parabellum
1 MW
The Idea of such low tech, low skill build was born after seeing post of friendly1uk and following to it discussion , criticized as ever but idea with improvement potential.
http://endless-sphere.com/forums/viewtopic.php?f=14&t=65718#p989001
Why?
I lately have lost the access to any professional equipment and machinery, ass well to material supplies, time only on weekends where stores nearby are closed, battery of my moped is getting older and 18650 batteries cheaper and energy denser.
Goals (more will be added or over lined in process):
-Minimize electric tools and eliminate machining.
-Limit tool count used
-Use materials from easily accessible (for me) sources, Amazon and Supermarket, added Hobbyking 14/02/15
-Pack must be easily reparable and cells replaceable
-Cell protection level (final trade off consists in lowering serial connection resistance but still 1 cell not damaging others kicking out whole serie in the block)
-Most parts reusable if disassembling
-Shape variable
-Easy to inspect and detect failed cell
Cons (more will be added in process):
-It gets bigger
-It gets heavier
Tools used (more will be added in process):
-Scissors (I have large format guillotine in the office, for nice copper strips, but its optional)
-Pliers
-Carpet knife
-Soldering Iron
-Laptop (To make orders)
-Coffee
Materials and prices for 1kWh pack using NCR18650PF 2.9Ah cells 4P24S (more will be added in process) :
25x 4P 18650 holders 55.65US$ (1 holder in reserve)
Source: http://www.amazon.com/gp/product/B00NPZ81U8/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1
1x Cooper foil roll 36Ga 12”x5' 30US$ (less thet 1' or 1/5 of the roll will be used)
Source: http://www.amazon.com/gp/product/B0042SWM98/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1
2x Roll of double sided foam tape 1.50US$
Source: Local supermarket.
1x Vinyl floor tile ???
Source: Materials junk box
1x #3 Abro Synthetic Lithium Grease ~5US$ (454gr(1lb)Lifetime supply :lol: ) added 14/02/15
Source: Local supermarket
Progress:
Springs should not conduct any current and just act as springs.
Using double side foam tape for serial holder connection
Note the balancing wire channels between 2 halves
Note the tinny balance strip, will be used as fuse.
Notice the connector hooked up and centered with the folds on positive end
View attachment 2
View attachment 1
Principe of my fusing is as following:
Those fuse balance strips of 1P will be interconnected with wider strip and to balance wire
If one cell shorts, current from others in P brakes the fuse then the current of 2S in next interconnection goes brakes next fuse (V difference) trying to run current in to 1S (1 good + 1 failed cell) and so on all 6 fuses of the serie are broken. Every 6S is connected to the bus negative with automotive 40A mini fuse, it brakes as well when other 3 series are trying to pump current in due to 3.0-4.1V differential. Now, failed 1P6S is isolated.
After that.
a)BMS shuts down after 1 of those remaining 6S reaches LVC and user notices the missing 2.9Ah and visually inspects fuses.
b)One of my 4 battery medics shows way lower and saggy now 3P6S group and I visually inspect the fuses of the block.
Note. Battery medics are permanently attached to the battery with firs negative wire interrupted by relay at moped switch off. For draining lower cell reasons they only operate at system ON condition.
That was my plan and now...
Any ideas, critics and suggestions welcome!
http://endless-sphere.com/forums/viewtopic.php?f=14&t=65718#p989001
Why?
I lately have lost the access to any professional equipment and machinery, ass well to material supplies, time only on weekends where stores nearby are closed, battery of my moped is getting older and 18650 batteries cheaper and energy denser.
Goals (more will be added or over lined in process):
-Minimize electric tools and eliminate machining.
-Limit tool count used
-Use materials from easily accessible (for me) sources, Amazon and Supermarket, added Hobbyking 14/02/15
-Pack must be easily reparable and cells replaceable
-Cell protection level (final trade off consists in lowering serial connection resistance but still 1 cell not damaging others kicking out whole serie in the block)
-Most parts reusable if disassembling
-Shape variable
-Easy to inspect and detect failed cell
Cons (more will be added in process):
-It gets bigger
-It gets heavier
Tools used (more will be added in process):
-Scissors (I have large format guillotine in the office, for nice copper strips, but its optional)
-Pliers
-Carpet knife
-Soldering Iron
-Laptop (To make orders)
-Coffee
Materials and prices for 1kWh pack using NCR18650PF 2.9Ah cells 4P24S (more will be added in process) :
25x 4P 18650 holders 55.65US$ (1 holder in reserve)
Source: http://www.amazon.com/gp/product/B00NPZ81U8/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1
1x Cooper foil roll 36Ga 12”x5' 30US$ (less thet 1' or 1/5 of the roll will be used)
Source: http://www.amazon.com/gp/product/B0042SWM98/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1
2x Roll of double sided foam tape 1.50US$
Source: Local supermarket.
1x Vinyl floor tile ???
Source: Materials junk box
1x #3 Abro Synthetic Lithium Grease ~5US$ (454gr(1lb)Lifetime supply :lol: ) added 14/02/15
Source: Local supermarket
Progress:
Springs should not conduct any current and just act as springs.
Using double side foam tape for serial holder connection
Note the balancing wire channels between 2 halves
Note the tinny balance strip, will be used as fuse.
Notice the connector hooked up and centered with the folds on positive end
View attachment 2
View attachment 1
Principe of my fusing is as following:
Those fuse balance strips of 1P will be interconnected with wider strip and to balance wire
If one cell shorts, current from others in P brakes the fuse then the current of 2S in next interconnection goes brakes next fuse (V difference) trying to run current in to 1S (1 good + 1 failed cell) and so on all 6 fuses of the serie are broken. Every 6S is connected to the bus negative with automotive 40A mini fuse, it brakes as well when other 3 series are trying to pump current in due to 3.0-4.1V differential. Now, failed 1P6S is isolated.
After that.
a)BMS shuts down after 1 of those remaining 6S reaches LVC and user notices the missing 2.9Ah and visually inspects fuses.
b)One of my 4 battery medics shows way lower and saggy now 3P6S group and I visually inspect the fuses of the block.
Note. Battery medics are permanently attached to the battery with firs negative wire interrupted by relay at moped switch off. For draining lower cell reasons they only operate at system ON condition.
That was my plan and now...
Any ideas, critics and suggestions welcome!