Any concerns with never fully charging battery

[Kirknc]

My bolt stays between 20-60% as I use free public charging. I have a level 2 charger at home but so far am not using it. Does the battery living in that range create any concerns? What about cell balancing.
Thanks

 

[IMAdolt]

You'll here arguing to the contrary but according to all recent testing and study lithium chemistries are typically happiest in the middle of the SoC, so around 50% and un happiest at the top or bottom, so in the lower and upper 20%.

It's important to know that just how these batteries are managed isn't common knowledge and in all likelihood they have buffers built into the BMS to avoid both extreme ends of the SoC issue. Si don't worry about it.

 

[RickCH]

What about cell balancing.

On another forum, a member collected data from their Juicebox EVSE that showed cell balancing happens when hill top reserve is on and the battery reaches its "full" charge. That would be the gentlest way for the battery to get it to balance the cells.

 

[joe]

What about cell balancing.

On another forum, a member collected data from their Juicebox EVSE that showed cell balancing happens when hill top reserve is on and the battery reaches its "full" charge. That would be the gentlest way for the battery to get it to balance the cells.

can you please supply a link for this?

 

[gpsman]

Also your range is a guess. Based on math.

You can’t “weigh” the charge in your battery or put a float or dipstick in it like gasoline to see how much is left.

This is why some people call the range meter, a “Guess-o-Meter”. Chevy calls it a “Confidence Gauge”.

The guess of how many miles you have left gets worse over time if you don’t fully charge.

The only 100% confident battery charge is 100% full or 0%. Since 0% does harm, we never want that!

When you fully charge, the car corrects the confidence meter, so what you see is what you get.

My charge estimate was off by -15% after a month or two of partial charges. That is, the battery was actually 15% lower than the guess-o-meter was telling me.

So always fully charge before a long trip when you will need confidence in distance. And I think it is a good idea to charge to 100% once a month, if you can tolerate 15% error. I charge to 100% about twice a month, because I want to have lower error on my range gauge.

But everything I have read agrees with keeping the battery “in the middle” state of charge for battery health and longivity and to store it for long periods at a low (20-30%) charge. So when I do take it to 100%, I get in and drive within an hour or two so it’s not parked at 100% for very long.

Cell phone batteries are noticably weaker after 2 years. Because most of us charge them to 100% daily, and we have no easy way to stop charging our cell phones at 80% in the middle of the night as we sleep.

Of course cell phone makers are probably pleased with this 2 year life cycle so you will buy another.

 

[GetOffYourGas]

Cell phone batteries are noticably weaker after 2 years. Because most of us charge them to 100% daily, and we have no easy way to stop charging our cell phones at 80% in the middle of the night as we sleep.

Of course cell phone makers are probably pleased with this 2 year life cycle so you will buy another.

I have a 4-year-old cell phone with like-new battery life. It's not too hard to charge only to 80%. I learned that my battery charges at about 1% per minute. Easy math. You just have to remember to unplug it X minutes later. And the proof is in the pudding as they say. After years of babying my battery, it still works pretty much like new.

I charge my car at work. It charges at roughly 10% per hour. I set a timer to be done at 9pm, so when I unplug at 5pm, it is roughly 60% charged. When I get back to work the next day (after an evening of errands and a round-trip commute), it's typically at 35-40% charge. Time will tell, but I expect my battery to hold up very well over time.

I do charge to "full" (hilltop reserve) every Friday to get me through the weekend. I only charge to truly full when going on a road trip. I may change that based on your advice above.

 

[gpsman]

Cell phone batteries are noticably weaker after 2 years. Because most of us charge them to 100% daily, and we have no easy way to stop charging our cell phones at 80% in the middle of the night as we sleep.

Of course cell phone makers are probably pleased with this 2 year life cycle so you will buy another.

I have a 4-year-old cell phone with like-new battery life. It's not too hard to charge only to 80%. I learned that my battery charges at about 1% per minute. Easy math. You just have to remember to unplug it X minutes later. And the proof is in the pudding as they say. After years of babying my battery, it still works pretty much like new.

Hybrid cars ALWAYS keep their batteries in the middle. The Ford Escape Hybrid (1.6 kWh battery) was reverse engineered and the battery is ALWAYS between 40% and 56% state of charge with a couple exceptions:

On a cold start, in cold weather, programming allows battery use down to 30% as the gasoline engine and catalytic converter heat up - this is to reduce harmfull emissions. But once you hit 30%, pollution be damnned. You don’t get a watt of more power.

Going down a grade, regen is allowed AT VERY LOW WATTAGE (like 20% of normal capability) up to 80%.

Hybrid cars (if you’ve never owned one) can EV drive when their batteries have sufficent charge. In the Ford Hybrid, it would be gas only if the battery dropped below 40%. (Or 30% first start of the day.) It could EV drive between 40% and 56% but typically not. Usually this would be hybrid mode with give and take of both battery and gas in this happy zone. The more you got above 56% charge, the car would force EV driving more and more aggressively to bring the charge back down to 56% as soon as possible.

When you drive around town on mostly flat ground, the battery is always between 40% and 56%. I would imagine this is 95% of the time.

I’ve had two Hybrids last me 16 years and still going strong with the original batteries. Which are NiMH but there must be some laws of physics that make them similar, but not equal to ours.

 

[SeanNelson]

I have a 4-year-old cell phone with like-new battery life. It's not too hard to charge only to 80%. I learned that my battery charges at about 1% per minute. Easy math. You just have to remember to unplug it X minutes later.

I was planning to do this with my new Galaxy S7 - bit Android Auto has done an end run around that plan. I have to plug the phone in to use it, and by the time I finish driving it's usually reached the 100% charge level.

 

[GetOffYourGas]

I have a 4-year-old cell phone with like-new battery life. It's not too hard to charge only to 80%. I learned that my battery charges at about 1% per minute. Easy math. You just have to remember to unplug it X minutes later.

I was planning to do this with my new Galaxy S7 - bit Android Auto has done an end run around that plan. I have to plug the phone in to use it, and by the time I finish driving it's usually reached the 100% charge level.

Good point. I have the same challenge with Apple CarPlay; the phone has to be plugged in and is therefore charging. It would be nice if Android/iOS offered a built-in means to force the phone to stop charging at 80%.

 

[gpsman]

Re: the phones:

Does anyone know if the data and power to charge use different pins/wires?

Maybe you could break the pin/wire for positive voltage and data would still flow? Of course you would need to use a different cable when you did want to charge, but aren’t the cables only a few bucks?

 

[WetEV]

Does anyone know if the data and power to charge use different pins/wires?

Yes, the connection is a USB connection, and there is a +5V pin and 6 data pins. 2 lower speed bidirectional lines, and (probably) 2 high speed pairs, one each direction. Some older/cheaper phones will not have the high speed pairs.

Maybe you could break the pin/wire for positive voltage and data would still flow? Of course you would need to use a different cable when you did want to charge, but aren’t the cables only a few bucks?

Sorry, but no. The voltage is needed to enable the data. No voltage, no data. Not a physical requirement, but a requirement of the USB standards.

 

[SeanNelson]

Maybe you could break the pin/wire for positive voltage and data would still flow? Of course you would need to use a different cable when you did want to charge, but aren’t the cables only a few bucks?

There are different wires for power and data, but the USB chipsets that manage the connection may not be happy with a cable that doesn't deliver power. There's a very specific protocol that's used wherein the "peripheral" device determines how much power it's allowed to draw from the "host" device before the connection is established.

 

[Anonymous]

Re. Over-Charge - I too was concerned and contacted my home charger mfr. (AV-Aerovirment Ph 1-888-833-2148). which their Engr. informed me that their chargers are specifically designed and meet GM requirements for BOLT & VOLT. He(AV) also informed me that the car's software (Not the charger) dictates the level and amount of charge needs outside conditions. I was also told you can charge the car full and it is recommended especially if the car will be idle for some time
Cheap chargers, like those found with Phones, do not have the basic components to prevent over-charge.

 

[SparkE]

Re. Over-Charge - I too was concerned and contacted my home charger mfr. (AV-Aerovirment Ph 1-888-833-2148). which their Engr. informed me that their chargers are specifically designed and meet GM requirements for BOLT & VOLT. He(AV) also informed me that the car's software (Not the charger) dictates the level and amount of charge needs outside conditions. I was also told you can charge the car full and it is recommended especially if the car will be idle for some time
Cheap chargers, like those found with Phones, do not have the basic components to prevent over-charge.

You are correct that the *logic* (how much to charge, how fast to charge) is located in the device:; however, that is true for both cars AND phones. The device stops charging when *it* decides is the correct time. So, cheap or not, it isn't the phone charger that causes overcharging of the battery.

And, technically speaking, it isn't OVER-charging if they are charged up to 'full', as determined by spec. It's just that a full charge (or a full 'empty') of Li_Ion batteries degrades it a little bit every time. Which is why I try to keep my phone (and iPod, and iPad, and ...) charged between 25-80% most of the time. It adds years of life to the battery (because the phone manufacturers want to brag about how long you can use the phone, and not that you won't have to buy a new battery {well, phone} in two years).