Max power you can draw from the 12 Volt battery

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scrambler

Well-known member
Joined
Jan 14, 2017
Messages
160
Hi,
Does anyone know what is the maximum continuous load you can safely draw from the Spark 12V battery.

My understanding is that for the Volt Gen1 it was 1500W, but on the Volt Gen2, it is more like 1200W, because the Gen2 DC-DC converter to maintain the 12V battery is not as powerful as the gen1 Volt, and you want to make sure the Volt has enough power for its own electronics.

I am wondering if anyone has the info on what is a safe number for the Spark 2014.

Thanks
 
If you are talking about just the battery, with the car not powered ON, it can put out way more than 1200W.
How long? That is the question.

If you are talking about the APM , or DC to DC converter, then those numbers are close to the rated 100A or 120A figure published.
But this is at ~ 13.8 VDC.

Either way a 1200 W inverter is a safe max, imoh....

Lead acid car batteries don't publish an Ahr or kWh rating as such. The Reserve Capacity, RC, is a similar rating at a constant (?) 25 or 20 A draw down to a (?) 10.5 V cutoff point.
You can convert RC to kWh,
 
Thanks
I was speaking of taking power from the APM with an inverter, and looking for the max capacity of the DC-DC converter, as no know what load not to exceed so the car still has about 500W to run its own electronics.

" then those numbers are close to the rated 100A or 120A figure published."
What do you mean by that, is the actual max capacity of the DC-DC converter published somewhere?
 
scrambler said:
...What do you mean by that, is the actual max capacity of the DC-DC converter published somewhere?
I saw on the Volt forum where someone found the Gen 1 Volt and Spark EV use the same APM .
And I think it was rated 120A.
Find a parts catalog for both cars to confirm.

But you'd never want to run an electronic component at max output continuously.

What are you trying to power at 120 VAC?
A fridge and entertainment system?
A home window AC unit?

You can take a survey of the power consumption of the 'appliances' in your home with a 'Killawatt' - https://smile.amazon.com/P3-P4400-E...id=1506451504&sr=8-1&keywords=killawatt+meter
 
I just need to know the max, so that I can make sure that I do go over the max minus a 500W buffer for the car internal electronics.
The inverter has a power meter than can help monitor how much is being pulled. I also have a kill a P3 Kill a Watt.

For the gen1 that number was around 1500W, for the Gen2, it was around 1200W, Just trying to get a feel where the spark lies.
 
scrambler said:
I just need to know the max, so that I can make sure that I do go over the max minus a 500W buffer for the car internal electronics.
The inverter has a power meter than can help monitor how much is being pulled. I also have a kill a P3 Kill a Watt.

For the gen1 that number was around 1500W, for the Gen2, it was around 1200W, Just trying to get a feel where the spark lies.

Found this second hit Google search "chevy volt apm":

https://docs.google.com/viewer?url=http://media3.ev-tv.me/VoltAPMUserGuide.pdf

SPECIFICATIONS:
• Input Voltage: 260-420 vdc
• Output Voltage: 11-15.5 vdc
• Output Current: 135 Amperes
• Output Power: 2000 watts
• Dimensions: 13” X 9” X 3.5”
• CAN data rate: 500 kbps

If the Spark EV shares this same unit, then there are our numbers.
I, too, am interested in this type of project...after Irma went through Ga. and took power away for 3 days...

-Bob K.
 
The DC/DC in the Spark EV is under the hood and appears to be water cooled. It looks similar to the Volt module but may be completely different.

The Spark EV is part number 24267785 if you want to do your own searching.
 
sTeeve said:
scrambler said:
I just need to know the max, so that I can make sure that I do go over the max minus a 500W buffer for the car internal electronics.
The inverter has a power meter than can help monitor how much is being pulled. I also have a kill a P3 Kill a Watt.

For the gen1 that number was around 1500W, for the Gen2, it was around 1200W, Just trying to get a feel where the spark lies.

Found this second hit Google search "chevy volt apm":

https://docs.google.com/viewer?url=http://media3.ev-tv.me/VoltAPMUserGuide.pdf

SPECIFICATIONS:
• Input Voltage: 260-420 vdc
• Output Voltage: 11-15.5 vdc
• Output Current: 135 Amperes
• Output Power: 2000 watts
• Dimensions: 13” X 9” X 3.5”
• CAN data rate: 500 kbps

If the Spark EV shares this same unit, then there are our numbers.
I, too, am interested in this type of project...after Irma went through Ga. and took power away for 3 days...

-Bob K.

Here is a link to something I found on the Bolt Forum that might help answer some of the questions for this topic - http://www.evextend.com/Emergency-Power-Kit.php.

Personally, I do not see why, in an emergency situation, it would not be better to have a 2 kWh, pure sine-wave, Honda generator. Once the EV's HV battery is depleted, you have a dead EV meaning you have no means of transportation and no power source for your inverter. Using a generator means you can power your needs without using an inverter and, with the generator properly connected to earth ground, you could use the L1 EVSE that came with your EV to charge it. I have two 1-kWh Honda generators that can be paralleled for a total 2 kWh [actually about 1.8 kWh running under a load]. If needed, my pickup truck's 25 gallon fuel tank could be used to provide additional fuel for the generators. I have actually used these generators during power outages and they worked great. When the power failed, I was able to run lights,a TV and the furnace.
 
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