Anyone know the low voltage point where my 2001 GEM with a T1 controller will throw an error and stop working? Reading the service manual, I think it is 63v? I’m getting this from the load testing section of the service manual, which seems to suggest it is at 10.5v per battery in the stock 6 battery configuration.
I believe the Mighty Mite pack I have now (which is great) could safely go lower than that. Still, not so bad at 63v, but I would like to know where the line is.
This brings up a few notable points.
Controller boot check
At KeyON, the controller checks packV and faults with a -15 undervolt error if the packV is below 68v.
Technically, if your pack is above that when you KeyON it will pass and let you drive but I’m not sure how low it would go. If you happen to KeyOFF, handbrake set, or power glitch to a reboot, the controller won’t let you start again.
Do you feel lucky, punk? -C. Eastwood
I believe the Mighty Mite pack I have now (which is great) could safely go lower than that.
If you found something that says 63 (on a load event), I’m not sure how much fun it will be, or if damage will be done to your cells going that low.
My rough math says that will put you around 2.625p/c. I’ll let @LithiumGods jump in on if that is too low for his pack as I don’t have much data on his current battery offering.
According to generic Lifepo4 info there really isn’t very much after 3.0v before it begins it’s fall off a cliff.
Charge it!
The other thing you need to check is the lower threshold of your charger. I previously thought the DQ was around 68, but have found it will start up around 61v (IIRC). It might depend on the profile you have set.
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Haven’t tested T1 but T4 & T5 shut off at 60v. Mighty Mite and lead have Very little power left below 70v. What happens is under load the voltages will sag hard and trip the low voltage in the controller. Once the load comes off battery voltage will jump up again. MM is fine going that low. The useable power is between 71v - 81v. LFP has a very flat discharge curve. It is one of the reason the power stays strong even when battery soc gets low
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The low-voltage cutoff for your 2001 GEM with a T1 controller is usually 63V (10.5V per battery for lead-acid). Since your Mighty Mite battery pack might safely go lower, check its manufacturer specs for the minimum voltage. To optimize performance, use a voltage monitor or BMS, and see if the T1 controller can be reprogrammed to adjust the cutoff point for your specific battery setup.
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