Re:Tesla adds bidirectional charging capability
by LeonM on Thursday May 21, 2020 @08:13AM
(#23257455)
I didn't realize EVs still have a 12V battery, I always assumed 12V accessories are ran directly of the DC-DC converter.
Thanks for pointing that out!
Re:Tesla adds bidirectional charging capability
by cmrdporcupine on Thursday May 21, 2020 @01:37PM
(#23261745)
So I'm not even sure in my Volt if the 12v battery even powers the accessories directly, because it's at the _back_ of the car, not up in the front by the accessories.
It's super handy for boosting other vehicles.
that's not how it works; the current is provided by the 12v battery, not the charging inverter.
Now, obviously the charging inverter isn't going to keep up for long, but as far as high current is concerned as 12v car battery can usually provide around 400-700 amps if given the proper leads, with a capacity of (typically) at least 45aH.
that's a lot of juice. even with the inverter inefficiency you should be able to get some fairly major work done if the inverter can supply the amperage -- especially if the EV systems are working alongside to maintain the battery.
>That would be very inefficient
absolutely.
>So, since it requires retrofitting anyway, it would make much more sense to have an inverter running directly of the high voltage battery.
that'd be nice, but I think EV groups would rather you wear out the cheaper replaceable battery with the erroneous usage. Sure, the loads still load the EV battery, but those charge/discharge rates can be more closely monitored or denied all together -- something that'd be harder to implement if the inverter had straight access to the ev primary battery.