aknies66
Posts: 6
Joined: Sun Apr 09, 2017 12:27 am

Power available at terminals of 12V battery

Thu Apr 13, 2017 1:26 am

In a gas-powered car, the alternator charges/powers the 12V battery when the engine is running. Depending on the speed of the engine, the alternator can deliver 100's of Watts to the 12V battery.

The Bolt has a DC-2-DC converter from the high voltage battery to the 12V battery. Question, how many Watts of power are continuously (e.g., until the high voltage battery is depleted, at least) available from the DC-2-DC converter at the terminals of the 12V battery when the car is ON and parked with all lights off, A/C and heat off?

Thank you,
Allan

drdiesel1
Posts: 128
Joined: Mon Jan 09, 2017 5:41 am

Re: Power available at terminals of 12V battery

Thu Apr 13, 2017 3:59 am

Read the data card on the battery and you should have your answer :idea:

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

Re: Power available at terminals of 12V battery

Thu Apr 13, 2017 4:10 am

drdiesel1 wrote:Read the data card on the battery and you should have your answer :idea:

The battery specs will show how much energy the battery can store, not how much power the DC to DC converter can supply to it.

drdiesel1
Posts: 128
Joined: Mon Jan 09, 2017 5:41 am

Re: Power available at terminals of 12V battery

Thu Apr 13, 2017 5:26 pm

SeanNelson wrote:
drdiesel1 wrote:Read the data card on the battery and you should have your answer :idea:

The battery specs will show how much energy the battery can store, not how much power the DC to DC converter can supply to it.


The battery data gives you amp hour rating information :roll:

SeanNelson
Posts: 1421
Joined: Tue Jul 05, 2016 2:43 am
Location: Vancouver, BC

Re: Power available at terminals of 12V battery

Thu Apr 13, 2017 5:44 pm

drdiesel1 wrote:
SeanNelson wrote:
drdiesel1 wrote:Read the data card on the battery and you should have your answer :idea:

The battery specs will show how much energy the battery can store, not how much power the DC to DC converter can supply to it.


The battery data gives you amp hour rating information :roll:

Yeah, but that's not what the OP is asking for. He wants to know how much power the car's battery charger can put out. The "charger" is the DC-DC converter that steps down the high voltage from the traction battery to the 14V or so that's used to charge the 12V battery. That's probably because he's thinking of running something (like an inverter) from the battery terminals with the car turned on so that he doesn't drain the 12V battery.

drdiesel1
Posts: 128
Joined: Mon Jan 09, 2017 5:41 am

Re: Power available at terminals of 12V battery

Thu Apr 13, 2017 5:52 pm

SeanNelson wrote:
drdiesel1 wrote:
SeanNelson wrote:The battery specs will show how much energy the battery can store, not how much power the DC to DC converter can supply to it.


The battery data gives you amp hour rating information :roll:

Yeah, but that's not what the OP is asking for. He wants to know how much power the car's battery charger can put out. The "charger" is the DC-DC converter that steps down the high voltage from the traction battery to the 14V or so that's used to charge the 12V battery. That's probably because he's thinking of running something (like an inverter) from the battery terminals with the car turned on so that he doesn't drain the 12V battery.


And that's gonna be based on battery amp hours/reserve power data.

wwhitney
Posts: 135
Joined: Thu Sep 01, 2016 4:05 pm

Re: Power available at terminals of 12V battery

Thu Apr 13, 2017 6:23 pm

drdiesel1 wrote:And that's gonna be based on battery amp hours/reserve power data.

Nope. In the use case proposed by the OP, the 12V system is being powered by the DC-DC converter from the main traction battery. The 12V battery should only come into play when the car is off, to provide standby power to the always-on loads.

Cheers, Wayne

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gbobman
Posts: 211
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Re: Power available at terminals of 12V battery

Thu Apr 13, 2017 9:05 pm

wwhitney wrote:Nope. In the use case proposed by the OP, the 12V system is being powered by the DC-DC converter from the main traction battery. The 12V battery should only come into play when the car is off, to provide standby power to the always-on loads.

Cheers, Wayne

I'd be interested in the answer to this/OP's question myself. If I know that I can run things without putting undo strain on the charging system, I'll know what options I can act on.
2017 Chevy Bolt LT (1st EV!)
2004 Chevy Monte Carlo SS
(found a new home :cry: )

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

Re: Power available at terminals of 12V battery

Thu Apr 13, 2017 9:49 pm

FWIW, the Leaf's DC-DC converter delivers up to 1800 watts.
2018 Nissan Leaf SL with Pro Pilot

2009 Vectrix VX-1 with 18 Leaf modules.

JeffN
Posts: 128
Joined: Fri Apr 01, 2016 7:32 am

Re: Power available at terminals of 12V battery

Thu Apr 13, 2017 9:54 pm

aknies66 wrote:In a gas-powered car, the alternator charges/powers the 12V battery when the engine is running. Depending on the speed of the engine, the alternator can deliver 100's of Watts to the 12V battery.

The Bolt has a DC-2-DC converter from the high voltage battery to the 12V battery. Question, how many Watts of power are continuously (e.g., until the high voltage battery is depleted, at least) available from the DC-2-DC converter at the terminals of the 12V battery when the car is ON and parked with all lights off, A/C and heat off?

The Bolt EV's DC-2-DC converter puts out a maximum of 1,600 Watts at ~14V, according to a GM engineer.

Of course, even with the heater, lights, etc. turned off the car's computers and other various components still draw a few hundred Watts. I wouldn't draw more than 800-1000 Watts continuously via a 120V inverter attached to the battery with the car turned on in "Ready" mode so the DC converter will be operating.

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