Lithium - breaking down the better battery------?????????????

[zamboni]

I'm pretty sure nobody thinks you were flaming the OP. Just the specs he was asking about -- which he also was pretty clear he did not believe. Thanks for being patient.

Certainly the comparison is unfair because it uses a crappy Pb battery to compare against. That's marketing, and I ignored it. The specs for the Battle-Born product do look over-stated, and that's disingenuous of them, which is enough reason to avoid it.

It sounds like, if someone sold an integrated-BMS LFP drop-in with realistic-seeming specifications, then aside from proving an actual track record of longevity and warranty support, the product would actually be attractive. But none of these things have been around long enough to have a track record.

- Jerud

[Sunking]

Sunking, your explanation re: balancing cells and balance currents is great, as usual. You've explained this to me before and I think I get what you're saying.

What I'm curious about, and what I believe dorff was asking about (where is he, anyway?), is whether these expensive integrated-BMS products are a good idea -- for those who wish to spend that kind of money. You ridiculed the marketing specs and claims in your first post...but everything you've said since then makes it sound like you think integrated-BMS batteries are a great idea.

OK stop right there. All consumer lithium battery products require a integrated BMS for the public safety and ignorance. In my use in golf carts, is not a consumer product. I know what I am doing. The ridicule is drawn for the false claims made by the equipment manufacture, not the OP. Everything made comparing PB to Li is absolutely false. That is what drew my fire. If there is any critique to the OP is if he/she believes that crap, needs a reality check and is naive.

I cannot tell anything about the battery the OP is referencing too other than the claims are pure BS. What I do know is who the battery manufactures are, and which ones are the best, and none make any such claims or remotely close. What this equipment manufacture is doing is buying cells from some battery manufacture and putting them in some box, and then claim something that is not possible. At the same time they use specs from the lowest quality Pb battery they can find to make a comparison against. I dare them to try to stack up their claims against say a Trojan Industrial line battery with a 10 year warranty you can actually file against at 1/3 the cost and at 80% DOD have 2000 cycles. In the end of life last 3 times longer at 1/10 the cost. Not even remotely close.

With that said, I am happy you are starting to grasp what I am saying, and I am more than happy to help you or anyone.

[zamboni]

Sunking, your explanation re: balancing cells and balance currents is great, as usual. You've explained this to me before and I think I get what you're saying.

What I'm curious about, and what I believe dorff was asking about (where is he, anyway?), is whether these expensive integrated-BMS products are a good idea -- for those who wish to spend that kind of money. You ridiculed the marketing specs and claims in your first post...but everything you've said since then makes it sound like you think integrated-BMS batteries are a great idea. As you say, Joe Consumer can't be trusted to handle LFP so the manufacturers have to bake in the BMS. What you're saying makes perfect sense to me, but I still feel skeptical of these super expensive products like Battle Born and ReLion.

Let's say you have a friend with loads of $ who wants LFP but doesn't want to learn all the technical stuff to do it. Joe Consumer...with deep pockets (Joseph Consumer III, Esquire). Joe wants to buy 4 of these Battle-Born 12V batteries and parallel them into a 400Ah 12V bank for his Motorhome. Would you tell him, "Great idea, have fun"? Or "That will work great for a while but don't expect to see 3000 cycles"? Or "That's a dangerous rip-off, stay away"?

- Jerud

[Sunking]

The HVD built into the BB batteries may not be intended to be the primary control for charge voltage, but the marketing is basically saying you can hook them up to any charge controller at 14.4V and let the battery worry about the rest. So the connected charge controller might not be capable of, or programmed to, charge to the right voltage. If it's a cheapo charger putting out more like 14.5, the batteries end up disconnecting the HVD to terminate each charge cycle.

Jerud here is what you are missing. A BMS cannot perform the initial Bulk Balance of any battery pack. A BMS can only make very small corrections. Example say you buy 200 AH LFP cells from a chi-com like CALB. When you receive them the SOC is all over the place. You can have as much a 10 to 20% difference in SOC values. In a 200 AH cell is 20 to 40 AH difference. A typical BMS Balance Current is 150 to 300 ma. So to use a balance charger do some simple math on the time it takes. 40 AH / 150 ma = 267 Hours to recharge or 11 days.

This is why if you buy cells the very first thing you do is connect all the cells in Parallel, and walk away for a day. Then you either Top or Bottom Balance with them in parallel. Then assemble them in series and you are ready to go. Balanced batteries stay in balance and only need very small minor corrections from time to time as they age and from parasitic losses. Example self discharge rate is NOT exactly equal in the cells. Example let them sit for a year, and you might have .05% difference in SOC.

When you buy a Lithium Battery pack, not cells, but say a 12 volt LFP for your car, or 48 volt pack for a golf cart or 360 volt pack for an EV or Solar System all the cells have already been matched in capacity and balanced for you already. The only charger they require is a very simple CC/CV charger with a fixed voltage of the appropriate current. Really any current less than 1C will work for most Lithium cells. As long as the charge current does not exceed the manufactures maximum charge limit is fine.

Right now today if you are foolish enough to pay $800 to $1100 you can buy a 12 volt battery for your car or truck. They are a drop in replacement for your Pb battery. No modifications are required to your vehicle. Today's automobiles have standardized the charge voltage to be 14.2 to 14.4 volts which is perfect for LFP, and Pb AGM batteries. So with the cells already balanced and the equipped BMS inside the battery make it a non issue for Joe Consumer. When you start the car engine all the cells reach 100% at roughly the same time. So even if the BMS only can bypass say 0.5 amps aka 500 ma is a matter of a few seconds. So if you were to measure charge current, initially you might see 50 amps for a few seconds, then drops to 0 amps almost instantly when the battery voltage equals the charger voltage and the battery is now 100% SOC.

Try it yourself with your PL8. Balance a set of batteries. Then discharge them down to say 50%. Now recharge at say C/2 and watch what happens. Example say they are 4S LFP 100 AH and you charge at 50 amps. The charger will pump 50 amps until the voltage reaches 14.4. As soon as they reach 14.4 volts, current will start to taper off. At 10 amps the charge will terminate and the Balance circuit likely never turned on, and if it did was only in the last minute or two.

With the exception of LiPo battery packs made for Hobby RC Planes, cars, quads, ect, all consumer Lithium batteries have built-in BMS in which the factory has matched the cells because they have 100's of thousands of cells to work with to match, and balance the packs at the factory. It is the only way you can make a commercial product work because Joe Public does not know how and it makes it a liability issue for the manufacture. Even with all that automation, lithium batteries still blow up. You hear it on the news all the time.

[zamboni]

I know the relays should be NO, but are the BattleBorn units are designed this way? That's the thing with the BB product, we just don't know how robust their innards are. Are they low-power two-coil relays or do they draw 2A to pull in and hold? Evidently nobody knows any of these details except the manufacturer. That's my point for why i'm skeptical.

The HVD built into the BB batteries may not be intended to be the primary control for charge voltage, but the marketing is basically saying you can hook them up to any charge controller at 14.4V and let the battery worry about the rest. So the connected charge controller might not be capable of, or programmed to, charge to the right voltage. If it's a cheapo charger putting out more like 14.5, the batteries end up disconnecting the HVD to terminate each charge cycle.

As for my final point being "phrased in Lead Acid POV": Yes, exactly -- it is. I'm not talking about the cells i'm talking about the packaged 12V BB battery products themselves. BB is targeting RVers and boaters, and they think in lead-acid. They are explicitly telling them they can series/parallel the individual BB batteries to make a higher voltage or higher capacity bank. But each of those individual batteries will have it's own internal BMS with HVD, LVD, temp controls, etc. and they aren't "talking" to each other so some BMS might disconnect themselves before the others. Couldn't that lead to trouble?

Someone recently mentioned ReLion batteries to me, a similar idea as the BB batteries. LFP with integrated BMS. Their website has more tech info than BB; it states a low-voltage cutoff of 8V and high voltage cutoff of 15.6V. And cycle life? 3000-5000. I wonder if the BB batteries use similar voltage cutoffs. 2.0 VPC and 3.9 VPC don't sound like operating limits that result in a 5k cycle life...sounds like an impossible claim.

- Jerud

[Sunking]

Is the internal relay NO or NC...will it fail open or closed?

NO

Also, disconnecting the charge controller "cold turkey" from the pack as a way to limit charge voltage is a poor approach.

Not really and it is not done to limit charge voltage. Charge voltage is fixed in the charger. It is a means to terminate a charge. Lithium batteries use a very simple CC/CV algorithm. Example your PL8 if you set it up for 100 AH LFP cells, it fixes the cell voltage to 3.6 volts. Initially when you start charging the charger is in Constant Current mode and say you set to 30 amps. As the battery charges the cell voltages rise to 3.6 volts and the charger holds 3.6 vpc and terminates when the charge current tapers down to C/10 or whatever value you selected.

And, what happens if a user decides to parallel a few of these and one BMS trips slightly before the other because of non-symmetric current?

Not sure there is a answer because it depends on how the system is set up. I think you have phrased the question in a lead acid POV which is incorrect. You do not connect Lithium cells in parallel like Pb batteries. Example a 12 volt Pb battery wired in 2P. Lithium batteries are paralleled at the Cell Level so you only have to use one BMS. See below.

What it all boils down to is Lithium batteries made for consumer products requires a BMS because they are dangerous and Joe Public is not capable of protecting themselves.

Pb on the left, Lithium on the right. As you can see below if you wired lithium like a Pb on the right would take a 6-channel BMS. On the left only requires 3 channels and you can monitor every cell.

[Sunking]

Note that this is not true in many tool batteries that use li-ion chemistry. They get around this by having the BMS in the tool and the charger - and since the battery cannot physically mate with anything else, protection is relatively assured.

Perhaps, but I am a power tool junky and being naturally curious all my tools with Lithium cells have a BMS in the battery pack, the charger has 3-wire connection which threw me the first time I seen it. At first I thought it might be like a NiCd Power tool pack where the 3rd wire was from a thermistor. What I discovered it is a signal lead from the BMS inside the battery pack. As long as the pack sends back a voltage enables the charger. When the battery is charged, or if there is a problem detected the voltage is removed which shuts down the charger. At least that is what I have found with Dewalt and Craftsman power tools. However I agree each pack is proprietary and other manufactures are likely to take a different approach.

[jflorey2]

Let's get down to the fact of the matter. BMS is a CYA liability issue. Without a BMS in consumer products, Li fires would be in the news everyday, and Li manufactures would be sued into bankruptcy. Li cells are dangerous, and the public does not know how to manage them.

Note that this is not true in many tool batteries that use li-ion chemistry. They get around this by having the BMS in the tool and the charger - and since the battery cannot physically mate with anything else, protection is relatively assured.

[zamboni]

Bottom line is Li consumer packs must have a BMS as Joe Public is not knowledgeable enough to work with them. Sort of like hot coffee, the public does not know you get burned if you spill hot coffee in your lap. So hot coffee comes with Lawyers.

Agreed. The problem is that your comment above seems like it would be in favor of these drop-in LFP batteries the OP is asking about. Perhaps I am mis-reading the initial post, but I think the dilemma is that a BMS-integrated LFP pack is actually a good idea. You've just said so. But I am still skeptical of these products because as we can all see, they are making ridiculous marketing-hype claims. Of course, that's what you have to do to run a business in America, so they (almost) can't be blamed. They state their batteries have internal BMS to prevent over-and under-charge, over-and under-temperature, to cap current at 1C, and to monitor the cell voltages for balance issues. Evidently inside those cases is a relay which will disconnect the internal pack from the external terminals in the case of any of these faults. Assuming they're not outright lying about any of this, it sounds like the product is basically doing the right things. I guess it's a question of whether or not the company did a good job. And how good their insurance is.

We don't know if they matched those cells, or balanced them, if they are low-quality junk cells, or if they're using vampire boards. So, those are all risks -- but we don't know.
Is the internal relay NO or NC...will it fail open or closed?
Also, disconnecting the charge controller "cold turkey" from the pack as a way to limit charge voltage is a poor approach.
And, what happens if a user decides to parallel a few of these and one BMS trips slightly before the other because of non-symmetric current?

Those are the only questions I know enough to ask. I'll be in Nevada later this year, although maybe not Reno. But if i'm there, i'll definitely drop in and see if they will show me what the insides of these things look like...

-Jerud

[Sunking]

If the whole concept of BMS-in-pack were fundamentally flawed, that would be a little easier to explain to folks.

Let's get down to the fact of the matter. BMS is a CYA liability issue. Without a BMS in consumer products, Li fires would be in the news everyday, and Li manufactures would be sued into bankruptcy. Li cells are dangerous, and the public does not know how to manage them. You cannot over charge or over discharge them without significant risk of fire.

With Nickel and Lead chemistry you can over discharge and over charge them with little risk, and most times does not destroy them. No automation is required. In fact you can leave both Nickel and Lead on a charger indefinitely. Having said that you can Float Li like you do Lead, but it requires more automation or you have to know what you are doing.

Bottom line is Li consumer packs must have a BMS as Joe Public is not knowledgeable enough to work with them. Sort of like hot coffee, the public does not know you get burned if you spill hot coffee in your lap. So hot coffee comes with Lawyers.

[zamboni]

No it is greatly exaggerated. NCO, NMC, and most lithium battery types are in the 300 to 500 cycle range with a 1-year warranty. The one exception is LFP cells, and the best of the LFP manufactures is A123 Systems, and they only claim 1000 cycles. That is why I scoff at such claims.

I stayed up too late on the forum and didn't proof my post before hitting the button. Not too short, should have said too long!

[zamboni]

???

I've dissected several of them. Often they have no BMS at all. The DeWalt standard li-ions, for example, have a thermistor and inter-cell taps going to a connector. That's it. They rely on the charger and the tool to do everything else - balance, overvoltage protection, over discharge protection.

If you hooked a car alternator to one of those you'd have a toasty fire.

I have dissected zero of them. But post #9 in this thread, SunKing explained that some battery tool packs do have internal BMS. So that's why I was looking for further clarification.

My point is that, like the OP dorff , I am naturally skeptical of this product. But skepticism alone is not a convincing argument without factual support. Telling some wide-eyed Facebook RVer with too much spare cash that BattleBorn are bad news because some dude on SolarPanelTalk says so...is a waste of time. To people who are not familiar or techincally-minded, a table of specs which is not realistic is not a big red flag as it is to us. But these are exactly the people being marketed-to. So giving them specific, understandable reasons to stay away from a trouble product is important.

If the whole concept of BMS-in-pack were fundamentally flawed, that would be a little easier to explain to folks. But if BMS-in-pack is actually a good approach (when done correctly), then it will take more understanding...such as how the BB product may not be doing it correctly.

-Jerud

[Sunking]

Although from that table alone (which is copy/pasted from the company website), the warranty period (either in terms of years - 3, or cycles - 3000) is pretty damn short for LFP.

No it is greatly exaggerated. NCO, NMC, and most lithium battery types are in the 300 to 500 cycle range with a 1-year warranty. The one exception is LFP cells, and the best of the LFP manufactures is A123 Systems, and they only claim 1000 cycles. That is why I scoff at such claims.

Everything on that chart is fiction

[jflorey2]

. . .you have (very) recently described to me how self-contained battery packs (such as power tools) with their own "black box" BMS systems can be extremely reliable and only need a rudimentary voltage source such as a car alternator to power them.

???

I've dissected several of them. Often they have no BMS at all. The DeWalt standard li-ions, for example, have a thermistor and inter-cell taps going to a connector. That's it. They rely on the charger and the tool to do everything else - balance, overvoltage protection, over discharge protection.

If you hooked a car alternator to one of those you'd have a toasty fire.

[zamboni]

Hilarious, i was just about to make this same post dorff ! Been hearing about these for months, and basically assume that they're crap but don't know. I was hoping to get the input of the knowledgeable folks on here. My BS alarm is going off...but i can't elucidate why exactly...

Although from that table alone (which is copy/pasted from the company website), the warranty period (either in terms of years - 3, or cycles - 3000) is pretty damn short for LFP.

Sunking : You've already scoffed at this, which i had expected...and let's remember that i'm pre-disposed to be skeptical of this company -- and probably so is everyone else on here. But you have (very) recently described to me how self-contained battery packs (such as power tools) with their own "black box" BMS systems can be extremely reliable and only need a rudimentary voltage source such as a car alternator to power them. The BattleBorn product is a pack of cells, with (allegedly) integrated BMS, which claims that you only need a rudimentary charger to power it (although who knows how well they're matching the cells). The claim is identical. But does anybody here know a reason -- a real, tangible, convincing reason -- that the BattleBorn units are no good? Anybody actually cut that black box open? I would love to do it myself but it's not in the budget!

Basically i'm looking for solid technical info i can use to smack down people on Facebook (and hopefully save them a lot of $ and pain). My BS alarm is enough for me...but i've found that other people tend not to listen to my personal alarm very seriously....they need more compelling info...

Aw hell, they still don't listen to me. But i have to at least try.

- Jerud