[ElectriCar]

But let's say you made your own buck charger, like jack. Let's say that the igbt fails on for some weird reason, which is their failure mode. You could end up with a situation that would dramatically overcharge. The constant current would fail. I think it's nice to know that if you use the wrong bolt or something, that the LiFePO4 cells that never blow up can actually blow up. Not following specs == dynamite is useful to know.

There's an app for that! Seriously there's devices called Voltage Relay's that monitor your pack and can be wired to interrupt the charger if it over volts. I installed one made by ABB. Click it then you can read the specs. It's adjustable up to 330V I believe. Mine is wired so that a contactor is energized until the voltage reaches a set point, whatever you want it to max at then it kills power to the contactor. Problem solved. The only drawback to this relay is the voltage is not very precise, you have to tweak it a few times to get it to cutoff where you want it. Mine shuts off now at just over 171V.

IMO, if you're going to invest the equivalent of the price of a small car in batteries, it's a no brainer to have a backup such as this IN CASE of charger failure to shut down and continues to ramp up in voltage. It's CHEAP insurance. I've been running it on mine for a month or so before I upgraded to lead. I wanted to get it working before I installed the new pack. Works like a champ.