GM Volt Forum banner

1 - 20 of 29 Posts

·
Registered
Joined
·
294 Posts
Discussion Starter #1
I have a 2018. I rarely run the high voltage battery to empty since my daily commute only use just half of it. As I have charging at work, I am never close to empty.

Should I deplete it and charge from there? If so, how often do I need to do this? Does this really help maintain the battery life to last as long as it should?

The manual says to keep it charged even when it is full, especially at extreme temperatures, it doesn't answer my question.

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

·
Registered
Joined
·
4,766 Posts
I have a 2018. I rarely run the high voltage battery to empty since my daily commute only use just half of it. As I have charging at work, I am never close to empty.

Should I deplete it and charge from there? If so, how often do I need to do this? Does this really help maintain the battery life to last as long as it should?

The manual says to keep it charged even when it is full, especially at extreme temperatures, it doesn't answer my question.

"Vehicle Charging/Maintenance
Charging
Keep the vehicle plugged in, even
when fully charged, to keep the
battery temperature ready for the
next drive and prolong battery life.
This is important when outside
temperatures are extremely hot
or cold."
No need to ever discharge the battery more than your normal driving would anyway. The only caveat is for long term storage of the Volt when it is not being driven. You can choose to charge your Volt every day or every other day. There might be some reduced wear and tear on the EVSE and charging port if you only charge every other day but this would be negligible. Eventually the charging port and or the EVSE is going to wear out and need replacement. Nothing lasts forever.
 

·
Registered
Joined
·
2,499 Posts
About once a month I take mine outside the range so it gets an occasional stretch and the ICE gets used to prevent EMM or old gas. I don't use it every day maybe two to three times a week, charge it up then disconnect and let it sit. It always says fully charged when I go to use it. Since it pretty much looks after itself, I think once a month is fine although there are no indicators from GM.
 

·
Registered
Joined
·
1,340 Posts
...
Should I deplete it and charge from there? If so, how often do I need to do this? Does this really help maintain the battery life to last as long as it should?
There's a pesky myth out there that says you need to fully cycle a battery for health. THIS IS NOT TRUE, especially for lithiums (IIRC it may have been true for some early NiCd that had a "memory effect"). In cell phones and laptops, I believe an occasional full cycle may make the run-time estimate more accurate, as the battery controller can track its performance as the voltage drops during the cycle. It's possible this is somewhat true on Volts. But again that's for range estimate, not actual battery health. There is very little difference to battery health in doing 3 33% discharge trips vs 1 100% trip (as long as the state-of-charge window for that 100% is restricted a bit from the cells' true 0-100%), indeed the 3 trips is likely more benign. So don't worry about it!
 

·
Registered
Joined
·
605 Posts
When I got my 2017, I bought it used with 19,000 miles on it. The previous owner appears to have used it mostly as a gas vehicle and rarely charged it. When I gave it the first full charge, it had an estimated range of 43 miles while my data was showing I was averaging 4 miles per kWH. Doing the math, 4 miles per kWH x 14 should be 56 miles of range.

OK, so I figured it'd sort itself out after a few charge cycles. I drove it a half dozen times but never drove it below about 40% battery level, then charged back up again. The estimated range stayed at 46 miles or below. Then one day I decided to intentionally drive it to empty and after doing this, I noticed that the total kWH used was 12.6 kWH. I knew it should be 14.0 to 14.1. After running it to empty that one time, it started displaying 56 miles of estimated range. I drove it all the way to empty again and got 14.0 kWH used.

So at least from my perspective, it looks like driving it to empty does at least help it "recalibrate". After that initial "recalibration", I now drive it to empty about once a month and I always get between 14.0 and 14.2 kWH used (the battery window capacity). Guess-o-meter estimate is always between 58 and 63 miles: I'm in FL and take the same general routes so it never changes.

Mike
 

·
Registered
Joined
·
13,683 Posts
There's a pesky myth out there that says you need to fully cycle a battery for health. THIS IS NOT TRUE, especially for lithiums (IIRC it may have been true for some early NiCd that had a "memory effect"). In cell phones and laptops, I believe an occasional full cycle may make the run-time estimate more accurate, as the battery controller can track its performance as the voltage drops during the cycle. It's possible this is somewhat true on Volts. But again that's for range estimate, not actual battery health. There is very little difference to battery health in doing 3 33% discharge trips vs 1 100% trip (as long as the state-of-charge window for that 100% is restricted a bit from the cells' true 0-100%), indeed the 3 trips is likely more benign. So don't worry about it!
Completely agree. Let the car take care of matters all by itself. Don't purposely drain the battery if you don't have to. Conversely, I drain my battery daily on my 50 mile round trip commute except on rare occasions where I can park at a spot 2 blocks from work. On cold icy days or humid hot days, I prefer to park close by and not deal with the walk. Then most of the time, someone else beats me to the spot.

Again, for cellphones and laptops, Apple recommends draining it at least once a month, but the Volt is different. You will never fully charge nor drain it completely. Both are restricted to give you extra long battery life. Just drive it, forget that it's an EV, and enjoy the ride
 

·
Registered
Joined
·
2,499 Posts
There's a pesky myth out there that says you need to fully cycle a battery for health. THIS IS NOT TRUE, especially for lithiums (IIRC it may have been true for some early NiCd that had a "memory effect"). In cell phones and laptops, I believe an occasional full cycle may make the run-time estimate more accurate, as the battery controller can track its performance as the voltage drops during the cycle. It's possible this is somewhat true on Volts. But again that's for range estimate, not actual battery health. There is very little difference to battery health in doing 3 33% discharge trips vs 1 100% trip (as long as the state-of-charge window for that 100% is restricted a bit from the cells' true 0-100%), indeed the 3 trips is likely more benign. So don't worry about it!
It was true for the Ni metal hydride that came after as well. I had a battery charger (made by a company that made batteries) and it had a feature to safely discharge the battery then automatically charge it to full whereby you could leave them in the charger to "maintain" them if you wanted. They recommended doing this every time for NiCads and every tenth time for NiMetalHydrides. Now you can't do that with Li ion because they don't like to be run empty or charge to full as the car only uses the center charge area. I suspect there is a natural law of physics somewhere about this center section that says "use it or lose it". I read somewhere (here?) GM expects 6,000 charges per battery. Is that 6,000 partial (half) charges or 6,000 full charges. If the later it would make more sense to charge every other day if your daily trips were half battery ones? Or is it worse to let your car stand a day on half a charge? Or does anybody know the answer to that (including GM)?
 

·
Registered
Joined
·
514 Posts
IMO (and that's all it is) draining it once every few months will recalibrate things and make the range estimates more accurate. Certainly doesn't hurt anything to either do so or not though. GM anticipated that owners would regularly run out of battery range and fully recharge pretty frequently, but driving it 100% of the time as a pure EV and never running it empty doesn't hurt it either

Don
 

·
Registered
2017 Volt Premiere
Joined
·
390 Posts
As the NiMH Insight battery aged, it would need maintenance due to the cells becoming unbalanced. After you hooked up the wiring harness (a one-time procedure), you could attached a light bulb socket. The discharge procedure was to go from a 200 watt bulb to a 50 watt bulb to a 25 watt bulb keeping each bulb in the socket until it went dark. Then you'd remove the light bulb socket from the harness and attach the trickle charger which would slowly recharge the battery so the cells would be re-balanced.

Fun times.

At the end, I needed to perform this procedure about every other month. The car was way out of warranty and Honda's stock of replacement batteries was notoriously bad as they had been sitting on a shelf way longer than was good for them. The only option was a $2,000 aftermarket battery.

Based on Chevy's track record, I don't think that I'll need to repeat that level care on the Volt battery.
 

·
Registered
Joined
·
194 Posts
It was true for the Ni metal hydride that came after as well. I had a battery charger (made by a company that made batteries) and it had a feature to safely discharge the battery then automatically charge it to full whereby you could leave them in the charger to "maintain" them if you wanted. They recommended doing this every time for NiCads and every tenth time for NiMetalHydrides. Now you can't do that with Li ion because they don't like to be run empty or charge to full as the car only uses the center charge area. I suspect there is a natural law of physics somewhere about this center section that says "use it or lose it". I read somewhere (here?) GM expects 6,000 charges per battery. Is that 6,000 partial (half) charges or 6,000 full charges. If the later it would make more sense to charge every other day if your daily trips were half battery ones? Or is it worse to let your car stand a day on half a charge? Or does anybody know the answer to that (including GM)?

To first order it doesn't matter. If you are a little bit paranoid like me, keep it at low charge. Li-ion batteries age when kept at higher charge. They age even faster with high charge + high temperatures. They also fail when charge level goes too low. The car will never let this happen unless stored with zero charge (on odometer) for a very long time (months). I keep the charge low and even start charging late at night so it is ready right before I leave. This way I keep the time it sits at full charge as short as possible. When I won't drive it for some time, usually this is 3 weeks at most for me, I keep it at around %20-30 charge. This should extend my battery's life.

One thing to note is the temperature. Heat is the #1 enemy of the battery. It shouldn't get hot regardless of the charge level. With an empty battery it will not start active cooling. So if you live in desert treat it accordingly.
 

·
Registered
Joined
·
4,766 Posts
To first order it doesn't matter. If you are a little bit paranoid like me, keep it at low charge. Li-ion batteries age when kept at higher charge. They age even faster with high charge + high temperatures. They also fail when charge level goes too low. The car will never let this happen unless stored with zero charge (on odometer) for a very long time (months). I keep the charge low and even start charging late at night so it is ready right before I leave. This way I keep the time it sits at full charge as short as possible. When I won't drive it for some time, usually this is 3 weeks at most for me, I keep it at around %20-30 charge. This should extend my battery's life.

One thing to note is the temperature. Heat is the #1 enemy of the battery. It shouldn't get hot regardless of the charge level. With an empty battery it will not start active cooling. So if you live in desert treat it accordingly.
That's interesting. On the following forum thread, in post #39, the author states their belief that there is no active TMS battery cooling when the Volt is not plugged in. https://gm-volt.com/forum/showthread.php?324979-Battery-TMS-in-Action-on-a-Very-Hot-Day&p=4596417#post4596417
 

·
Registered
Joined
·
3,723 Posts
I don't worry about how often I use up the complete battery charge. My opinion is GM implemented a comprehensive system to maintain battery health and there's little to be gained trying to overthink or outthink the system. I just drive it and plug it in regardless of the charge level. If it gives you a warm fuzzy feeling that periodically depleting the charge is good for the battery, go ahead a do it. I think it's not likely to make a measurable difference one way or the other.

On the other hand, not keeping the battery fully charged might mean you'll need to burn more gas if you don't have sufficient charge for an unplanned for trip; still not a big deal I guess.
 

·
Administrator
Joined
·
20,231 Posts
Of the factors affecting the kWh used display, a charge routine of always recharging the car before the battery is completely drained (i.e., topping-off) seems the most common way the "kWh used" display can become distorted. To reset the display, drive the Volt until the battery is fully depleted, give it a full recharge, then repeat this process a few more times. The kWh used display will likely slowly skew back to more realistic values approximating the numbers you were originally seeing when the car was newer. This has proven to be the case in a number of cases reported here on gm-volt.com.

Check out this story on the "tale of two volts": https://gm-volt.com/2013/02/26/a-tale-of-two-volts-the-summary/
 

·
Registered
Joined
·
194 Posts

·
Registered
Joined
·
1,265 Posts
In this post, the author claims that batteries can get lazy and it's a good idea to aggressively accelerate and use heavy regen for a few cycles--drive it like a teenager.

https://gm-volt.com/forum/showthrea...ences-between-two-Volts&p=4566298#post4566298

I haven't tested it, because I'm aways trying to maximize my range to make my 54-mile round trip commute totally EV. Unfortunately, it's mostly highway so I can only make it a few months out of the year when temps are ideal.

Would be curious if others have tried that out to see if it helps.
 

·
Registered
Joined
·
241 Posts
...Should I deplete it and charge from there? If so, how often do I need to do this? Does this really help maintain the battery life to last as long as it should?

The manual says to keep it charged even when it is full, especially at extreme temperatures, it doesn't answer my question.
Uh, I think it did answer your question.:p
If there was something else required, I'm pretty sure they'd have added it to the manual.
Don't overthink any of this. The designers got paid to do that, and after eight years, they've proven they knew what they were doing!
 

·
Registered
Joined
·
1,389 Posts
And remember.... the Volt never lets the battery get charged to actual 100% and never lets it get discharged to actual 0%. What you use while driving and see in the instrumentation is the working charge that is buffered by software to protect the battery.
 

·
Registered
Joined
·
294 Posts
Discussion Starter #18
I am happy to not worry about doing this manual battery maintenance. However, the guess-o-meter is reporting larger than before EV miles now. I have driven about 2000 miles. When I bought it, the EV miles were reported right around 53-54. Now it is reporting 70! Is that because the battery already needs to be recalibrated, like some folks already mentioned to bring the number back down to what it is actually capable of?
 

·
Registered
Joined
·
4,766 Posts
I am happy to not worry about doing this manual battery maintenance. However, the guess-o-meter is reporting larger than before EV miles now. I have driven about 2000 miles. When I bought it, the EV miles were reported right around 53-54. Now it is reporting 70! Is that because the battery already needs to be recalibrated, like some folks already mentioned to bring the number back down to what it actually capable of?
No, it is because the Volt adjusted the estimate EV range based on your driving history. You are driving efficiently so the estimated range has gone up. If you continue to drive the same route and pattern it will stay the same or continue to rise, at least until the weather cools. Then you will experience a drop in EV range that is beyond your control.
 

·
Registered
Joined
·
294 Posts
Discussion Starter #20
Glad to hear! My follow up question is: what is the max EV miles that Volt can go under ideal conditions? The total energy must be conserved and it can't keep increasing its capacity, right?
 
1 - 20 of 29 Posts
Top