AndyH
10 kW
BMI said:
Nothing personal to anyone at PSI, BMI, or LiFeBatt. But my data collection and analysis suggests the existence of data inconsistencies...
1. BMI and LiFeBatt have made great use of a mis-representation that green cells are old. BMI continues to do so in their ebay ads, website text, and in written articles. Not only are green cells old, but they could very well be cheap Chinese copies made with inferior components.
Here's the problem: Green cells are current production cells from PSI - the only company that makes 40138 LiFePO4 cells with this terminal construction. Green is their color, as grey and red are used by BMI/LiFeBatt. PSI produces cells with and without Phostech material. Their standard green cells does NOT use Phostech. I know that PSI manufactured LiFeBatt and BMI cells under contract as recently as fall quarter 2008.
One demonstration of that fact is this: Visit Armin's product page, scroll down 1/2 way, and look at the photos of his grey cells. Note the serial number barcode and sequence: 4BF1M305-0593. Compare it to one of the cells I received from PSI in Dec 08:
View attachment IMG_1557.JPG
IF these cells were produced by BMI and/or LiFeBatt in another facility, why did they duplicate the PSI barcode, the PSI serial number sequence, and then choose to begin numbering their 'new' cells 'within' the PSI serial number sequence?
[edit] Could 'old' mean 'first generation'? It's obviously not 'old' with regard to time. Since the cells share the same cannister, manufacturing crew and (presumably) processes, this could leave 'old' to mean that a Phostech forumula, or other formula change, makes 'next generation' cells. Could be. But since it's the same factory, and they would presumably make a run of Urban-Assault black Endless-Sphere cells with a proprietary amount of Phostech if we wrote a check, could we claim all the other colors to be 'old copies' too? [/edit]
2. It's very easy for anyone to say device 'a' is an improvement over device 'b'. The first question this creates in my mind is 'compared to what?' They're an improvement how? They're better how? In regulated industries, confirmation must be performed by independent labs in accordance with established ISO, ANSI, or other specification. I don't know of a performance specification for LiFePO4, so it appears we're in a bit of a 'wild west' situation where anyone can say what they wish. It would be a significant marketing advantage for the folks at LiFeBatt and/or BMI to produce charts to prove the claimed superiority of their products. I cannot understand why they do not - unless they cannot. I've already placed a bet in Doc's testing thread that he will find no significant difference between the BMI cell and a PSI cell once his testing is complete.
3. Armin states that BMI and LiFeBatt cells now come from another manufacturer and are no longer connected with PSI. That could be. It appears that as of at least December 11th 2008 BMI and LiFeBatt purchase cells from the same manufacturer. As already stated, I have it from the source that it was PSI until fall '08.
I understand that PSI holds the patents on the design and manufacturing of these non-standard size cells with their terminals posts and seals. I also suspect that PSI is a larger corporation than BMI and/or LiFeBatt (this could be incorrect - I cannot find any information on BMI. I would expect a larger company to act a bit more 'corporate' though. This seems to favor PSI.). It doesn't make sense to me that a small company would put themselves in a position to be sued out of existence by violating PSI's patents - that's generally not a good long-term business strategy.
In addition, the photos posted on Armin's site, and that he may have supplied to the folks at Electric Echo, do show the manufacturing facility used to make these cells - and it's the PSI production floor with PSI's equipment and people. I don't know where they assemble packs with the completed cells. It would seem that a company with a new production facility might use photos from that facility instead of a facility they go to so much trouble to distance themselves from in print.
4. BMI continues to cling to the '20C' marking on their packs, and uses it in their advertizing. LiFeBatt did as well, but Don Harmon posted on this forum that it was an erroneous discharge rate and would no longer be used by LiFeBatt. Here are two facts that suggest this is marketing-speak only and has no function in the 'real world'. First is that 20C on a 10Ah cell means a 200A discharge rate. Even if the cell could flow that much energy, it would be very dramatic - for about three minutes. Then the cell is empty. Assuming they follow pack building guidelines published by the VMS manufacturer, All New Energy, the packs are built with a 100A fast-blow or a 75A slow blow fuse between two adjacent cells. The pack won't produce more than 10C for very long before the fusible link blows and the pack is off-line.
[edit] This portion about pack construction, though correct, doesn't speak to the capabilities of the cell. There might be differences in performance, but it doesn't appear to be openly available. [/edit]
If any of this is incorrect, I ask anyone to correct my position. If they can prove their point, I will correct my posts. I will provide sources and contact info if an independent party wishes to verify my comments. I don't care who the company is or what they sell - I am interested only in accurate information. I'll take my store down before I'll use bad info or untruth to sell. That dog don't hunt.
Sorry mods...maybe this stuff can be stripped out and moved to fix the severe thread creep.
