GM Volt Forum banner

1 - 20 of 29 Posts

·
Registered
Joined
·
39 Posts
Discussion Starter #1
After one month of ownership I've got questions regarding the electricity draw when my volt is plugged in and fully charged. With my driving habits, I could probably charge my volt every other night using my standard household outlet. This first month, I plugged my Volt in every night as recommended, and my first electricity bill revealed a significant increase in usage.

Now, it's just my first month, and I can't really say how much my Volt has consumed, but $50 more on my bill for 800 miles of driving has me wondering how much electricity I am using after the volt is fully charged.

Should I bother to charge overnight if I've only driven 20 miles and have a similar commute the following day?
 

·
Registered
Joined
·
2,130 Posts
After one month of ownership I've got questions regarding the electricity draw when my volt is plugged in and fully charged. With my driving habits, I could probably charge my volt every other night using my standard household outlet. This first month, I plugged my Volt in every night as recommended, and my first electricity bill revealed a significant increase in usage.

Now, it's just my first month, and I can't really say how much my Volt has consumed, but $50 more on my bill for 800 miles of driving has me wondering how much electricity I am using after the volt is fully charged.

Should I bother to charge overnight if I've only driven 20 miles and have a similar commute the following day?
Your charge pattern is an individual decision. You do not need to plug in every night. GM recommends leaving the car plugged in if you experience extreme temps either way on the thermometer. Since the Volt is not a pure EV, ABC (Always Be Charging) isn't required.

If charging every other night works for you and keeps you on EV during the entire commute, feel free to continue that schedule. It's what works best for YOU and not what the interweb says that matters :)
 

·
Registered
Joined
·
133 Posts
I don't know where you live in Florida, but where I live power supplied by Duke Energy isn't cheap but still a littler cheaper than using gasoline at current prices. If you are charging on a 120 volt circuit, you can buy a "Kill-a-Watt" device and plug the Volt EVSE into it. You can program your electric costs into the device and monitor the actual power and electric costs used by the Volt. There are too many variables to consider to say that the Volt added X amount of cost to my utility bill.
 

·
Registered
Joined
·
34 Posts
I also have one month of ownership (30 days today as a matter of fact) I receive my first full month power bill on the 19th, but I already have a pretty good idea what the increase will be. I am in similar situation as you. My commute is not quite doable on one charge, but I am able to charge for free at work, so I have been doing that and then topping at home overnight for a full charge in the AM. I have calculated my morning commute at several different speeds and now realize I only need about 2KWh overnight at home to make it here (I have been using about 6KWh to top it off at night) After I get the first bill, I will probably start using only the 2KWh nightly which should save me about 200KWh monthly on my home bill. With a ridiculous 38 cents per KHh here in San Diego on SDGE, that should save me about some $.
 

·
Registered
Joined
·
39 Posts
Discussion Starter #5
I don't know where you live in Florida, but where I live power supplied by Duke Energy isn't cheap but still a littler cheaper than using gasoline at current prices. If you are charging on a 120 volt circuit, you can buy a "Kill-a-Watt" device and plug the Volt EVSE into it. You can program your electric costs into the device and monitor the actual power and electric costs used by the Volt. There are too many variables to consider to say that the Volt added X amount of cost to my utility bill.
Great suggestion. Just ordered a kill-a-watt device which should answer my question.
 

·
Registered
Joined
·
44 Posts
I was just about to chime in about using a Kill-a-Watt meter also, as I have. In my experience, during temperate weather, I found no additional power was used after reaching 100% charge. Zero watts. No vampire draw at all. My JuiceBox Pro 40 EVSE also reports 0.00 kW usage when charge is complete. Maybe the solid green "charged" LED draws a few mW.

Now in winter time there may a couple hundred watts occasionally cycling to keep the battery pack at ideal temp for departure. Doesn't sound like that would impact you based on your location. So I would argue that you are not saving any cost by only charging every other day, just consuming twice as much half as often. Assuming you charge immediately after driving, there should be minimal ramp-up current used to get the battery pack to charging temps.
 

·
Registered
Joined
·
39 Posts
Discussion Starter #7
I was just about to chime in about using a Kill-a-Watt meter also, as I have. In my experience, during temperate weather, I found no additional power was used after reaching 100% charge. Zero watts. No vampire draw at all. My JuiceBox Pro 40 EVSE also reports 0.00 kW usage when charge is complete. Maybe the solid green "charged" LED draws a few mW.

Now in winter time there may a couple hundred watts occasionally cycling to keep the battery pack at ideal temp for departure. Doesn't sound like that would impact you based on your location. So I would argue that you are not saving any cost by only charging every other day, just consuming twice as much half as often. Assuming you charge immediately after driving, there should be minimal ramp-up current used to get the battery pack to charging temps.
You may be right. I would actually prefer to plug it in every night just to have the fully charged vehicle in case I unexpectedly needed to drive.
 

·
Registered
Joined
·
3,396 Posts
Unless it's >~25C or <~4C ambient (ranges where it might decide to add or remove heat to maintain battery temp), volt shouldn't use any* power once charge is complete.

*It may use a tiny amount to top up the 12V battery, if required. But negligible compared to the amount used for charging the main battery.
 

·
Registered
Joined
·
6,661 Posts
I pay 6.5 cents per kW 11 with all taxes etc. I also installed a Level II EVSE and my Volt is plugged in when ever it's in the garage 24/7 day in day out. I average 8500 miles per year as a DD and my electric bill went up about $25 a month sometimes more, sometimes less.

I got rid of a 20 year old fridge I had in the garage for drinks and was blown away how much it used, easily $30 a month. It more than covers my electricity bill for my Volt so I guess you could say I'm driving for FREE. OH and I'm averaging over 93% electric on the three Volts I have owned since 2012.
 

·
Registered
Joined
·
1,992 Posts
Does a gas car use more fuel if you fill it up every day, at half a tank or on empty? And what does your manual say? Mine says:

Charging
Keep the vehicle plugged in, even
when fully charged, to keep the
battery temperature ready for the
next drive. This is important when
outside temperatures are extremely
hot or cold.
 

·
Registered
Joined
·
39 Posts
Discussion Starter #11
Does a gas car use more fuel if you fill it up every day, at half a tank or on empty?
Thanks for that snarky answer that has no bearing on this discussion.

You cannot deny that an electric car plugged into the wall outlet when fully charged still has the ability to use electricity and cost me money.

I read the manual. Now I'm trying to figure out how much electricity a plugged in and fully charged Volt uses. I guess I will find my answer when I plug into the Kill-a-watt device.
 

·
Registered
Joined
·
1,109 Posts
With my OEM 120V EVSE, I was drawing 2.5w from the plug on a fully charged battery. I suspect that was just parasitic draw to keep the EVSE powered on, however I could hear the relay inside the EVSE click on when I would precondition the vehicle and it would draw about 1KW for that with moderate (70-80F) ambient temps.
 

·
Registered
Joined
·
5,782 Posts
My ELR uses so little electricity compared to the total that it's not even worth accounting separately.

Letting go of the seldom-used 'garage refrigerator' named by someone above saved me WAY more than ELR ever uses. I also got a SEER 16 HVAC, LED bulbs everywhere (that saved a ton when I replaced those 90w bulbs with 11w!), and efficient appliances like washer/dryer/dishwasher, and a complete attic insulation package. So, over all, I'm using less electricity than before I got the Volt and subsequent ELR.
 

·
Registered
Joined
·
1,992 Posts
Thanks for that snarky answer that has no bearing on this discussion.

You cannot deny that an electric car plugged into the wall outlet when fully charged still has the ability to use electricity and cost me money.

I read the manual. Now I'm trying to figure out how much electricity a plugged in and fully charged Volt uses. I guess I will find my answer when I plug into the Kill-a-watt device.
Just saying it takes as much to put back 1kWh per day as it does to put 2kWh in one day. The TMS would use very little after the initial charge and cooling/heating unless it was extremely cold or extremely hot climate. It which case you would want it plugged in anyway.

So in essence we are talking about pennies.

I drive about 1500 miles per month per car. My electricity costs per car averages about $30. I keep both plugged in whenever they are not in use. Can't imagine a significant savings by only plugging in sometimes. The added benefit is having a full charge on the off chance you need it. And not having to worry with it.

There are plenty of posts about how much it costs to charge and how much is used to recharge and run the TMS. Take a look at one of those and replace your electricity costs per kWh with theirs. In the end it will not be a significant difference than what you will measure.

In fact, the cost of the device to measure your usage will likely be more than the extra electricity used to run the TMS over a couple of years.
 

·
Registered
Joined
·
354 Posts
I can't remember for sure where I found the information, but I think the battery charger will lose less power charging on 240v than it does with 120v wall outlet charging. So if the charger is 86 percent efficient, then 10kWh of charge really takes 11.4 kWh from the utility. I would recommend patching the included portable evse to 240v from a dryer outlet as just the fact that you can charge in 4 to 5 hours is worth it just for the time savings.

I don't think the evse delivers any power once the battery has reached full charge. I have gone out to the meter to see before. Also, an led light draws only 15-20ma at about 2 volts so I think the dash light indicator is an insignificant power draw (.04 watts or .24w if you calculate on 12v drop on a resistor).
 

·
Registered
Joined
·
89 Posts
I'm on 240 charger at home, but used to use a kill-a-watt for my CMax. Never noticed it drawing current after fully charged. On my Volt with the 240 charger, there's nothing that suggests parasitic draw either.

Whether the Volt costs you a few pennies a week being left plugged in or not isn't going to matter the first time you decide you need to detour on some morning to work and end up burning gasoline because you didn't top off the battery overnight. You'll pay for those lost electric miles with much more expensive gasoline. Why take the risk?

Sent from my Nexus 6 using Tapatalk
 

·
Registered
Joined
·
1,109 Posts
I can't remember for sure where I found the information, but I think the battery charger will lose less power charging on 240v than it does with 120v wall outlet charging. So if the charger is 86 percent efficient, then 10kWh of charge really takes 11.4 kWh from the utility. I would recommend patching the included portable evse to 240v from a dryer outlet as just the fact that you can charge in 4 to 5 hours is worth it just for the time savings.
You are correct, 240V will use slightly less electricity than 120V due to the efficiency at running higher voltages. We're probably only talking somewhere on the order of a hundred watts or so total throughout a full charge cycle, but over several of them, the savings can add up.
 

·
Registered
Joined
·
926 Posts
Friendly reminder, be careful with those power measurement pass-through devices. I had one that was a bit warm on 8A charging. I wouldn't feel comfortable using it on 12A charging.
 

·
Registered
Joined
·
1,109 Posts
Friendly reminder, be careful with those power measurement pass-through devices. I had one that was a bit warm on 8A charging. I wouldn't feel comfortable using it on 12A charging.
I certainly wouldn't recommend using it all the time, but just occasionally to monitor usage might be ok.
 
1 - 20 of 29 Posts
Top