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15 amps or 20 amps

Posted: Mon Nov 19, 2018 12:45 am
by Vic
Brand new EV owner. I just bought a 2015 B250. All I have is the slow charger that came with it. I may not need more than that, given it will be a true commuter car. I have a 15 amp 110 charger plug very close to my car there's another 110 outlet that's 20 amp, it's not as convenient. Would the 20 amp charge the car substantially faster? I also noticed on eBay for about $200 I can buy a cord that fits my clothes dryer its 220 and not far from where I park. How much faster will that 220 charge than the 15 amps or 20 amps 110? Thanks for your help for the Newbie.

Re: 15 amps or 20 amps

Posted: Mon Nov 19, 2018 5:25 pm
by JeffRay
Vic,

Welcome. In general, as my last physics course was back in the day, a 220v charges up to 5x faster. If you are saying you will be charging overnight, you are right that a solid 10 hour charge will restore around 40% of the battery. If you are in warm climate area, 40% will get you over 40 mile roundtrip. So you can top up every night with your existing convenient outlet. I can't comment on 15 v 20 amp but you can search this forum for topics on charging.

It is generally not advised to use a long cord to charge using 220v given a concern about overheating the cord or outlet. I figure one hour gets me 25% of my charge back, so only four hours to get 100% back.

Hope this helps directionally if not specifically.

Enjoy the ride Vic.

Re: 15 amps or 20 amps

Posted: Mon Nov 19, 2018 10:45 pm
by GlennD
At work I charged for free. In my case a 208VAC EVSE worked for me. Now as a retired person I charge at 240VAC at 40A. As much as I drive I could get away with 120VAC trickle charging, I charge at 75% of the 80% default. The EVSE was upgraded to 40A but just because,my 30A EVSE was fine. The Quick Charge Power cable replaced the cable on a EVSE I sold so the charge was minimal. I really have the time to trickle charge

I really like the size of the Quick Charge cable. I purchased a 40A cable from TucsonEV and the cable was huge. Both worked for a fixed installation.

Re: 15 amps or 20 amps

Posted: Tue Nov 20, 2018 8:07 pm
by Vic
Good info, thank you. Vic

Re: 15 amps or 20 amps

Posted: Thu Jan 17, 2019 9:16 am
by hallcp
I was curious about this too. On the Clipper Creek website they have a chart of the charge times for various cars, based on which charger you use.

My interpretation of the chart is below:

Max charge rate: 9.6 kw
Battery capacity: 28 kwh

Time to charge:
120V 15amp: 20 hours
240V 20 amp: 7.5 hours
240V 25 amp: 6 hours
240V 30 amp: 5 hours
240V 40 amp: 3.5
240V 50 amp and up: 3 hours

The original chart is here: https://www.clippercreek.com/charging-times-chart/

By comparison, my Chevy Volt charges as fast as it's ever gonna charge with a 20amp 240V circuit.

Re: 15 amps or 20 amps

Posted: Thu Jan 17, 2019 1:23 pm
by GlennD
Do not forget the Lear (Mercedes) charger defaults to 8A. For 12A would have to select it each time . 8A on a B would take forever.

Beware of Chinese EVSE's on eBay. Many claim to be J1772 compliant even though they are not. There is very little to no regulation in China. It is the technical Wild West.

Do not forget that any circuit must de-rated to 80% for EVSE use. For example my 40A EVSE requires a 50A circuiit.

Re: 15 amps or 20 amps

Posted: Thu Jan 17, 2019 1:35 pm
by GlennD
hallcp wrote:
Thu Jan 17, 2019 9:16 am
I was curious about this too. On the Clipper Creek website they have a chart of the charge times for various cars, based on which charger you use.

My interpretation of the chart is below:

Max charge rate: 9.6 kw
Battery capacity: 28 kwh

Time to charge:
120V 15amp: 20 hours
240V 20 amp: 7.5 hours
240V 25 amp: 6 hours
240V 30 amp: 5 hours
240V 40 amp: 3.5
240V 50 amp and up: 3 hours

The original chart is here: https://www.clippercreek.com/charging-times-chart/

By comparison, my Chevy Volt charges as fast as it's ever gonna charge with a 20amp 240V circuit.
The car charger sets the current. No B charges at 50A.

A Volt charges at 14A at 240VAC.. I was under the impression that it charged at 16A but I was wrong.

Every car's charger sets the current. Buying a larger than necessary EVSE is a waste of money.

Re: 15 amps or 20 amps

Posted: Mon Jan 21, 2019 4:21 pm
by GlennD
I would assume that Clipper Creek wants to sell large EVSE's. Anyone that knows electric cars knows that the car not the EVSE sets the current as long as there is enough. My B will charge at 40A from the spec 80A max but half the current would be unused.,

You are certainly right hat a 20A circuit works for your Volt. A 20A circuit is good for 16A with the 80% rule and a Volt draws 14A so it is properly rated.