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

[transmitterdan]

Dave,

I think the consensus of this thread is that you have to charge cells in parallel when you first get them because you don't know the individual state of charge. After that, put them in series and don't worry about balancing unless the cells measure too far out. So the consensus on balance seems to be trust but verify. So you need HV cutout for charge sources, LV cutout for the load bus and individual cell monitoring (but not balancing) to warn about cell balance problems. Set the cutouts well away from the upper and lower knee's. Seems pretty simple.

[goboatingnow]

Originally Posted by transmitterdan

Dave,

I think the consensus of this thread is that you have to charge cells in parallel when you first get them because you don't know the individual state of charge. After that, put them in series and don't worry about balancing unless the cells measure too far out. So the consensus on balance seems to be trust but verify. So you need HV cutout for charge sources, LV cutout for the load bus and individual cell monitoring (but not balancing) to warn about cell balance problems. Set the cutouts well away from the upper and lower knee's. Seems pretty simple.

Yes I agree with one initial balance. , after that it's fairly irrelevant. , after all it's just a small effective loss in overall achievable capacity, equivalent to many other similar losses that reduce effective bank capacity.

Dave


Sent from my iPad using Tapatalk

[hellosailor]

Jerry-
Please note that Cat 9 Hazmat or not, even UPS in their "Does it combust?" guide at http://www.ups.com/media/news/en/us_...egulations.pdf

explicitly says that batteries under 30 pounds or 300Wh do NOT have to be sent via Hazmat at all. They can just be sent via UPS ground.

This would allow cells up to ~70AH to be shipped via conventional ground shipping, based on the 300Wh limit. If the limit is applied based on state of charge rather than capacity, way better still.

The main difference Balqon and others have, as compared to US battery distributors, is exactly that. DISTRIBUTORS have a distribution network in place, allowing economical full truckload deliveries nationally. Even so, DEKA (PA) can't compete with Seattle, or Houston, locally. Each "owns" a region based on transport costs. That's just the way it is.

Balqon certainly could compete by setting up their own network, but they exist in order to supply traction batteries to *one* seaport, that's all. The rest is collateral business to them. And last I heard, their main business wasn't so profitable either.

Shipping costs? Check out the price of a dozen eggs or a gallon of milk in Alaska.(G)

[OTTCT]

Originally Posted by Lagoon4us

Lloyd has hijacked this thread with constant negative remarks, he has done it before to other good threads, frustrating good people to the point of not bothering sharing the knowledge, i think he needs to back off as he has no intention of any positive input.

The thread prior to his 'de-contributions' was a good one/best one, informative and fresh, there are 6 or so very VERY knowledgeable people here that are being treated as fool's by his incessant one track jibe's.

Had enough of his rot....rant over, Ciao Lloyd it needs to be said, you are a tosser!

I think I will 2nd, 3rd, 4th & 5th that one .
I'm assuming Lloyd has a 1937 boat and is happy with his 1850 technology battery.

Don't understand how someone who does not own 1ah of LifeP04 can even have an opinion on the subject ???? His negative comments are very distraction to folks who wanna actually wanna learn something like T1 Terry who has real life experience.

If it was up to Lloyd I bet it would be another 100,000 before humans can use fire - look how dangerous that is.

PS Lloyd I only own 7,000 ah of 12 v lithium, 1250 ah right under my bed.

Cheers OTTCT

[diugo]

It has now been two years since I acquired four used 260Ah ThunderSky cells from Balqon (manufactured Dec 2010). So I thought I would report on how they are holding up.

A year ago my capacity tests revealed a sharp decline to 206Ah, a 21% decline from the year before. This year the same test lasted 89 hours at 2.1A for 187Ah---less than a 10% slide, so that was encouraging.

But a second test at 39A lasted just four hours for 156Ah. Hardly bionic by any stretch of the word! At least the Peukert constant has been pretty consistent since I got them---just under 1.06. But for just $600 delivered (including the 30% solar tax credit they qualified for) they were fun to play with, and still are.

I am hoping they will continue to limp along for another twenty months, when funds become available to replace them with brand new CALBs.

[JayH]

Originally Posted by klaus53123

Victron mulitplus: I will change the programming so it matches the above mentioned values. My only question here is the following: The charge and supply cable for the inverter are the same. So I can only hook it up either to the load bus or the charge bus. I have seen recommendations in earlier post to hook it up to the load bus, but how can I than still cut it off in case of a HVC event? Coudnt't find anything in earlier post.

I believe Victron has a software "agent" for the MultiPlus that tells it to turn off the charger if auxiliary contacts are closed. It's intended to allow a BMS to signal high voltage. Best to check with them for more info.

With that in place you could connect the MultiPlus to the load bus.

[OTTCT]

Originally Posted by hellosailor

Jerry-
Please note that Cat 9 Hazmat or not, even UPS in their "Does it combust?" guide at http://www.ups.com/media/news/en/us_...egulations.pdf

explicitly says that batteries under 30 pounds or 300Wh do NOT have to be sent via Hazmat at all. They can just be sent via UPS ground.

This would allow cells up to ~70AH to be shipped via conventional ground shipping, based on the 300Wh limit. If the limit is applied based on state of charge rather than capacity, way better still.

The main difference Balqon and others have, as compared to US battery distributors, is exactly that. DISTRIBUTORS have a distribution network in place, allowing economical full truckload deliveries nationally. Even so, DEKA (PA) can't compete with Seattle, or Houston, locally. Each "owns" a region based on transport costs. That's just the way it is.

Balqon certainly could compete by setting up their own network, but they exist in order to supply traction batteries to *one* seaport, that's all. The rest is collateral business to them. And last I heard, their main business wasn't so profitable either.

Shipping costs? Check out the price of a dozen eggs or a gallon of milk in Alaska.(G)

Hellosailor

Please don't make a mistake by dropping a 7lb 70ah cell into the regular mail. The fine is $55,000 per day plus criminal prosicution for willful neglect of the law.

It's very complicated wording & I'm still checking on the info but this came straight from GBS - ELITE POWER, it must be shipped with a company account & packed by a certified lithium lifep04 shipper. They had to jump the hoops to ship their units.
I know if the LifeP04 is inside equipment such as a powers supply it can be shipped from a ups store up to 30kg no problem. However they can not touch the single cell if it's over 100 watts RATED !!

IF someone out there is actually a hazmat shipper of class 9 lifep04 batteries I would love hear from them. As to more details on this issue.

Cheers OTTCT

[OceanSeaSpray]

Originally Posted by diugo

It has now been two years since I acquired four used 260Ah ThunderSky cells from Balqon (manufactured Dec 2010). So I thought I would report on how they are holding up.

A year ago my capacity tests revealed a sharp decline to 206Ah, a 21% decline from the year before. This year the same test lasted 89 hours at 2.1A for 187Ah---less than a 10% slide, so that was encouraging.

But a second test at 39A lasted just four hours for 156Ah. Hardly bionic by any stretch of the word!

Thanks for sharing this, it is not good, but interesting. What kind of charge/discharge regime and charge control do they see? Have they been cycling significantly, or spending a lot of their time charged up?

[hellosailor]

Jerry-
All that I'm saying, is what the three major carriers in the US have all told me. USPS, UPS, FedEx, all have different restrictions and definitions of hazmat. Apparently AS ALLLOWED by the CFR because of the different ways they choose to handle business.


For instance, one item I needed to ship (not batteries) was simply verboten by the USPS and UPS. But FedEx would allow any account holder to have it picked up as long as the carrier (driver) was told what it was.


Yes, they all follow the same federal codes but if the carrier chooses to interpret or apply them one way not the other? No court in the land is going to fine me for anything when I can say "Here's the carrier's terms, this shipment was expressly allowed by the carrier." That makes it not my problem.


I have seen all three carriers say "that's hazmat" in their hazmat telephone support departments, while their printed documents said something wasn't. These guys are all human, and trained to err on the side of protection, so when they don't understand something or don't see the exemptions (like small quantity) they just say "No" and most business shipping departments will do the same thing.


Hell, I've seen businesses charge a reasonable $6 UPS fee for an item, and when you point out "That can go in a #10 envelope for 49c" some will say "Oh! Sure, we can do that!" while others just say "We don't ship USPS."


You can guess which get my business.

[diugo]

Originally Posted by OceanSeaSpray

Thanks for sharing this, it is not good, but interesting. What kind of charge/discharge regime and charge control do they see? Have they been cycling significantly, or spending a lot of their time charged up?

In constant use but pretty lightly cycled. I only use about 50Ah a day, so that's less than 200 cycles the past two years. But I suspect the cells were heavily cycled before I got them, because they have always exhibited major sag from day one.

Charge regime is a simple coulomb counter with 20A max bulk current exclusively from a solar array. I periodically force a longer charge because coulombic efficiency is obviously not 100%.

Discharges for the most part are light, with average daily current just 2A. But several minutes a day are spent microwaving (60A) and vacuuming (80A).

[OTTCT]

Hellosailor

First thanks for your help & I might hope your right.

Since you have not claimed to be a certified hazmat shipper, and I'm sure you won't fund my legal criminal defense, I'd like to stay on the side of caution considering the fines.

Under federal law the shipper "you" is always responsible to comply with the law. Your argument is that should you meet a dumb clerk - your free and clear.

This is same argument where a contractor says the building inspector approved the job so case closed. FALSE Builder or permit holder is always on the hook no matter what to comply with the state or federal code.

[FlyingCloud1937]

Well Hello JERRY.

I installed two life...4 banks years before this thread, began at post #1.

Lloyd

Originally Posted by OTTCT

I think I will 2nd, 3rd, 4th & 5th that one .
I'm assuming Lloyd has a 1937 boat and is happy with his 1850 technology battery.

Don't understand how someone who does not own 1ah of LifeP04 can even have an opinion on the subject ???? His negative comments are very distraction to folks who wanna actually wanna learn something like T1 Terry who has real life experience.

If it was up to Lloyd I bet it would be another 100,000 before humans can use fire - look how dangerous that is.

PS Lloyd I only own 7,000 ah of 12 v lithium, 1250 ah right under my bed.

Cheers OTTCT

[Dod42]

I have tried to read the whole forum but its sooo much to digest. Most of it I think I have understood, however where I'm a little confused I seem to read that its not good to leave then fully charged, don't float charge, and use them down to 70% DOD then recharge. So what happens with Solar panels? Is the theory that you basically turn them off until you need to charge or do you just turn the "Bulk"charge rate on the solar controller to a lower voltage like 14volt, disable float on the solar controller and let the BMS sort it out. I currently have just under 1KW solar that seems, on a good day to kick in anything up to 50 amps per hour, well in excess of what we use. If everyday I'm topping it back up to 100% from say 90% via solar is it death by 1000 cuts for the batteries?

[transmitterdan]

The consensus is that LiFePo (and other LI chemistries) will suffer shortened life if kept fully charged for extended periods of time when not being used. The general advice is when not actually in use they can be left at 50% charge. Since they have very low self discharge it might be months before they would need to be topped back to 50%.

Likewise, they will suffer reduced life if left fully discharged. Hence the recommendation to leave them stored at 50%.

This issue is one reason some have not jumped on the LiFePo bandwagon.

[offpist]

I ordered the winston WB-LYP1000AHC from EV-Power | Your Complete Power Solutions
They have an limited offer now at 1,018.00$ each, and its on stock.
Still a lot of money, but it makes a huge battery pack..

(I have no relations to this company btw)