I have a setup with a 24V starter battery and a 700V traction battery. There is an onboard DC-DC converter that steps the 700V down to 27.6V, with a 150A capacity, to run the system after start-up. The onboard DC-DC doesn't have fine enough control to operate as a battery charger which results in the battery life degrading due to never charging above 27.6V.
By connecting the Input to the DCDC and the output to the battery would the charger function without having to disconnect the battery from the system? The input would be connected to the same circuit as the output.