codekitchen

how are 12v accessories powered?

Mon May 08, 2017 9:03 pm

Does the Bolt use a DC-to-DC converter to run 12v accessories (things plugged into the cigarette lighter) directly from the main battery? Or if not, does it at least use the main battery to keep the 12v starter battery charged? Essentially, I'm wondering if I could leave an ARB fridge plugged in for about 3 days while the Bolt is sitting outside, or if I'd just quickly run down the starter battery and be stuck not able to start the car.

The fridge uses about 220 wh per day (at 12v), it seems like a lost opportunity if we can't tap into that giant 60,000 wh battery pack to run it. :lol:

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

Re: how are 12v accessories powered?

Mon May 08, 2017 10:05 pm

The DC to DC inverter that powers the car's 12V systems is only active when the car is turned on or is charging. And I believe that the car will turn itself off after a certain period of time if it's not being driven. So the short answer is "no", you can't run a fridge off it over a multi-day period without running down the relatively small 12V battery.

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

Re: how are 12v accessories powered?

Mon May 08, 2017 10:25 pm

It's SOP now for EVs to have to be in 'Ready" mode to be able to power accessories for any length of time. It's a shame that the so-called "accessory mode" is generally worthless and runs down the 12 volt battery, but that's how it is.
2018 Nissan Leaf SL with Pro Pilot

2009 Vectrix VX-1 with 18 Leaf modules.

MichaelLAX

Re: how are 12v accessories powered?

Mon May 08, 2017 11:08 pm

LeftieBiker wrote:It's a shame that the so-called "accessory mode" is generally worthless and runs down the 12 volt battery, but that's how it is.

How does that compare to the "accessory mode" on a ICE vehicle; aren't they all worthless for such usages?

Hey OP, here is an idea!

My 2nd car is a 2008 Chrysler Sebring hardtop convertible that I must park on the street, not having a 2 car garage. I now almost never drive it! To trickle charge the battery, so that it stays topped off, I have a solar panel that I purchased some years ago off of Amazon that plugs into a utility cigarette lighter outlet that is always "on" and is propped up in the rear window facing south towards the sun!

If you have access to the sunlight and a large enough solar panel, maybe you can use this idea too! They disconnect easily enough:

https://www.amazon.com/Sunforce-50022-Battery-Trickle-Charger/dp/B0006JO0TC

codekitchen

Re: how are 12v accessories powered?

Mon May 08, 2017 11:44 pm

Haha yeah, we already use solar power to charge our aux battery bank on our "expedition" vehicle where the fridge normally lives. Bummer that I can't just utilize the Bolt's battery when driving the Bolt though. I hope EV makers catch on to that use case eventually.

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

Re: how are 12v accessories powered?

Mon May 08, 2017 11:50 pm

How does that compare to the "accessory mode" on a ICE vehicle; aren't they all worthless for such usages?


In that case the most common use is running the radio, For that it usually works OK. There is another factor: ICE vehicles tend to do a better job of recharging the battery when they are restarted. EVs tend to only gradually charge it, so if it's run down it might not get fully charged again.
2018 Nissan Leaf SL with Pro Pilot

2009 Vectrix VX-1 with 18 Leaf modules.

MichaelLAX

Re: how are 12v accessories powered?

Mon May 08, 2017 11:53 pm

codekitchen wrote:Haha yeah, we already use solar power to charge our aux battery bank on our "expedition" vehicle where the fridge normally lives. Bummer that I can't just utilize the Bolt's battery when driving the Bolt though. I hope EV makers catch on to that use case eventually.

I had the EVExtend kit for my leased Chevy Volt with its 12v DC to 120V AC inverter as an emergency backup power source to my home. I wired a heavy duty extension cord from the garage to my kitchen so I could run the refrigerator and a couple of lights.

The original Volt would stay "on" all the time when powered up; I would turn off the lights and radio. This meant that the large battery would keep the 12v battery charged up for days during the emergency!

This was later considered a "hazard" and subject to a recall that I never had installed. I also of course removed the EVExtend kit before I returned the lease!

http://www.evextend.com/Emergency-Power-Kit.php

During the one true power emergency we suffered during my 3 years of Volt lease, I ran to the garage and someone had stolen my Inverter!!! The best laid plans of mice and keyboards...

MichaelLAX

Re: how are 12v accessories powered?

Tue May 09, 2017 12:26 am

LeftieBiker wrote:
How does that compare to the "accessory mode" on a ICE vehicle; aren't they all worthless for such usages?


In that case the most common use is running the radio, For that it usually works OK. There is another factor: ICE vehicles tend to do a better job of recharging the battery when they are restarted. EVs tend to only gradually charge it, so if it's run down it might not get fully charged again.

Good point!

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

Re: how are 12v accessories powered?

Tue May 09, 2017 3:03 am

MichaelLAX wrote:
LeftieBiker wrote:It's a shame that the so-called "accessory mode" is generally worthless and runs down the 12 volt battery, but that's how it is.

How does that compare to the "accessory mode" on a ICE vehicle; aren't they all worthless for such usages?

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.

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

Re: how are 12v accessories powered?

Tue May 09, 2017 3:23 am

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
2018 Nissan Leaf SL with Pro Pilot

2009 Vectrix VX-1 with 18 Leaf modules.

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