Cruising
Posts: 9
Joined: Tue Aug 06, 2013 8:33 pm
Delivery Date: 06 Aug 2013

Can the 480v DC charging port accept a lower voltage?

Tue Aug 06, 2013 9:07 pm

Scenario is:
Driving out to my Father's cabin for a couple of weeks, secluded up in the islands (75 miles away).
There is no 220v/ 120v electricity up there at the lake, with exception of the emergency only generator.

So, question is: is there a way to plug my 60w (12v) DC solar blanket into, that is currently stored on my boat, into the 480v DC port on my Leaf somehow, to just slowly trickle it up over the 15 days I'm there.

Or in other words, is there any reason why LESS DC current cannot be charged thru that fast charging DC port.

Thanks

Kyle

User avatar
planet4ever
Posts: 4674
Joined: Sat Apr 03, 2010 9:53 pm
Delivery Date: 02 May 2011
Leaf Number: 1537
Location: Morgan Hill, CA, south of San Jose

Re: Can the 480v DC charging port accept a lower voltage?

Tue Aug 06, 2013 9:43 pm

The LEAF will protect you from this, but it is a universal fact of battery charging that you can't charge a battery using less voltage than the battery is producing. If you manage to try that, the battery will discharge through your charging device, usually with disastrous results. Think of it this way: If I set a cup of water on the ground beside my above-ground swimming pool, can I siphon water from my cup into the pool? Voltage is like the height of the top of the water in the two containers. (And stored energy, i.e. kWh, is like the volume of water in the container.)

In case you are wondering why you can charge a LEAF battery using 120 volts or 240 volts, when the battery produces nearly 400 volts, that's because there is a charger inside the car which boosts the voltage (and converts it from AC to DC).

By the way, you could get an inverter that converts 12 volts DC to 120 volts AC, and plug the output of that into the normal AC plug into the car, but see my comments just above about relative sizes of the swimming pool and the cup of water. That 60w 12v DC device might indeed be able to half charge your LEAF battery if it ran continuously for 15 days, but what is its energy source? If it is the boat battery, forget it.

Come to think of it, that wouldn't work, either. Even if the onboard charger was willing to accept half an amp (and I'm sure it isn't) the car runs a liquid cooling system while charging that draws more than 200 watts. So your 60 watt source would only end up draining the battery to supply the cooling system.

Ray
End of April 2013: Traded my 2011 SL for a 2013 S with charge pkg.

Cruising
Posts: 9
Joined: Tue Aug 06, 2013 8:33 pm
Delivery Date: 06 Aug 2013

Re: Can the 480v DC charging port accept a lower voltage?

Tue Aug 06, 2013 10:10 pm

Thanks.
The 60w, 12v charging device is in fact a solar panel.
Thoughts?

K

User avatar
DaveEV
Posts: 6242
Joined: Fri Apr 23, 2010 3:51 pm
Location: San Diego

Re: Can the 480v DC charging port accept a lower voltage?

Tue Aug 06, 2013 10:36 pm

Cruising wrote:The 60w, 12v charging device is in fact a solar panel.
Thoughts?
You need enough power to run a J1772 EVSE (120VAC min, 6A if you get the right one that can turn down the pilot signal that far) or you need something that complies with CHAdeMO.

A 60W 12V solar panel is neither of those things.

Cruising
Posts: 9
Joined: Tue Aug 06, 2013 8:33 pm
Delivery Date: 06 Aug 2013

Re: Can the 480v DC charging port accept a lower voltage?

Tue Aug 06, 2013 10:45 pm

I suppose the answer then may be to use his two 12 volt deep cycle batteries up there with his 3000w power inverter.

Plug in my Level 1 (Nissan supplied portable charger) thru the night. Drain the batts down to 50%.

Then - solar charge the batts for a day DC.

Then run inversion again thru the night, draining down the the batts, etc, etc, etc

User avatar
DaveEV
Posts: 6242
Joined: Fri Apr 23, 2010 3:51 pm
Location: San Diego

Re: Can the 480v DC charging port accept a lower voltage?

Tue Aug 06, 2013 11:02 pm

Cruising wrote:I suppose the answer then may be to use his two 12 volt deep cycle batteries up there with his 3000w power inverter.

Plug in my Level 1 (Nissan supplied portable charger) thru the night. Drain the batts down to 50%.
How good are those batteries? Even if they are beefy 200 Ah, a 50% DoD is only good for about 2.4 kWh or 100 minutes of charging the LEAF on L1.
Cruising wrote:Then - solar charge the batts for a day DC.
A 60W panel might generate 300 Wh on a nice sunny day (ignoring charging losses which are significant on a lead-acid system). Or enough to charge your LEAF on L1 for about 12 minutes/day.

A 60W panel is probably just barely enough to keep the batteries topped off. If you have two 100Ah deep-cycle batteries, you probably want at least 200W of solar and probably more like 300-400W of solar to keep them happy.

Cruising
Posts: 9
Joined: Tue Aug 06, 2013 8:33 pm
Delivery Date: 06 Aug 2013

Re: Can the 480v DC charging port accept a lower voltage?

Wed Aug 07, 2013 7:51 pm

Well, I suppose tying three 30w panels together would be possible.
Inversion to recharge is just such a wasteful way to produce DC power.

Maybe by incorporating his gen set, we can scrape together enough over two weeks.

Thanks again

DarkStar
Posts: 2066
Joined: Sat Jul 17, 2010 10:06 am
Delivery Date: 25 Mar 2011
Leaf Number: 568
Location: Hillsboro, Oregon, USA
Contact: Website

Re: Can the 480v DC charging port accept a lower voltage?

Thu Aug 08, 2013 1:19 pm

If you're using the portable charging cable, you'll want a generator that is at least 3,000 watts sustained (not surge) and enough gas to operate it for about 12 hours at 50% capacity (1,500 watts).

You'll also need to make an adapter so the portable charging cable functions properly on the generator: Ingineer's Generator Modification
Mikiko (2011 Nissan LEAF ETEC) Status:
Reserved: 04/20/10 | Ordered: 10/01/10 | EV Project Blink Installed: 03/22/11 | Delivered: 03/25/11 | VIN: 568

Oregon Electric Vehicle Association | Electric Auto Association

User avatar
EVDRIVER
Moderator
Posts: 6746
Joined: Sat Apr 24, 2010 7:51 am

Re: Can the 480v DC charging port accept a lower voltage?

Thu Aug 08, 2013 1:45 pm

Having you unit upgraded at http://www.evseupgrade.com" onclick="window.open(this.href);return false; may solve some or all of your issues you mentioned.

Return to “Engineering”