Originally Posted by JohnVirginia
On a slightly different tack, is battery internal resistance constant or at least linear versus battery voltage (at the same temperature). I would guess that IR changes with temperature. Any links known that have plots of typical IR versus various parameters?
Battery IR is not constant and changes dramatically with both temperature and SoC.
Here's a pic from a NREL study that shows the batteries IR under charge and discharge at various SoC.
What about the idea of substituting a low resistance/high current capable shunt in for a battery stick (or two battery sticks) as a fix for a high IR (bad cell(s)) situation? Fool that battery tap to make appear to the BCM/MCM/whatever that all is well at all times. Fool the total battery voltage reading (if there is one) to the BCM to be whatever it needs to be to operate the system at a reduced voltage. Removing one stick would reduce the battery voltage by 6 X 1.2V = 7.2V to 144V-7.2V=136.8V or 129.6V if two sticks. If these voltages are input to the MDM can it still convert the DC to three phase AC suitable to running the assist motor? Stupid idea?
The voltage is high enough for the DC-DC to still work, but I don't think it would work overall. The Insight has many checks and balances. It wouldn't throw codes as long as the voltages match, so that might not be necessary. But you're crippling an already crippled pack.. Don't think there would be many benefits.
The minimum voltage under 6.5kW of assist seems to be 140V.
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