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Old 01-22-2021, 07:38 PM   #12 (permalink)
serialk11r
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Join Date: Jan 2012
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spyder2 - '00 Toyota MR2 Spyder
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Alright, I connected it to the Porsche (2.7L 12.5 compression ratio) when it was almost empty (11V). The ECU was reading only 10.7V and all kinds of warnings were flashing on the screen.

It had to crank over several times before firing up fully warmed up. Just to see how it would do, I switched the car off after a few seconds, and the BMS shut everything off! I'm still not quite sure why that would happen, since I don't think it was near the low voltage cutoff. After disconnecting a cable to reset the BMS, I tried again, and it started just fine.

I only thought of measuring the charging current after a few minutes (at which point the voltage had risen 0.5V), and got an incredible 76 amps. The ECU was showing 12.3V at 800rpm, but revving the engine up to 2000rpm to get the 180A alternator putting out full power brought the voltage to 12.8V, so I think it's safe to say the battery was happily charging at well over 100A with no issues. Due to the chemistry, it can do this all day long, which is quite incredible!

I think for a car with a big V8 or something, I would want a true 40Ah, maybe 45 just to maintain the ability to start the car when it's near 0%, but this ~3xAh pack seems adequate for most applications. I was thinking of getting a 1st gen 2.5L Boxster as a toy car, this battery will work nicely there.

Last edited by serialk11r; 01-24-2021 at 01:13 AM..
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