EVDRIVER
Well-known member
- Joined
- Apr 24, 2010
- Messages
- 6,753
LEAFfan said:GroundLoop said:walterbays said:That said, I have no idea why the Leaf has such a huge battery. Seems like total overkill to "boot" the car.
The reason it has a regular car battery is to run most of the accessories including the LED headlights. It isn't just to boot the car starter.
The size of the battery is specified based on the parasitic loads of the car when off, like the RF transmitter, etc, etc. It is likely a generic medium amp-hour battery with average cold cranking amps, possibly slated to deep cycle but I doubt it since auto makes use cheap batteries.
I'm not sure why there is so much speculation on what is a basic electrical system and so many false statements being made on this forum about how EVs operate. The entire 12V system is very basic and consists of a med sized 12V lead battery (needed to close the contactor) and a high current DC/DC converter which runs the car accessories when on, and charges the 12V battery. The reason the Leaf has a smaller battery than an ICE car is because it has a large battery pack and DC/DC. If the entire pack were low to the point where the car won't drive the DC/DC will likely still run and they have different cut off points to protect the pack. The electronics of a Leaf are similar to any other modern car except it has an inverter and DC/DC converter, the rest is basically the same.
If you removed the 12V battery and had no accessory load and a charged pack, you could likely close the contactor with one or two tiny 9V batteries and then drive the car will everything on. For those people that are truly interested in learning how an EV works there are books available with wiring diagrams, they all are basically the same and have been for years. A basic wiring diagram can be done on a napkin in about 5 minutes that shows the main systems and how they connect.