to make information available so people reading forums like this can make an informed choice.

My BMS was $400AUD INCLUDING hardware and software to use a PC to monitor / reprogram cell shunts.. There was no further cost other than contactors for HVD and LVD.

Sunking, you keep banging on about how expensive this is, yet you then turn around and say you use a powerlab 8 to recalibrate your bottom-balanced cells.

So now not only do you have to deplete your cells to 10%SOC (so you have to monitor the last part of your load while you wait for your cells to reach this point), then you use a powerlab 8 which I just checked on ebay and it averages $350AUD.

Who's the crazy one! Now all of a sudden my BMS is less expensive than your bottom balancing system that also requires a cell-monitoring system, and a unit to activate a contactor for HVD (assuming you use your inverter for LVD and have no redundancy)

So for less cost, my system will keep the cells at the same voltage where they spend the majority of their life, it has a backup HVD and LVD, and can be connected to a laptop to log or monitor the cell temp / voltage / bypass current, as well as pack voltage and current.

Anyone reading this thread that is in the process of setting up an off-grid system can make their own decisions. Either system will work, take your pick based on the info available.

With regard to your drop in replacement batteries, I only personally know of one manufacturer making these (lifetech lithium), and they do contain a BMS, I looked at the link you provided, how do you know these batteries don't have inbuilt BMS ?

[Sunking]

Good for you, I hired an Electronic Engineer to write our Quality Assurance manual, wouldn't hire him to design anything...

Simon

I knew it, you are a manufacture. Busted. Explains it all. You do not want anyone to know you do not need a BMS. Would be bad for biz.

[karrak]

BS. A solar system you do not design for 5 day reserve capacity, more like 2 to 3 days. I do not know what Utopia you live in, but the rest of us live in places with cloudy days and our batteries spend most of their life around 50%.

SK, I haven't seen any evidence that you actually have an off-grid solar powered power system with an LFP battery. As I have stated before the average SOC of my battery is 71% and has about tree days of storage in it.

Then we have to take vacation once in a while and cannot be there every day to take corrective action. I guess you guys down under never leave home or have a cloudy day?

This is exactly the reason we have a BMS, to take care of the system when we are away or not monitoring it. In my case, I can look at my battery state and query or reprogram my Solar Controller or my Battery Monitor (https://github.com/simat/BatteryMonitor) anywhere via the Internet. At some point I might get my Battery Monitor to send me an email if something is going wrong.

Here is the bottom line. I don't care how you manage your batteries. Karrak already admitted he does nothing and has no BMS so i have no idea what he is squaking about. If you want to use Top Balance have it. I prefer to get the most out of my investment. What you do with your investment is your problem.

Wrong again. My first BMS was me and a modified Cellog8, which with all the other bits and pieces would have cost me less than $50. The Cellog8 generates an alarm if any cell voltage gets out of the range of 3.6 volts to 2.8 volts, I will act on the alarm. A few days after I installed my battery this simple setup saved my battery. Still use the Cellog 8, but now have my Battery Monitor. The Cellog 8 will be retired when I get around to putting alarms on my Battery Monitor. Another part of a BMS, balancing is done manually by me. Am looking at doing it automatically using my Battery Monitor.

But no commercial EV uses Top Balance.

Evidence please, you have been wrong on so many things so why not this.

12, 24, and 48 volt LFP batteries right now today and no need for any BMS. If drift was a real problem they could not give you 2 to 5 year warranties.

It is probably a matter of economics, not so much reason to put a BMS which might cost up to several hundred dollars on a battery worth less than $1,000. Now for batteries costing several thousand on even tens of thousands of dollars it is a different story.

I am not looking at 2-5 years. I am hoping than by putting as little stress on my LFP battery while storing enough energy to make it financially viable that I will get around ten years use out of the battery. Time will tell...

Simon

[karrak]

You are nucking Futs Simon. No EV manufacture goes anywhere near the Top or Bottom. They could not offer 8 and 10 year warranties doing that. Top Balance is for amateurs and novices. Chevy volt operates 80/20, Tesla and Nissan 90/10. Tesla's controller never turns off, which is why it cannot set for long periods without being plugged in.

I didn't say they go near the top or bottom, I said, "Fully charging a lithium battery using this technique is equivalent to top balancing a battery.". Is it that you don't read or comprehend other peoples posts unless they agree with your viewpoint, or unless you think you can use it against them?

I try not to go near the top or bottom except to balance my pack which I do around once a year. If you were to balance your pack you would have to take it to the very bottom 0% SOC.

By the way, it is very hard if not impossible to middle balance SOC of an LFP battery using voltage between the SOC range 20%-80% due to the very flat charge profile with around 0.1 volts between an SOC of 20%-80%. This flat profile means that the battery voltage will be in balance without outside intervention unless the battery is badly out of balance.

It use 1 Kwh per day doing nothing but monitoring batteries and shuffling power, heat, and cooling around Brick to Brick.

Please give me evidence of Tesla shuffling power around.

Simon

[karrak]

I have done contract work for him, and was offered a position as Executive Engineer at his company 2 yyears ago before I moved to Panama.

Good for you, I hired an Electronic Engineer to write our Quality Assurance manual, wouldn't hire him to design anything...

Simon