Amps, Time and Battery Health

[emm3t]

This may be a strange question but I am preparing to install a charging station at home and I have some questions.

Even though I have power in my garage from from a 10A line, I have two garage door openers and a freezer hanging off it. As such, I'm going to run a dedicated 16A cable from the fusebox to the garage where my Outlander will live.

Right now I have 4.4kW power available from the electricity company, so the 3.7kW that the charger will pull is close to the limit (especially if someone turns the dishwasher or air-conditioning on). I can increase the power supply, but this bears an additional cost (not a lot, but it exists).

I am looking at this wall charger: http://www.ratio.nl/en/catalog/e-mo...-charger-type-1/for-use-at-16a-230v/g+c+s+i+a which can be switched between 6,10,13 and 16A. I know that 6A is horribly low, but at least I can set it on 10A and be only using 2.2-2.3kW. This gives me some margin for the rest of the house at night. If I choose to increase the power to the house, then I can then use the 16A setting, but at least I can see what works for my specific situation. I will probably leave it plugged in from the 1am - 7am period when I get an extremely low night-time tariff (0.056 euros per kWh ~ 4p per kWh), so I don't think I'm in any hurry.

Now, here are the questions:

1: The car I have ordered has the electric heater, so if I have the PHEV plugged in at 10A, will this still heat the car in the morning (assuming the battery is full) and not deplete the battery level? I'd still ask this question even if I was using the portable charger that comes with the car.

2: Is the same true for the air-conditioning? This is Madrid, so it can get a tad warm in the summer, although last night it was -5 degC !

3: I've heard that charging at lower amps is better for battery health, is there any basis in this - specifically for the Outlander?

Many thanks in advance,

Emmet

BTW - the reason my father-in-law (qualified electrician) and I (dogsbody) are doing the installation is because you can get charged up 1,500 euros to install the charging box here. It's only about 15m and I already have a cable run between the two places.

 

[Sunder]

1. Yes - the standard charger is only 10A, and it keeps the heater going for pre-heat

2. I'm not so sure on this one, but I would assume so.

3. It is true, and it may come into play for the rapid CHAdeMo charger, but for the J1772 chargers, the absolute maximum you can ever charge at is 16A. This is a hair over 1/3rd C rate. This is considered a good charge rate for most forms of Lithium, and it is unlikely that charging any slower would extend battery life. You'd be better off watching your regen rates. That's where the >1C charge rates come into play. If you know you have a big hill coming up, don't regen hard when you're going too fast, start early, and regen more gently over a longer period.

Hope this helps.

 

[davebodger]

If I was doing this I would run a 32A cable (6mm CSA, SWA) from the fusebox to the garage and fuse it to 16A (if you need to).
That way you future-proof yourself for a few years time when you get a car that will take a higher charge, and guarantee the cable will not get hot.
Where I live (UK) it only makes a small difference to the price of the cable.

When you set your EVSE charge station to 16amps the car will probably not pull 16 amps.
The most I have seen pulled is 14.5A but our voltage here is 240V, so on 230V you might pull 15.1A
The on-board charger is rated at 3.3KW but my one pulls about 3.5KW from the wall socket.

If you are plugging it in for 6 hours overnight there is no advantage to drawing more than 10A.
The higher charge rate would only be of use if you needed a quick top-up during the day.

1. As I understand it, the pre-heat draws about 4.5KW from the battery, but any charge it can get from the cable offsets this.
So if you pre-heat on a 10A charge then you will need to leave it plugged in for another 10 minutes afterwards for the battery to be topped-off again, if maximum charge is important to you.

2. I would think so, yes, but the A/C should not draw so much as the heater, because it is a heat pump, so 1KW of A/C power should give about 4KW of cooling. I have not measured this.

3. In the last year (6000 miles) I have done at least 50 rapid charges (from 30% to 80%) and many more slow charges and my battery is still in top condition (according to EvBatMon) - all cells within 3mV of each other. The car has done over 13650 miles since new.
The standard 10A EVSE brick and the 16A connection are both types of slow charger really, they both go through the 3.3KW charge unit in the car.
Just make sure you charge until the charge stops itself (so the batteries can balance) at least once every two weeks and you should be fine.

 

[emm3t]

Many thanks both Sunder and davebodger for your comments and suggestions.

This is really, really useful. I was thinking about putting 32A cable through, since there are two garages side-by-side and I'm pretty sure that the wife's next car will be an EV (since she does about 15km a day).

Now I've just got to wait for the delivery of the wallstation (next week) and the car (end of February).

Thanks again!