120v or 240v, which is the better choice?

Hello,

I have a level 2 EVSE coming, but for now am only using the 120V included charger.
So far, I have been able to fully recharge every night on 120V. That is, if I plug it in right when I get home from work.

So my first question is, does it take more or less Wh's to slow charge vs fast charge?
Next, does it help battery life and capacity to slow charge?

If charge time is not a concern, which is the better choice?

Thanks

240V is the better all around choice. The temperature management system works 100% with 240 (heating or cooling the batteries and interior of your car if you use GO times or remote start). 110V uses almost all the amperage to charge the batteries, there is little left over for temperature management.

I've used both and would recommend using 240V if you have a choice (just leave the Ford charger in the car).

Ford seems to have done a great job with maintaining battery life - don't think you'll see any difference with either charging.

For almost every reason, 220 is better.

Totally apart from the fact that 120 charging is painfully slow, your battery is happier with 220 charging provided you try to do "just in time" charging.

220 charging allows you to charge shortly before needing the vehicle, thus more time is spent before charging, with lower charge levels and usually lower temperatures. 120 charging requires the battery to start taking on charge much sooner, so it spends more time with charge on it.

While it would seem that 120 charging results in lower battery temperature, that isn't necessarily so. The battery is very well insulated, so the temperature rise is more dependent on the amount of energy delivered, rather than the power level. But at a low charge rate, the duration is higher.

On the other hand, if you charge immediately, 220 doesn't have that advantage...it maybe is worse because it charges and heats the battery right away and leaves it in that state till you depart.

We don't seem to have a clear answer (and I don't know either) how much effect the TMS has when on 120 V, but we know it works as intended on 220.

And if you're wondering why I call it 220....because it's sometimes 240 and sometimes 208 so I use the term "220" to wrap in both possibilities.

My thought is that with a level 2 charger, the thermal management can run. I returned home from work one day and I plugged in the LVL 2 charger. The thermal management immediately started although value charge wasn't set to start till midnight...5 hours later. I don't think I've ever heard the thermal management run with the car using the LVL 1 charger, which I use frequently at work.

So I believe that the best overall thing to do is plug into a LVL2 charger whenever you can.

davideos said:

I don't think I've ever heard the thermal management run with the car using the LVL 1 charger

Click to expand...

I have.

So, it does happen, just not very frequently it seems.

I suspected that it might. Sometimes in the summer it seems to take even longer to charge on LVL 1. My guess was that thermal management was running, but I personally never heard it.

Slower charge is better and preserves battery life.

I've never used anything other than 120v at home.

TonySpice said:

Slower charge is better and preserves battery life.

I've never used anything other than 120v at home.

Click to expand...

I don't know any evidence to support that contention.

Slower charge does not decrease the battery temperature...it remains constant at 98 F when the TMS kicks in.
Slower charge increases the amount of time that the battery is at an elevated charge level.

The best thing for the battery is to charge at the maximum available level, starting just in time to reach the necessary charge right before departure. I'm not saying 120 V charging is bad for the battery, but I am unaware of any study that shows it is better for the battery.

Concepts that applied to NiCd and PbA batteries do not apply to Lithium cells.

6 kW class charging charges the battery at the 4 hour rate. This is VERY small compared to the maximum recommended.

I'm not a battery expert, but I do know that enemy to lithium batteries is heat while charging or discharging. Fast charging isn't your enemy unless heat is causing the batteries to heat up. The heat generated by batteries is due to the internal resistance of the battery itself; which would occur regardless of charge or discharge. If charging at 6.6KW was damaging, then discharging while driving would be even worse....rough math says that at 75MPH (depleting the battery in under an hour) is 4 times worse than charging with a level 2 charger at 6.6KW. Driving at 19MPH uses roughly the same energy as charging at 6.6KW.

TonySpice said:

Slower charge is better and preserves battery life.

Click to expand...

Probably not completely true. Sure, at rates high enough (1C or higher), battery life is reduced slightly. Regeneration going down a hill, for example, at 24kW or more is at 1C (or more). But there is data suggesting that 0.1C or slower is very slightly worse for some Li-ion batteries than at higher charging rates. 120V is less than 0.1C, 1kW/24kWh = 0.04C. This is a very small effect, a few percent fewer cycles.

However, I suspect that lots of other factors are far more important, and no one will be able to tell the difference in battery life between 120V and 240V charging.

The main reason why I would suggest 240V L2 at full current is to allow the car to be driven more. Come home at 5pm, plug in and charge, leave at 7pm with nearly full battery...Nice.

Second reason is better charging energy efficiency. Your electric bill will be lower.

I need about 2 hours of charging at work to get home using a 6 kW charging station. Or 4 hours using a 3 kW station. Or 8 hours using a 120 V charging station.

I go home about 6 PM, so with 6 kW, I don't need to charge until around 4. So all through the day, my battery is at a moderate state of charge, and it's not being heated by charging. It's at 98 F for about 2 hours. It's a happy battery.

If I were to use 120 charging, I'd need to start soon after my arrival. My battery would quickly heat up to 98 F and remain there for most of the day while charging. It would be a less happy battery.

3 kW charging would be an intermediate case.

Another thing no one has mentioned is that the battery voltage is 300+ volts. The more you have to bump up the voltage to charge the battery the less efficient the charger will be. Since 240V is much closer to 300+V than 120V charging on 240V will be inherently more efficient. If ford ever builds my car I plan to charge off 240V but manually set a lower maximum current draw on my JuiceBox EVSE so I get the efficiency of 240V and can slow charge the battery which in theory is better for the battery.

Why does nobody believe me....Slow charging is not better.

michael said:

Why does nobody believe me....Slow charging is not better.

Click to expand...

I think most ppl think slow charging is better because they've heard Nissan say that DC quick charging will damage the Leaf battery. They don't realize that 6.6 kW charging at home is slower than almost all of your regen braking charging. The Fusion Hybrid with a pack capacity less than 2 kWh allows regen at up to 35 kW. That's very fast charging! The Energi models with a 7.6 kWh pack allow charging up to 35 kW from regen and discharging up to 65 kW to drive the car in EV Now mode. Clearly the battery is just fine with that usage and will be just fine charging at 6.6 kW.

WetEV said:

Second reason is better charging energy efficiency. Your electric bill will be lower.

Click to expand...

Thank you! That was my first question. I tend to agree, higher voltages are more efficient in total energy used at performing work.

I was asking about the charging effect on the battery because I agree that common thinking of lead-acid, NiCd, and even NiMh do not apply to LI-ion.

I don't need the car after I get home from work, as I have 2 other vehicles. But, it would be nice to go out for the evening after work and still have it fully charged in the morning. I do not charge at work. My full commute leaves me with about 33 miles showing on the guess-o-meter. I could easily tool around all evening, but the trickle charger would not have me ready in the morning.

So, today I install my EVSE. I chose the Schneider EVLink. I like the detached connector storage.
Home depot has it for $499 + tax, ($599-$100 web promo) free shipping until 9/30/2014
here is a link

http://www.homedepot.com/p/Schneide...ic-Vehicle-Charging-Station-EV230WS/203670265

Level 2 charging, here we come!

SpecVStrom said:

So, today I install my EVSE. I chose the Schneider EVLink. I like the detached connector storage.
Home depot has it for $499 + tax, ($599-$100 web promo) free shipping until 9/30/2014

Click to expand...

Did you need a coupon code for that? If Home Depot had been offering that deal when we were getting our EVSE we would likely have bought that one.

hybridbear said:

SpecVStrom said:

So, today I install my EVSE. I chose the Schneider EVLink. I like the detached connector storage.
Home depot has it for $499 + tax, ($599-$100 web promo) free shipping until 9/30/2014

Click to expand...

Did you need a coupon code for that? If Home Depot had been offering that deal when we were getting our EVSE we would likely have bought that one.

Click to expand...

Nope, just the promo code that they give you in the + drop down.


Promotion Details

Price Valid : 07/03/2014 - 09/30/2014
Save $100 Add the Schneider EVlink Charging Station to your cart & use promo code EVLINKSUMMER.

Enter promo code EVLINKSUMMER during checkout to receive $100 off the purchase price of the Schneider Electric EVlink Residential Charging station (model EV230WS).  Limit one unit per order. Valid through September 30, 2014 only while supplies last.