2nd Gen Battery Cooling Fan Mod.

My battery pack gets me good MPG and doesn't seem to be failing. With normal driving my bars stay within normal ranges as well. However, on my 19-year-old battery, I have an internal resistance on each cell of 21 on Dr Prius. My ECM also doesn't seem to turn my cooling fan on soon enough, so if I'm going up a mountain, or breaking for prolonged period, I would get codes thrown for the pack overheating. I attempted to modify the wiring for the pre-existing fan to where I could turn it on when I desire, but the way Toyota built the system, and with signal wires, it would also produce an error when I turn the fan on manually. Because of this I opted to install a secondary fan. I traced out where the ducting was, purchased a 12v fan, and secured it to the ducting. I then traced the wiring under the rear seat, under the carpet, and into the center console where I plugged in to the 12v source there. So far it's been working well!