New England Hybrid Festival 2013
Mikes You Tube Videos
Mikes Saturday Hybrid-Solar- Electric Workshop
Insight 20 AH lithium battery system
assembling the pack core
BMS board mounting position?
Capturing the mounting boss positions
Cell tester is modified and lithium test fixture takes shape.
Charging experiments
Cleaning the cell tabs
fixing and deburring the heat spreaders
Final assembled pack core
Finishing the connection blocks
finishing the fins and end plates
First discharge graph
Getting started on the final design and build
Heat sink fins
heatsink vs no heatsink comparison
Higher thermal sensitivity look at the cell heating still shows no dents
Hot and cold cells compared.
How do the big guys do it
Is using this asking for a problem?
main I/O terminals and Heat shrink
Making the 50 insulating strips
Painted cells to increase emissivity
Punching the holes in the tabs
Same discharge with huge heat sink on one side of cell
Testing the fans and layout of the BMS boards
The Battery case starts to take shape
The case is nearly finished
the connector plate is made and mounted
The tab punch
The world in IR Cool
Grid charger Users page
Mikes Surplus Loft
Renewable energy exhibits
New England Hybrid festival 2014

Hot and cold cells compared.

Hot and cold cells compared.
hot and cold cells compared

I charged both cells, then put one in the sun, and one in the freezer, and then once the temperatures stabilized, as quickly as I could, placed them in the test fixture and ran a medium 50A discharge to see what happened. The cold cell had a much bigger voltage drop that got better as the cell self heated, and the hot cell actually dropped in temperature before turning around and rising towards the end.
Looks like the cells like between 90-110F as their best performance zone.
Ran another run where I let the cells drop right out, and we see evidence that the self heating gets worse as the cells start dropping that last 2V.