Posts: 1462
Joined: Tue Jul 05, 2016 2:43 am
Location: Vancouver, BC

Re: how are 12v accessories powered?

Tue May 09, 2017 4:59 am

LeftieBiker wrote:
The difference between an EV and a traditional ICE vehicle is that the battery in an ICE vehicle has to have enough capacity to deliver literally hundreds of amps of current to the starter motor in order to prod the beast to life. In an EV, the battery only needs to power the computer systems that command the high voltage battery's contactor relay to close. So the 12V battery in an EV is much smaller and will be drained much faster if it's under any significant continuous load.

Actually, the 12 volt battery in my Leaf is about the same size as the battery was in my 1986 Civic Si. It's also a standard "starting" type battery, unfortunately (deep cycle would be much better). Still, it could start a small ICE if necessary. I think it's that size just because of accessory loads

Interesting, I wasn't aware that Leafs had full-sized batteries. I think that's the exception rather than the rule for EVs. Even my Prius C, which actually has an ICE engine, has only a very small 12V battery because the engine is started by the electric motor, which is driven by the high voltage traction battery.

Posts: 793
Joined: Tue Jan 10, 2017 7:13 am

Re: how are 12v accessories powered?

Tue May 09, 2017 7:03 am

The Prius was designed and built a bit better because it doesn't use really expensive components like lithium packs (until this year, in some models) that necessitate cost-cutting elsewhere. The Leaf was probably designed for a medium-sized AGM battery, but the cheap starting battery was likely swapped in to save on cost.
2018 Nissan Leaf SL with Pro Pilot

2009 Vectrix VX-1 with 18 Leaf modules.

Posts: 38
Joined: Mon Jul 31, 2017 8:11 pm

Re: how are 12v accessories powered?

Wed Aug 16, 2017 7:00 pm

We know that a DC-DC converter powers the 12 volt system. Does anyone know what the power output rating is (amps or watts)?

I use my I-MiEV as a mobile battery from time to time with its 80 amp DC-DC converter (960 watts). Just curious if I can run a 600 watt load from the Bolt.
2012 i-MiEV ES with quick charge - White
2012 i-MiEV ES with quick charge - Silver
2017 Bolt EV LT - Orange Burst

11.8 kW Solar Array

Return to “Technical Discussions”