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Discussion Starter #1
Before posting, I read a few of the other posts on the site about degradation. However, I couldn't figure out a good search term for my question, which is really kind of two parts.
First, I have noticed that I seem to be switching over to the gas motor a little earlier lately, maybe around 11.7kwh (or whatever the proper units are). I'd have to go back through old posts to find out what my 'new' capacity was, but lets just assume 12.3. So 6 tenths isnt a huge amount, 5%, but that seems to be a bit much for 2 years and 20k miles. What I'm wondering is if maybe that amount would correspond well so say maybe having one (or more) 'cells' go bad (or bad connection, etc).
For example, if there were 20 'cells' and you had a sudden drop in 'capacity' of about 5%, it might lead you to believe there was something wrong with a cell/connections rather than normal degradation.
Secondly, I know there are diagnostic tests the dealer can run, but would something like a failure of a cell or a loose connection cause a DTC?
 

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I've seen my g1 volt go between 10.1 and 10.6, but the key here is that it changes on any given day. So keep watching it. If you never get over 11.7 then maybe something is going on. As for DTCs, I'd wait for WOT to give you an answer as he seems to know (works for GM).
 

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Sounds like normal variation to me.

Do you fully discharge every day? See thread "A tale of two Volts".

Unless meticulous records are kept... Saying things like "assume 12.3" tells us that we don't really know. One point on a graph is not a trend.
 

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Discussion Starter #4 (Edited)
I rarely discharge fully, so I dont really have a lot of examples of when I have seen this. I was just curious. Arguments could be made either way, so I thought I would see what an expert said. I cant get to the SandyBlogs website from work, but I do remember a techlink article on some indications of individual battery failures or connection issues.
I said 'assume 12.3' because I thought that was what I had (I dont think I have the higher capacity battery that some have) and it just provided a nice even number to get 5%. I also sometimes notice what I might characterize as a pretty quick drop to zero (a faster rate than at other times during that charge under similar conditions) the last 2-3 miles so it just adds up to curiosity. On my drive today, I pulled up to the chargepoint station with a little more than 47 miles driven on the charge, about 2 remaining and 11.4 kwh used. Some would say typical, some would say within the tolerances of the battery system accuracy, others might say its a bit off.... However, I will add that it just finished charging and according to Chargepoint it took about 13.7kwh, which is a little less (~.3 kwh) than it typically takes for a full charge.... A lot of this is splitting hairs, but I do have some good info, at least on charging, from chargepoint....
 

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I rarely discharge fully, so I dont really have a lot of examples of when I have seen this. I was just curious. Arguments could be made either way, so I thought I would see what an expert said. I cant get to the SandyBlogs website from work, but I do remember a techlink article on some indications of individual battery failures or connection issues.
I said 'assume 12.3' because I thought that was what I had (I dont think I have the higher capacity battery that some have) and it just provided a nice even number to get 5%. I also sometimes notice what I might characterize as a pretty quick drop to zero (a faster rate than at other times during that charge under similar conditions) the last 2-3 miles so it just adds up to curiosity. On my drive today, I pulled up to the chargepoint station with a little more than 47 miles driven on the charge, about 2 remaining and 11.4 kwh used. Some would say typical, some would say within the tolerances of the battery system accuracy, others might say its a bit off.... However, I will add that it just finished charging and according to Chargepoint it took about 13.7kwh, which is a little less (~.3 kwh) than it typically takes for a full charge.... A lot of this is splitting hairs, but I do have some good info, at least on charging, from chargepoint....

Just the ambient temperature can affect how much energy is required as the battery may need heating/cooling during charging. That factor alone can probably account for more than 0.3 kwh variation.
 

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I rarely discharge fully, so I dont really have a lot of examples of when I have seen this. I was just curious. ...A lot of this is splitting hairs, but I do have some good info, at least on charging, from chargepoint....
you are looking up at clouds and seeing elephants and alligators... after 3 years and 60,000 miles I switch over anywhere from 9.9 to 10.5 Kwh reported consumed (on a 2013), this varies depending on weather, driving style and even traffic, just as range does, though not by as much. this is no different than when the car was new or 1 year old or 2 years old. Sure, its possible that Cells are failing, and I don't know how many have to fail before the pack asks for service through a DTC, but I have seen no evidence of this. I think it helps to regularly run through the full available charge, but even when I go a few weeks without doing so, I don't see any difference.

Besides, if your battery did ever start to lose capacity, (it has to eventually, doesn't it?) what would your mental math be: "hmmmm.. this week I used $12.50 worth of gasoline, last year at this time I was using $10.50 worth of gas a week, is it worth my spending time worrying about my battery???....hmmmm $2.00 /week...."
 
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