Bad to use 12amp portable charger all the time?

[CSW]

I use the portable charger that came with the car for almost all of my charging needs. Due to my schedule, I have plenty of time to charge back up to full after driving about 60 miles a day. I always set it to 12amps. Is this "trickle charging" all the time bad for the battery? Or is it better to do 240v, level 2 charging all the time? I have heard conflicting info and would like some input. I would assume the slower the better for charging a battery? But that is just an assumption on my part. I have had my spark for about 1.5 years, have 23k miles on it and the range shows in the high 90s range consistently.

 

[Nashco]

The battery won't care if you're charging at 1 kW (Level 1) or 3 kW (Level 2), those are both very low charge current for the battery. You do charge less efficiently with the Level 1 charger, so more power from the wall is wasted on other things besides charging the battery, but that's about the only difference.

Bryce

 

[CSW]

Ok. Good to know. How much energy loss are we talking here? 10%? More?? Cuz that is not good. If it too too much, I just upgrade to 240v I guess.

 

[Zoomit]

The difference in efficiency won't be enough to justify the expense of a 240v installation. The savings might be $50 per year.

 

[NORTON]

A Spark EV can charge at 0.96kW - 1.4kW - 3.3kW or 46kW (if it has the DCFC option)
I have only used L2/3.3kW (at work) and DCFC/43kW (on weekends) since I've owned it.
I haven't charged at home yet and haven't spent a dime to drive this car ~ 5800 miles.

 

[kevin]

Ok. Good to know. How much energy loss are we talking here? 10%? More?? Cuz that is not good. If it too too much, I just upgrade to 240v I guess.

I measured the efficiency when I first got my Spark two years ago and they indicated an efficiency of 83% for Level 2 and 78% for Level 1. I can't remember whether I had selected 12A charging or not.

So it's not a great reduction in efficiency. I would expect the efficiency to be be better on 12A than 8A.

kevin

 

[CSW]

Ok. Good to know. How much energy loss are we talking here? 10%? More?? Cuz that is not good. If it too too much, I just upgrade to 240v I guess.

I measured the efficiency when I first got my Spark two years ago and they indicated an efficiency of 83% for Level 2 and 78% for Level 1. I can't remember whether I had selected 12A charging or not.

So it's not a great reduction in efficiency. I would expect the efficiency to be be better on 12A than 8A.

kevin

That is very good info. Thanks for that. Just curious, how do you measure the efficiency? Is there some sort of device?

 

[NORTON]

Measuring accurately requires a kWh meter on your L1 or L2. A 'Killawatt' is easy and cheap for an L1. Installing an L2 kWh meter is more work.
You then compare your kWh meter on the wall to what the car displays for kWh used.

It basically comes down to the fact that the car's onboard charger is powered up (with its cooling system as needed) and the battery's TMS is using power to heat or cool the battery as required.

These are called 'Background' loads that do not put electrons into the battery.
They are a constant and mostly the same, L1 or L2.
The load from the grid/wall, (L1 or L2), is constant, 1.3kw @120v/12A or 3.3kw@240v.
This background load is not going to the battery.

Therefore, L2 is more efficient because proportionately less is being used by the background consumption.

Edited for clarity

 

[nikwax]

Norton,

I don't think that's what is meant by efficiency when charging a battery. I believe efficiency refers to how much power that is being applied to the cells is being taken up by the cells. There would also be some losses in the AC/DC conversion by the onboard inverter.

 

[kevin]

Norton,

I don't think that's what is meant by efficiency when charging a battery. I believe efficiency refers to how much power that is being applied to the cells is being taken up by the cells. There would also be some losses in the AC/DC conversion by the onboard inverter.

Efficiency can be whatever we define - what we are interested in is System efficiency, which is what that calculates - i.e. AC input power to energy delivered by the battery. The car display is actually measuring the energy output of the battery.

This does include; AC/DC conversion losses, parasitic losses (running pumps, control logic etc) as well as battery losses.

Lithium-Ion batteries usually have extremely high coulomb efficiency (>99%), whereas Lead-Acid and NiMH may only have 70-90%, so ampere-hours in and out will be essentially the same. However even with lithium-ion batteries the voltage when delivering power will be less than when charging so there is some energy loss there - mainly in the battery internal resistance.

kevin

 

[CSW]

Well, I just went ahead an put a 240v evse in my garage. Got the basic clipper creek model. I really like it, no more switching to 12 amps every time I park the car. Car charges quickly, went from 7 miles to 95 miles in 6 hours. I am pleased.... and more efficient to boot! Also, I don't mind the extra expense really, I am now going to be an EV driver for life and much better to have 240v charging.... even if only 3.6kw max.