The skinny on PHET LiFePO4 cells and packs

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I've learned a lot in the past week in researching batteries and packs from PHET due to several requests I've had from people who were interested. I thought I'd share the good and the bad about working with PHET and their LiFePO4 batteries.

First of all, I'll be upfront that we're going to be selling their ebike packs so the reader can know my biases - they're the most nicely designed and packaged LiFePO4 e-bike/pedelec packs I've come across (a few pictures on my website. No duct tape here - it is a professional design on a mounting rail in a pretty solid package that should withstand years of ebike use (with 3 yr warranty). I am using one daily on my CurrieUSPD 36/48V BMC setup, and am happy with it. Not only is the exterior design solid, but the electronics and protection devices appear to be top notch, both in terms of operational characteristics, and from an aesthetic perspective when I opened the pack up (pictures on the website soon of pack internals). Based on that, I decided to order more of them to sell to others here in the USA, since I want to make this kind of technology available to the people who don't want to fiddle with things, but just want a nice, lightweight pack that works and integrates with a bike well.

Given that I was already dealing with PHET, several people inquired about larger packs for scooters. I did some research into this, including getting several quotes from PHET on these packs.

The bottom line is, PHET packs for larger vehicle use are an expensive proposition. The reason is this: all PHET packs for EV use are designed around their prismatic 18650 cells (at least, that's the only thing they've recommended and said they will warrantee for EV). These cells are 3.2V 1.2AH, slightly larger than an AA battery. To build up larger packs, they place them into 3.2V strings, each with a voltage balancing board, and then for higher voltage, place these strings together using a battery management board. For my ebike pack which is 36V 7.5AH, they used 72 of those cells. This may have the advantage of better thermal transfer (higher surface to volume ratio), and more fault tolerance, since so many cells are connected in parallel. But, it has the disadvantage of high cost, particularly for high capacity systems. This is because PHET gives little price break even for 100's of cells*, and each pack requires multiple VBB and BMS boards, along with all the soldering and etc. The cells themselves are $5ea, so for a recent 51V/44AH pack I had spec'd out, the cells alone were ~$2,900 (576 cells * $5 each), and that's wholesale price with no markup. The VBB and BMS units, along with labor for pack assembly, adds another $1,200 (the only way to get the warrantee is to have PHET assemble the pack). And, PHET apparently has no means of economically shipping these in less than container load quantities, other than Fedex overnight (I have inquired several times, and they tell me they can't find an economy shipper who will take batteries!). So, after shipping, the cost of a 51V/44AH pack was going to be around $3,800 (again, wholesale without any markup for us).

Since the above prices are already so high, we can't really make any kind of reasonable margin on these for our efforts in getting quotes for people. So I decided to just share the information here for anyone who wants to contact PHET directly to have a custom pack built. Right now they don't differentiate between wholesale and retail buyers, which is another downside for us dealing with them (but could be good for the motivated buyer, who's willing to wire transfer money to them 1.5 months in advance of receiving the pack - no credit card or buyers protection option there!).

I'll also say that they don't seem quite ready for these kinds of small scale transactions yet. They don't have any kind of dealer support or differentiation between dealer and retail prices, they don't have any economical shipping set up, and on several occasions my inquiries have seemed to stymie them. Their USA division is Shoprider, and I think they haven't figured out whether to eventually start selling the batteries through that division, or what. When I inquired about the lack of wholesale/dealer pricing, they mentioned that this was still "in discussion" and that they were trying to figure out whether to make sales through Shoprider. The following story further adds to this point.

PHET also makes a line of e-bikes that we inquired about, and they told us to get in contact with Shoprider USA if we wanted to obtain them for selling in the USA market. When we did, Shoprider quoted us "wholesale" prices that were more than 2X the wholesale price on the bikes direct from Taiwan. The markup was far more than shipping and customs fees - plus we would have had to pay additional shipping from California to the East Coast. The quoted wholesale price was akin to typical retail prices for quality ebikes from reputable sellers here in the US. I found out the difference between the Shoprider/US price and the PHET/Taiwan price because someone from the Taiwan division sent me their prices, not knowing that I'd already been quoted a price by Shoprider USA. Needless to say, I wasn't pleased, especially given that this is for a low-power ebike (~250W) with only 5AH battery, brushed motor, and etc. Strangely, there is no mention of these bikes on any of their websites (Shoprider US or PHET) - but they do appear to be selling them in Europe - there was a recent review of them by Extraenergy.org. And, the retail price in Europe is not a lot higher than the "wholesale" prices quoted to us here. In any case, I don't think they've figured out how to deal with the US market yet for anything but their medical mobility devices, which they seem do be doing quite fine with.

Someone recently asked me where the motivation was for PHET to develop these LiFEPO4 cells in the first place, and I think it was because they wanted to have batteries that were a) significantly lighter than lead acid for their mobility devices, and b) extremely safe for medical compliance (no good having batteries that might explode or catch on fire in a nursing home!). I think they have realized that there is a big market now for these batteries aside from mobility devices, but haven't figured out a business model for how to scale that up and truly penetrate the market here in the US with them. Once their production capacity goes beyond their sales demand, they'll probably start thinking about that problem a lot more, and perhaps we'll see some changes in both the pricing and dealer support. But for those who are hoping for a short-term reduction in price, I'm not so sure. It seems that they have a lot of demand for now, even at present prices (it took them 1.5 months to get my first e-bike battery done).

In any case, I think that PHET makes top-quality batteries, and I'm excited about the e-bike packs. But I thought I'd put all this information out there for anyone interested in working with them to build custom packs, since it is not worth it for us to mess with that right now. I'm happy to give contact information, or you can find it on their website, and they'll usually come back with a quote within a few days.

I hope the info helps someone.
Morgan
Cycle9.com

*I have asked PHET for a quote on a very large volume of cells to see if there is a price break.

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Efried's picture
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Re: The skinny on PHET LiFePO4 cells and packs

Thanks for this info. It's a pity that way I wont get a new pack for my 1.9kW scoot car...
BTW: is there a company having some cells as on board replacement which step in in case a cell breaks or several degrade?
In my understanding with LIFEPO4 you can safe a lot of money by not having battery management, am I wrong?

cheers

efried

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Re: The skinny on PHET LiFePO4 cells and packs

Thanks a bunch for the information! I have a strong feeling my next pack is going to be LiFePO4. Can you point me to a link on how this chemistry is affected by temperature?

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cycle9's picture
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Re: The skinny on PHET LiFePO4 cells and packs

Hi

I thought I saw a temperature graph somewhere on PHET's pages, but I can't find it right now. In any case, on their cell specifications sheet, they say that the effective discharge temps are -20C to +60C. I've seen reports from people that mention a slight reduction in output below 0C, but maybe only by 10% or so.

Morgan

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Re: The skinny on PHET LiFePO4 cells and packs

Hi,

Quote:

BTW: is there a company having some cells as on board replacement which step in in case a cell breaks or several degrade?

It is my opinion that before anyone here in the USA would want to make this commitment to end-user support, PHET would have to do a better job of setting up a pricing and support structure for dealers/distributors. As long as anyone can just call them up and order directly at the same price as a dealer can, there is not a lot of incentive for the dealer to stock or support these.

I've seen it argued by certain members of this forum that "middlemen" should be cut out of the loop to minimize costs. But the key point is those "middlemen" can add value, in terms of having someone who is a lot nearer than Taiwan, and who is doing business on a small enough scale that every customer counts (and hence customer satisfaction is a priority). Those two items would translate into having someone that would support buyers when/if an issue arises. But nobody is going to do that for free. If there is no profit, there's no reason to do it except as charity work.

So here we have exactly the situation some here seem to wish for: anyone can call PHET up directly to order this stuff, without any middlemen. This may work for a few people who have lots of time and patience, and want to save a few dollars, but honestly, I don't think there will be any kind of widespread adoption of this technology if it requires people to do that.

I believe PHET couldn't care much about the little customers right now - I just got an email from someone else who was previously thinking of becoming a dealer for PHET batteries in North America, but had a negative experience with them and decided it wasn't worth it. My experience working with them can at best be classified as "neutral". They don't seem motivated, at least so far.

Quote:

In my understanding with LIFEPO4 you can safe a lot of money by not having battery management, am I wrong?

While LiFEPO4 is less sensitive to abuse or misuse, clearly they will last longer if they are treated well, and a BMS can help with this. So it can be thought of as an investment to protect your investment. However, when these batteries are in a configuration involving a large number of cells, this becomes not just desirable, but necessary for proper lifespan. That's one reason the PHET setups are so expensive. That's probably one of the various reasons the YESA packs are so much cheaper - they use large cells that require much less "management" circuitry and wiring. On the other hand, I am pretty convinced that my PHET pack will actually last for the advertised lifespan. I'm not sure that some of the others will (but, they should still last longer than any other battery technology, so may nonetheless be worth consideration).

Morgan

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Re: The skinny on PHET LiFePO4 cells and packs

By no means I was trying to put your job at risk, but to avoid costly repair during operation or premature failure which puts BEV-penetration at risk. But I feel I have to say something in response:

Quote:

I've seen it argued by certain members of this forum that "middlemen" should be cut out of the loop to minimize costs.

The problem is that the sum of the optima for the people won't create the optimum for the systems. So please consider to do the middleperson consulting people with regards to battery choice but not adding 100% to the cost simply distributing stupid hardware. Often new retail systems have been turned out to be effective - think of on line configuration of PCs.
In another thread I'm discussing the options of the new Tata 2000$ car. The point is that with this decrease in price, the car manufacturer no longer has the biggest added value but the producer of the drivetrain and/or battery. So there is room for a new intermediary. If you as consumer are able to choose the power train and batteries combining it with the car this is a completely new business model. So the middleperson is setting up an internet platform where people may select the body shape, power trains, and the battery size and type, and order the vehicle.
I would be very happy to see this dream come through since you don't save much energy if you have the wrong car with the perfect drivetrain. The intermediary of course has to secure the interoperability - so the BMS communicates with the powertrain over the CAN bus.
cheers
Efried

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Re: The skinny on PHET LiFePO4 cells and packs

I think this cell is not good enough for most of our applications:
Quick Discharging 1C only
60% energy at -20°C

Efried

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Re: The skinny on PHET LiFePO4 cells and packs

Very interesting, thank you for the report.

Are the prismatic 18650 cells also C-LiFePO4 chemistry? I ask because other 18650 cells I've seen are normal Li-ION and hence susceptible to explosion. Ah.. The ones sold by batteryspace are 3.6v and you say PHET's are 3.2v which is in line with LiFePO4.

low-power ebike (~250W) This is compatible with being sold in Europe. I understand that in Europe there is a law saying electric bicycles can be at most 250 watts.

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Re: The skinny on PHET LiFePO4 cells and packs

Quote:

I think this cell is not good enough for most of our applications: Quick Discharging 1C only60% energy at -20°C

I'm not sure which one you are referring to. The link I gave above (http://www.phet.com.tw/Products/Cell_Spec01.aspx) is for a cell that has a specified rate up to 5C. I use my pack based on these cells regularly at 3C, and have not seen a problem with that so far. There is minimal heating. These are exactly the same cells that PHET sells and warrants for 3 years for EV usage. There are discharge curves for these cells shown at http://www.phet.com.tw/DM.htm (on page 3). Use at a 2C rate slightly decreases lifespan, but not substantially according to the lower left graph.

(BTW - the the astute reader may notice that PHET lists large high capacity cylindrical cells on that page, but either they are not in production yet, or they don't want people like me using them for EV's, because they have never recommended one to me).

I think most of the temperature degradation comes at the low end of that range. The question is, what other cell type is there that does substantially better?

Regarding the other issues, if I sounded defensive, it was not because of anything you said, it was simply because I am frustrated trying to deal with PHET. They make a great cell, but they are not making it easy for us as enthusiasts for gaining access.

Morgan

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Re: The skinny on PHET LiFePO4 cells and packs

Hi David,

Quote:

Are the prismatic 18650 cells also C-LiFePO4 chemistry? I ask because other 18650 cells I've seen are normal Li-ION and hence susceptible to explosion. Ah.. The ones sold by batteryspace are 3.6v and you say PHET's are 3.2v which is in line with LiFePO4.

low-power ebike (~250W) This is compatible with being sold in Europe. I understand that in Europe there is a law saying electric bicycles can be at most 250 watts.

These are advertised as being LiFePO4. And all the labeling on the examples I have in hand says LiFePO4... I doubt PHET is mislabeling, though it's always good to be suspicious when large profit motives are involved.

Regarding ebikes, while it's true there are limits in Europe, even the European testers of this particular bike thought it was a bit underpowered, and that the range was too short. It's interesting how much of the chinese Ebike market right now is focused on Europe. If only the US of A would catch up at some point!

Morgan

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Re: The skinny on PHET LiFePO4 cells and packs

Morgan,

I found your description of shopriders obvious dismissive attitude regarding US demand for e-bikes pretty interesting.

We face a cultural barrier in the US - the facts are, you really can't justify two-wheel e bikes/scooters/motorcycles from cost alone - the motivations has to come from somewhere else. For 95% of the US climate change or conservation is completely off their radar.

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Re: The skinny on PHET LiFePO4 cells and packs

Hi Morgan,

Very interesting study. Hope you have a good bussiness.
I'm also very interested in switching my 48V 55A LAB to a PHET battery set. PHET will quote me soon. But I have a question about charger. I heard from PHET that I must not change my current charger, because their batteries work fine with such applications design for LAB. But the e-Scooter maker, EVT, says differently. I wonder if you can share your experience of that. For shuch an expensive battery set. It's not a good idea to ruin the warrenty.

Jay from Taiwan

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Re: The skinny on PHET LiFePO4 cells and packs

The reason is that PHET does not have access to these large format cylindrical cells. They only can furnish the smaller 18650 cells in strings as you know.

Best,

Don Harmon

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Re: The skinny on PHET LiFePO4 cells and packs

Don wrote:

The reason is that PHET does not have access to these large format cylindrical cells

Don H - not sure I understand your post? The reason for what is based on PHET having no access to large format cylindrical cells? If I remember right your packs are no cheaper than PHETs - or am I missing something?

All - I'd like to put in a good word for Morgan/cycle9. I was one of the folks who contacted him and we shared several emails back and forth. He was very open and straightforward to deal with. Alas, the large Ah packs are not economical yet. I'd also like to point out that Morgan (perhaps like Don H?) is trying to become a true value added reseller by offering customer service and reducing communication barriers to getting the packs we all want. So, I for one, wish him success and would advise folks that at present getting a PHET pack for an e-bike from Morgan seems like a good plan.

This is not meant to "dis" the competition - it's just I've had some first hand dealings with Morgan and I liked how they went (even though they ended up not resulting in a sale).

Thanks.

P.S. I'm a DIY sort-a-guy so don't be surprised if I end up attempting to cut out the middleman - I do so with the knowledge that I'm taking way more risk by doing that.

P.P.S. That risk is not the risk of not receiving what I ask for but instead it's the risk of not asking the right questions!

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Re: The skinny on PHET LiFePO4 cells and packs

All I said was that PHET cannot supply large format (40138 Cells)that I am aware of?. That has nothing to do with the price point of our packs. I also appreciate Morgan/cycle9 for their honesty in explaining things that many people want to know about PHET.

Best,

Don Harmon

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Re: The skinny on PHET LiFePO4 cells and packs

Quote:

JUST TRYING TO BE HELPFUL!

...and I, for one, appreciate it. The more information and insights we have on this topic, the better informed we are when it is time to make our decisions.

Don, I'm sure everyone is also grateful for the various insights. Challenges are hopefully intended to respectfully draw out all perspectives and information as these types of batteries remain somewhat of a mystery in terms of brand performance, etc.

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Re: The skinny on PHET LiFePO4 cells and packs

If I inadvertently offended then I apologize - however, let me try again...

Dear Mr. Don Harmon,

I appreciate your offer of help. You typed the following response to this thread: The reason is that PHET does not have access to these large format cylindrical cells. The formatting is mine - the part in bold would imply to the reader that you are responding to something specific. If as you later say that you simply wanted to state that PHET does not have access to large cells then why not say that specifically (as in the non-bold part of what I quoted)? If that's what you wanted to say I would have thought you'd take the time to educate the reader why this is important (higher C draw, better performance, better price, whatever...).

It was a genuine question based on your post. It was a simple guess on my part that the thing you were responding to was price point. It might have been performance or packaging related. You didn't say so I picked one that most of us are keenly interested in - why are these things so darn expensive!?

The other part of the post was not related to the question - it was something I wanted to do for independent reasons. However, recognizing that it might be taken that way I even went so far as to mention that I meant no disrespect to the competition. However, I do think that providing partial information to the casual reader as you did that you might damage PHET's reputation and thus Morgan's nascent business opportunities.

I'm not really sure why anyone would think of my question to you as a challenge and/or imply that they are done disrespectfully. It was a straight forward question that just required a straightforward answer. You gave a straightforward clarification - but I'm not sure I can figure out why you first posted what you did. So this mildly sarcastic post is aimed at both you Don and to you Vinnie (what's with the implications of "challenges"?.

Yeah, it's late and I probably shouldn't have posted this - but it just struck me that I still don't understand Don's reason for posting what he posted nor Vinnie's reason for feeling we need to couch things "more respectfully" when dealing with Don (or anyone else). Not being "more respectful" does not equate to being "disrespectful".

Have fun everyone. Just here to help. All opinions are mine. I'm not a lawyer or a soothsayer. My other car's an e-scooter. And feel free to suggest any other platitudes you feel I should include.

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Re: The skinny on PHET LiFePO4 cells and packs

I am not sure what your question really is John? And I certainly meant no disrespect to PHET or Morgan's nascent business opportunities. You seem to have a bit of a problem understanding a simple fact. PHET doesn't offer a 40138 large format LiFePO4 Cell.

Don

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Re: The skinny on PHET LiFePO4 cells and packs

No, I have no problem understanding that PHET doesn't offer that large format cell. What makes you think that I don't understand that?

Don, I would like to understand why you posted the fact that PHET doesn't offer a large format cell. The discussion was about the pricing of large capacity packs from PHET.

Morgan graciously (at some risk to his business and his relationship with PHET) gave us all a detailed breakdown of that price. Then you posted this statement "The reason is that PHET does not have access to these large format cylindrical cells. They only can furnish the smaller 18650 cells in strings as you know".

Why did you post that? What does that post add to the basis of this thread?

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Re: The skinny on PHET LiFePO4 cells and packs

Because Morgan stated in his/her post: (BTW - the the astute reader may notice that PHET lists large high capacity cylindrical cells on that page, but either they are not in production yet, or they don't want people like me using them for EV's, because they have never recommended one to me).

Do you get it NOW ????

Best,

Don

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Re: The skinny on PHET LiFePO4 cells and packs

Yes, thank you I do "get it NOW". I stated many times I didn't understand what you were responding to but up until now you didn't help me clarify that - you just told me I misunderstood you but you didn't tell me what you meant. Now, with your grammar and formatting you seem to be suggesting it was as plain as day all along (and from that I guess you might imply I'm either dense or being purposefully dense). Sorry if I was dense - I truly did not understand. However, you seem quite defensive about your pack price.

Sorry, but personally, I still don't believe that a vendor of high priced (and most likely high quality) LiFe battery pack is really ever going to be an impartial bystander when discussing the competition. Thus I find your tag line a little disingenuous - but I do VERY much appreciate your clear affiliation with your company. Thank you for that. Also, that doesn't mean that I don't welcome the insights that you can bring to the discussion. Just because I think this way shouldn't affect how you post - that's your call. However, nor should your world view affect how I post (it doesn't).

BTW - last time around there was some discussion of who can get the large format cell and there was a reference to another potential vendor. Probably PHET (might have been YESA)? And that was in conflict with your claim that LiFeBatt was the only vendor with a cell of this format. Because I can't get to a publicly served page that shows the higher capacity pack doesn't mean much to me. If you want I can go back and find those references?

Good luck selling your packs.

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Re: The skinny on PHET LiFePO4 cells and packs

John, when did I ever say I was an impartial bystander when discussing the competition ? Just so you know I am a big fan of any quality LiFePO4 product out there. I want this chemistry to succeed - why wouldn't I ? I don't try to dis other competitors - I try to make them live up to what they are selling by publishing specs. stating warranties, and showing results of independent tests. This is what LiFeBATT is doing and it takes time and diligence to do that. I am all for competition - it will be best for our market if we have quality competitors that offer a quality product to compete with.

What I am against is inferior LiFePO4 packs being sold by "no-name" vendors who don't back up their product, have no warranty, and when these packs fail - will give us all a bad rap. But perhaps that's just my nature ?

As for the availability of large format cells - there are other offerings out there. You have to carefully compare the specs. for these and ask the supplier where they are made, how "old" are these cells, what kind of warranty will the mfg. offer, and what kind of support will be available for them ? Do they offer a VMS/BMS ? Do they offer a charger ?

You can find out a lot more about what LiFeBATT is currently doing within the e-bike market by having a look @ this link on the Endless Sphere Forum if you want to learn more: http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=2903

Cheers!

Don Harmon

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Re: The skinny on PHET LiFePO4 cells and packs

I decided to dig up the 40138 cell references. At the end of the day a high capacity cell is always going to be a better "building" block for those of us who want replacement packs for 2000W+ scooters/mopeds. So, here's some info:

According to this thread: http://visforvoltage.org/forum/batteries-and-chargers/1770 YESA can get the 40138 format cell. This does not refute Don's post above that PHET doesn't have access to that cell.

However, this thread: http://visforvoltage.org/forum/2226-lifebatt-now-taking-preorders starts with Don's LiFeBatt announcement and mention of LiFeBatt's exclusive access to this cell. Then this thread becomes a debate on who has access to the 40138 cell. I believe in the end Don conceded that LiFeBatt does NOT have exclusive access to the 40138 cell.

This thread: http://visforvoltage.org/forum/2296-lifebatt-real-calculations-and-costs compares the costs of LiFeBatt vs. YESA at that point in time for that cell configuration. Again, it devolves into an argument (some would blame usatracy, personally I realize it takes two to tango and my experience is that Don quickly takes up the offense (the best form of defense?)). Bottom line is that YESA is significantly less expensive than LiFeBatt for the 40138 cell.

Aside from price and cell format the last point of comparison is the chemical formation of the LiFePO4 itself. PHET claims to have the exclusive rights for C-LiFePO4 and that this formulation is better for power applications (i.e. high discharge usage). I believe Don stated that LiFeBatt was also using the same formulation? Or another "special" formulation that improves over the "basic" LiFePO4 cell? Finally, I don't think YESA publishes any specific claims about "special" LiFePO4 formulation.

The last point that I can think of that someone might want to consider is to read the report of different cells tested in a side by side comparison. Unfortunately I haven't been able to find reference to that! TS cells were at the bottom of the pack. A123 at the top. Can't remember where the others were (or who they were).

I believe this is germane to the general gist of the thread. If people think otherwise we can always start another thread.

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John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas. No Worries." - JDH, CuMoCo || "Make Volts Not War" - anon.

jdh2550_1's picture
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Re: The skinny on PHET LiFePO4 cells and packs

Don wrote:

John, when did I ever say I was an impartial bystander when discussing the competition ?

Err, at the point when you changed your signature line to read "JUST TRYING TO BE HELPFUL" and responding to any thread where your competition is discussed. As the signature change is retroactive - that means every single post you made on this board.

Personally I'm trying to be helpful too (although there's no JUST about it).

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John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas. No Worries." - JDH, CuMoCo || "Make Volts Not War" - anon.

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Re: The skinny on PHET LiFePO4 cells and packs

Quote:

and to you Vinnie (what's with the implications of "challenges"?.

Quote:

nor Vinnie's reason for feeling we need to couch things "more respectfully"

John, I've got nothin but love for ya! I really didn't mean to direct anything at you or imply anything in your direction. What I typed did not read at all the way I meant it. When I reread it now, I see why you are calling me out. Rather than a lengthy explanation of what I did mean and how I meant it, please accept my apologies both for chiming in unnecessarily and for any disrespect I threw your way. It was immensely unintended.

And a little more on topic, it does seem like we are at a point where we need to get a few of these various brands of packs into large scooters and see what happens. Anyone wanna go first?

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Vinnie
Broomfield, CO

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Re: The skinny on PHET LiFePO4 cells and packs

Tagline removed. Now what else can I do to please the posters here - or maybe just leave the Forum ?

Best,

Don Harmon

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Re: The skinny on PHET LiFePO4 cells and packs

DCP_0946.jpg

I'm trying to find some info on these chinese ebay packs. I just can't believe no one is buying any. He can make me a nice 2x 36v10ah for 72v 10ah, 2 chargers, bms, delivered to my door for $500. Now that I've found out the size of the individual cell, I see a nice 4.8 ah @ 72v battery is wha I want.

his email:

Hi Victor, The standard size of our 36v10ah battery is 150x110x150mm. Actually the size of the battery pack is 135x105x140mm and size of BMS is 120x65x12mm. To fit your size, we can resize it to 300x110x87mm. It will cost 3 to 4 business days to resize the standard batteries or produce new batteries for you. If you have made decision, just reply and confirm. Then I will put it on ebay as a buy it now item for you. Our single cell is 3.2v4950mah. Size 135x105x6mm. We don't have any experience and application data on more than 2000w load. The size of 36v200ah will be 20 times of 36v10ah. Best regards, Ping

As soon as I convert these measurements tp inches, I can make sense of it.

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Re: The skinny on PHET LiFePO4 cells and packs

Hi,

I have a bit more information to add. PHET does appear to make the large format cells, but after I inquired directly with them about those cells, they made it clear that they will not sell them to us. They said those were reserved for "high quantity" orders, and they wouldn't give me a price.

This is my speculation: that they are using the large format cells in their Shoprider line of medical devices, and either: 1) their full capacity producing those cells is used meeting demand for these devices, or 2) their licensing agreement with Phostech/Hydro Quebec/UT for the large cells prevents them from making those cells available for EV usage.

I plan to obtain a pack from YESA now for real-life usage comparison against the PHET pack, and I will report back when there is useful data. However, this will only be an e-bike sized pack, so results may not apply to larger vehicles. Unfortunately, I cannot currently afford destructive testing of the packs, so I won't be able to immediately evaluate the full lifespan of these.

An earlier poster (I think it was Paul) mentioned he had seen a site testing the various cells. Was it this one? It provides a nice rundown on the various cells, though this doesn't necessarily reveal how they will hold up in real life usage consisting of large strings of cells with BMS :?

Morgan

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Re: The skinny on PHET LiFePO4 cells and packs

Hi Morgan,

You are on the right track regarding the PHET agreement with Phostech/Hydro Quebec/UT for the large (40138) cells. It covers the medical devices - specifically wheelchairs which is a huge market in itself. The patent rights for the large format 40138 Cell are owned by another Taiwanese company who is in partnership now with LiFeBATT.

Best,

Don Harmon

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