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Discussion Starter #1
So what happens if the 12V battery goes down over night? Does the ICE auto start to recharge it as well as the traction battery? Or should I bring along a small jump box as well?

I'm about to set off on a 2 week trip tomorrow, and I will be bringing a small 12VDC refrigerator with me (actual compressor fridge, not one of the thermoelectric style jobs, and it is intended to be run off 12VDC. I'm not running a dorm fridge off an inverter). I can run the fridge off a Group 24 industrial deep cycle battery for over 24 hours easy, but I don't know how long the little 12V battery in the Volt will run it....and I'd hate to be in the middle of nowhere and find out that it wasn't enough to take it through the night. The fridge draws roughly 4 to 5 amps while the compressor is running, but just like a house fridge, it cycles on and off.

I'll likely be spending at least a couple nights in dispersed camping sites, or somewhere along the road in the middle of nowhere, as opposed to camp grounds with electric, so the car won't be plugged in at night. I'll run it in Mountain Mode while driving, so I'll at least have those miles of charge, but it likely won't be a fully charged traction battery either.

From what I've been reading here, it sounds like I should be OK - the APM charges the 12V battery from the HV battery, and when the HV battery reaches zero, the ICE fires up to bring the HV battery back up (simplifying, of course. I know the HV battery never truly reaches zero, and the ICE will charge only a small bit to bring the HV back to whatever the HV is at zero miles range). I just want to make sure, as all the threads I was reading appeared to assume that the charge cord would be plugged in. I'm thinking that the HV battery should have enough capacity as well as I'll have the car in Mountain Mode the whole trip, so I'll be ending each night with ~15 miles of range. Assuming I'm not running the heat or AC, I'm thinking the HV battery will be plenty of power to run just this fridge.
 

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It's not that simple. The car will shut down on it's own if it doesn't see any driver control input after a certain period (90 minutes?) You need to finagle things to keep the car running.
 

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So what happens if the 12V battery goes down over night? Does the ICE auto start to recharge it as well as the traction battery? Or should I bring along a small jump box as well?

I'm about to set off on a 2 week trip tomorrow, and I will be bringing a small 12VDC refrigerator with me (actual compressor fridge, not one of the thermoelectric style jobs, and it is intended to be run off 12VDC. I'm not running a dorm fridge off an inverter). I can run the fridge off a Group 24 industrial deep cycle battery for over 24 hours easy, but I don't know how long the little 12V battery in the Volt will run it....and I'd hate to be in the middle of nowhere and find out that it wasn't enough to take it through the night. The fridge draws roughly 4 to 5 amps while the compressor is running, but just like a house fridge, it cycles on and off.

I'll likely be spending at least a couple nights in dispersed camping sites, or somewhere along the road in the middle of nowhere, as opposed to camp grounds with electric, so the car won't be plugged in at night. I'll run it in Mountain Mode while driving, so I'll at least have those miles of charge, but it likely won't be a fully charged traction battery either.

From what I've been reading here, it sounds like I should be OK - the APM charges the 12V battery from the HV battery, and when the HV battery reaches zero, the ICE fires up to bring the HV battery back up (simplifying, of course. I know the HV battery never truly reaches zero, and the ICE will charge only a small bit to bring the HV back to whatever the HV is at zero miles range). I just want to make sure, as all the threads I was reading appeared to assume that the charge cord would be plugged in. I'm thinking that the HV battery should have enough capacity as well as I'll have the car in Mountain Mode the whole trip, so I'll be ending each night with ~15 miles of range. Assuming I'm not running the heat or AC, I'm thinking the HV battery will be plenty of power to run just this fridge.
What year Volt are we dealing with here?
 

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Suggestions

Suggest:

  1. Use Hold from the start of the trip instead of MM if your car has it. Save the full charge on the HV battery. Only when SOC dips below 40% change to MM; you don't want the engine to cycle on in the middle of the night if not necessary. Given only a few nights, you may never dip below below 40%.
  2. Assuming you've had the update to prevent the car from staying on in Park . . . when camped, use a heavy duty rubber band to depress the button on the gearshift, and shift to Park. The depressed button will prevent the car from realizing you've shifted to Park and turning off after ~2 hrs. Select Normal mode and put the emergency brake on. Leave car ON.
  3. Lock doors if you exit the car, leaving one fob inside and use the second to lock the doors. If you don't leave a fob in the car, you'll get the dreaded triple honk when you shut the door.
  4. Connect directly to the battery by running the wires under the floor and up through the access cover on the driver's side of the trunk if possible.
 

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The 12v battery is Group 47
Capacity 20hr: 60AH

If your fridge is running while your driving you won't have issue. However, if your running it overnight you will need to leave the car powered up to maintain the 12v battery.

Use the calculator on this website to determine the recommended battery sized for the load draw.


https://www.batterystuff.com/kb/tools/calculator-sizing-a-battery-to-a-load.html

I ran yours at 5 amps for 10 hours it calculated 108AH Battery to handle the continuous load. This is assuming no continuous HV inverter charging.

The Volt Battery is 60AH.




Sent from my iPhone using Tapatalk
 

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Discussion Starter #6
What year Volt are we dealing with here?
2013, and judging from the Candian Goose volume triple honk when leaving the car, I'm assuming the auto shut down update was already applied before I bought the car.

Suggest:

  1. Use Hold from the start of the trip instead of MM if your car has it. Save the full charge on the HV battery. Only when SOC dips below 40% change to MM; you don't want the engine to cycle on in the middle of the night if not necessary. Given only a few nights, you may never dip below below 40%.
  2. Connect directly to the battery by running the wires under the floor and up through the access cover on the driver's side of the trunk if possible.
But I'll be going through/over actual mountains here. The Rocky Mountains, and several passes through Colorado to be exact. I would imagine if I'd want Mountain Mode anywhere, it would be there?

I suspect that I won't be needing the HVAC running during the over-nighters. I'll be going through Colorado, Nebraska, Wisconsin, and Michigan, so it won't be hot enough at night to need AC and I know from prior experience that my sleeping bag will keep me plenty warm enough even in sub freezing temperatures when inside a shelter at night (I was homeless, and living in my truck for a bit in the middle of a Detroit winter some years ago).

Connecting directly to the battery will not be an issue. I already have an additional fuse block that I added down there to connect my ham radio and GPS to.
 

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Discussion Starter #7
I ran yours at 5 amps for 10 hours it calculated 108AH Battery to handle the continuous load. This is assuming no continuous HV inverter charging.

The Volt Battery is 60AH.
It's not a continuous load. As I said, it's like a house fridge, but tiny - it will cycle on and off as needed to maintain temp. I don't recall what the AH rating is on my deep cycle, but going off the standards chart, it would be 70-85AH, and that battery will run the fridge for over 24 hours in the middle of a Phoenix summer day.

My suspicion is that the 12V battery would be plenty enough to run the fridge on it's own over night given that the nightly low temps I'll be seeing will be in the 40-60 degree range, but I just want to be covered just in case. If it won't be getting auto recharged off the HV battery, then I should probably carry a small jump box with me in case I draw the battery down too much at night.
 

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2013, and judging from the Candian Goose volume triple honk when leaving the car, I'm assuming the auto shut down update was already applied before I bought the car.



But I'll be going through/over actual mountains here. The Rocky Mountains, and several passes through Colorado to be exact. I would imagine if I'd want Mountain Mode anywhere, it would be there?

I suspect that I won't be needing the HVAC running during the over-nighters. I'll be going through Colorado, Nebraska, Wisconsin, and Michigan, so it won't be hot enough at night to need AC and I know from prior experience that my sleeping bag will keep me plenty warm enough even in sub freezing temperatures when inside a shelter at night (I was homeless, and living in my truck for a bit in the middle of a Detroit winter some years ago).

Connecting directly to the battery will not be an issue. I already have an additional fuse block that I added down there to connect my ham radio and GPS to.
What if you are sleeping in the car with A/C while charging, or want to leave it on indefinitely? The solution for 2014+ Volts is to clamp the gear lever closed without shifting out of park.

Link to previous post.

Step-by-step instructions for keeping a 2014+ Volt powered on indefinitely (Should work for 2012-2013 models with the recall performed [currently untested]).

Turn the Volt Off.
Plug in the EVSE (the charger) and wait for the acknowledgement honk and solid green charge light. [Note: If you are remote and without power, the Volt will cycle the engine on for a few minutes once the traction battery is depleted. You can use Mountain Mode to charge up the battery if you know you are going to be without power at your destination. Half a battery will get you through the night with the A/C running and still have power to spare.]
Press the brake petal and push the Power button to power up the car like normal. A message will display alerting you that the charge cable is connected and the Volt will prohibit you from shifting out of park.
The lights will still auto-on if dark. Simply switch them off on the stalk like normal.
Clamp the shift lever button closed (as if you were going to shift out of park) to keep the car power up beyond the 150 minute limit.
Enjoy unlimited AC/Heat/Radio/12v Accessory power while your Volt continues to charge. Perfect for camping, mobile office, using with an inverter.


Last edited by saltsman; 03-12-2015 at 03:01 PM.

You can't charge in N and leaving the car in neutral, even with parking break on, could be dangerous on a hill or inclined surface. Clamping the gear selector closed looks to be a bit safer.

The above solution was originally designed for this of us who camp in the Volt at campgrounds with power. Also works for inverter use without power. The Volt makes an amazing mini-RV as long as you can keep the car powered up.

http://gm-volt.com/forum/showthread.php?162762-Auto-Off-Recall-for-All-2011-2013-Volts/page6

I like the clamp solution as it solves your issues, just have plenty of gas and you will be set for as long as you want. Enjoy your trip. As an aside note, I would have a battery booster like a Noco Genius, just in case...

The link above is a LONG discussion about this if you want to read over it.
 

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So what happens if the 12V battery goes down over night? Does the ICE auto start to recharge it as well as the traction battery? Or should I bring along a small jump box as well?
The Volt only requires the 12V AGM battery to be connected in order to initially turn it ON. Once the Volt is successfully started and as long as the 14V APM is providing voltage correctly , you can then remove the 12V AGM from the circuit by lifting the negative lead off of the 12V AGM battery terminal and the Volt can be driven around normally and won't latch any CEL warnings either (at least my Gen1 acts this way). Granted, if you were then to shut OFF the Volt with the 12V AGM still disconnected you would be unable to turn it back ON until you were to reconnect the 12V AGM once again.

As srmarti pointed out, the auto-off timer 'feature' added to Gen1s during the reprogram of the K9 BCM as part of the N140617 recall prevents the Volt from being left on overnight w/o some form of intermittent action to reset the timer and prevent the inevitable shut-off. Some folks have used the workaround of keeping the gear shift button depressed to prevent the shut-off. I instead chose to install a simple Pushbutton Mod to in order to be able to bypass on-the-fly this timed Auto-Off 'feature': Pushbutton Mods to Enable/Disable Triple-Honk Vehicle ON Warning and Auto-Off recall

Having a small jump pack avail as you mentioned is also a good idea especially since it could be used in lieu of the 12V AGM in order to turn the Volt ON: Small & Cheap lithium-ion replacement for the 12V AGM battery
 

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Discussion Starter #10
What if you are sleeping in the car with A/C while charging, or want to leave it on indefinitely? The solution for 2014+ Volts is to clamp the gear lever closed without shifting out of park.
This is part of what I had said before - that all these posts are assuming the car will be plugged in at night. When I'm sitting somewhere in the middle of the San Juan Forest between Silverton and Ouray, I'm not going to have electric to plug into, unless someone has figured out how to get 120VAC out of a tree, lol.

I'm wondering what happens when I'm NOT plugged in, sitting with the car on, and a 12 volt accessory is connected somewhere that potentially will pull enough juice to drain the 12V battery in the hatch. I don't know if the fridge will pull it down enough to be an issue or not.

The Volt only requires the 12V AGM battery to be connected in order to initially turn it ON. Once the Volt is successfully started and as long as the 14V APM is providing voltage correctly , you can then remove the 12V AGM from the circuit by lifting the negative lead off of the 12V AGM battery terminal and the Volt can be driven around normally and won't latch any CEL warnings either (at least my Gen1 acts this way).
I would imagine that the car expects somewhere in the neighborhood of 12 volts to fire up though? How low can the voltage be and still start the car?
 

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I'm wondering what happens when I'm NOT plugged in, sitting with the car on, and a 12 volt accessory is connected somewhere that potentially will pull enough juice to drain the 12V battery in the hatch.
As long as your Gen1 stays turned ON (auto-off bypassed), it would be near impossible to flatten the 12V AGM unless the 14V APM is defective since the 14V APM is capable of supplying up to 180 Amps of 12 volt DC according to the service manual!;)


I would imagine that the car expects somewhere in the neighborhood of 12 volts to fire up though? How low can the voltage be and still start the car?
As I posted in my previously linked thread, I was still able to start my Gen1 with only @10VDC left in the small lithium-ion battery pack. Once it dropped below <10VDC, no joy.:(
 

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Detroit, you seem to missing what actually happens here. You don't have to be plugged in. You simply have to leave the car on. If you don't do the "push" on the stick, the car will shut off after 150 minutes. This allows the car to stay on and keep the 12 volt battery charged.
 

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If you run the battery down, you shorten the life of the battery, which is a bad idea.

Leave the car powered on, absolutely.
 

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Discussion Starter #14
Detroit, you seem to missing what actually happens here. You don't have to be plugged in. You simply have to leave the car on. If you don't do the "push" on the stick, the car will shut off after 150 minutes. This allows the car to stay on and keep the 12 volt battery charged.
Yes, you are absolutely correct - I wasn't fully understanding how this stuff works, which is why I was asking for clarification :)

Heck, up until today, I didn't even realize there was a APM module, or DC-DC converter. I was under the impression that there was a separate 12 volt generator inside the transmission that was spun by either the electric motors or the ICE, and that was what was charging the 12V battery. Obviously, I was wrong about that one too, lol. But after reading a bunch of threads, mainly about people sleeping in AC bliss while it was 95 degrees outside, AND charging the car too, I was even more confused on whether I could do what I was planning.

So in short, I arrive at my destination, clamp down the shifter button, shift to park, apply parking break, leave car on. HV battery will keep 12V battery charged through APM, and if HV battery depletes, ICE will fire up to recharge HV battery. Rinse, lather, repeat?
 

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You got it ;) As a precaution, I would check after the 150 minute window just to make sure all is well. I would also keep a small battery boost like a Noco Genius as a back up just in case (I actually keep one in the car at all times). Enjoy your trip
 

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But I'll be going through/over actual mountains here. The Rocky Mountains, and several passes through Colorado to be exact. I would imagine if I'd want Mountain Mode anywhere, it would be there?

I suspect that I won't be needing the HVAC running during the over-nighters. I'll be going through Colorado, Nebraska, Wisconsin, and Michigan, so it won't be hot enough at night to need AC and I know from prior experience that my sleeping bag will keep me plenty warm enough even in sub freezing temperatures when inside a shelter at night (I was homeless, and living in my truck for a bit in the middle of a Detroit winter some years ago).
It sounds as if you think MM provides some additional power above what a fully charged traction battery can provide for the mountains . . . it doesn't. It is just a set point for the buffer at 40% SOC. You want the set point to be at 100% SOC which is what Hold will do if you turn it on at the start. If you forget to use Hold and your traction battery drops below 40% SOC, MM has the added advantage of being able to rebuild the SOC to 40%. That's why my original recommendation was to use MM only if/when the SOC drops below 40%.

As firehawk72 suggested, you are missing the point on why you want to keep the car turned ON. It's not to run HVAC or radio, it is to allow the dc-to-dc converter to continuously uphold the charge on the 12v battery. You will in essence be running off the giant traction battery, not the limited capacity of the 12v.

Edit: I guess I type too slowly. You obviously have it now.
 

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Discussion Starter #17 (Edited)
It sounds as if you think MM provides some additional power above what a fully charged traction battery can provide for the mountains . . . it doesn't. It is just a set point for the buffer at 40% SOC. You want the set point to be at 100% SOC which is what Hold will do if you turn it on at the start. If you forget to use Hold and your traction battery drops below 40% SOC, MM has the added advantage of being able to rebuild the SOC to 40%. That's why my original recommendation was to use MM only if/when the SOC drops below 40%.

As firehawk72 suggested, you are missing the point on why you want to keep the car turned ON. It's not to run HVAC or radio, it is to allow the dc-to-dc converter to continuously uphold the charge on the 12v battery. You will in essence be running off the giant traction battery, not the limited capacity of the 12v.
I was planning on leaving the car turned on anyways (though I may not have been clear in the way I wrote things). I just didn't know if the ICE would still automatically turn on if both the traction battery AND the 12V battery became discharged without having the car plugged in...such as if I forgot to use Hold or MM, and stopped for the night with the traction at 0%SOC and then ran the 12V too low with the fridge running.

I thought the Hold mode wouldn't allow the car to consume any extra battery juice when climbing the steep grades, which is why I would use MM - so both the engine AND battery power would be used to keep the car moving at speed up the grades? Does this happen in Hold mode as well?
 

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Yes, you are absolutely correct


Yea, you got it now. Assuming you plugged the fridge into one of the 12v sockets and the car is accessory mode, it shuts off after about 10 minutes. You have to leave the car on to get power longer than 10 minutes. The car will still shut itself off after about 150 minutes. That's what holding the gear shift button in (others have propped the brake pedal I think) gets around it. Fools the safety feature designed to keep people from getting CO poisoning by forgetting to turn the car off when parked in the garage.
 

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I was planning on leaving the car turned on anyways (though I may not have been clear in the way I wrote things). I just didn't know if the ICE would still automatically turn on if both the traction battery AND the 12V battery became discharged without having the car plugged in...such as if I forgot to use Hold or MM, and stopped for the night with the traction at 0%SOC and then ran the 12V too low with the fridge running.

I thought the Hold mode wouldn't allow the car to consume any extra battery juice when climbing the steep grades, which is why I would use MM
[ quote]

The car will pull what's necessary from the battery (even at "zero charge remaining" there's still a buffer. Use up that and it will go to reduced power mode) and the engine will just continue to run until the SOC builds back up to the set point whether that's HOLD or MM.
 

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If I recall correctly, the HV to 12v battery charging is done differently with later Gen1s than early models. This may affect what you are trying to do. You will have to search to find the details, I can't do it for you right now.
 
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