3000 watt Inverter

[wax87]

It really annoys me when people just say "I suspect" without actually... doing any research at all?

It is well known that Hybrid Mavericks, do not in fact share much similarity with a normal car engine. Instead, they use the eCVT transmission, which needs two three phase AC motors, often labeled "generator" and "traction", or "MG1" and "MG2".

During hybrid engine startup, the generator motor spins up the engine through the planetary gearset, while the PCM injects fuel and allows it to start. During idle, the generator instead produces AC electricity, which is turned into DC for the high voltage battery by the ISC/SOBDMC (Inverter System Controller).

There is NO separate starter motor, and this startup process does not require 12V power except to engage the computer which controls the high voltage relays.

Videos from WeberAuto have teardowns/cutaways and helpful demonstrations on how this works:


In any case, the main reason that the 12V bus still needs to be able to supply large amounts of power appears to be because the PSCM (Power Steering Control Module) is connected on the 12V bus.

Presumably, if you are idling rather than maxing out the power steering, you should be safe to pull several hundred amps from the 12V bus. I've successfully run a 2000W inverter for hours at a time (with a ~1700W heating load) while idling to no ill effect: I monitored it via OB2-II and the computer was perfectly aware of the consumption and properly commanding the engine to idle more often in order to maintain the high voltage battery level.

The 12V battery voltage did not decrease, in fact, it ended up being more charged than normal because the bus voltage was always higher due to the DC/DC being constantly commanded to be on. This is similar to the advice to "keep your headlights on" to cause the 12V battery to be charged more (because that also draws enough power to kick on the DC/DC).

Ford appears to have chosen the cheapest 12V battery they possible could have for the hybrid, I imagine the CCA is simply a byproduct of it being a lead-acid battery and not something specifically required.

So not the best engineering decision but maybe an economical one?

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