eMark
100 kW
The current thinking by at least one member seems to be that the Parallel cells in a 18650 pack should always be referred to as a "group" and never (God Forbid) as a "string" otherwise those in the KNOW will see it as "Ridiculous poppycock" if ever someone were to refer to parallel cells in a rectangular pack as a "string". This lock-step thinking is in no small measure (IMO) due to the preponderance of larger triangle packs (e.g. 14S8P, 13S17P or 12S6P). However, not all packs are wired the same. Let's use as an example a rectangle pack (14S5P, 12S5P or 10S5P) that can be wired at least a couple different ways.
One way would be to use all five Series Strings of 14, 12 or 10 cells with each of the five "strings" connected with busbars of sufficient size/magnitude. These would be tied together with parallel busbars between each of the cells in the five (14, 12 or 10) Series Strings. But to be correct these single (parallel) connections are perpendicular (not parallel :wink: ) to the Series "Strings", and as lone rangers they aren't in a group whose purpose is to maintain/equalize continuity (e.g. as a pack ages) in case a Series "string" cell should become somewhat disfunctional. Another way would be to just use two Series Strings with each one separated by single (so-called parallel) busbar connections. So whether a pack (rectangle or triangle) is 14S5P, 12S5P or 10S5P do we know if the pack has 5, 3, 2 or just 1 Series (center) "String" without seeing the layout sketch ?
Another way would be to wire a rectangular pack (14S5P, 12S5P, 10S5P) in 5-cell Parallel "Groups" with only the center "String" being a Series "String" of the appropriate number and size of busbars having sufficient size/magnitude to handle the ebiker's need for raw performance. In some of these DIY youtube triangular pack builds it appears there is only one meandering Series "String". Is that possible (only ONE)? Could that be one reason why another member eluded to his (non-longevity) belief that most ebikers using triangular pack layouts having Parallel "Groups" of 4, 6, 8 (and up) may be fortunate to get 200 cycles out of their expensive triangular pack with large Parallel "Groups" and only one meandering Series "String".
So here's 4 questions to consider:
(1) Has anyone ever buillt (or heard of someone who built) a triangular 12S_P 48V pack having as many as 6, 4 or even 3 Series "Strings" and if so would you post the layout sketch showing either the 6, 4 or 3 Series meandering "Strings" ?
(2) Has anyone ever built (or heard of someone who built) a triangular 14S8P 52V pack having two Series "Strings" with Parallel "Groups" of 4 cells instead of 8 cell "Groups" and if so would you post a layout sketch showing the two Series meandering "Strings" ?
(3) Can you visualize a rectangular pack layout where both the Series and Parallel cells are in a "String" OR when the Parallel cells are neither in a "Group" or a "String" ?
(4) Is there more than one meandering Series "String" in this 13S17P customized triangular? pack ... https://endless-sphere.com/forums/download/file.php?id=262218 ... and if so could you please explain/elaborate ?
One way would be to use all five Series Strings of 14, 12 or 10 cells with each of the five "strings" connected with busbars of sufficient size/magnitude. These would be tied together with parallel busbars between each of the cells in the five (14, 12 or 10) Series Strings. But to be correct these single (parallel) connections are perpendicular (not parallel :wink: ) to the Series "Strings", and as lone rangers they aren't in a group whose purpose is to maintain/equalize continuity (e.g. as a pack ages) in case a Series "string" cell should become somewhat disfunctional. Another way would be to just use two Series Strings with each one separated by single (so-called parallel) busbar connections. So whether a pack (rectangle or triangle) is 14S5P, 12S5P or 10S5P do we know if the pack has 5, 3, 2 or just 1 Series (center) "String" without seeing the layout sketch ?
Another way would be to wire a rectangular pack (14S5P, 12S5P, 10S5P) in 5-cell Parallel "Groups" with only the center "String" being a Series "String" of the appropriate number and size of busbars having sufficient size/magnitude to handle the ebiker's need for raw performance. In some of these DIY youtube triangular pack builds it appears there is only one meandering Series "String". Is that possible (only ONE)? Could that be one reason why another member eluded to his (non-longevity) belief that most ebikers using triangular pack layouts having Parallel "Groups" of 4, 6, 8 (and up) may be fortunate to get 200 cycles out of their expensive triangular pack with large Parallel "Groups" and only one meandering Series "String".
So here's 4 questions to consider:
(1) Has anyone ever buillt (or heard of someone who built) a triangular 12S_P 48V pack having as many as 6, 4 or even 3 Series "Strings" and if so would you post the layout sketch showing either the 6, 4 or 3 Series meandering "Strings" ?
(2) Has anyone ever built (or heard of someone who built) a triangular 14S8P 52V pack having two Series "Strings" with Parallel "Groups" of 4 cells instead of 8 cell "Groups" and if so would you post a layout sketch showing the two Series meandering "Strings" ?
(3) Can you visualize a rectangular pack layout where both the Series and Parallel cells are in a "String" OR when the Parallel cells are neither in a "Group" or a "String" ?
(4) Is there more than one meandering Series "String" in this 13S17P customized triangular? pack ... https://endless-sphere.com/forums/download/file.php?id=262218 ... and if so could you please explain/elaborate ?