Advice Needed - Headway vs Thundersky

[Jay64]

No offense guys, but kinda seems like business battling should be done somewhere else. Just my 2 cents. I understand where you both are coming from, but time and a place. Perhaps start your own thread.

You can't really blame cell_man for jumping in to defend himself....no one likes to be accused of stealing. Sounds like sour grapes. How much are BMI cells nowadays... $35 for a 10AH cell? Thats $3.5/amp hour! No wonder everyone has jumped to Headways (which may be BMI cells now??).

No, I wasn't blaming him for defending, just suggesting it be taken to another, thread. And I was talking to both of them. Look what this has turned into now. Seems like the original poster has been totally forgotten in all this.

 

[MitchJi]

Hi,

Earlier post:

I don't doubt the performance claims of the cells for one minute since we know that A123 manufacture very high discharge rate cells. I only question the origins of the cells (where cell_man gets them from). It is my understanding that A123 Systems does not authorize the sale of these cells to individuals/end users and does not know where these cells are coming from (yet). Somewhere along the line from the factory where the cells are manufactured in Korea to their intended destination (the EV manufacturer in Shanghai, China where the cells are supposed to end up) some cells are being either stolen or bypassing the authorized supply route to the manufacturer.…

Of course that is not to stop end users here from using the cells if they so chose. It just comes down to the individual end users honesty and ethics.

Later post:

When asked about where cell man's cells came from (not only on this forum but other forums as well) the seller was less than forth coming about the source and did not want to explain exactly why they couldn't say much. Furthermore I recall reading a while ago on one of the other EV forums that the A123 markings would be scratched off the cells. In fact why on the forum are cell mans cells termed as being "A123 alike"?

Either they are genuine A123 cells or they aren't. That sounds dubious to me.

If the seller would have just been up front and totally honest from the start there would be no problem and there would have been no suspicions raised.

You didn't question the legitimacy of his cells. You specifically stated that you didn't question the legitimacy of the cells. You said he was either selling stolen cells or cells obtained in a dishonest manner. Accusing someone else of dishonesty is pretty amazing when you don't even truthfully respond in terms of your own comments from this thread!

 

[jonescg]

Where's the popcorn?

 

[BMI]

Hi,

Earlier post:

I don't doubt the performance claims of the cells for one minute since we know that A123 manufacture very high discharge rate cells. I only question the origins of the cells (where cell_man gets them from). It is my understanding that A123 Systems does not authorize the sale of these cells to individuals/end users and does not know where these cells are coming from (yet). Somewhere along the line from the factory where the cells are manufactured in Korea to their intended destination (the EV manufacturer in Shanghai, China where the cells are supposed to end up) some cells are being either stolen or bypassing the authorized supply route to the manufacturer.…

Of course that is not to stop end users here from using the cells if they so chose. It just comes down to the individual end users honesty and ethics.

Later post:

When asked about where cell man's cells came from (not only on this forum but other forums as well) the seller was less than forth coming about the source and did not want to explain exactly why they couldn't say much. Furthermore I recall reading a while ago on one of the other EV forums that the A123 markings would be scratched off the cells. In fact why on the forum are cell mans cells termed as being "A123 alike"?

Either they are genuine A123 cells or they aren't. That sounds dubious to me.

If the seller would have just been up front and totally honest from the start there would be no problem and there would have been no suspicions raised.

You didn't question the legitimacy of his cells. You specifically stated that you didn't question the legitimacy of the cells. You said he was either selling stolen cells or cells obtained in a dishonest manner. Accusing someone else of dishonesty is pretty amazing when you don't even truthfully respond in terms of your own comments from this thread!

I am sorry you have missed my point Mitch. I have no problem with any claims as to the performance of genuine A123 cells made by A123 Systems. My point relates to whether the cells which cell man is selling are genuine A123 cells made by A123 systems or copies which are just made to look like A123 cells.

I raise this question because cell man has stated in his own words-

" The cells are shipped with all identifying marks removed as best I can".

Why would you remove all identifying marks from the cells if it is a genuine A123 product?
Would you not be proud to show the A123 markings on the cell to give customers the confidence they are buying a genuine product made by A123 Systems?

If someone offered me cheap A123 cells but they told me all identifying marks would be rubbed off (such as A123 logo and cell serial/batch number) I would automatically be suspicious and ask myself if the cells were stolen (so they were not traceable by A123 Systems from batch number markings on the cells).
After all, cell man does not appear to be an authorized distributor that I can see from the A123 Systems website.

Perhaps to you this is not a reasonable assumption but to me it is.

I respect your right to have a different point of view.

 

[TylerDurden]

So you see the problem here from the manufacturer’s point of view? Since that time our policy has changed and we (as the manufacturer) decide who we will supply the cells to which is why we mainly supply to manufacturing companies. I am sure it is for similar reasons why A123 don't sell their cells directly and why tens of thousands of A123 cells have had to be salvaged from Dewalt tool packs.

SHOCKING NEWS:
A123 sells to VARs and OEMS, like many mfrs do. Getting cells from packs is simply cheaper (at the expense of support and warranty).

MORE SHOCKING NEWS:
Cell-Man is not an authorized VAR or OEM. Yet.

EVEN MORE SHOCKING NEWS:
The Cell-man cells could be copies or undestroyed factory-seconds, but extensive testing confirms quality.

EVEN MORE MORE SHOCKING NEWS:
Developers will acquire these cells as cheaply as reasonably possible.

EVEN MORE MORE MORE SHOCKING NEWS:
Competitors will try to dissuade developers and end-users from buying A123 cells.


EVEN MORE MORE MORE MORE SHOCKING NEWS:
BMI will pick up where Don Harmon left off, slamming other sources and propagating BS about who makes lifetech cells and whether they have pixie-dust or not. PSI made the greenines, Headway makes the 40152 reds/greys/whatevers.

 

[BMI]

It is easy to make claims I know, so we can always let the "cells do the talking".
I know everything I have said has been the truth (whether people choose to believe me or not it doesn't really matter).

I put the challenge out there and am more than happy to provide cells for independent testing against any other brand.

Of course if people are all just talk and aren't willing to take the challenge to provide cells for testing any criticisms aren't worth a cent.

I am not here to get into a slanging match with Tyler (or anyone else) so I am sure independent testing would quickly silence any critics.

 

[pgt400]

"I am not here to get into a slanging match" just curious, what are you here for? I never read of anyone buying your rebranded overpriced battery packs? It doesn't appear as anyones buying your pitch? We have seen discharge curves for PSI/BMI cells in the past and yes they were better then headway past 4/5C)....but Headways meet the need at 1/3 price....plus we can buy individual cells and select our own BMS. Have not heard of Headwways rusting....maybe I missed that post?

 

[BMI]

"I am not here to get into a slanging match" just curious, what are you here for? I never read of anyone buying your rebranded overpriced battery packs? It doesn't appear as anyones buying your pitch? We have seen discharge curves for PSI/BMI cells in the past and yes they were better then headway past 4/5C)....but Headways meet the need at 1/3 price....plus we can buy individual cells and select our own BMS. Have not heard of Headwways rusting....maybe I missed that post?

LiFeTech battery packs certainly aren't re-branded. If as you claim they are re-branded who is the actual manufacturer?

There are two separate threads regarding the Headway rust issue on this forum alone. There is also discussion on other forums for example here including photos of some of the rusting cells- http://www.diyelectriccar.com/forums/showthread.php/headway-rust-issue-42203.html

 

[Jeremy Harris]

BMI,

The way you may be seen on here may, unfortunately for you, be coloured by our collective experience of dealing with another battery supplier, who was selling similar cells to you, but who clearly didn't realise that not being very technically savvy and making claims worthy of the worst kind of used-car salesman might just lead to his reputation becoming a little tarnished. The fact that the cells you're selling are similar in name, logo and price (I'm not asserting they are connected in any way), together with your tendency to come on here and bad-mouth what you see as the competition for your product (a technique that the other guy used also) means that a fair few people here are going to treat you with suspicion. This isn't your fault, it's just an unhappy coincidence.

Most on here are pretty savvy and can spot the difference between real facts and a sales pitch, so you'd probably be better just letting your products strengths sell it for you. Once one or two people on here start using your cells and reporting their real-world performance, then they should sell themselves on the basis of reputation alone. This is a multi-national forum and quite a few here (like me) will automatically shy away from what looks like a "hard sell", just on a point of principle. Mybae my brain is wired up differently, but when any salesman starts being pushy about promoting his product, then I automatically think "what's wrong with it? If it was so great, wouldn't it be selling itself?". Similarly, being critical about competitors products is another area of advertising that would be guaranteed to make me walk away.

Jeremy

 

[BMI]

Thanks for your comments Jeremy. I accept your points made.
I guess I feel it is unfair when people criticize my product by saying it it the same as another product (in this case Headway) only with a different label when they don't have any evidence for this and just go on what it looks like externally.
It is a bit like saying two identical cars, because they look the same from the outside will have identical performance. Unless you can see that both cars have the same engines fitted it is not fair to judge they will both share the same performance just from their external appearance.
Perhaps I should say nothing about the other product but unlike the majority of people on a forum like this one, I am fortunate enough to have a good understanding of not just my product but the other product also (since we have tested thousands of cells manufactured by them). Therefore if I have said something that is negative about the other product it is because it is the truth. I welcome anyone who questions a claim I have made as not being the truth and am happy to clarify any claims made further.

I absolutely agree with your comments about sales pitches. As I stated previously I would prefer to "let the cells do the talking".
This is why I have issued the open challenge to have all cells independently tested and then the arguments can rest.
It is my belief that the performance of high power discharge testing would show that LiFeTech Power cells and A123 cells would be very similar. I believe that the same test would show how far apart LiFeTech and Headway cells really are and quash any assertions they are the same cells in a different wrapper.

 

[maydaverave]

Ok, this is a question that I've been flipflopping on for about a year now. So far I've been able to put it off by saying "Oh, well I don't really need the batteries until X is finished" but now it is the home stretch, I've got everything I need except the batteries. So for my motorcycle with a 72V 60AH pack do I go with Thundersky or Headway. The choice is between getting 24 60Ah TS cells or getting 144( ) Headway cells. (Although if I went headway I'd probably make only a 50AH pack to start and then add another 10AH later if I needed it)

The advantage of Headway seems better performance, but it is more expensive and although I've seen it done in the "Headway Pack Builders" thread it seems pretty troublesome to make a large pack of them like this. Given the rate I work at it might be large enough an obstacle to prevent me from getting this thing on the road anytime soon.

Also there are now those LiFeYPO4 Thundersky cells which promise better performance than the older thundersky cells. I don't have any realworld experience to back this up but I'm under the impression that motorcycles will be pulling 70-80 amps continuous and 200-300 amps peak, which seems like it should be within the limits of a 60AH thundersky cell. The only thing that makes me hesitate is the fear of getting the AH calcuations wrong, I'm trying to get around 50 miles a charge on this thing) and needing to expand the pack. It seems to me that it would be easier to add more headways to a headway pack than TS cells to a TS pack, but maybe I'm wrong there too.

Can anyone offer advice to help me break my decision deadlock?

As interesting as this this thread has become :wink: I wouldn't mind hearing more about your build. Do you have a link to another thread with more details about your bike?

 

[MitchJi]

Hi Jeremy,

BMI,
… with your tendency to come on here and bad-mouth what you see as the competition for your product (a technique that the other guy used also) means that a fair few people here are going to treat you with suspicion. This isn't your fault, it's just an unhappy coincidence.

Jeremy

The "tendency to come on here and bad-mouth what he sees as the competition" is more than an unhappy coincidence.

Therefore if I have said something that is negative about the other product it is because it is the truth. I welcome anyone who questions a claim I have made as not being the truth and am happy to clarify any claims made further.

False. You accused someone of selling stolen or unethically obtained cells without any proof or justification. Then when I called you on it you denied doing that (and you just repeated that incorrect statement).

If you won't even tell the truth when referring to your own slanderous statements who do you think will believe your claims about the quality of your cells? And who do you think will trust any waranty you provide?

 

[BMI]

Hi Jeremy,

False. You accused someone of selling stolen or unethically obtained cells without any proof or justification. Then when I called you on it you denied doing that (and you just repeated that incorrect statement).

If you won't even tell the truth when referring to your own slanderous statements who do you think will believe your claims about the quality of your cells? And who do you think will trust any waranty you provide?

I certainly stand by my comments because that is the way I sincerely feel.
If someone was to offer me cells and I was told all identifying marks would be rubbed off and the seller was not an authorized or recognized distributor for the manufacturer it is natural to suspect that they could possibly be stolen or obtained by somewhat dubious means. I think it is pretty natural to think that.
A while ago someone was selling consumer electronic goods quite cheap with serial numbers removed at my local pub. I wouldn't touch them at a million miles because of the very strong chance they were stolen and by buying goods from a suspect source you simply encourage more illegal activity. Perhaps this possibility didn't even cross your mind. It all comes down to your own personal sense of ethics and how you were brought up. I can't comment on how you were brought up but I certainly was brought up with a strong sense of ethics/honesty which is why I always always do the right thing by my customers and go out of my way to help them far more than would normally be expected.

Our warranty is in writing and the customer can always take legal action if we don't honor our warranty.
What sort of written warranty do Headway provide with their products I ask you?

As I said previously, LiFeTech cells can "speak for themselves" when it comes to real life performance.
You can always provide some Headway cells for an independent test against our cells and show if you are up to the challenge :wink: .

 

[cell_man]

I had a quick look on your website but couldn't find any discharge curves or data on cell weights etc. As far as I can see your cells seem to offer performance possibly in the region of A123 26650 but in larger formats. They don't appear to offer very high energy density whrs/kg and due to their cylindrical shape they cannot be as densely packed as a prismatic cell.

What exactly are you hoping to achieve by comparing some of my cells against Lifetech cells. Even if they meet or exceed the C ratings that the prismatics offer, the main attraction for many to the prismatics is their form factor which gives high energy density, very high volumetric energy density and very good power density. A cylindrical cell can never compete on many of these points just by the fact of the less than optimal use of available space. The 20Ah cells offer energy density of over 140whrs/kg when the typical value is 100whrs/kg (for high energy density lifepo4) and they achieve this with a C rating equivalent to what most would class as high discharge rate LiFePO4 that generally has energy density significantly lower than 100whrs/kg.

 

[BMI]

I had a quick look on your website but couldn't find any discharge curves or data on cell weights etc. As far as I can see your cells seem to offer performance possibly in the region of A123 26650 but in larger formats. They don't appear to offer very high energy density whrs/kg and due to their cylindrical shape they cannot be as densely packed as a prismatic cell.

What exactly are you hoping to achieve by comparing some of my cells against Lifetech cells. Even if they meet or exceed the C ratings that the prismatics offer, the main attraction for many to the prismatics is their form factor which gives high energy density, very high volumetric energy density and very good power density. A cylindrical cell can never compete on many of these points just by the fact of the less than optimal use of available space. The 20Ah cells offer energy density of over 140whrs/kg when the typical value is 100whrs/kg (for high energy density lifepo4) and they achieve this with a C rating equivalent to what most would class as high discharge rate LiFePO4 that generally has energy density significantly lower than 100whrs/kg.

Thanks for your input cell_man. I value your comments.

I have to say that I don't agree with some of your comments for reasons I will explain.
For example it is my belief that a cylindrical cell will provide greater discharge power compared to a prismatic cell (all things being equal). Why is it that in the high discharge stakes, A123 26650 cells have "walked all over" the packs which use prismatics (such as Ping for example)? Don't you think that manufacturers like Ping would of made a higher discharge rate battery to match A123 if it was possible?
Of course when we are talking high rate discharge prismatics I am not talking about Li-Po's like Kokams etc.
Strictly LiFePO4.
Secondly regarding the form factor issue. It is much more difficult to terminate the A123 prismatic cells (after all there is an entire thread devoted to this issue). It is also more problematic should a prismatic cell in a pack require replacing at some time down the track. In my opinion it is much easier to unbolt a M6 bolt, remove the cell, and bolt a new one in place.
Just my opinion.
Not taking into consideration the differences in form factor, it would be an interesting test to compare the same Ah capacity of A123 prismatic cells with LiFeTech Power cells.

 

[CroDriver]

I have Headways, ThunderSkys and cell_man's cells.

We have tested all of them. Cell_man's are the best, by far.

Headways are quite OK for the price, just like ThunderSkys.

HAL has professional testing equipment but he needs 4 cells in series (12V equipment). I will donate 4 TS, 4 Headway and 4 Cell_man cells if you send me 4 of these BMI cells.

 

[Tiberius]

I have a professional lab full of equipment.
I can test discharge to 150 A, either constant current or constant resistance. Charging to 40 A. Internal Resistance at 100 Hz or 1000 Hz.

What would be the best comparison?

Nick

 

[cell_man]

I had a quick look on your website but couldn't find any discharge curves or data on cell weights etc. As far as I can see your cells seem to offer performance possibly in the region of A123 26650 but in larger formats. They don't appear to offer very high energy density whrs/kg and due to their cylindrical shape they cannot be as densely packed as a prismatic cell.

What exactly are you hoping to achieve by comparing some of my cells against Lifetech cells. Even if they meet or exceed the C ratings that the prismatics offer, the main attraction for many to the prismatics is their form factor which gives high energy density, very high volumetric energy density and very good power density. A cylindrical cell can never compete on many of these points just by the fact of the less than optimal use of available space. The 20Ah cells offer energy density of over 140whrs/kg when the typical value is 100whrs/kg (for high energy density lifepo4) and they achieve this with a C rating equivalent to what most would class as high discharge rate LiFePO4 that generally has energy density significantly lower than 100whrs/kg.

Thanks for your input cell_man. I value your comments.

I have to say that I don't agree with some of your comments for reasons I will explain.
For example it is my belief that a cylindrical cell will provide greater discharge power compared to a prismatic cell (all things being equal). Why is it that in the high discharge stakes, A123 26650 cells have "walked all over" the packs which use prismatics (such as Ping for example)? Don't you think that manufacturers like Ping would of made a higher discharge rate battery to match A123 if it was possible?
Of course when we are talking high rate discharge prismatics I am not talking about Li-Po's like Kokams etc.
Strictly LiFePO4.
Secondly regarding the form factor issue. It is much more difficult to terminate the A123 prismatic cells (after all there is an entire thread devoted to this issue). It is also more problematic should a prismatic cell in a pack require replacing at some time down the track. In my opinion it is much easier to unbolt a M6 bolt, remove the cell, and bolt a new one in place.
Just my opinion.
Not taking into consideration the differences in form factor, it would be an interesting test to compare the same Ah capacity of A123 prismatic cells with LiFeTech Power cells.

I don't doubt that a cylindrical cell has the potential to possibly have higher power and for the very high power applications A123 have stuck with cylindrical cells. The prismatic cells are their High Energy Density Cells and will likely sacrifice some power in exchange for the additional energy density. I do not claim these cells are the highest C rated cells available. They have a very respectable C rating but it's not just the C rating that makes them special. It is the combination of high energy density which massively surpasses any other LiFePO4 cell, along with a form factor that means they can be mounted with the minimal amount of wasted space. The termination method which I've now got adds about 350g to a 16S pack and only about 7mm extra length to the cells. The flat and rather thin shape was unlikely to have been arrived at by accident as it also lends itself quite well to temperature control. Their price is pretty good too...

C rating is only 1 of many ways to rate a cell, you also have energy density per kg, volumetric energy density, power density per kg, power density per l. The prismatic cells I have do a pretty good job of either exceeding the previous best LiFePO4 cells or at least achieving very respectable figures in all the important areas. I can stack 16 terminated 20Ah cells in a space of 110mm * 165mm (actually about 160mm) * 235mm. That will weigh well under 8kg (terminated, ~7.5kg unterminated) and have the ability to deliver 200A constant no problem and if you wanted to push things a bit 300A plus (not recommended without cooling panels) but more than that it will deliver very high short term current of 500 or even 600A. I have independent tests from a well respected Engineer that has conducted tests on 15Ah cells which produced short term power figures of over 1700W from a single 400g 15A cell with peak current of almost 700A. So for a high energy density cell, they do a pretty good impression of a high power cell in both my opinion and the opinion of other more knowledgeable people who have tested them.

If you really want to do some comparison tests I think it is only fair to put your cards on the table and give others the choice to pick the cells that they feel will give the best comparison (or send different cell types, ie. high power and high energy), so if possible could you please give a breakdown of the possible cell types available including size, weight, capacity, C rating, discharge curves and list price if possible.

 

[flashedarling]

As interesting as this this thread has become :wink: I wouldn't mind hearing more about your build. Do you have a link to another thread with more details about your bike?

Yeah, while I'm glad this thread has gotten attention it hasn't quite been the attention I'd been hoping for. I still am a bit at a loss as to if Thundersky's would be underpowered for my bike. If I should go with Sky Energy cells. Or if I should just get the Headways.

Here is the thread I started on my bike.
http://endless-sphere.com/forums/viewtopic.php?f=10&t=8634

Wow, I guess it has been a year since I've actually done anything on my bike. That certainly has given me a kick to the seat of the pants. Right now I'm leaning towards headways, even though the rust thread does give me some pause. Partially because I have the funds to by a small array (24-48 cells) right away and get going with that then build it up until I have enough to make distance I'm looking for.

That is of course unless someone can make a case for the Sky Energy or Thundersky cells over Headways. I am not considering other cells unless they are in the same price range.

 

[vanilla ice]

Assuming a decent cap pack I'd go with the lowC TS and parallel an a123 m1 on top of each cell. I'm not sure how well it would boost the Cmax, but IMO it would be worth a shot. You've already got some m1 cells right.. Which TS cells are you considering, the 60's in 1p? For what'd you say 2-300 amps peak?

 

[flashedarling]

Assuming a decent cap pack I'd go with the lowC TS and parallel an a123 m1 on top of each cell. I'm not sure how well it would boost the Cmax, but IMO it would be worth a shot. You've already got some m1 cells right.. Which TS cells are you considering, the 60's in 1p? For what'd you say 2-300 amps peak?

Yes I am considering the 60AH TS cells. My vehicle calculation spreadsheet tells me I'll be drawing about 60amps continuous when cruising so it seems that 60Ah is the minimum. The problem is I don't know how much current will be needed for acceleration. There will be points where I will need to accelerate uphill from a stop on my commute so I'll need some power there. So the issue is if the cells will have enough oomp to get me accelerated. For what it is worth my controller is rated up to 400Amp and 200 amp continuous.

 

[frodus]

Here's the latest example of a thread that BMI just jumps into bashing other cell manufacturers.....


BMI, you're doing the same thing that a few other unamed salesmen did in the past....stop it. Rather than JUST provide prices, discharge curves, good proven specs and examples of use in the real world, you would rather resort to bashing the competition by badmouthing them. You lose respect and you aren't doing much to prove the cells are "better". Offering them to people to test isn't doing much, you should be testing them and providing that data yourself, PUBLICALLY and EASY TO FIND. At 3x the price, I'll still go headway because my cost/performance ratio is acceptable.... I'll take them over TS and SE, and I'd take A123 over Headway. For the price, they're decent batteries. The quality matches the cost.

Who else sells BMI/Lifetech? Where's the discharge curves? (found em, thanks pm_dawn.. http://endless-sphere.com/forums/viewtopic.php?f=14&t=6586&hilit=xps&start=240) Do you have real Examples of customers using them in their vehicles? I don't mean pictures of a vehicle with a lifetech pack next to it, I mean installed inside, bolted up and running.....

The thing I find really intresting is you say you manufacture, which is PARTIALLY correct. You manufacture the packs. You put the BMS/batteries/cases together and test them fully..... that doesn't mean you make the BMS, batteries or the cases......Why are there only pictures on your website of the cells after they're assembled in packs or being tested? There are NO PICTURES of the battery cell production facility, only some people putting together packs with BMS and busbars, or testing the cells.....

Its because you guys manufacture the PACKS. Headway manufactures the cells FOR YOU (according to your specs/formulas.... I realize they're made different from headway-branded cells).... but still, they MANUFACTURE the cells, and I have emails to support this, from Headway and from someone else who has told me that the XP cells are manufactured by Headway for Lifebatt/Lifetech.

[edited to add some info on the discharge curves for BMI, they do look like good cells BTW, I still don't like his aproach]

 

[pm_dawn]

Hey hello now !

Wait a minute. I think you need to back off a couple of inches Travis !
If you do a search here on the Forum you will find the curves from LiFeTech.
Like here:
http://endless-sphere.com/forums/viewtopic.php?f=14&t=6586&hilit=xps&start=240
since early December.
So don't go bashing him about that. They are here and from what I can read they look really good.

I would say that you at EV-components aren't that much better when it comes to bashing Hi-Power Cells.
.....

Regards
/Per

 

[frodus]

Sorry pm_dawn, edited previous post to reflect the test information so people can find it easily when reading this thread). I used Google to search for any info I could find on Lifetech and BMI and couldn't find anything on the first 4-5 pages of search results. I'll look a little harder next time. Personally, I think the info should be readily available on the website of the company selling the product. BMI, you might want to repost the curves on your website.

As far as Hipower. I said some of those things before I started working at EVComponents. I see what you're saying though, I've been more careful recently. I try to remind people of limitations of different batteries and components so they don't have issues later. I never said they're a crap battery, just that they have decent voltage sag at high currents, so make sure it matches the application.



That being said:
I think all the batteries out there have their pro's and con's. Each one has a different level of quality, energy and power.....and a price to match. Hipower is low, TS is a little higher, SE is a little higher, Headway is a little higher, A123 is higher, Kokam is higher..... Where does BMI/Lifetech/Lifebatt fit in? Probably somewhere between Headway and A123. I don't think anyone disagrees. The problem is, the pricing seems like its above what we pay for Kokam or A123, and the aproach of the "sales team" is to bash everyone else in their way to promote the product.....

BMI: Let your cells stand for themselves and release pricing info. See where they fall in the big picture. The market will ultimately decide where they fit, not us (the distributors and manufacturers).

 

[morph999]

As interesting as this this thread has become :wink: I wouldn't mind hearing more about your build. Do you have a link to another thread with more details about your bike?

Yeah, while I'm glad this thread has gotten attention it hasn't quite been the attention I'd been hoping for. I still am a bit at a loss as to if Thundersky's would be underpowered for my bike. If I should go with Sky Energy cells. Or if I should just get the Headways.

Here is the thread I started on my bike.
http://endless-sphere.com/forums/viewtopic.php?f=10&t=8634

Wow, I guess it has been a year since I've actually done anything on my bike. That certainly has given me a kick to the seat of the pants. Right now I'm leaning towards headways, even though the rust thread does give me some pause. Partially because I have the funds to by a small array (24-48 cells) right away and get going with that then build it up until I have enough to make distance I'm looking for.

That is of course unless someone can make a case for the Sky Energy or Thundersky cells over Headways. I am not considering other cells unless they are in the same price range.

Have you seen these? Thunderksy has a 2C discharge rating. These have a 3C rating and are only $12 more for the 60AH 4-cell pack on EPS. http://elitepowersolutions.com/products/product_info.php?cPath=25&products_id=91
They are called GBS.