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accessory voltages

4282 Views 9 Replies 5 Participants Last post by  pennor1
With a 300 VDC battery pack, any idea about what voltage (or voltages) the accessory bus will run?

Here's my guesses:

12 VDC where ever practical so off-the-shelf devices can be used.

They are re-engineering wiper motors, heat pump compressors, and other high wattage accessories to get the watts down, so I'd guess they might as well go to higher voltages (maybe 48 VDC?). The lower amps would reduce motor cost and wire sizes.

I suspect they'll need a DC-DC converter to step down the voltage, as just tapping a few cells off the 300 volt pack for the lower voltages would unbalance the cell loads.
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I agree totally about the wiper (non)issue. I still cannot fathom that it is worth a dime of extra cost. Even in rainy Florida, the amount of time that the wiper are run is minor and the load is minimal.

I think someone claimed earlier on this blog that GM confirmed there will be a separate 12V battery for some auxiliary loads. Kind of makes you scratch your head more about the wiper issue. Can't imagine that will be powered from the main.

I don't think the current generation of LED's are better replacements for HID headlamps yet. They are great for lower output but have a little way to go to be cost effective and reliable for hedlamp application. They will be there soon enough.

At Voltnation, GM people spoke about "economode" for the energy misers and regular AC for the hogs.
This has been discussed many times before...

If you live in the north, the wipers can run for very long periods during the winter, to keep the slush off the windshield from the cars (and especially the big SUV's and trucks!) in front of you. You also use quite a bit of windshield washer fluid to keep the windshiels clean...........

You have to remember than not everyone lives where it is warm all the time, or where you get a 30 minute shower every now and then!

So with no alternator being run by the big ICE to power these loads, it is a concern to the engineers! And the last thing they want is bad reviews of the car's AER, because the wipers draw too much power!
I just don't see it, even with wipers on a lot. Maybe a couple of miles saved per year at best. Where is all this wasted energy going now?
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