LiFePo4 House Bank Using SmartHousePower BMS

[hellosailor]

Dockhead-
"In the absence of a reasonable economic case, lead-acid is the way to go for the time being, at least, for anyone who does not have unlimited money to throw at such things."
Of course if I were campaigning a race boat, I'd say the case for at least trying Li-stuff already IS compelling. Heck, compared to the cost of a couple of titanium fittings or longboarding the hull...Li-stuff would be awfully tempting, but I expect that IF anyone is finding it works well, they're not going to tell the competition.<G>

GBN-
"most lead-acid based boats have some form of bms even if " I think there's a major break in what "bms" means. To me, it ain't bms unless you are talking about managing the charging on a CELL BY CELL basis within the battery. That's what gets expensive and complex very quickly. Simply looking at the gross amperage and voltage of the combined battery, ain't BMS. Yeah, I know, it is, but that's not what lithium cell battery management systems are all about. They manage CELLS not just the battery.
And by that definition, boats with conventional lead acid batteries never have BMS systems, let alone systems that cost as much or more than the batteries themselves!

"it's suprising in this day and age that the Dc systems on most boats out of the wrappers is apalling." Not really. Most boats are a mass market commodity, and most buyers have near-zero technical knowledge in electrical systems, and could care less about learning. Same reason that the Droid and iPhone have gotten slammed as having lousy voice quality. (They're so intent on being pretty, that the antenna is buried in the middle of the phone, where the hand holding it blankets the signal. Ooopsie. Pretty pretty, shiny shiny, who cares how it works?)

[electric1]

Wow, I take few days to focus on my work and the thread adds another page

Thanks everyone for great discussion, excellent points made by both nay-sayers and yey-sayers

And, as usual, the truth is probably somewhere in between.

I totally agree that BMS should not double the cost of the battery and does not need to be complicated, this is the sole reason I got into BMS development myself. I offer most cost effective, simple BMS for EV conversions, and I wanted to do the same for house banks. However, its difficult to compare the two because in EVs you have many cells and much more overall bank cost, so in percentile BMS looks pretty good at 5%-10% cost of the pack. In house bank you only have a few cells, so BMS cost becomes a larger percentage, but it should still be reasonably priced against the cost of the pack.

I just completed BMS-in-a-box project and figured out all material and labor costs, and the best possible price I can offer is $500 for this unit. This barely covers parts and labor and I am not even talking about hours spent programming microcontroller, since I find that work fun ( yea, I am a geek, I know ) so I don't charge for it. The unit contains Tyco EV200 contactor, which is hugely popular in EVs, that alone is the most expensive part of the system. The system is set for 200AH bank because contactor limit is 500Amp continuous and up to 2000Amp burst. If your house bank usage is within those limits, you can easily use this BMS on 400Ah bank, by simply coupling 4 200AH cells in parallel to another 4 200AH cells, thus reducing percentage of BMS cost in half.

Also, cell prices posted by Tinkerer007 were based on prices set in US by the company called "EV Components", which for the past year was selling LFP cells at $1.2/AH ( door-to-door ). They could not possibly make any profit at that price level and they effectively pushed all other LFP resellers in US out of business. Well, as it turns out EV Components was a huge Ponzi scheme, not as huge as Bernie Madoff, but pretty damn big. Lots of EV converters prepaid their cells and now have nothing to show for it. This was a huge blow to EV community and will take long time to recover trust in battery resellers. However, it finally allows good guys to offer cells as a real business with legitimate profit margins and the price point is now $1.40-$1.50 /AH door to door. That is how much I paid for those 4 cells inside the drop-in box that I offer for sale now. That's $1200 bare cost of cells alone. Then add $500 for BMS, $100 for Todd 4D box, plus all the little stuff ( cables, lugs, etc ), plus all the work to put it all together and suddenly $2000-$2500 for a 200AH drop in solution doesn't seem outrageous, does it?

Anyway, I am completely finished with 2 products that I set out to offer to this community. Most of my work is in EV market, so this stuff is basically a custom made solution which is still priced better than competition, so if there is any interest PM me, but I have no plans for mass production based on the current market needs.

If anyone is interested I can offer bare electronics at much better price, if you want to source your own contactors, boxes and labor to put it all together, like Tinkerer007 did. I spent too much time packaging everything and making it look pretty, while my specialty is making PCB boards and programming controllers.

Here is the pic for BMS-in-a-box unit, I will add it to my post in Classifieds section where I offered drop-in box.

[Dockhead]

Originally Posted by goboatingnow

Let's return to the cost argument. Firstly comparing the costs directly of Lifepo and lead acid is disingenuous. Lead acid is probably the worst solution to a boats electrical storage requirements. We use it because that's all we really have available. But all the issues such as depth of discharge, weight , 100 charge requirements, absorbsion cycle time, premature failures due to sulphation etc are actually cured by LiFepo4. I really don't think
people realise this. Hence the cost comparison is more like why do you nit buy 4 Honda generators rather then one expensive marine diesel generator ( why becUse the solution is technically better and that's worth a Premium)

it's suprising in this day and age that the Dc systems on most boats out of the wrappers is apalling. Clients will spend literally tens of thousands on sails or deck gear ( most of which add fractional improvements) yet below is a Dc system out of the dark ages.

It's a perfectly legitimate argument -- cost be damned; it's so much superior that it is still the right way to do it.

I was not gripping that argument; I was just debunking the idea that the greater cycle capacity of LifePO's cancel out the cost difference to lead-acid. That idea is clearly nonsense.

But for some people the sheer superiority of LifePO's will make them worthwhile, even now in their toddler days in terms of development and mass production. A race boat comes to mind, as well as a cruiser who simply has enough money to indulge himself in expensive superior solutions.

But I don't think that it's exactly the same as Honda portable generators versus a proper marine diesel generator. The portable generators simply don't do the same job as a proper marine diesel generator. But lead-acid batteries do do the job, and perfectly well for the vast majority of cruisers. They are heavy, slow to charge, and have limited capacity for cycles, they are light enough for most cruisers (what percentage of your boat's weight is batteries, anyway?), and charge fast enough for 90% of more of all cruisers. Their life cycle limitations are no problem at all for the majority of cruisers who don't cycle their batteries more than a few dozen times a year.

I look forward very much to my first set of lithium house batteries on my boat. I am sure they are the wave of the future and can't wait for them to get a little further down the development and mass production road. But for the moment they are absolutely not worth it for me (like for the vast majority of cruisers), who has a limited budget for equipment upgrades, and many more urgent projects in the pipeline waiting for funding.

[electric1]

Originally Posted by goboatingnow

I still remain to be convinced as to the need for BMS systems in LifePo technology. There's a bit of an " industry" being generated here ,rather then dealing with the electronics.

You bring lots of valid points. Many of the same discussions have been going on on EV forums for past 2 years, since LFP cells became widely available.

Yes, it is very much possible to run LFP pack without any BMS, just like with Lead Acid. Yes, all the same rules apply, like dimming lights as indication of low battery, etc. However, there a couple of important differences:
1. Lead Acid has more or less linear curve, so as your lights dim, you still have time to finish your dinner, light up a cigar, have a drink, etc. Battery voltage will continue to drop linearly until you get your butt down below and start the genset. No harm done, especially with flooded LA cells. With LFP, the curve is flat during 80% of the time and sharp vertical edges at both ends. That means you have much less time between lights starting to dim and going complete dark. No time for drinks and sigars. LFP cells taken to 0% SOC will significantly shorten their life cycles, further increasing cost of LFP investment long term, hence the need for reliable LVC action.
2. Even though HVC with 14.4V charging source is unlikely, its not impossible to overcharge individual cells in the bank if you have no idea how well they are balanced. Even a few AH imbalance can cause severe overcharge of individual cells, so IMHO, cell level HVC protection has its benefits. Severe overcharge damages LFP cells just like severe overdischarge, reducing their capacity and lifecycle, although none of these events kill them instantly, so you can still function in limited capacity unti you get to the shore and find replacements.

My point has always been that BMS must be simple, affordable and reliable, and I think I reached those goals in my products. I agree, however, there are a few BMS examples out there where engineers and marketing people really need to get their head out of their a$$

[billgow]

Great stuff!

I’m sketching out a catamaran and lead acid batteries are not even an option. I had LiFePo batteries and solar in mind from the beginning with wind generators as a back up while at anchor. Lead acid batteries in monohulls can be a perfect match as they add ballast. In the right location, they can play a double roll.

One feature of the LiFePo batteries that I think is being overlooked in this discussion is the amount of energy available. In round numbers, a lead acid battery will only have ~15% to 20% of it’s total capacity available where a LiFePo will have ~75% to 80% available.

I admit to being a neophyte when it comes to electrical things but to me, this looks like somewhere around 3 to 4 times as many lead acid batteries need to be available for the same amount of power the LiFePo batteries produce.

In my very rudimentary calculations, the weight, amount of energy available, the charge rate and the number of cycles and years of service, the LiFePo option stacks up nicely price-wise against lead acid today. I won’t be ready to start building for a couple years so I’m expecting this technology to be even more reasonably priced by then and at that time, I expect the LiFePo package to actually be more of a value.

[McG]

Well now, this semi heated discussion was really worth it thus far. One little point that I'd like to raise is the safety issue of LiFePO4 over FLA. Ever seen how a battery pack goes up in flames if a short occurs close the SLA vapours?

This can have a reasonable impact on how much you fork out for insurance on your cruiser too I recon.

I have just imported a Lifepo bank for my RV.:
800AH 12V for $3902 + 15% GST,
$500 shipping + 15% GST,
$440 for MeanWell 1500W mains charger (I'm selling 2 x 25A Cteks to offset some expenses here though),
BMS system $429
Sub Total: $5931 - $640 for 2 Cteks
Total $5291 = $6.61/ah

Now I also actually need to subtract the costs of replacing the battery locker lid that is corroded to bits from acid vapour and spills. Also add the inconvenience of having to top up and constantly monitor fluid levels. (I am aware that AGM/GC is exempted from this bit at a little premium).

I can now go for 6 days at 100A/day before I need to start thinking of charging - that is if there was zero sunshine on the solar panels and zero wind and zero grid connection. I can connect to grid and fill up in 6 hours with the 100A charger or run my 2KVa gen for 6 hrs still with no solar or wind. How good is that?

People pay hundreds of dollars for "luxuries" like big screen tvs, sky dishes, fancy ipads and all sorts of stuff. I paid my dollars for peace of mind and rest from acid spills and battery topups and the dramas of running out of power in the most awkward situations by getting lifepo.

Not knocking anyone, just giving you a real scenario and I'm wrapped!

Oops - and I'm saving over 100kg in weight!!!

[LiFeTech Energy]

Originally Posted by McG

People pay hundreds of dollars for "luxuries" like big screen tvs, sky dishes, fancy ipads and all sorts of stuff. I paid my dollars for peace of mind and rest from acid spills and battery topups and the dramas of running out of power in the most awkward situations by getting lifepo.

Not knocking anyone, just giving you a real scenario and I'm wrapped!

Oops - and I'm saving over 100kg in weight!!!

It is one of those things. You get knockers who have never tried LiFePO4 batteries. Once people try them and have the opportunity to compare the benefits with lead acid they rave about the superior lithium performance and never ever go back to lead acid.

[hellosailor]

"Once people try them" Steep price of entry. Poor warranty, as compared to the claims for lifetime performance, and the solidity of the warrantor. Comes back to "steep price of entry" no matter whose economics you accept, and considering the widely varying claims of the suppliers (you may or may not need a BSM that doubles the battery price?!), people aren't so hot to try them.

McG?
"the safety issue of LiFePO4 over FLA. Ever seen how a battery pack goes up in flames if a short occurs close the SLA vapours?"
Speaking in tongues won't make your point. If you are trying to say there's a danger of a hydrogen fire from the SEALED vent when someone ABUSES an SLA battery and offgasses it...that's just scare talk. Even SLAs should be mounted in a safely vented battery box, and SLAs aren't known to cause hydrogen fires. On the other hand, the press are full of reports of recalls for various Lithium technologies, all of which have had fires and explosions during NORMAL charging operations.
Yeah yeah, LiFePo is different. Well, the makers are so busy arguing about competing technologies, they haven't pushed that point either.

The compelling points to switch to LiFePo seem to come down to only one: If you need maximum power in the smallest package and you have unlimited funding...Otherwise? The case just isn't being made.

[McG]

Originally Posted by hellosailor

"Once people try them" Steep price of entry. Poor warranty, as compared to the claims for lifetime performance, and the solidity of the warrantor. Comes back to "steep price of entry" no matter whose economics you accept, and considering the widely varying claims of the suppliers (you may or may not need a BSM that doubles the battery price?!), people aren't so hot to try them.

Speaking in tongues? Battery pack = $3900, BMS (not BSM ) = $429
Do you mean double the battery price or double the BMS price or are you trying to blow the cost of lifepo out of proportion

McG?
"the safety issue of LiFePO4 over FLA. Ever seen how a battery pack goes up in flames if a short occurs close the SLA vapours?"

Speaking in tongues won't make your point. If you are trying to say there's a danger of a hydrogen fire from the SEALED vent when someone ABUSES an SLA battery and offgasses it...that's just scare talk.

Sorry, my typo - should read "FLA vapours" as in the preceding sentence. Lot's of motorhomes come with FLA because it is even cheaper than SLA and AGM - as was the case with mine.

Even SLAs should be mounted in a safely vented battery box, and SLAs aren't known to cause hydrogen fires. On the other hand, the press are full of reports of recalls for various Lithium technologies, all of which have had fires and explosions during NORMAL charging operations.
Yeah yeah, LiFePo is different. Well, the makers are so busy arguing about competing technologies, they haven't pushed that point either.

This is a rather sweeping statement to try and shoot down LifePo. You are spot on with the quote "Lifepo is different". What you're disguising in that statement is that Lifepo was proven far safer than other lithium technologies.

The compelling points to switch to LiFePo seem to come down to only one: If you need maximum power in the smallest package and you have unlimited funding...Otherwise? The case just isn't being made.

You are free to your opinion against all odds

However, in New Zealand the average household spends in the region of $200/month on electricity. After 7 years living in my bus, I'm home free including ALL costs of the WHOLE LiFePO4 system including solar panels, generator and wind charger. So, even for your home you should go Lifepo and have free power after 7 years.

[hellosailor]

"Do you mean double the battery price or"
One of the major vendors mentioned says that a charge management system is required, not optional, and yes, it doubled the price of the batteries in question, adding about $2000 to $2000 worth of batteries.
Even among electric car makers, there are major disagreements about how sophisticated a charge controller is needed. The point being, as a consumer, if I see every vendor insisting a different and contradictory approach is the only one that will work, what does that tell me?
That the technology is nowhere near mature, let alone understood. Even by the makers.

"Lots of motorhomes come with FLA because" as do boats and cars. Wet lead is still a very robust technology and hydrogen fires still rare among deep cycle users--when the battery bank is properly set up. There's really no excuse for a hydrogen fire besides "Bozo Built It!".

"This is a rather sweeping statement to try and shoot down LifePo"
That's outright paranoid. I've never tried to shoot down LiFePo but I have suggested, and continue to suggest, that the folks who are so excited about it simply cannot support their enthusiasm with facts and warranties. Especially not with warranties. There are anecdotal tales and promises, but apparently no studies of multiple units over long time periods (i.e. 5-10 years) in realistic loads or independent lab tests.
And the vendors, who are so certain that the technology (which usually only they sell, each unique) is great, usually offere a fairly meager warranty, backed by no bond and no long corporate history.
If "Batterific!" sells me a new LiFePo battery with a ten year warranty, but that company has only been around for a year, three years? Has a tiny share of the market and no mass market recognition...Why should I expect them to be around in fiveyears to honor the warranty? In recent years, plenty of bigger older firms have gone belly-up and left warranty orphans.
If the top-tier battery vendors on the market (JCI, Deka/East Penn, Rolls, etc.) haven't cast their votes for the technology, should I think they are...dumb? greedy? or, right to think it is not ready for prime time yet?


" Lifepo was proven far safer than other lithium technologies."
You think so? WHICH LiFePo technology? Because again, there are several different ones being sold under that same generic name. Proven? You seem to have omitted any citation on that.

"After 7 years living in my bus, I'm home free including ALL costs of the WHOLE LiFePO4 system including solar panels, generator and wind charger. So, even for your home you should go Lifepo and have free power after 7 years. "

And what's battery type have to do with that, except distract from the point?

Perhaps NZ is terribly windy, because here in the US the repayment period for solar panels, under the best of conditions, is about 25 years unless there are serious grant moneys and incentives applied to hide the real costs. That's right, 25 years. And in areas where the wind blows less than 10mph all day and night, wind is also generally never going to pay itself back.
Forget the battery type, solar and wind simply do not and cannot compare with 'grid' power prices for home users. Nowhere near it, except for heavily subsidized cases and geographically rare places. Anyone who says solar power is price competitive with grid power, is either talking niches or using bad math.

Back on point: It still remains, LiFePo (of any kind, brand, or patent) hasn't been able to sell itself, except to the customer with lots of money and a dream. Or a special need.

Seen it in any EVs and hybrid cars, when there are car makers spenidng literally BILLIONS to choose the optimum battery type? Seen how many different battery systems they can't agree are best? LiFePo may be great, or it may not. But my point remains: No one has been able to make an overwhelming case FOR LiFePo. Which should be easy, if it really is tops.

[McG]

Hellosailor,
what counts is, your opinion and reasons are out there and so are mine. Other forum friends can read it and get totally or or . I am expecting my Lifepos to arrive any moment. The proof of the pudding.....so I'll be able to let you know for sure in time to come. I'll try to get discount on my insurance anyhow - nothing to lose. Thanks for your view from another angle. It's what its all about.

Interesting piece from WIKI:
The LiFePO4 battery uses a lithium-ion-derived chemistry and shares many of its advantages and disadvantages with other lithium ion battery chemistries.
However, one key advantage over other lithium-ion batteries is the superior thermal and chemical stability, which provides better safety characteristics than lithium-ion batteries with other cathode materials.[6] Due to significantly stronger bonds between the oxygen atoms in the phosphate (compared to the cobalt), oxygen is not readily released, and as a result, lithium iron phosphate cells are virtually incombustible in the event of mishandling during charge or discharge, and can handle high temperatures without decomposing.[6]
Lithium Iron Phosphate chemistry also offers a longer cycle life over standard lithium ion cells.[6]
The use of phosphates also reduces the cost and environmental concerns of Cobalt cells, particularly in regards of cobalt entering the environment through improper disposal,[6] with considerably increased safety over the cobalt chemistry type of lithium battery cell, particularly when compared to LiPo battery cells commonly used in the aeromodeling hobby.

[McG]

Just 4 FUN - LiFePO4 short circuit test: http:

//www.youtube.com/watch?v=Vf2LlZPy3GM

[goboatingnow]

Hellosailor you miss several important points

Firstly nobody denies lifpo4 is bleeding edge technology with few firms in the Market. This is really a result of the patent position rather then anything else.

The major battery companies are all participants in Li technology. Equally the EV space is heavily involved with Li technology.

Right now the patent position and hence the price point of course mitigate against widespread adoption. But that's not the point. Li technology has already completely dominated small format battery systems. ( like cordless your iPhone etc) that debate is over. Li won

As to large format. Yes some of the issues like exact charging techology, warranties etc remain as this is a young industry. But the underlying technology improvement cannot be denied

Lead acid survives because it's cheap other then that it would be dumped in the morning. But dumped it ultimately will be.

Nicd, Nimh and now Li technologies are merely a path on the road to Wh/Kg nirvana. When we get close to hydrocarbons that's the tipping point.

Value or cost is merely a function of Market position, availability etc. In time that will resolve itself.

Beleive me I have one of these cells, they are quite amazingly compared to FLA.

Dave

[hellosailor]

McG, that video is exactly the type of "proof" and "science" that I'm talking about.

What did you see? An unknown battery, of unknown type, in unknown charge condition, smoking a wire of unknown gauge in a short-circuit test.

I could get the same results with any chemistry. And I'll note that the common 9V "transistor" battery is built so the output cannot exceed 125mA even in a dead short, to prevent battery fires when the exposed terminals DO short out.

But looking at a picture...you can't tell any of that stuff. It's meaningless to assign any claims to that video beyond "you can smoke a cable".

Dave-
I don't doubt there's SOMEthing there, I just haven't seen anything except disputes about which patent is best. And last month the folks at MIT came out with their own news, about a liquid battery technology (no conventional solid plates) using a black sludge that apparently has 10x more power than any lithium plate technology on the market. Apparently liquid (plateless) batteries have been around a long time, they just haven't been competitive. MIT thinks that if this one works out, all the conventional plate batteries, including LiFePo, will be obsoleted almost immediately.

Personally, I'd call anything that can't acid eat my cloths a miracle compared to wet lead.<VBG>

[McG]

Originally Posted by hellosailor

McG, that video is exactly the type of "proof" and "science" that I'm talking about.

But looking at a picture...you can't tell any of that stuff. It's meaningless to assign any claims to that video beyond "you can smoke a cable".

In all seriousness, that video WAS "Just for FUN" . (excuse the pun). It is obviously some backyard fun & games. If you want to see more serious videos, there are quite a few good ones on youtube. If yourefuse to believe the videos, then there is only one way out for you, you'll have to do the tests yourself. Did you go to these lengths before getting LA? I guess not, because you believe all the pics, videos, hearsay of everyone else. That's life. New tech gets shot down mostly due to people that have just recently invested in old technology and want to kick themselves for it or they cannot readily afford the new tech stuff.

I was in the excellent position where I bought 6 old used 220Ah FLAs for my housebus which cost me approx NZ$500 (US420 roughly). These kept me going for 2 years while I was mostly connected to the grid and didn't need gridfree power for more than 3 days. The FLAs just managed.

Now I need to go offgrid for weeks on end and I had to decide between the old and new tech. Also, I'm planning to use this housebus for at least 10 more years. So In my position, I guess most people would have taken the lifepo route.

If I planned selling the vehicle in a few years, I would have gone AGM most likely.